Roadracer's #997 build

[Just 1 More]

Can you explain the helper springs? Why do you need them? What do they provide?

[RoadRacer]

Can you explain the helper springs? Why do you need them? What do they provide?

Yes, for sure.

In my case I'm using 7" springs now. This certainly makes the problem worse, but you also may still have this problem with longer springs.

If you jack your car up and you see a significant (>1"?) gap between the top of the spring and the tophat, you should ideally use helper springs (sometimes called tender springs) to fill that gap.

Without them, if you went over a sufficiently large bump the spring may not re-seat to the tophat properly. Imagine the spring falls sideways a little, and then the car drops down. (You could tie wrap the spring to the top hat, but then you move the problem to the bottom of the shock)

This is even worse on the QA1 than the Koni, because the top hat isn't held in place by a circlip, so it could (in theory) just fall off the car while airborne. And I think you can imagine what happens next.

The helper spring just flattens to solid when sitting or running normally, so no harm done, but will hold everything in place under droop.

[Just 1 More]

Yes, for sure.

In my case I'm using 7" springs now. This certainly makes the problem worse, but you also may still have this problem with longer springs.

If you jack your car up and you see a significant (>1"?) gap between the top of the spring and the tophat, you should ideally use helper springs (sometimes called tender springs) to fill that gap.

Without them, if you went over a sufficiently large bump the spring may not re-seat to the tophat properly. Imagine the spring falls sideways a little, and then the car drops down. (You could tie wrap the spring to the top hat, but then you move the problem to the bottom of the shock)

This is even worse on the QA1 than the Koni, because the top hat isn't held in place by a circlip, so it could (in theory) just fall off the car while airborne. And I think you can imagine what happens next.

The helper spring just flattens to solid when sitting or running normally, so no harm done, but will hold everything in place under droop.

Great explanation, Thank you

[progmgr1]

Thanks for posting this great information. Copies going into the file for future reference.

Keith HR #894

[RoadRacer]

As I posted elsewhere, I'm trying to educate myself on the "proper" way to set up a car using math, not the seat of my pants. I was fed up not knowing things like suspension frequencies, motion ratios, etc.

I know about corner weights and the basics of car dynamics, but I wanted to go deeper. So I read a few books and subscribed to "Suspension Set-Up With the "Weight Transfer Worksheet (WTW)" (https://www.suspensionsetup.info/store)" amongst others. I'm going to post about my journey into learning how to measure or calculate the inputs into Dale's spreadsheet (the WTW).

First step was to measure corner weights again. I did it last year, but this time I wanted to go further and measure enough to calculate the Center of Gravity of the car.

To walk you through my process though.. first I don't have corner weight scales, so I wanted to experiment with the idea of using bathroom scales :D The scales I bought were 400lb scales for $15 each on Amazon, but I needed to use a lever to measure more like 600-700lbs per corner. So I fabricated these levers and when I place a weight half way along the scales weight half the weight. I calibrated each one by standing on the "center" and making sure each scale measured half my weight.

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I made sure they were level too, of course. Then I lowered the car onto the scales.. and it was a dismal failure. I did get a couple measurements, but there are some big problems with this method.

1. The car does not want to balance on these.. and falling off is painful
2. The car cannot effectively be lowered onto these scales using a quickjack.. because a quickjack lowers sideways, not vertically. So as it touches the scales.. everything falls over.
3. The scales turn off 15s after weighing! You have to really run around the car writing down the answers!

LOL. So a $60 experiment that i do NOT recommend, but I did use the scales later to measure unsprung weight.. and worse case my kids each get a nice digital scale for Christmas.

[RoadRacer]

Next, I called my friend and he was free to help me use his proper Longacre scales. So next day off I went with an expensive bottle of bourbon..

192764

Measuring corner weights was straightforward. here are my results. Same as last year, I just had to raise the front right shock by an inch or so to get perfect 50/50 cross weights. The 2581lbs was with me (255lbs) so the car in racing trim was 2326lbs.

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Next, we needed to raise one end of the car at least 10", and measure the weight at the wheels again. You only need to measure the weight of the lower wheels, but we raised the scales by 11" and measured all 4 wheel weights again. (It's red because we "lost" a few lbs when raising the car, so my sheet highlights that potential error)

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This data allows you to calculate the COG using this calculator: Car Center of Mass Calculator (https://www.omnicalculator.com/physics/car-mass-center)

The biggest surprise of the whole process was that this was so high- it showed the COG was 24" off the ground. More than I expected, although a few people had told me that it was normal to use the height of the camshaft as a "rough guess" on race cars with a big v8.

So at this stage I have balanced corner weights and a COG.

[RoadRacer]

Measuring motion ratios was next. This is the ratio between wheel movement and shock/spring movement.

BTW, this is a good time to say again that this is all pretty new to me, so forgive me if I use a wrong term, or make a mistake, or describe something poorly.. just let me know and I'll fix it :D

On the front suspension you can remove the spring and then jack up the wheel and measure how much the shock travel was. E.g. mark shock, raise wheel 100mm, and measure distance shock moved. Doing it this way is the best because it takes out all angles and variables, and directly measures you exactly what you want.

I, of course, didn't do it this way. Having just installed the new QA1 shocks and springs the previous weekend I was all done with farting around with the shocks, so I just measured the cantilever suspension, and factored in the angle of the shocks. Ended up with a motion ratio of ~0.78.

At the live rear, I used a commonly used ratio of 1.05 because the shocks are behind the axle. The shocks are at 3º so only applied a 0.99863 correction, which left the ratio at.. still 1.05

[RoadRacer]

I measured unsprung weights next. I disconnected the top shock mount and (with car at ride height) lowered the wheel directly onto the bathroom scale. The unsprung weight was 96lbs each side at front.

At the rear, I jacked up the car and lowered the chassis onto some wood that was a couple of inches above ride height. Then jacked up the live axle, slid the scales under and lowered the wheels to weight them. I made sure the springs were unloaded (I could turn them by hand), so I was just weighing the live rear, and roughly half the control arms, driveshaft, etc.

The rear unsprung weight was 454lbs total.

[RoadRacer]

Motion Ratio of the rear, in roll, is calculated from the ratio between the track width (centerline of tires) and the distance between shocks. That was (for me) 40" / 61.5", so 0.65

[RoadRacer]

Next was the Motion Ratios of the ARB's (sway bars). This is the ratio of how much the ARB moves in relation to the wheel movement. I just measured the distance along the UCA where the ARB connects, and divided by the total UCA length. This was 6.375" / 10", or 0.64.

At the rear, the ARB motion ratio was dictated by the angle of the ARB lever arm from vertical, which worked out to be 0.88

I also had to measure the ARB width, diameter and lever arms to calculate the effective ARB spring rates. The units are inch lbs per degree. ARB rate adds to wheel rate in roll.

Mine worked out to be 239.87 (front) and 109.32 (rear)

[RoadRacer]

The last thing (yay) I had to do was to calculate the roll center at front and rear.

At the front I used this calculator: Suspension Geometry Calculator (https://www.racingaspirations.com/apps/suspension-geometry-calculator/)

I'm not sure if this pic was the final setup, but I measured all the suspension pickup points and entered into the calculator - it calculated the roll center at 1.6" from the floor

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At the rear, i found this youtube video (https://www.youtube.com/watch?v=k6ZiCYVouAk) that described how to calculate from 3 link geometry.. and since my LCA and Panhard bar are all parallel to the ground, it made it easy - the roll center is the height of the panhard bar, at 8".

Phew, that was a lot. Now to get to the results...... tomorrow!

[Just 1 More]

I'm absolutely loving this, I'm very impressed watching you go down this rabbit hole

[RoadRacer]

Ha, thanks Frank, it's been fun.. and worthwhile I hope. The more we know, and all that.

As I said earlier, I subscribed to this guy and his car dynamics program and I've been very happy with it. He has been very helpful and answered questions along the way.

Suspension Set-Up With the "Weight Transfer Worksheet (WTW)" (https://www.suspensionsetup.info/store/zJMrV3f9)

Now that I had gathered all the info for his calculator, I plugged it all in.. note the units used - kg, mm, etc.

192785

The first main point of this sheet is to calculate the suspension frequency. For autocross, all the experts I spoke to agreed on 2.5hz being the goal. 2.5hz (per second) in CPM (cycles per minute) is just 2.5*60 = 150cpm.

For reference, this was confirmed by the material in this course - but be aware that I'm deliberately focused more on autocross than road driving, so you may go for a lower cpm, like 120.

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The initial results show I'm too high with my current springs:

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Rather than the 150 I want, we're at 180 front and 199 rear! Ooops. A little about why this happened. Early on, the roll on the car was excessive. The tires were rolling into positive camber, and it was horrible.. no grip. There's no sway bar setup for the hot rod, and even FFR said "fix it with springs" so I did, eventually working through 400>550>650>800 on the front and 250>350>450 on the rear. Each time going stiffer to get the car to behave.

Each time I increased the front by an arbitrary amount and kept the ratio of front/rear similar to the stock ratio, i.e. 400/250 = 1.6, 800/450 = 1.8

Then I found a solution for f/r sway bars, so I added those too and started "tuning."

So here we are. Way too high a spring frequency. Next up - an easy fix, we hope.

[RoadRacer]

The beauty of these calculators is that you can play around with numbers and see the results. Of course, everything needs to be validated in the real world, but the idea is to get close enough to start fine-tuning.

Given I want to be around 150cpm, I just lowered the spring rates until we got there.. I went from 800/450 all the way down to 550/250!!

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Wow, I had no idea I was that far off. And notice that the rear spring rate went all the way back to stock springs. All I've done is stiffen the front - but not to 800 ;)

Next, I noticed that the balance was a little off.

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But I improved that by increasing the lever arm length of the rear sway bar from 150mm to 250mm.

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Next step is to get back to the real world and see if ANY OF THIS WORKS!

Luckily I have these exact springs in a box, and the sway bar is adjustable, so we'll see. An evening or weekend project.. my next race is on the 10th!

[Just 1 More]

I had Auto-X experts tell me i need to increase the spring rate on the rear of my Camaro. When I called Ridetech to discuss the spring increase, they explained that adding a rear sway bar would actually act to increase spring rate and that would be better than increasing spring rates. So, I installed the Ridetech Muscle Bar on the rear and it handles great with even more adjustability. I'm looking at doing the same with the 33.

[RoadRacer]

As I speak to my autox members (or at least the ones who have been running very successfully for decades) I'm being persuaded to start at 2.2hz (135cpm) front, and 2.5hz (150cpm) at rear.

Quotes:
"you might want to go a little stiffer on the rear. I have generally kept a +0.2 or 0.3hz on the rear of the car compared to the front."
"but also, with no aero, you might want to go lower in general. 2.2ish at front"
"i think that ~2.2/2.5 is a better starting point. I think a lot of people start too stiff. I was at 2.2/2.5 before I added the wing and front body work, and now I'm at 2.5/2.8."

I have a 450lb front spring, which is exactly 2.2hz..

Ironically - and this won't be lost on some of you - the car shipped stock with 400/250. And here I am, after 2 years of experimentation, back down to 450/250 because that's what the math says. But I do now have sway bars f&r. And I'm a better driver now. I feel I've gone full circle here. Of course, I may HATE how soft the car is.

Never stop experimenting!

[Just 1 More]

As I speak to my autox members (or at least the ones who have been running very successfully for decades) I'm being persuaded to start at 2.2hz (135cpm) front, and 2.5hz (150cpm) at rear.

Quotes:
"you might want to go a little stiffer on the rear. I have generally kept a +0.2 or 0.3hz on the rear of the car compared to the front."
"but also, with no aero, you might want to go lower in general. 2.2ish at front"
"i think that ~2.2/2.5 is a better starting point. I think a lot of people start too stiff. I was at 2.2/2.5 before I added the wing and front body work, and now I'm at 2.5/2.8."

I have a 450lb front spring, which is exactly 2.2hz..

Ironically - and this won't be lost on some of you - the car shipped stock with 400/250. And here I am, after 2 years of experimentation, back down to 450/250 because that's what the math says. But I do now have sway bars f&r. And I'm a better driver now. I feel I've gone full circle here. Of course, I may HATE how soft the car is.

Never stop experimenting!

Sorry James but it is kind of funny that you've run full circle only to end up back where FFR started. The swaybars have got to be a huge help. I have my front on order but will probably make a rear myself. Probably use someone like https://www.rhodesracecars.com/Anti-Roll-Bars_c_10548.html or https://timmcamis.com/shop/chassis/suspension/anti-roll-bars/ or https://www.portcityracecars.com/collections/front-suspension/sway-bars-mounts

[RoadRacer]

It’s not lost on me :D

I’ll still probably do the 550 first. It’s a toss up for sure.

The rear sway was the easiest part and basically off the shelf.

[Just 1 More]

It’s not lost on me :D

I’ll still probably do the 550 first. It’s a toss up for sure.

The rear sway was the easiest part and basically off the shelf.

Well.. post some info on the rear "off the shelf" swaybar. (i'm sure you already did somewhere back in the build thread)

[RoadRacer]

Well.. post some info on the rear "off the shelf" swaybar. (i'm sure you already did somewhere back in the build thread)

Here are the main posts that concern it. Literally bolt on.

https://thefactoryfiveforum.com/showthread.php?24163-Roadracer-s-997-build&p=466372&viewfull=1#post466372


https://thefactoryfiveforum.com/showthread.php?24163-Roadracer-s-997-build&p=467981&viewfull=1#post467981


https://thefactoryfiveforum.com/showthread.php?24163-Roadracer-s-997-build&p=473046&viewfull=1#post473046

[progmgr1]

Just to confirm, you guys are using the 3-link rear, right? I'm wondering if I could adapt something like one of those to my 2015 IRS? When I spoke to FFR (several years ago) about this they said that it wasn't possible without some major work.

What front sway bar are you using or have on order? James, could you point me at the relevant posts in your build thread for that? Sorry, but my search engine skills are sub-par.

Thanks,

Keith HR #894

[RoadRacer]

Yes, this is for 3 link - it's bent around the "banana bracket".

But VPM have an IRS one: https://vpmcobras.com/

I used one from them for the front too, but it's not on the website. Ping them and ask.. it's narrower. [they said "We do have a front size that is 37.25" overall. With a width at bend of 26.5". And a max arm length of 12".]

As for my posts on the front "fabrication" required:

https://thefactoryfiveforum.com/showthread.php?24163-Roadracer-s-997-build&p=498711&viewfull=1#post498711

[RoadRacer]

Don't you love doing experiments in front of the whole world, so people can see you f up? LOL

You know how they say "measure twice, cut once"? Well.. I'm glad I did.

When I calculated the front Motion Ratio (MR).. I "knew better" and didnt follow the instructions and instead measured the cantilever lengths accurately, and applied a correction for the shock angle.

What I was told to do was remove a spring, reinstall the shock, then measure accurately the vertical travel of the wheel, and the distance the shock shaft moves. This takes all the guesswork out of it, because it's directly measuring the MR. No need to do any calculating.

MR = shock shaft movement / vertical wheel travel.

Well, tonight I had the shocks apart to change springs, and while I was there I thought I'd do it the recommended way. I did it 6 times, and each time it was 0.59. Not the 0.78 I put in the calculator.

Don't guess wheel motion, measure it.

Guess what? Using 0.59, the 800lb springs I already have (and love, they work) are 2.3hz, 136cpm. A bit LOW if anything. 950 would be perfect 148cpm. Eeeeek.

The rear springs still need changing, as planned 450 down to 250.

But wow. It's a shame I overnighted some 550lb springs haha. Now you can learn from my mistakes! BTW, I never did quite believe that the stock springs were 2.5hz.. the car had so much roll in stock form at autocross speeds.

[progmgr1]

Great information! Thank you Sir!

Keith HR #894

[TxMike64]

James, this is great! Not just building, but making it work using the maths! I'm thoroughly enjoying watching the process you are going through. Keep it up!

[Just 1 More]

This is awesome watching James sort out MY suspension set up for me.. lol

[RoadRacer]

This is awesome watching James sort out MY suspension set up for me.. lol

Haha, well the trick is to DO NOTHING until I've finished this journey.. :D And then wait another few weeks until I've thoroughly worked this through ;)

[RoadRacer]

Today I (just for grins) did the MR measurements again, this time on the inside of the tire. I woke up thinking that what I really want is the vertical measurement at the centerline of the tire.

Having done the outside tire last time, I did the inside tire this time. The MR was different, at 0.67. Outside was 0.59. So, MR using the center of the tire is 0.63.. I wear I'm going to stop measuring and calculating MR now. (So far I've had 0.78, 0.59 and now 0.63!).

Final answer. 0.63.

800lb springs at 0.63 MR equals a frequency of 145cpm, 2.4hz. So that's almost perfect, and I'll leave as they are. No change needed for me at the front (but for those following along, mine came stock with 400lb springs, so for autocross I have doubled the stiffness, AND added a 7/8 sway bar).

At the rear, I haven't changed my mind about anything, being that a live rear is always basically 1. I'm using 1.05 for reasons stated earlier.

So to get 2.5hz, I do need to go back down from 450lb to 250lb springs - which was the original set that came stock. My earlier thinking was to always increase both ends in proportion, but that was a false "common sense" idea. I didn't need to touch the rear to get the correct frequency, although I have added a 3/4" sway bar.

I do wonder why FFR sends it out with a 1.7hz front and 2.5hz rear setup. I would expect that the rear should be lower for road use - but I remember that many have gone down to 150lb, which seems a wise idea.

Anywho, I made all these changes and went for a drive. I did seem much better - softer of course, but really "digged in" under cornering and seemed much better balanced. But it could be confirmation bias.. I just want it to be better!

The only data (until next week's autocross) is that my favorite 'test' long sweeper has never been taken faster than 80/81mph, and today I saw an easy 84/85 and that's with me being careful on the new setup. :cool:

[Just 1 More]

James, I'm curious to see what you do with the tuning of the shocks once you get the spring rates sorted out, using a double adjustable shock like the QA1's, you should have a field day playing with the compression and rebound settings.

[RoadRacer]

Shock settings are next!

Final prep for this weekend autox; I bought some longer lever arms from speedway motors to soften the rear sway bar. I went up from 8" to 10" which allowed me to move the adjustable bar out 2" - this will give me less oversteer, almost to the point of neutral, according to the calculator.

192946

[RoadRacer]

A quick aside from the normal.. at a recent track event I didn't have any "offs" but many did, and it made me realize that there is NOWHERE to tow a 33 from, safely.

All the chassis is covered up by the gril, and I don't want to be pulled from a gravel trap on an a-arm.

So we looked around and came up with a v1 version of a tow hook, that bolts to some existing holes on the radiator bracket. I think this is a great MVP, but I'll probably brace it diagonally to the chassis to increase strength further.

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[RoadRacer]

My fastest run at Spokes #11 autocross today. Man oh man, the car was SO MUCH BETTER. As I thought on the road test, the car just sticks on corners now, and hooks up and powers out of corners without drama. The car is balanced, with maybe a smidge of understeer. I was still pushing the car on the fifth run, so I never got to the limit to see which way it was going to go. It's pretty neutral.


https://youtu.be/bWFAkgitWtE

So, if any of you want to know a starting point for autocross-suitable springs, I recommend the 800/250 that I'm using, which gives a 2.4/2.5hz spring frequency.

Since there are no "factory" sway bars you'll always be needing to figure that out yourself, but my longer arms on the rear (softening the sway bar) may have helped too. Note that the calculator said that a sway was needed at the rear, but fairly soft.

[progmgr1]

Congratulations on a great run! Thanks again for posting all this data - it's valuable even if we never do an Auto-x session.

Is there anything different that you could recommend if someone wanted a daily freeway driver / canyon carver setup? In my ignorance, it seems like your spring rates and sway bars would be well suited for those conditions - but maybe backing off on the shocks a click or two?

Keith HR #894

[RoadRacer]

Congratulations on a great run! Thanks again for posting all this data - it's valuable even if we never do an Auto-x session.

Is there anything different that you could recommend if someone wanted a daily freeway driver / canyon carver setup? In my ignorance, it seems like your spring rates and sway bars would be well suited for those conditions - but maybe backing off on the shocks a click or two?

Keith HR #894

Yeah going back to the recommended spring frequencies in #763.. you’d need to pick sports car or super car.. you might want to go lower than I have. Sports is 1.5-1.7, super car is 1.7-2.5.

Unfortunately I’d need more info to calculate sprint rates for you though because it needs corner weights and unsprung weight.

[RoadRacer]

Of course I could use my numbers.. if the general build is similar enough ¯\_(ツ)_/¯

[progmgr1]

I could run the numbers - I was just being lazy. What I didn't know was the frequency range to shoot for.

Keith HR #894

[RoadRacer]

Quick update.. my brakes felt ineffective when I got back in the car after a trip to uk. I’d been thinking about it before I left but coming back it was very noticeable.

I figured I have another MC going bad (I’ve already replace the rear a year ago) but I wanted to be able to quantify my brake performance in some way. I bought a brake pressure gauge and it screws into the bleed screw.

As an aside we’ve talked about this before - the balance bar doesn’t do you any favors when you have a brake issue. And I saw it this time. First thing I did was remove the dash and watch the MC’s while pressing the pedal - one side (the front) went to the floor and the rear seemed to be acting normal.. but guess what.. all of my foot pressure goes to the BAD SIDE.

So I figure the front MC is leaking internally. I put the brake pressure gauge on the front caliper.. 0psi. Zero. I have no front brakes.

I put it on the rear caliper. 0psi. All my effort on the pedal is effectively useless. (To be honest this surprised me because the car did have some brakes.. some pressure was getting to the rear otherwise I’d be typing this from a hospital bed. But I had been messing about by this point, losing fluid, messing with balance bar).

Anyway.. I decided to bleed the front just in case, before I swap out my MC. I have a couple spares that someone paid forward but they aren’t new.

I reverse bled the front (I always prefer to reverse bleed, because it’s so easy, you can truly do it on your own and it bleeds the MC too).. and had a ton of bubbles. A lot. You can hear them in the reservoir. I did the other side.. nothing more came out. I did the rear.. nothing more came out.

I felt the pedal - damn, felt very different. Much harder (duh).

Put the pressure gauge on the front - 750psi. The rear? 1500psi.

Now I haven’t checked the bias again yet.. that’ll be today. But at least I have baseline pressure readings so going forward I can check my brake pressures and get ahead of a problem.

[RoadRacer]

Excited to hear that I'll be picking up a new motor (from a friend in Georgia) some time mid-March. I'm still running a mystery motor, bought super-cheap from a local drag racer, but I suspect that it's way under 300hp. The new motor will be ~425hp, and lighter (aluminum heads).

I'm going to trailer there and swap over a few days.

[Just 1 More]

Excited to hear that I'll be picking up a new motor (from a friend in Georgia) some time mid-March. I'm still running a mystery motor, bought super-cheap from a local drag racer, but I suspect that it's way under 300hp. The new motor will be ~425hp, and lighter (aluminum heads).

I'm going to trailer there and swap over a few days.

Congrats.. 425hp is what I was shooting for but ended up with 401. Would love to hear the engine combo if you know what it is

[RoadRacer]

So far all I know: built to rev higher than stock, don’t remember what was said though.. but likely 6500 vs 5500.

The heads are AFR 210. Runs pump gas (9.5 to 1). Hydraulic roller cam 555 lift. Wisco pistons and steel crank and rods.

[Just 1 More]

So far all I know: built to rev higher than stock, don’t remember what was said though.. but likely 6500 vs 5500.

The heads are AFR 210. Runs pump gas (9.5 to 1). Hydraulic roller cam 555 lift. Wisco pistons and steel crank and rods.

Sounds like a nice combo, should be fun for sure

[33fromSD]

Sounds like it's going to be wicked fast James and possibly squirely.

The LS3 in my 08 C6 Vette has 430HP and that at 3,217 lbs. and is fast & squirely, in the 33 you're easily 700-800 lbs lighter.

Should be fun.

Jim

[RoadRacer]

Sounds like it's going to be wicked fast James and possibly squirely.

The LS3 in my 08 C6 Vette has 430HP and that at 3,217 lbs. and is fast & squirely, in the 33 you're easily 700-800 lbs lighter.

Should be fun.

Jim

Yeah it will be interesting! I’ve always waited to do this until last. I’m amazed the cheap motor I picked up lasted this long (it’s still going) but it’s allowed me to sort everything else before adding power. Suspension first, then brakes, then power. And brakes I’ve put on the “nice to have” list.. the stock brakes with better pads are still fine for me. I rarely get on circuits where I’d (possibly) need them. On the road and autox I can lock tires up a will.. which is the only point, to be better than the tires. No fade in my world.

So yes, more power! I’m ready ;)

[JimLev]

If you are getting an LS3 and find 430HP isn’t enough, there’s a GM cam swap that will give you 480HP.
There is also a 525HP upgrade to, it’s a bit more involved than just a cam.

[RoadRacer]

If you are getting an LS3 and find 430HP isn’t enough, there’s a GM cam swap that will give you 480HP.
There is also a 525HP upgrade to, it’s a bit more involved than just a cam.

Ah, no, I'm staying old school as long as I can!!! No computers!! This is just another 350 SBC (well, it may be a 377/383, I'm not sure yet)

[RoadRacer]

As some of you saw on FB, I hit something heavy on the toll road last night at about 80.. and got away with it. No idea what it was; it was in the frame of my dash cam for a fraction of a second before it took out my radiator and grill. I couldn't see any suspension damage on the side of the road, just a lot of water, so I drove it off the next exit and into a Jack In The Box parking lot.

195555

The tow guy took a few hours to arrive, but at least I got a burger and fries, and ate it on a nice cool evening :D

195556

The tow guy had a neat way of towing; I had never seen this idea for the front wheels before.

195557

I was only 4 miles from home, so that was easy. Today I jacked it up and was a little anxious of what I'd find underneath. It was a hell of a bang, like I'd hit something heavy.. but I couldn't see anything underneath. The radiator (this is a 33 gen1 radiator, btw, in spite of the fact it looks like a "deluxe" front.. this was done before the deluxe was an option. Which was way worse, because the deluxe radiator is much shorter. I probably would just have lost the grill shell with a proper deluxe setup. The radiator just got bent backwards under the chassis.

195558

I stripped it all off, ready for other replacement parts, so here we are, waiting on UPS! BIG shoutout to Just 1 More, aka Frank, who was at the UPS store bright and early and shipped a full deluxe setup (https://thefactoryfiveforum.com/showthread.php?48179-32-33-Deleux-grill-and-radiatior) that he had for sale. Really appreciate it Frank!!

195559

[RoadRacer]

What was it? Answers on a postcard..


https://youtu.be/fu8PoNmm_ss

[Jim1855]

James,
Sorry to hear about the damage. You're OK, car can be fixed.
New engine will be big fun.
Some days the planets align, some days they don't.
Jim

[33fromSD]

Bummer James, hopefully she is back on the road soon.

My kids hated when something went wrong in their lives when they were younger because the first thing I would them is "in life you'll have good days and bad days, and sometimes the bad days will outweigh the good days". Now that they are adults, they are starting to use it too.

At least there wasn't more damage or worse any injury. Glad you're good.

Jim

[RoadRacer]

Thanks both Jim’s! Yeah I wasn’t bummed in any way.. strangely.. just a thing that happened and can be pretty easily fixed. It does confirm my decision to leave unpainted and just have fun with it, I can’t imagine this happening while being fendered and painted!

[Mastertech5]

Bummer dude! Glad no personal injury. Can you look at the footage frame by frame to see what it might have been?

[RoadRacer]

Some people have tried.. seems most likely it’s a big tire fragment from the Semi that’s parked a 1/4mile down the road..

[Just 1 More]

Some people have tried.. seems most likely it’s a big tire fragment from the Semi that’s parked a 1/4mile down the road..

That's exactly what it looks like to me.. we call them Road Gators

[RoadRacer]

Ok, I'm baaaaaack!

After my recent "adventure" I was lucky enough to score a complete Deluxe setup (aka "32" grill and radiator) from Frank, who was so on the ball that I swear he was already at the UPS store the next day when I said "hell yeah". Kudos to "Just 1 more" for helping me out.

My smashed radiator was a stock FFR 33 setup with an Ebay radiator and some aluminum bracketry I made to fit, so I knew there was going to be some fabrication required, even though this was a deluxe kit. I have a Gen 1 first of all (the deluxe wasn't an option) so I assume the brackets are different nowadays. Secondly, more importantly, I have my radiator tipped back at 19º to match the side panel body line and make it more swoopy.

I got the package from UPS on Wednesday and had some shopping to do. First, there's only one bung in the bottom of the radiator (my old one had 3!) so I have to use that for temp sensor.. but it was smaller 1/4npt so I had to order that. Second, there's NO RADIATOR CAP! wth? So I ordered an inline Moroso one to put in the top hose for now (you'll see why).

In the meantime I started mocking it all up. Didn't take much to modify the brackets to fit, chopped some off, laid them over a bit. Mocked up the 19º slope and it all started to look pretty nice.. and then I noticed that because the radiator is like a foot shorter than the old one, the bottom hose goes straight into the chassis. At least where I have it placed, and sloped, the hose goes RIGHT where the horns are bolted to the chassis plate that joins the rear of the LCA bolts.

Right here:

195814

Moving the horns was easy, I moved them to the front of the chassis, below the radiator, but still behind the shell. But the chassis wasn't going anywhere, so.. I cut it out. ¯\_(ツ)_/¯

The plate is welded all around the main chassis, so I figured that part was superfluous so I waved it goodbye. The radiator hose fit nicely through the gap left there.

Here we are, all better.

195817

This is the only part I don't like.. for obvious reasons. Looks like a** and annoying that you can't effectively bleed it. So next month when I'm installing my new motor I'll get a cap welded to the top of the radiator. But surprisingly, this works well enough.

195819

I removed the temp sensor from the block, then filled the radiator until the motor was full, then put the sensor back in. Then filled rad as much as I could and threw the hose on. There's going to be air in there but I've run it through 4 full heat cycles (thermostat open, hot enough for fan to come on, etc) and a "spirited drive" that this will be good enough for the race next weekend.

Oh.. I did find more damage from the semi-tire. It had hit the front lower bodywork just in front of the door. Nothing visible but I noticed the door sounded different today. Just more rattly. When I looked, all these rivets were sheared! They look normal, but none were attached to chassis.

195818

For some strength, I replaced them with a strip of aluminum.

195820

[RoadRacer]

So far all I know: built to rev higher than stock, don’t remember what was said though.. but likely 6500 vs 5500.

The heads are AFR 210. Runs pump gas (9.5 to 1). Hydraulic roller cam 555 lift. Wisco pistons and steel crank and rods.

Btw, I talked more with the guy who built this motor - he said that the cam runs out at 6800, but the motor is built to 7500. LOL

[RoadRacer]

My fastest run today - everything was working great. Could always do with one more run of course - but today we were cut to 4 instead of 5 without warning!

My gopro 12 quality is incredible if you compare to my dashcam that I normally use. :D duh! The image stabilization and 4k quality is amazing.


https://www.youtube.com/watch?v=QqbF8rWJq1U

[Just 1 More]

That's awesome James, looked like a tight course

[Just 1 More]

James, Have you been playing with the QA1 compression and rebound settings? Curious where you've settled at?

[RoadRacer]

James, Have you been laying with the QA1 compression and rebound settings? Curious where you've settled at?

I haven’t yet. I did some initial setting up and then we had a winter break with no racing. Then the accident and now only two weeks until the new engine and the next race only a week after that! I suspect I’m not going to be focused on them for a while.

Having said that, I’m very happy with the setup right now.

Here are my current settings though:
Front: c2 r4
Rear: c3 r5

[RoadRacer]

Now I'm back and recovered from my marathon motor swap trip, it's time to post about it here!

We left Austin on Tuesday with the car on a rented trailer, for a 16hr drive to Atlanta. It was a long day, we left at 3:30am!

197051

Wednesday morning we headed out to the shop. First job was to remove the motor from the 55 chevy it has been in since the early nineties. They've modified the intakes over the years, even with a blower at one point, but the motor hasn't been out of the car for 30 years. The motor bottom end was properly built with steel crank, pink rods, AFR heads - no need to touch any of that. Cam runs out at 6800, but engine can rev to 7500. (I later set my shift light at 6400, but no rev limiter)

It took us all day to disconnect and remove the motor - slower than we expected! But by end of the first day it was on the engine stand.

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We took a trip to the local Summit Racing that evening and bought a bunch of parts. We reused my intake and carb, but had to buy a new oil pan, noisy gear drive (something I've always wanted) and a new 3.73 gear set (changed from my stock 3.27). Plus gaskets and some misc. Total was ~$1,000.

197054

[RoadRacer]

Day 2..

My first job was to remove my motor, while my friend worked on the new one, removing oil pan, swapping gear drive, cleaning up.

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You can see the original builder's name written on the crank from 30 years ago - the current owner's brother Alex. Also the "pink" rods.

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This second day was just as long and hard - we thought removing from my car would be easier with all the access, but it wasn't! We removed with the transmission attached and the tight tunnel made it tricky. But we got there!

End of day two we had the new motor buttoned up with my intake, carb, new oil pan and transmission attached. The clutch showed virtually no wear btw. This pic is the closest I have to end of day 2:

197057

[RoadRacer]

Day 3, the last day.

We had an assembled motor, so put it into the car. This part was easy.. by then we'd learned how best to do it, took under an hour to get it back in.

197058

Then it was adding radiator back, re-plumbing everything, timing, headers, etc etc. I experimented with a few alternator brackets but ended up with the factory header setup.. rock solid and easy. Got a 15555 belt, but have a 15557 on order for some extra wiggle.

Filled with PennGrade 10w40 green oil, added NGK R5671A-7 plugs at 50". Fired right up! Noisy as hell.. perfect! I've never had a SBC that can rev to 7500, let me tell you it is quite something. Changes the way you drive, and that gear drive whine.. wow.

The motor is a beast. I don't know what you guys with 500+ hp think, but this 400-430hp motor built to rev like this is kinda insane.

197059

There were two problems though.

1. I melted the electric fan.. literally. I tie-wrapped a wire to the fan cover, and although I spin-tested it, somehow the tie wrap moved to a position where the fan stopped. We smelled "something bad," but it took a minute to track it down. The fan and wiring were (literally) toast by then. Put in a new one!
2. This next one took longer and wasn't fixed until I got home after another 16hr drive on Saturday. The passenger side of the motor was covered in a fine mist of oil. Dripping from everywhere. Even the windshield had so much oil on it I couldn't see through it. Easy, right? Nope. I could not find the leak. Even the SHOCK was covered in oil.. how? That's a foot in front of the motor! In hindsight it makes sense, but took us a while. A racing friend from the local autocross club suggested something that made no sense to me. "Put a bolt in the top mounting hole on front of the engine". That was a blank hole for the 55 engine mount, now not used. But guess what.. the motor was issuing a very fine high-pressure mist from that "blank hole" above 4000 rpm. You'd never see it. Added a bolt, and DONE!

[RoadRacer]

So with the rear ratio of 3.73 and the more hp (probably up from 250-270 to 400-430, pretty significant jump) AND revs up from 5200 to ~7000 - it's a very different car. At idle (now at ~1050rpm) it sounds evil.

When driving, it feels like the difference between a 9mm and a 12 gauge slug.

I can't wait to race it on Saturday - my next autocross.

[Jim1855]

James,
Glad it's working out and coming together. Should be great fun.
Yup, there's just something special about 7,000. I shouldn't but...
Jim

[RoadRacer]

https://youtu.be/53gJixnNPMY?si=FvLhNFLzAkJrPUBv

[Just 1 More]

Seems we have very similar setups, i'm 401hp with a 3:73 gears. Except mines a 700R4 w/3500 stall. I'm looking forward to see how the new horses work with your driving skills.
Congrats on the upgrade, this sure is a fun hobby

[33fromSD]

Great story Jim, 3 day marathon is right, all exciting but I'm sure tiring too.

I'm sure it will be a blast to drive but squirely too, so obviously be careful

Jim

[RoadRacer]

https://youtu.be/8DHIWfAx5IQ?si=44mfmJmgkps4A_Q-

[Just 1 More]

https://youtu.be/8DHIWfAx5IQ?si=44mfmJmgkps4A_Q-

SO how's the new engine feeling?

[Jim1855]

Nice run, looked smooth & fast.
How's the new motor? Meeting expectations?
Jim

[RoadRacer]

The new motor is fast! Ironically I was quite slow at the race as I had no idea how the car would run so was quite tentative and only running about 70%.

[RoadRacer]

I missed #3 even being in Australia for a few weeks, but event #4 was quite something - it was 150 miles away at Beeville, which is where they do the Texas Mile event I believe - an absolutely massive abandoned airfield that used to house B24-B29's (again, so I'm told). The runways were enormous - perhaps 100m wide? This course used an area where two runways crossed, and times ranged from 70sec (ridiculous race cars) to 120sec (novices). It was a looooong course to remember!

I had a lot of fun using the new power and rev range. The drive there and back was almost equally fun - 300 miles in a car that seems to spit flames nowadays. :)


https://www.youtube.com/watch?v=K3FGfXIP_AU

[RoadRacer]

Steering.. again.

So we've had a few threads on steering improvements, and many of us have tried a few different options. Well, I went through it again, this time with the full expectation that I was going to do something radical. Spoiler alert - it didn't work out that way :D

I started out thinking; I can make my steering go straight to the rack. Maybe two joints! I was quite convinced, but the longer you look at it, the more you realize that you just can't. It's SO CLOSE, though. I was going to rotate the rack so the spline pointed up by adding a wedge spacer. Then I placed a rod as below.

199164 199165 199166

I also tried a different way - behind the headers and straight through the firewall. They were close, and if I'd done this when building the car maybe you could tweak enough to make it work, but not in a built car.

I was quite disappointed!

So I went back to basics, what am I trying to fix? The answer - continually loosening joints. I've been through this cycle a few times. You start off with tight joints, and after 6-12 months the slop is back. The steering wheel moves up to an inch before anything happens at the rack.

I've seen a few theories, but digging in myself I didn't want to use other folks' assumptions. I wanted to find the slop. I measured the rotation at the wheel. Then I clamped on a piece of aluminum to the d-bar just before and after each joint, all the way through to the rack. The aluminum bar was the steering wheel radius. I measured the movement at each point, to pinpoint exactly where the movement changed.

I found two things.

The first was that the rack spline joint at the very end was again sloppy. The splines (on the joint) just get worn out by the hardened rack spline. But these are $30 joints so my practical and very simple solution - just replace that last joint once a year! I replaced my joint overnight from amazon (https://www.amazon.com/gp/product/B07Z76PVP6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1). Done - and that was half the slop. Let's not fight it - treat it as a maintenance item.

Secondly, as I measured the slop, it was not the FFR joints themselves that had the movement, it was the D-bar-to-joint interface. This was very surprising to me - I assumed the UJ part of the joint was wearing out - not the case. The d-bar was rotating inside the joint, and the grub screw did nothing to stop it. In other words, if you clamped the joint you can feel the d-bar moving inside it.

My solution took some time, but bear with me because it really worked.

I removed the d-bars, all of them, and drilled straight through them, and tapped them. I got longer screws and replaced the grub screws with longer version that went into the d-bar, and held them tight. This changed the feel more than anything I've done before. It's some work to tap those d-bars, but so far so good.

As always, I'll report back in 6 months and tell you if this works long-term over many road/race miles and bumpy roads. Only time will tell. For now I have close to zero slop, and it changes the driving experience.

[Just 1 More]

Steering.. again.

I removed the d-bars, all of them, and drilled straight through them, and tapped them. I got longer screws and replaced the grub screws with longer version that went into the d-bar, and held them tight. This changed the feel more than anything I've done before. It's some work to tap those d-bars, but so far so good.

As always, I'll report back in 6 months and tell you if this works long-term over many road/race miles and bumpy roads. Only time will tell. For now I have close to zero slop, and it changes the driving experience.

I've thought about drilling straight through and putting a bolt all the way through with a lock nut on the other side

[RoadRacer]

I've thought about drilling straight through and putting a bolt all the way through with a lock nut on the other side

That was my first thought - much easier. But it wouldn't work as well - the bolt would not be able to clamp the d-bar in place. It would stop some motion for sure, but the threaded version pulls the d-bar hard against the side of the joint. If you exaggerate the problem, think of the d-bar swimming in a much larger tube, you'll see what I mean

[Just 1 More]

That was my first thought - much easier. But it wouldn't work as well - the bolt would not be able to clamp the d-bar in place. It would stop some motion for sure, but the threaded version pulls the d-bar hard against the side of the joint. If you exaggerate the problem, think of the d-bar swimming in a much larger tube, you'll see what I mean

Makes sense, thanks

[J R Jones]

Faced with configuring steering components, I see OEMs use spline shafts and pinch bolt (female) coupling. I have used that configuration exclusively in RWD and mid-engine and I never have steering shaft loosening issues.
I have seen D-shaft applications for crash-collapse but the engagement surface area is greater than the couplings you have documented. I assume you acknowledge that drilling the shaft reduces cross section and creates a stress riser.
jim

[RoadRacer]

I assume you acknowledge that drilling the shaft reduces cross section and creates a stress riser.
jim

haha, absolutely!

[RoadRacer]

Weird issue with my speedo.. I plan on calling autometer hotline tomorrow.

The pigtail was yanked out of the transmission sensor when the engine was pulled. We missed one wire to disconnect!

So yesterday I put in the new pigtail.. and there’s no signal getting to the Speedo. When I’m in calibration mode the number stays at zero when the rear wheels are in motion.

So I pulled the sensor out but it doesn’t look broken in any way. It could be but looks perfectly normal. So I went behind the dash and the ground is grounded and the feed wire voltage does change between stationary and moving. And the pigtail is similarly grounded on one wire (the grey).

This all worked before so I guess that the sensor didn’t like being yanked on and broken somehow subtly inside? Yet it generates a voltage signal. Now whether it’s the right one I don’t know. I’m just testing this with a standard 12v dc meter.

[RoadRacer]

Oh and I did run a brand new temporary wire for the signal from pigtail to dash.. no difference

[Just 1 More]

I know this probably doesn't help but, I eliminated and chance of a trans sender and went with the Autometer GPS module. Works great https://www.autometer.com/universal-gps-speedometer-interface-module.html?gad_source=1&gclid=Cj0KCQjwxqayBhDFARIsAANWRnRg1dkFnmn2vPpaSr1h 6ii2G1ii6Ja1H703Keaq0F79XAi9vfRW5bwaAvZ4EALw_wcB&gclsrc=aw.ds

[RoadRacer]

I know this probably doesn't help but, I eliminated and chance of a trans sender and went with the Autometer GPS module. Works great https://www.autometer.com/universal-gps-speedometer-interface-module.html?gad_source=1&gclid=Cj0KCQjwxqayBhDFARIsAANWRnRg1dkFnmn2vPpaSr1h 6ii2G1ii6Ja1H703Keaq0F79XAi9vfRW5bwaAvZ4EALw_wcB&gclsrc=aw.ds

That’s not a terrible idea.. but whenever I put my 18” race tires on to drive to an event I have to ignore the speedo anyway

[Just 1 More]

That’s not a terrible idea.. but whenever I put my 18” race tires on to drive to an event I have to ignore the speedo anyway

That was my other reasoning, won't matter what tire size I have , it'll always be accurate

[RoadRacer]

I bought a stock GM sender from the local parts store, looks identical. I fitted it tonight and it worked perfectly. Comparing the old to the new, it was twisted 20deg so must have been broken inside.

Calibrating was interesting though - it was outputting twice the signal than the old one - it used be ~43000 per 2 mile, this new one is ~86000.

[TxMike64]

James, how often would you say you are using your heater? If you were to built again would you still install the heater?

[RoadRacer]

I have never used it.. ever. Didn’t even finish wiring the switch. With this new engine I didn’t even plumb the water line back in.

So, no, completely pointless. And I drive without windows in the winter.. just wear a coat!

[RoadRacer]

My latest autocross at COTA this weekend was both a failure and a triumph :) Well, not really a failure but my first run was really hard to control, like my car would NOT stop wanting to spin, finally taking out 3 cones and me sheepishly crawling back to the grid. I crawled all over the car trying to see what had broken, only to finally discover that I'd pulled the handbrake on in grid, and kept it on throughout the whole first run.

I rarely use the handbrake, usually just stick it in first. But the grid was on a slight slope and I wanted to warm the engine, so..

So that was run 1:


https://youtu.be/RwTGWgnT91k

Then I had a couple of better runs, a 41.7 and a 41.2, but you know.. meh. Fun and all, but slow. The car was fast on the straights, but couldn't make the turns. Look how wide I was on one of these runs:

200608

[RoadRacer]

But then I had an "ah-ha" moment and realized that my new motor (50% more power, another 2000rpm redline) was simply getting me to the corners too fast to coast around. Sounds dumb I know, but with the old engine I could go around the corners as fast as I could get to them. Now I'm relearning the car, and have to brake much more into each corner. So on the last run I tried that. Hard acceleration followed by hard braking.. and I went from 41.2 to 39.9, which as you can imagine is a huge improvement. It felt slower, more relaxed, but was WAY quicker.


https://youtu.be/tzxpyY3o2U4

I've been about 85% of top pax for over a year, but with this run I jumped up to 91% of top pax - a massive improvement against the field. I'm pretty stoked, but cannot wait until the next event. We only got 4 runs this meet.

[Just 1 More]

Hopefully you can laugh about it now.. lol

[RoadRacer]

Hopefully you can laugh about it now.. lol

Oh I was laughing as soon as I saw it. The folks around me in grid loved it too ;)

[RoadRacer]

Installed brake pressure gauges in the dash so I can log data as I change f/r bias. My version of datalogging ��
The pressures I measured at the calipers in January (see here (https://thefactoryfiveforum.com/showthread.php?24163-Roadracer-s-997-build&p=543427&viewfull=1#post543427)) were 750psi/1500psi - these still show the same.


https://youtube.com/shorts/dunQsxBcSD0?si=4vNUXiA3e9UeQ0Qx

200708 200707

[RoadRacer]

Did another autocross yesterday, I missed one while on vacation so it's been a while.

It rained heavily in first session, dried in second and I was luckily running in third session. So it's hard to judge improvements against others who may have been running in worse sessions. But I did get 24th fastest (and the R class was running third session too). Car felt good!


https://youtu.be/cE7cxiCdUpw

[RoadRacer]

Following on from this post about 3-link panhard bar mounts (https://thefactoryfiveforum.com/showthread.php?49909-3-Link-Rear-Panhard-Failure), I braced mine - for no other reason than it's a quick fix

204753

[RoadRacer]

Following on from my thread "Has anyone built headers for side pipes on hot rod? (https://thefactoryfiveforum.com/showthread.php?49894-Has-anyone-built-headers-for-side-pipes-on-hot-rod)" - the headers are an easy fit (with one caveat)!

They bolted up just fine to my SBC, with loads of space around the chassis. This opens up space for potential easier steering routes too.

And remember, these headers (Schoenfeld part #1346 (https://www.schoenfeldheaders.com/street-rod2.html)) are just $469.95

Take a look:

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Now here's the caveat.. it touches the 'glass body here. Tight.

204936

So I'll talk to them about attaching the collector at a slightly different angle - they may want to send me another set to test. We'll see. Otherwise I'll modify these myself. Now onto the side pipe/muffler investigation.

BTW, I did measure dB at 50ft to the side just to compare. The current FFR w/borla muffler was at ~89db at ~6000.

The new open headers were ~108db. They sound great! But would get me kicked out of any autocross I tried to go to. :D

[progmgr1]

Considering that 6 dB is a doubling of loudness, I can see the issue. :o However, this will look wicked cool when its done. :cool:

I always appreciate builders who "color outside the lines" to make their cars unique.

Keith HR #894

[RoadRacer]

Considering that 6 dB is a doubling of loudness, I can see the issue. :o However, this will look wicked cool when its done. :cool:

I always appreciate builders who "color outside the lines" to make their cars unique.

Keith HR #894

Yeah it’s fun. This was driven by two things.. 1. The gen1 floor touches the exhaust throughout so is a rattly mess. 2. I wanted bigger primaries for my motor. Now 1.75 up from 1.5.

[GoDadGo]

Great News!

[RoadRacer]

I never mentioned it here, but I went to a hub dyno at the weekend. They only gave me wheel speed, not rpm, but luckily you can calculate it given 4th gear (1:1) and rear ratio (3.73). From there I could calculate torque using t = hp / (rpm/5252)

So here's the result, I've adjusted this by 115% to account (somewhat) for wheel hp vs motor hp, but of course that's a complete guess.

peak hp 5500-6000, peak torque 4200-4800 - both pretty flat at their peak.

205029 205030

[RoadRacer]

Having discussed with Schoenfeld, we decided to send mine back, and they'll send a new set out (I did move to 3" from 3.5" though, after noticing 3.5" is far less supported for mufflers).

This new set will be sent fully welded up, except for the collector which will be loose in the box. That will allow me to adjust the angle and space from the bodywork.

[Just 1 More]

Having discussed with Schoenfeld, we decided to send mine back, and they'll send a new set out (I did move to 3" from 3.5" though, after noticing 3.5" is far less supported for mufflers).

This new set will be sent fully welded up, except for the collector which will be loose in the box. That will allow me to adjust the angle and space from the bodywork.

https://youtu.be/Z0YIJQ1jgEI

[RoadRacer]

Haha well the exhaust is on. It’s been a journey and I’m not quite there yet. A friend and I spent all day yesterday getting it on and it’s not bolt on.. but it could/will be. Schoenfeld need to make a little tweak to give more body clearance and I’ll talk to them about that.

We spent most of the time heating and bending the headers with oxy-acetylene torch - had to put a lot of heat into them to bend them out. Heated along the top curve of the header. The angled bend I bought from collector to muffler was wrong angle too - hard to estimate off the car. So more heat and bending. But that’s going to be replaced with a proper and removable piece soon.

Ultimately we had to get it all on, hung and tacked together so I could drive home. Our first step in morning was to cut the old stuff off ;)

Most parts leak (not fully welded), the old header gaskets got damaged (will put my new set on, but I saved them until final fit) and currently it’s rigidly welded to the car. No rubber mounts. So this is very much in proof-of-concept mode.

Worse, for most people anyway, is that the body curve is pretty significant. I decided to lose the bottom of the door completely, and cut the corner. Better to have close to body (much less chance of burns). I have so far found that the way I get in and out does still work.


205798205799205800205801

[Just 1 More]

Looking good James

[RoadRacer]

My latest autocross.. pretty tricky and car felt loose even though I was trying to tune it between runs. So I was too timid this time.


https://youtu.be/gWpNh47UvSw?si=LkSVx0Tfw4IiKjGP

Everyone loved how the car sounded though, I had all the seams welded during the week. It was right at the sound limit though.. the sound check guys were alternating between "just under" and "just over" the limit. I still got all 6 runs, but I'm going to rotate the end pipe to point down rather than sideways which usually helps.

The 200 mile drive though.. this is the first time in thousands of miles that I felt beaten by the sound. It's too loud honestly. But sounds amazing LOL. This morning I drove to home depot and got some 26db corded ear plugs and it makes a huge difference. At least for longer drives.

[GoDadGo]

Thanks For Taking Us For A Ride!
.....Also, I Love The Headers!

[RoadRacer]

Exciting! Since I want to do a lot more circuit running in 2025 I just ordered some big brakes from Gordon Levy

Basically this setup: https://a.co/d/3uSAT1t

Aero6 14” and superlite 4 13”

206959

[Just 1 More]

Exciting! Since I want to do a lot more circuit running in 2025 I just ordered some big brakes from Gordon Levy

Basically this setup: https://a.co/d/3uSAT1t

Aero6 14” and superlite 4 13”

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We talked about brakes a while back and you seemed pretty happy with the factory brakes with the upgraded pads...... I'm Looking forward to hearing the amount of improvement.

[RoadRacer]

We talked about brakes a while back and you seemed pretty happy with the factory brakes with the upgraded pads...... I'm Looking forward to hearing the amount of improvement.

Yeah I am happy with stock for road and autocross.. but will run out of brakes at the track. A lot more sustained heat.

[RoadRacer]

Just realized that I hadnt posted my latest video from our club's "track sprint" - basically a 2/3 lap of a lap private track called Harris Hill (https://www.harrishillroad.com/).

I hadn't done any laps here since this event a year ago, so I really need to get more practice and get quicker at this track. Unlike autocross, this track doesn't change!

In 2025, this is one of my focuses: knocking 6-7s a lap off this (quite timid) lap. Part of that is the reason to upgrade the brakes above. 6-7s sounds like a LOT (and it is) but others in corvettes are hitting 8-9s quicker than me, and that must be stopped :D


https://youtu.be/bIyJC16RsY4

[RoadRacer]

My last official autocross of the year, although I hope to get some more track time to get a base time for my push at much-improved track time in 2025.

I was very happy with this run. I had 5 clean runs, and each one improved on the last by at least 1s.


https://www.youtube.com/watch?v=hiiKLJcll_U

[RoadRacer]

These were some basic runs to give me a baseline time around Harris Hill Raceway in Austin to use as I aim to improve my time throughout 2025. I didn't even change gear out of third in any of these runs. These were with the OG Mustang brakes, which will be replaced in Q1.

My best lap was 1.32.888


https://youtu.be/7e34so56tdM

[GoDadGo]

James,

How has your new header and exhaust system worked out for you.
I know it looks totally Bad A--, but what is your takeaway on this recent change.

Steve

[RoadRacer]

James,

How has your new header and exhaust system worked out for you.
I know it looks totally Bad A--, but what is your takeaway on this recent change.

Steve

Oh it was definitely the way to go for me and my car. I can’t imagine anyone would do it.. the body shape means that you have to cut the bottom of the doors off.. and live with the hole. In reality there was no filling the hole left because you need the straight line for the pipes.

I love it, but it requires a no paint, GSD car. The engine is much happier and I have more flexibility for tuning. Plus.. it removes a lot of interior heat from an old Gen1 hot rod. I don’t think I’d need to do it with a gen2.. very different floor that I could have run an exhaust through and no heat problems.

[RoadRacer]

My upgraded Wilwood brakes arrived from Gordon Levy, so I wanted to make a quick update on progress so far. I use my car a lot and I have a autox on 3/1, so minimizing downtime is important. I've taken a staged approach so I can complete parts of the upgrade while I wait for parts or helpers to be available.

1. install front brakes
2. install rear brakes
3. install new MCs, flush fluid, and bleed
4. install parking brake

Why? I can do the front brakes on my own, no helpers, and I have all the parts. And fitting bigger front brakes doesn't affect balance for a few days. (Putting wilwoods on the back first would have). The rears need helpers, as does the brake flush/bleed.

I did step 1 last night, so I now have the aero6 14" setup at the front and the 10.5 stock setup on the back ;) On Saturday I'm visiting friends to help with the rear.

Firstly, the Wilwood instructions are great. Very easy to understand and covered everything. Gordon told me I'd have to grind some of the upright to fit the front brakes, but you'll see it was easy.

Here's a before picture!

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The day before I'd spent an evening safety wiring the rotors and hats. Considerably easier on the front rotors! The rears put the bolts in a narrow valley so I compromised the safety wire a little by choosing a more direct line since you couldn't do the s-shape that you really need and can see below on the fronts.

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On the car I removed the wheel, caliper and rotor, and left the caliper hanging from an S hook on the sway bar.

Then I modified the upright to allow the caliper bracket to fit. I used a dremel disc of the same curve as I needed to cut into the upright (see pic 1 below). It's tricky to get a nice clean cut without touching other parts around it, but now the bracket fits. I also took some off the bracket.

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The shims they get you to start with didn't need changing - the caliper lined up with the rotor centered and the pads flush without any other shims.

I had to drill out the rotors to fit over the shoulder on the wheels studs, and that required a 5/8" drill bit - way larger than you probably have in your toolbox.

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I did have to buy a bigger INCH/lbs torque wrench, my small one didn't go up to the 155 In/lbs you'll need. But this did the trick for $33 (https://www.amazon.com/dp/B07M68FY3X?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1)

The last step was to fit the included hose - no banjo fitting this time - I found the best direction was to aim the fitting at the center line of the suspension.

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As always, the second one took a fraction of the time because no thought required. And this is where I ended up that evening.. and drove it the next day!

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[RoadRacer]

I fitted the rear brakes on Saturday, but it was a bit more involved. It shouldn't have been, but I made a few mistakes early on. First, make sure your vendor (Gordon Levy in my case) knows exactly which rear end you have and, more importantly, which axle shafts. I had replaced mine with some from Summit when I found my junkyard axles were bent.

It's a bit of a story, but posted to save someone else the pain. I had bought SUM-700128 which are 30.63" long. They are theoretically the correct ones for my 2002 GT, but you can buy shorter ones (since Wilwood removes the backing plate). If you're using Wilwood (and only then), then you can buy SUMN-700126 which are 29.94" long. 0.69" shorter.

Wilwood's kit relies on a 2.5" offset, but I had a ~3.2". But here we are on Saturday morning at my friend's machine shop, so we push on. I always think we can find/build a solution.. and we did - but it took a 10-hour day without breaks. :)

Picture so you can follow along.

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The first step is to remove all the old stuff, easy.

Then, measure the slop in your axles using a dial indicator. We had 0.020 on one side and 0.013" on the other. We want to make this zero or close to it. Otherwise any axle sideways movement in corners can push the pad away from the rotor. And you'll have extra pedal travel to take that up before you get braking.

Then drain the rear, pull the c-clips, and slide out the axles (don't rest on, or damage the seals).

To take up the slop, use shims behind the c-clips. Sounds easy, but.. I'd forgotten to look for shims in the box and there weren't any. Check for this stuff! Ask your vendor if anything is missing! :) Anyway, it's the day of installation, and no local shops have any. Luckily my friend has shim stock. a box of thin metal sheets that you can cut any shim from!

We used the C-clip as a template, cut them slightly larger, sandwiched the shims between the C-clips, and made the perfect size on the belt sander. It worked great! We made two 0.013" shims, installed them, and measured again.

This time, we measured 0.006 and 0.004 slop (yeah, the math doesn't add up, I know), and we left it there. This is barely detectable movement.

DO NOT FORGET to put the drum brakes (the parking brake) on before the axle goes in. :D We installed the axles, glued the cover back on and everything before realizing this, so it all came off again.

Installed the drum brakes, and mocked everything up. This is where we found that the rotor was 0.69" away from centered in the caliper.

So we removed the spacer (#12 in picture) which is 0.48" so that got us closer. But we were still 0.21" off, so we got on the lathe and made 8 x 0.21" spacers from stainless steel stock and placed them behind the drum assembly. That got us to a perfect spot again. (The original bolts still worked, I have 0.25" longer bolts coming today to give us some extra thread)

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The rest of the installation went great - super easy to bolt bits on, and if I had the correct axles in there (and checked for shims beforehand) none of this would have been necessary. But hey, it was kinda fun.

I may still buy the shorter axles; it's the "right thing to do," and then I can use the kit as-is. But that will pull the wheels in 0.69", and it'll be close to the bodywork and narrow my track. So I'm still deciding.

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One last comment about Gordon Levy—he's been very responsive and took calls on Saturday when I had questions. Although he couldn't help directly, I'm still very glad that I got the brakes from him and had direct-line support. He knows what he's doing!

[RoadRacer]

One last thing for now.. the master cylinders. I bought new ones, but they are slightly different design nowadays. The supplied ones are 0.75" for front and rear, but I still have the 0.62" rear installed today.

I flushed the old fluid on Sunday and installed a much better fluid (Castrol SRF (https://www.amazon.com/dp/B002TM4GBQ?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1)) which has a much higher boiling point. Also installed 6 speed bleeders (https://www.amazon.com/dp/B000CPARVA?ref=ppx_yo2ov_dt_b_fed_asin_title) to help with bleeding.

Once I had a hard pedal I went and bedded in using the Wilwood process - basically stop, cool, stop, cool at higher and higher speeds to get a good temp in the brakes.

Then did the 40mph balance test.. this is where I was concerned I'd need to 0.75" rear MC. But the balance bar adjusted the bias perfectly, so at least in my case I dont need the 0.75 MC. The rears locked up first initially, but I quickly adjusted to fronts locking first.

First impressions are great btw, so I'm looking forward to putting some miles (and especially track miles) on them to get a feel for them.

[RoadRacer]

Here's my first autox run since the new Wilwood brakes were installed. I had a ~2.5% increase against the rest of the pack - probably due to the increased confidence than the brakes themselves - but whatever works!

My fastest run (49.352s) didn't record, so here's my second fastest 49.707s.


https://youtu.be/WO03Wmd_OQA

[RoadRacer]

Got some track time yesterday in Track Night in America event at Harris Hill Raceway.


https://youtu.be/zTBYq4YU2Fw

[RoadRacer]

Not been posting much here for a while, but I'm always tweaking and improving the car.

The most recent thing was to stiffen my front sway bar. As you know, driving a car faster is a journey. You start off (hopefully) with an understeering car, because it's safer and easier to drive. But it's slow, so over time as you get to know your car you want to remove the understeer (the 'push') and have an oversteering car ('loose'). So over the last year, I've made my front sway bar stiffer, and eventually had to disconnect my rear sway bar entirely in the search for a faster car.

But the front bar was full stiff, and the rear bar disconnected... so what next? A stiffer front bar. Then I can add the rear sway bar back, and start tuning over again.

FYI I run 3.5º camber and 10º caster (so there's a fair bit of dynamic camber too), and the tires (currently vitour P1, 315/345) show perfect wear patterns, so no real gains to be made there.

My front sway bar was from VPM, documented earlier in my build thread, but it was pretty soft - we measured it as 137lb/in, even though the calculators show ~230lb/in. As we measure sway bars on the bench we notice roughly a 1.5x discrepancy - no idea why. But it doesn't matter relatively, you can still compare in the calculators to get a 2x or 3x stiffer setup, and it will be in real life.

ASIDE: Here are the measured and calulated numbers for old and new setup:


Calculator says: old one 230lbs/in, new one 584lbs/in (2.5x stiffer)
Measurement says: old one 137lbs/in, new one 392lbs/in (2.9x stiffer)
measured with a dial indicator to measure deflection and 65.5lbs weight.

I bought a Rhodes Race Cars Sportsman Series Anti-Roll Bar (https://www.summitracing.com/parts/RHC-19-0001). Stiffer because of the bigger bar, but also because of the shorter arm. More importantly for the 33, I needed to support it much further outboard from the chassis. The VPM setup suffered because the 33 chassis is so narrow.

So we built a support bar out of angle and bolted the sway bar to it, then welded it all up. Here are some final pics:

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The funny part - I decided to test it without the rear bar attached at today's autocross. It's always better to test one thing at a time, and I wanted to know if I'd even feel the difference of the stiffer bar. In theory it should push, but I have NEVER understeered with this car, it's been loose since Day 1.

Well, today was the day!

In the first run, it was astonishingly bad - the car felt like it wouldn't steer at all. Just went straight on! I had to unwind so much lock just to get around. On subsequent runs, I softened the front shocks and lowered rear tire pressures to try and counter this as much as possible, but it was just too far out of balance. I even left before the last two runs!

Next event is a track sprint at Harris Hill Raceway, so I'll take at least one day at the track ahead of that to tune in the rear sway bar which has a lot of adjustment.

[RoadRacer]

Today's lesson kids: Problems are always related. Remember that. If you do X, and then a week or do later Y happens.. look again at X.

As I write this out, it'll be obvious to everyone where I went wrong, but hindsight is 50:50 :D Come along for the ride!

The last time I removed my radiator (when I fitted my new front sway bar) my thermostat switch in the bottom of the radiator broke. It's about the 4th time one has, so I got fed up and fitted a bung, and moved my thermostat switch to the intake manifold, where it's less exposed to road debris. Great! While I was there, I fitted a fan override switch, so I never have to worry about broken thermostat switches again.. if the engine gets too hot, knock on the switch.

[one week later]

I go out and park up at the track. My car starts, but the starter is slow.. uh-oh. My battery is failing. In Texas heat, this happens, and batteries don't last long. In fact, I've had warranty replacements when mine has failed "early". So I test it - I have a massive truck battery in the trunk - and it's perfect. Passes the load test. Hmm.

I check the alternator cable, seems ok. Voltmeter shows 14v running.

A few days later I go out again, and this time it really doesn't start. I bump start it down a slight gradient in the parking lot. Then later, I get some kind guys to push me.

The battery health is still perfect (literally, 90-100% by the tester). So I get onto chatgpt (much better since 5.1 if you gave up on 4.0 like I did). Had a long conversation about possibilities and it came to battery cable.. I said that 4 years ago I used 4AWG and a cheap kill switch and hammer-on crimps and no dielectric grease. All of which SUCK in hindsight, but it was a long time ago.

Apparently all of that is sub-par, at best. And over 4 years, every connection gets worse, and the voltage drop gets larger, until.. it's just not up to it.

I tested the voltage drop a few different ways.

First, I measured the voltage (all while cranking) at the battery, and at the starter. The difference should be 0.5-0.8v.
I saw 12.5 not cranking, 11.8 cranking (so a good strong battery), and ~10.4v at starter (bad)

To diagnose further, you measure the voltage drop on positive, and ground.

To measure ground, voltage meter red on starter housing, black on battery ground. Crank. Reading should be 0.2-0.4v. Mine was 0.3v
To measure positive, voltage meter red on battery positive, black on starter positive terminal. Reading should be 0.4-0.6v. Mine was ~1.7v

So all/most of my error was on the positive cable, and the ground side is good. Could still be the cheap kill switch, but I decided to change it all.

[NOW, before too many people jump in here and tell me all sorts of ways that I'm wrong, that's ok. I've been through the wringer on FB, and I've heard it all. But just keep reading for a second on where I end up]


I ask for recommendations, and go through a few product options, and ended up (with a trunk mounted battery, 10:1 SBC) that I should be using:

- 1/0 OFC (oxygen free copper) welding cable (https://www.amazon.com/dp/B08Y7CW5J8?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1) - specifically not CCA (copper clad aluminum)
- 10 ton hydraulic pressed crimper (https://www.amazon.com/dp/B0CFV249X3?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1)
- tinned, closed, copper crimps (https://www.amazon.com/dp/B0CS6NR1D5?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1)
- a good quality kill switch (https://www.amazon.com/dp/B001NN79ZW?ref=ppx_yo2ov_dt_b_fed_asin_title) (ie not $20)
- dielectric grease on everything

For quick fix, I did use some 1/0 CCA that my son had laying around, removed my cheap kill switch, and hammer crimped it together, and it did help. Then ordered all these parts ^

I included the links above on the parts I ordered.

I've yet to final fit the new stuff, but I expect it will stop any problems that I have with low quality parts.

===

Now to loop back to the beginning. I did need to do all this stuff, but why, after 4 years did it suddenly start failing? The thermostat fan switch!

I used to run a switch in the radiator, and after turning off the car, the fan would run on until the radiator cooled - pretty quickly actually. I never gave this any thought at all.

When I moved it to the motor, the fan ran until the motor got cool enough, which the fan wasnt even helping. The fan ran for many minutes, and drained the battery. All this happened because when building the car I wasnt paying attention and did not snip/replace the red loop wire on the fan relay that you are clearly told to do "if you have a computer". I don't have a computer, but I should have paid attention! Because the fan did not have switched power, it had always-on power.

Snip the red loop and connect switched power to 86, and the problem goes away. The fan stops when ignition is off. No more running the battery down. Here are some diagrams that will help (found one on another thread here (https://thefactoryfiveforum.com/showthread.php?51936-Cooling-fan-help-switch-and-wiring-(no-build-docs)))

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