Softer springs or not, that is the question

[alexmak]

I like the stiff ride, but sometimes I feel like it gets a little bit too stiff. I've read some threads on going from 350lbs springs to 250lbs springs in the back, and that it will increase amount of understeer. So questions:
1. is this increase noticeable in everyday driving, no track/autoX?
2. what springs to get? the links in other threads to Breeze are dead, so any suggestion for springs to buy or what specs to look for?
3. if you went for softer spring, did you later go back to stiffer ones? Why?

[ggunter]

I'm awaiting anxiously for the answers to your question. When I was young the stiff ride was "cool" but now that I'm old not so cool.

[swwebb]

I thought the default spring rates were 500 front and 750 rear for IRS, which is what you have per your signature line. The rates are 500 front (same as IRS) and 350 rear for the solid axle I believe.

I'm also interested in this answer because Gordon Levy talked me into 600 front and 650 rear. I'm wondering if I should go back to the standard springs or not - how will the ride change? I still have the old springs.

[Jeff Kleiner]

Softer rear will indeed promote more understeer. Noticeable on the street? Around town, no but if you take some highway exit & on ramps briskly you'll probably feel that the car has more body roll and the front will wash out requiring you to keep adding more steering input to get it to turn. You'll have to decide for yourself where your priorities lie and what compromises you're willing to make. I went the other direction and changed to 750# front and 500# rear on a 3 link.

Jeff

[Bob Cowan]

I would consider different shocks before changing springs.

[Jay-rod427]

Middle ground go a good quality progressive spring. soft for comfort first short travel, then firmer the harder you lean on it. And as said good shocks. Preferably with high and low speed compression valving adjustments.

[SDhemmings]

Don't mean to hijack but How do you know which springs you have? I bought my coil overs from another local builder and have no idea what spring they have.

[stacked33]

I realize this is in the roadster forum but I think what I did on my 33 Hot Rod may be applicable. I ordered the kit without springs and bought springs that were exactly 1/2 the rate of what would have come with the kit. From 500# to 250# front and 350# to 175# rear. I also added/fabricated my own anti roll bar in the back to help with body roll. I am extremely glad I did this as it has been a good combination of ride and handling. It would have been too harsh for me the original way. Some may say this wasn't a good idea but it worked well for me. See photo of car on the autocross course, it stays pretty flat on the corners.136039

[alexmak]

I would consider different shocks before changing springs.

In the threads that I’ve seen, a lot of conversion focused on the springs as a main reason for a harsh ride

[alexmak]

Middle ground go a good quality progressive spring. soft for comfort first short travel, then firmer the harder you lean on it. And as said good shocks. Preferably with high and low speed compression valving adjustments.
Any specific model you have in mind? That would be a bolt on for FFR?

[alexmak]

Softer rear will indeed promote more understeer. Noticeable on the street? Around town, no but if you take some highway exit & on ramps briskly you'll probably feel that the car has more body roll and the front will wash out requiring you to keep adding more steering input to get it to turn. You'll have to decide for yourself where your priorities lie and what compromises you're willing to make. I went the other direction and changed to 750# front and 500# rear on a 3 link.
Jeff

I have IRS, which is supposed to be the most comfortable ride, but I guess it’s just not what I expected. Personally I don’t mind the stiff ride but when I’m with my wife, I feel a little bit sorry for her.

Ok, what about air pressure? I have 15’’ wheels/tires. 25psi or lower?

[Desert Cobra]

I dropped 100 lbs. front and rear and will never go back. No change in handling. Got from Summit Racing made by Eibach. Most springs come with a painted on spring rate. Usually as part of part number (ie B2000-350). I tried a 50 lbs. under but that wasn't enough. You can also adjust some shocks for less compression. Visit their web site for how. I have stock and 50 lbs springs for sale if interested. With softer springs you get more body roll in corners, but full travel on most Cobras is 4-5 inches so is 1/2 inch more roll going to kill you?

[Jeff Kleiner]

.... With softer springs you get more body roll in corners, but full travel on most Cobras is 4-5 inches so is 1/2 inch more roll going to kill you?

Oh heck, just soften it up until it feels like you're riding on a cloud and don't worry about a little body roll or understeer

https://thefactoryfiveforum.com/attachment.php?attachmentid=136040&d=1602112607

:p :D

Jeff



136040

[alexmak]

Oh heck, just soften it up until it feels like you're riding on a cloud and don't worry about a little body roll or understeer

https://thefactoryfiveforum.com/attachment.php?attachmentid=136040&d=1602112607

:p :D

Jeff



136040

This roll was added when picture was inverted!

[NAZ]

https://www.roadandtrack.com/car-culture/a10385629/why-stiff-suspensions-have-less-grip/

[CraigS]

Concentrate on the rear springs for a better ride. Drop 75-100# because in my experience a 50# change can be one of those 'it must be better because I just spent $ to change it' deals. If you find out that it understeers a little more on the street you are driving too dang fast. Go to an autocross or a track event. Shocks can also make a difference but unless you go to the expense of getting double adjustables you won't get much change and it's almost impossible to know what change you will get before you own them. I like the High Travel springs from QA1. Buy them from Summit.

[rich grsc]

Oh heck, just soften it up until it feels like you're riding on a cloud and don't worry about a little body roll or understeer

https://thefactoryfiveforum.com/attachment.php?attachmentid=136040&d=1602112607

:p :D

Jeff



136040

Thats an odd car? Right hand steer, yet it has a USA plate, maybe California?

[CobraboyDR]

Oh heck, just soften it up until it feels like you're riding on a cloud and don't worry about a little body roll or understeer

https://thefactoryfiveforum.com/attachment.php?attachmentid=136040&d=1602112607

:p :D

Jeff



136040That boy makes a good case for a big-a$$ sway bar.

If you're gonna go softer springs on a street car, make sure you also go with sway bars, front and rear.

[CobraboyDR]

https://www.roadandtrack.com/car-culture/a10385629/why-stiff-suspensions-have-less-grip/That's a terrific video at the end of that article. Thanks for posting.

[Jay-rod427]

Any specific model you have in mind? That would be a bolt on for FFR?

Springs are somewhat universal for coilovers. Just need to know the diameter, length, and spring rate. I don't personally know what the FFR Roadster uses. The shock remains and just gets a new spring on it. Unless you change shocks as well, then they need to match to fit.

[mike223]

I thought the default spring rates were 500 front and 750 rear for IRS, which is what you have per your signature line. The rates are 500 front (same as IRS) and 350 rear for the solid axle I believe.

I'm also interested in this answer because Gordon Levy talked me into 600 front and 650 rear. I'm wondering if I should go back to the standard springs or not - how will the ride change? I still have the old springs.


500 front and 750 rear were default for the older Tbird based IRS, I think this car is the newer Mustang based IRS and I don't know what the spring rates are for that.

I have the older Tbird based IRS and found that I use full suspension travel on launch, so I did not feel comfortable going to a lighter spring in rear.

Unfortunately, with the 500 fronts installed, autocrossing it was an experience in tail happy - completely tail happy.

I generally run 650 or 750 front springs now to keep the rear end hooked up - much better (but a little harsh on the ride).

[NAZ]

That's a terrific video at the end of that article. Thanks for posting.

Folks should know why changing spring rates (front or rear) will affect the handling of the car. Increase the spring rate in the rear on a car that is neutral (handling) and you will have a loose handling car, the bigger the spring change the looser. Reduce the spring rate and you get the opposite effect. Spring rates affect traction, higher rates = reduced traction (again, starting with a neutral car). This is one of the methods chassis tuners have to adjust handling for track conditions. For a street car I want a neutral handling car and I can make a car neutral with softer springs same as I can with stiffer springs, but softer will tend to have more traction (up to a point of diminishing return). Asphalt cars are moving toward softer front springs and more anti-roll bar as it provides greater traction and lowers the front end at speed for better aero. So stiffer ain’t always better.


Also, I see people using stiffer springs as a crutch to limit body roll. There are other ways a chassis tuner has to affect roll, and spring rate is usually not the ideal way as every change you make on a suspension has an affect on other areas so it’s an effort of compromises. Body roll is not necessarily a bad thing as it’s what helps weight transfer and induces camber gain which maintains tire contact on hard corners. But when it comes to chassis tuning, too much of anything can be detrimental (see Jeff’s photo of the 1959 Impala and the reverse camber gain – that car doesn’t just push, it plows).

[JohnK]

Thanks NAZ. That's very helpful. Do mind sharing your thoughts on shock compression/rebound damping? I know a little from my days tuning motorcycle suspensions but would love your insights. One thing I hear sometimes is that folks will crank up the compression damping to try to stiffen the suspension or limit body roll. My understanding is that the correct compression and rebound damping is simply a function of spring rate. You want enough damping to properly limit movement. Too much damping and you end up with problems like jacking the suspension up or down (too much compression or rebound damping).

-John

[Jeff Kleiner]

... I think this car is the newer Mustang based IRS and I don't know what the spring rates are for that...


500 front, 400 rear

Jeff

[NAZ]

Thanks NAZ. That's very helpful. Do mind sharing your thoughts on shock compression/rebound damping? I know a little from my days tuning motorcycle suspensions but would love your insights. One thing I hear sometimes is that folks will crank up the compression damping to try to stiffen the suspension or limit body roll. My understanding is that the correct compression and rebound damping is simply a function of spring rate. You want enough damping to properly limit movement. Too much damping and you end up with problems like jacking the suspension up or down (too much compression or rebound damping).

-John

OK, I don’t want to hijack a spring thread but will briefly give some thoughts to contemplate. Most folks, especially the off-road guys, tend to put way too much damping into their shocks. It’s best to start at the lowest setting and tune from there. We can use damping to control weight transfer during corner entry and during breaking and acceleration. This is in addition to spring rate. We use weight transfer to increase traction – in fact, I’ll submit that the two major “controllable” things that affect traction are weight (static and dynamic) and tire compound. Contact patch and tire size are not directly affecting traction but further explanation of that can be found here: https://www.stevemunden.com/friction.html

Drag racers live and die by traction and weight transfer is of paramount importance. Spring rate and damping greatly affect traction. I run the minimum rebound damping and aggressive bump damping on the front shocks of my drag car. This helps unload the front end faster which transfers weight to the rear quicker. Conversely, I run the stiffest bump on my rear shocks the track will support and tune the rebound to the spring rate. That stiff rear bump damping slows down the shock from the launch and holds rear ride height (weight transfer again) as long as possible. So, shock tuning & spring rates can be used to help tune to track and load conditions.

[CobraboyDR]

Thanks NAZ. That's very helpful. Do mind sharing your thoughts on shock compression/rebound damping? I know a little from my days tuning motorcycle suspensions but would love your insights. One thing I hear sometimes is that folks will crank up the compression damping to try to stiffen the suspension or limit body roll. My understanding is that the correct compression and rebound damping is simply a function of spring rate. You want enough damping to properly limit movement. Too much damping and you end up with problems like jacking the suspension up or down (too much compression or rebound damping).

-JohnAs a motorcyclist, think of riding a track bike on a forest trail. That thing would break traction constantly, whereas a soft-spring dirt bike will stick like glue.

Yes, the physical forces on two wheels is different than four, but keeping the rubber in contact with the road as much as possible is still the goal.

I have a friend with way more money than sense. He bought a newer 'Vette with a special hard track suspension...and drives on our really bad roads here (Dom. Rep.). He complains constantly how disappointed he is that his fancy, powerful car is squirrely in rough, twisty roads, and bounces all over the place around even the smallest potholes in the city.

[Mark Reynolds]

AlexMak,

I have QA1 9HT650 (13% softer, you will notice it, but the change will be slight) and 9HT550 (27% softer, more noticible, still not super soft) in stock and can offer them at $45 each plus shipping at $13 in a priority mail flat rate box.

Mark Reynolds

[Avalanche325]

Comfortable ride? I thought I was on a Cobra forum. :p

[rich grsc]

Comfortable ride? I thought I was on a Cobra forum. :p

Comfortable ride----what handling?:rolleyes:

[alexmak]

AlexMak,

I have QA1 9HT650 (13% softer, you will notice it, but the change will be slight) and 9HT550 (27% softer, more noticible, still not super soft) in stock and can offer them at $45 each plus shipping at $13 in a priority mail flat rate box.

Mark Reynolds

Thanks Mark, per your suggestion I purchased springs from Summit, and plan to install them over the weekend to try

[alexmak]

Comfortable ride? I thought I was on a Cobra forum. :p

Yeah, yeah. I’m sure your energy will be well spent in the threads about power steering and power brakes!

[walt mckenna]

I have thought about this issue since my first go-kart drive. The stock springs are just too stiff for a comfortable ride on roads that are not smooth. I compensate by running my tire pressure at 15 psi, but there must be a better way. I track my car as much as possible, so compromise between comfortable cruiser and capable track car is an important issue. I think that the correct springs, for cruising, coupled with the correct sway bars too increase spring rate, for the track, coupled with the correct shocks to control wheel movement would result in a vehicle with the right stuff. I have not gone down that road because of the trial and error and extra money involved, but would hope that those of you that have, will contribute to this thread.

[bobl]

My car has the 3 link setup. When driving on bumpy roads it would trigger my pacemaker and my heart rate would go crazy. On the advice from this forum I switched to 250 lb. rear springs. I also added some foam in my seat. It made a huge difference. My pacemaker very seldom triggers now, so I've got proof it rides a lot smoother. I preferred the handling with the stiffer springs, but everything is a compromise.

[Avalanche325]

When driving on bumpy roads it would trigger my pacemaker and my heart rate would go crazy.

You, Sir, get an exception. YIKES!

One thing is that you cannot change spring rates without affecting handling. Maybe not in the envelope that you normally drive in, but definitely at the limit (on the street, known as an emergency maneuver). It may also change where the limit is. Unless you are going to do skidpad testing, go with a known setup from one of our resident experts.

[Avalanche325]

Yeah, yeah. I’m sure your energy will be well spent in the threads about power steering and power brakes!


Power steering - You got me there. I'm a big fan. I autocross and track my car. Hydraulic, not electric for me. Gotta stay a little tough.
Power brakes. How dare you! Start taking Wilwoods, and I'm all in. ;)

[alexmak]

Power steering - You got me there. I'm a big fan. I autocross and track my car. Hydraulic, not electric for me. Gotta stay a little tough.
Power brakes. How dare you! Start taking Wilwoods, and I'm all in. ;)

If I keep my standard mechanical brakes, can I get softer springs then, mom? Pleeeeeeease! I’m gonna behave! (Yes, I completely understand the part about springs affecting handling and that’s why I am doing this as a trial and if I don’t like the effect, I can always go back. )

[CraigS]

If I keep my standard mechanical brakes, can I get softer springs then, mom? Pleeeeeeease! I’m gonna behave! (Yes, I completely understand the part about springs affecting handling and that’s why I am doing this as a trial and if I don’t like the effect, I can always go back. )

Exactly the right answer. Try softer springs. Relatively speaking at about $100 it's a cheap experiment. I have also installed the QA1 double adjustable shocks from Breeze. For the street I ran them on full soft in bump and and about 5 rebound. Get to an autocross and changed to a slightly stiffer setting for both. I could change all 4 shocks in about 5 minutes by jacking up one side at a time w/ my handy small aluminum jack from HF. I know that autocross is different than track but another huge advantage of the DAs was I could change handling balance between runs.

[Hoooper]

When I was starting my alignment this weekend and setting ride height my first thought was that the springs seemed probably too stiff to handle correctly on track. The stiffness might be right for an autocross on perfectly flat parking lot but the tracks here have a lot of elevation change and mid corner camber changes that can be problematic for oversprung suspensions. I suspect FFR chose such stiff springs because their kits are sold base without sway bars and needed the stiffness in order to still handle great under the right conditions. With swaybars the spring rates should be reduced, it would be nice if FFR offered the choice of buying the setup for use with or without swaybars, especially for those spending quite a bit to upgrade to the double adjustable konis

[Avalanche325]

I haven't done spring changes on my car. I have added and adjusted my sway bars. A company like FFR would be supplying what works for 99% of their customers.
You might be surprised at how much body roll you get with the stock springs.

OK Alexmak, You can have the springs. It's close enough to Christmas and you have been good all year.

[Jeff Kleiner]

You might be surprised at how much body roll you get with the stock springs.




Here ya' go. Granted, we're running different lines (possibly because his car is pushing) but the photos show a significant difference between my black car with 750# front/500# rear and my friend's blue car with 450# front/250# rear:

http://farm5.static.flickr.com/4125/5076501931_ca7c524b93.jpghttp://farm5.static.flickr.com/4052/5076502337_db2f724613.jpg

http://farm5.static.flickr.com/4091/5077095836_6f2d439613.jpghttp://farm5.static.flickr.com/4103/5076502429_8bf9fa9109.jpg

Jeff

[Railroad]

Here ya' go. Granted, we're running different lines (possibly because his car is pushing) but the photos show a significant difference between my black car with 750# front/500# rear and my friend's blue car with 450# front/250# rear:

http://farm5.static.flickr.com/4125/5076501931_ca7c524b93.jpghttp://farm5.static.flickr.com/4052/5076502337_db2f724613.jpg

http://farm5.static.flickr.com/4091/5077095836_6f2d439613.jpghttp://farm5.static.flickr.com/4103/5076502429_8bf9fa9109.jpg

Jeff

Those pics raised my pulse rate. I have a 20th Anniv edition with IRS and both sway bars. 500# front, 250# rear, I think.
I can relate to the speed and G's to get that much body lean out of my car. Awesome. That extra passenger is probably over 150#.
I hope to get on Barber Motorsport by next year.

[rich grsc]

The head of the driver in the blue car tells the story. :rolleyes:

[alexmak]

In a car that weighs 2200lbs adding 200 pound passenger would seriously affect, well, everything. I remember having 350lbs NASA instructor in my 3800lbs Camaro at Pocono, and boy did I feel it. Especially the brakes that were cooked after 4 laps.

[alexmak]

Just to close this gestalt, I mean thread: I installed 350 lbs springs in the back instead of 400lbs stock. Along with lower tire pressure feels much nicer without losing firmness. Did not see any effect while doing regular (and somewhat spirited) street driving.

[AdamIsAdam]

I believe my car has the springs that came with the standard full kit (I could check the packing slip if necessary). I've got a 3 link rear with coil-overs and power steering. The car steers VERY twitchy and it so firm that over bumps/joints that are like speed bumps on the crappy NY roads, the car bounces painfully, with the harness pressing to keep me inside the car! What I fear most about driving it fast is hitting a bump mid-turn and having the rear end jump out from under me.

So, if I read this thread correctly, I should change my rear springs to a softer version. Is stock 500#? So try 400#? Where do I get them? What part numbers and brands are they?

Oh, and I changed to Nitto NT01's this year which helped. I'm running 19 PSI at all 4 corners.

TIA,

[AdamIsAdam]

http://www.factoryfiveparts.com/14675-roadster-coupe-koni-solid-axle-coil-over-kit/

350# in rear. Can I go softer?

[NAZ]

http://www.factoryfiveparts.com/14675-roadster-coupe-koni-solid-axle-coil-over-kit/

350# in rear. Can I go softer?

I think most folks here are in the higher spring rate camp and equate stiff suspension and little body roll as a good thing. After all, race cars have big tires and stiff springs so that must be better, right? You’re likely going to have to experiment for yourself like a racer does and that takes time, $$, and some basic suspension design knowledge. That last part requires a great deal of time commitment as there are a lot of physics going on in a suspension.



As I’ve mentioned before, spring rates (spring frequency) front to rear have a significant effect on handling. Basically, the softer the spring the more traction but there has to be a balance between front & rear, not only to maintain a neutral handling car but if you make big swings on one end, the car may tend to porpoise when going over a bump if the front and rear spring frequencies are significantly out of phase. Typically, a passenger car has a higher rear spring frequency (10% or more) so that the rear can catch up to the front over a bump. When you start changing spring rates you need to watch for not only loose or tight conditions but also you want to avoid that hobbyhorse ride like some of the old cars from the 50’s had.



Don’t make drastic changes on one end, the front & rear suspensions act in concert as a system. Here’s a calculator to get you started but be mindful there is lot’s more to tuning a suspension system than just spring rates and shock settings. Have fun and learn from the experience. You can always reverse any change you make that doesn’t improve the handling.
https://www.ridetech.com/tech/spring-rate-calculator/

[AdamIsAdam]

After watching this, I'm even more convinced that I need to reduce spring rates as my car is VERY stiff. Not only is it uncomfortable, which could be ok, but I worry of the safety of losing traction mid-turn due to bumps.

https://youtu.be/hGZRairqHNI

[Avalanche325]

AdamIsAdam,

You should seriously consider doing a few autocross events. It will get rid of any fear while street driving because you will learn both the cars limits and your skill level, which will go up considerably. That is assuming your aren't doing something completely insane on the street.

[AdamIsAdam]

AdamIsAdam,

You should seriously consider doing a few autocross events. It will get rid of any fear while street driving because you will learn both the cars limits and your skill level, which will go up considerably. That is assuming your aren't doing something completely insane on the street.


Agreed. I was planning to Auto-X it this summer but COVID laughed at my plans. My local club is now doing auto-x events but it's probably too cold in NY for my Nitto NT01's. But you're totally right that I need to safely explore the car's limits. Or just do donuts! :D

[AdamIsAdam]

...Don’t make drastic changes on one end, the front & rear suspensions act in concert as a system. Here’s a calculator to get you started but be mindful there is lot’s more to tuning a suspension system than just spring rates and shock settings. Have fun and learn from the experience. You can always reverse any change you make that doesn’t improve the handling.
https://www.ridetech.com/tech/spring-rate-calculator/

That link calculator calls for about a 225 spring.

[NAZ]

That link calculator calls for about a 225 spring.

You're only looking at one end of the car. If your goal is a softer ride you will have to calculate the spring rate for both ends of the car. Make a big spring change on one end of the car and you will not be happy with the result.

If your goal is to adjust the handling from loose to neutral you will need to determine what factors are causing a loose condition. Loose (over-steer) can be caused by more than spring rate and it is very likely that you have more than one thing contributing to a loose condition. It starts with confirming your alignment, minimizing bump steer, optimizing ride height for YOUR combination, cross weight & tire temps are all optimized for your car. Since you have a 3-link, something as simple as the attitude of your LCAs can cause a loose condition from something called roll over steer. If the LCAs are set at an angle sloping up at front you will have some amount of roll over steer. Don't jump to the conclusion that you need to change springs until you have systematically gone through all your suspension settings.

There's more to chassis tuning than springs and much more than can be listed here but here's a link to get you started on finding several things that can contribute to a loose handling car: http://www.longacreracing.com/technical-articles.aspx?item=8164&article=Chassis%20Dynamics

[AdamIsAdam]

Thanks, I'll take a read... I do understand that there's A LOT more to suspension tuning than just springs and especially just springs on one end. I posted a question on the Ask a FFR Tech forum to see if there are already known combinations that work for me to start with. The car handles very well, but it's just so firm as I said. But yes, it's also a bit quick, possibly too quick, in the steering. It has never come around on me by any means, but it is quick. Yea, I need to auto-x it for sure!

If I had a genie lamp to rub, I'd ask for it to be a bit softer and not so quick/twitchy on the steering, but without giving up my ride height and stance. I have big speed bumps in my community and cannot give up any ride height at all.

[Avalanche325]

Of course as soon as you autocross, you will like how stiff it is.....and be adding sway bars. LOL.

Just to throw out additional info. A lot of people put rake in. 1/4 - 3/4" higher in the rear. I took that out of mine and it really helps the rear grip. I am running the same height all the way around.

[AdamIsAdam]

Of course as soon as you autocross, you will like how stiff it is.....and be adding sway bars. LOL.

Just to throw out additional info. A lot of people put rake in. 1/4 - 3/4" higher in the rear. I took that out of mine and it really helps the rear grip. I am running the same height all the way around.

LOL. I don't intend to make this an auto-x rat. I'd sooner buy a Miata for that. But I do want to auto-x it. It's safer than taking it on a full size road course. I might take it to the drag strip one day just to see if I can break into the 10's with 450hp!

My car is pretty level and I like it that way, like you (I just put a level on the frame with the car sitting in my garage and it's VERY SLGIHTLY raked back actually with the front end being a tiny bit higher).

EDIT: I JUST MEASURED THE FRAME AND IT'S 4" TO THE GROUND IN THE REAR AND 3.5" IN THE FRONT. INTERESTING.

Here's a few pics.

136876

136877

136878

[Avalanche325]

I did a couple events post COVID. The SCCA was doing a very good job at precautions. Drivers only, single use pens for sign-in, etc. The participants however were doing very little mask wearing and social distancing. One or two guys just stayed in their cars to keep away from everyone else. For me, most of what makes it a great day is the social aspect. So I am out for the season.

I built an iRacing rig to fill my speed needs. That's a slippery slop also.

As far as twitchiness goes, what are your alignments specs and rack ratio? I have a really quick rack and love it. Some guys don't get comfortable with them though.

[AdamIsAdam]

I did a couple events post COVID. The SCCA was doing a very good job at precautions. Drivers only, single use pens for sign-in, etc. The participants however were doing very little mask wearing and social distancing. One or two guys just stayed in their cars to keep away from everyone else. For me, most of what makes it a great day is the social aspect. So I am out for the season.

I built an iRacing rig to fill my speed needs. That's a slippery slop also.

As far as twitchiness goes, what are your alignments specs and rack ratio? I have a really quick rack and love it. Some guys don't get comfortable with them though.


Post COVID? Has that happened yet? But I agree about the fun/social aspect of most things car related (shows, races, etc). It's not the same now and I can't wait for a world that actually is post COVID.

I don't know my rack's ratio nor alignment specs. The alignment I'll get done when I do springs I suppose. Aside from the steering being quick, it drives fine otherwise. Are you thinking it may need more caster perhaps?

The power steering rack was an upgraded/improved rack and not the FFR one as I recall. I'm not sure. How can I tell which one it is? I'm sure I can count turns lock-to-lock. Anything else to look for?

I don't even know what iRacing is but can guess. But don't tell me. I don't need more hobbies! LOL

[Avalanche325]

I guess my term "post COVID" was wishful thinking.

Twitchy could be 0 or toe out. Lack of caster especially if it wasn't increased from manual to power specs. Lock to lock will give you how quick it is. Limiters of course can change that, but it will be in the ballpark. I'm something like 2-1/2 turns which is a 15:1 IIRC.

iRacing = racing simulator where you race other people on line - realistic enough where a few guys have turned real world pro. Pros use it to practice. Some retired NASCAR, sports car, and F1 guys show up, which is pretty cool. It is another hobby that you can throw a whole lot of money at. $8k so far.

[AdamIsAdam]

$8k!!!!?? wow. Do you go on there and curse and use racial slurs and lose your sponsors? Oh wait, that's already happened I think. ;)

I'll have to find a good alignment shop after I swap out the springs. I'm sure it's in that 4" binder I have, and I'll search the threads, but is there a general starting point on alignment specs I can give to the shop?

[AdamIsAdam]

ok, so the weather was amazing this weekend and there was one last auto-x going on locally, so...

https://youtu.be/XeZ0zhI_3PQ

The back end of this thing DOES NOT want to stay the back end! On the gas, off the gas, on the brakes, all of it wants to kick the back end out! My NT01's never really got up to temp, and it was the last two runs that I dropped PSI in the back from 20 to 16 which I think helped. That being said, the car CARVED up the slaloms. It really goes where you tell it to (when the tires agree with my commands at least).

And yes, NOW I feel like the suspension is great and not too stiff. But I ordered the new Eibach's already so I'll put them in and see of things go.

I just realized, the oversteer I get on the auto-x is the same thing I'm feeling in the street. It's as if the back end has bald tires or something. The steering is great, precise and quick. But it causes the back to just kick out even when I'm off the gas on the big left hand sweeper (which, btw, had enough g-force to spit gas out of the filler neck and onto the fender! WTF is up with that?)

Feedback welcome.

[CraigS]

FFR supplied 250# rear springs for a very long time. When they went to the custom FFR konis they started w/ the 350s. Personally I prefer the 250 to 300 on a solid axle car. If you have Koni, be sure they are on their softest setting. Also if there is an o-ring on the shock shaft push it up against the body of the shock. Drive on your bumpy road and see if the o-ring moves down to the bump rubber. If it does you may need to raise the ride height some. PS if there is no o-ring, install a plastic wire tie and snip the end as short as you can.

[nelsond003]

I have the stock 500 in front and 350's on my IRS. I cant feel a noticeable change yet. Ill swap out the fronts to 350 also when the weather warms up and see if I notice the body roll or not. My biggest "notice" was reducing my tire pressure from 35 to 22.

[AdamIsAdam]

FFR supplied 250# rear springs for a very long time. When they went to the custom FFR konis they started w/ the 350s. Personally I prefer the 250 to 300 on a solid axle car. If you have Koni, be sure they are on their softest setting. Also if there is an o-ring on the shock shaft push it up against the body of the shock. Drive on your bumpy road and see if the o-ring moves down to the bump rubber. If it does you may need to raise the ride height some. PS if there is no o-ring, install a plastic wire tie and snip the end as short as you can.

Wait, the FFR Koni's are adjustable? I thought those shocks were not.

[egchewy79]

Wait, the FFR Koni's are adjustable? I thought those shocks were not.

yes, remove the dust cap on the piston side. I believe softest setting is with the piston rotated all the way counterclockwise. there are 3-4 settings and a button to depress to make the change.

[Jeff Kleiner]

Wait, the FFR Koni's are adjustable? I thought those shocks were not.

The red 30 series Konis are adjustable for rebound. With your springs (or the softer ones) you want them on the lowest, softest setting. With heavier springs like my 750/500 combination they should go up one click. Check them and assure that they are all the way soft when you change to the new springs.

Jeff

[AdamIsAdam]

the red 30 series konis are adjustable for rebound. With your springs (or the softer ones) you want them on the lowest, softest setting. With heavier springs like my 750/500 combination they should go up one click. Check them and assure that they are all the way soft when you change to the new springs.

Jeff


Thank you both!

[AdamIsAdam]

ok, and now to thoroughly hijack this thread, I think I should have the time this weekend to swap the springs. I have never worked on coilovers before. After watching this (https://youtu.be/OpcXubr0ACQ) video, am I correct in assuming that I will need to change the ride height adjustment in order to disassemble and reassemble the unit with the new spring? I REALLY like the current ride height, so will I be able to count threads before I start and simply set it up back the same way to get the ride height the same despite the softer springs? I'm thinking that will work because the car is so light.

Also, is the above description on rebound adjustment confirmed? Do I rotate the piston all the way counterclockwise in order to be on the softest setting? (I assume counter-clockwise while looking down the at the shock.)

TIA,

EDIT: In reading the assembly directions, I don't see why the guy in the video removed the top of the shock in the vice? Will removing the snap ring and then the hat be all I have to do in order to remove the spring? (which means I have to adjust the ride height down to make slack I assume)

[Jeff Kleiner]

You’re going to have to adjust the ride height because the softer springs will compress more than what you currently have with the same vehicle weight on them.

Here is the adjustment procedure:

http://https://www.koni-na.com/en-US/NorthAmerica/Technology/Adjustment-Guides/mono/

Jeff

[AdamIsAdam]

You’re going to have to adjust the ride height because the softer springs will compress more than what you currently have with the same vehicle weight on them.

Here is the adjustment procedure:

https://www.koni-na.com/en-US/NorthAmerica/Technology/Adjustment-Guides/mono/

Jeff

Thanks. One last question (for now! LOL). When measuring ride height, where is the best place to measure? I was thinking from the 4" tube frame at each end to the garage floor.

EDIT: I found this thread... https://thefactoryfiveforum.com/showthread.php?30170-Ideal-Ride-Height-and-Adjusting-Koni-Coil-Overs&highlight=ride+height+adjustment

[AdamIsAdam]

The head of the driver in the blue car tells the story. :rolleyes:

I think I finally get this comment. The blue car is biting more and causing more lateral g-forces while it is also leaning more. It's digging in. And therefore, the driver in the blue car has his head tilter more because of that lateral force. Is that right? If the cars were doing 5 mph around that turn the heads would be perfectly vertical, but at 50mph they are at a 45* angle (for example). Right?

ok, this weekend, I'm going in! Hopefully the weather will warm up a bit to take it out for a spirited test drive Sunday!

[Jeff Kleiner]

I think I finally get this comment. The blue car is biting more and causing more lateral g-forces while it is also leaning more. It's digging in. And therefore, the driver in the blue car has his head tilter more because of that lateral force. Is that right? If the cars were doing 5 mph around that turn the heads would be perfectly vertical, but at 50mph they are at a 45* angle (for example). Right?



No, the blue car was going much slower through the turn than my black one but was rolling more due to the softer suspension.

Jeff

[CraigS]

My spring change technique is loosen the height adjustment collar 15 turns (put a paint mark on the collar to make counting easier). This will usually give enough space to remove the spring seat and then the spring. Do your shock adjustment check and re-assemble. Put the 15 turns back in and then a WAG of one more turn for the softer spring. When done w/ this on the first coil over (assuming you haven't corner weighted the car) count how many threads are exposed above the collar. Before taking the second one apart adjust it so there are the same number of exposed threads. Now repeat the above procedure on the second coil over. Test drive and check your ride height. If you need to change it do the same # of turns on both sides.

[AdamIsAdam]

My spring change technique is loosen the height adjustment collar 15 turns (put a paint mark on the collar to make counting easier). This will usually give enough space to remove the spring seat and then the spring. Do your shock adjustment check and re-assemble. Put the 15 turns back in and then a WAG of one more turn for the softer spring. When done w/ this on the first coil over (assuming you haven't corner weighted the car) count how many threads are exposed above the collar. Before taking the second one apart adjust it so there are the same number of exposed threads. Now repeat the above procedure on the second coil over. Test drive and check your ride height. If you need to change it do the same # of turns on both sides.

THANKS! I'm about to do this job this morning. Please clarify a few things:

WAG?

When you wrote "before taking the second one apart, adjust IT so there are the same number of exposed threads."

I'm confused. Please explain. I understand and love the idea of turning the adjusting collar 15 turns, then 16 upon tightening, but don't understand what you're saying after that.

[Jeff Kleiner]

WAG?



Wild As* Guess (it's a technical term)

I think you said that you like your current ride height so check it at all 4 chassis corners before beginning and adjust the spring collars to come back to that after installing the new springs. Assuming that the car has been aligned previously if you set it back to the same ride height will not change the alignment.

Jeff

[AdamIsAdam]

Ok. Got it. Watch the door I'm going in. 😁

Measuring from the ends of each four-inch frame tubes I am at 3 7/8" front and 4" rear.

Too early for a garage beer? Lol

[rich grsc]

I think I finally get this comment. The blue car is biting more and causing more lateral g-forces while it is also leaning more. It's digging in. And therefore, the driver in the blue car has his head tilter more because of that lateral force. Is that right? If the cars were doing 5 mph around that turn the heads would be perfectly vertical, but at 50mph they are at a 45* angle (for example). Right?

ok, this weekend, I'm going in! Hopefully the weather will warm up a bit to take it out for a spirited test drive Sunday!

No sir, you do not get it. Just the opposite in fact. You will be well advised to follow the advice of the people who drive their cars hard, so has to not end up with a poorly handling car. Good luck

[AdamIsAdam]

UPDATE: Overall, this was very easy. I can see how one could do this even faster and often to dial in the suspension. @CraigS your one extra WAG turn was spot on! Near as I can tell, that left the ride height exactly the same as before. I took it for a ride and the car seems to ride nicely. Perhaps a little smoother/softer now - hard to tell on a short ride on cold tires, but sawing the steering wheel back and forth does generate a little more body lean than before, but the car also feels much more composed over bumps. Before it honestly rode like there was no suspension at all. I'll take it out for a longer ride if the weather holds out.

My shocks don't have that adjustment feature. There is no button / hole to depress and it looks different than the one on Koni's site. See pic.

So far, so good. Thanks all.

137713

[Jeff Kleiner]

My shocks don't have that adjustment feature. There is no button / hole to depress and it looks different than the one on Koni's site. See pic.

137713

Yes, you do have the adjustment feature. You have to pop that black cap loose to access the button.

Jeff

[AdamIsAdam]

Yes, you do have the adjustment feature. You have to pop that black cap loose to access the button.

Jeff

Ya know, that thought had occurred to me! Oh well, it's all buttoned up now. I'll check it another time. I am working in a VERY tight garage on QuickJacks. It takes me almost as long to get the car on the jacks and wheels off as it does to swap out all 4 springs!

[CraigS]

Adam, sorry I didn't get back to this thread soon enough. To fill in a little. You have probably read about checking corner weights but there are very few who have the equipment to do it. Think of a 4 leg table w/ one slightly longer leg. It rocks on the long leg and it's obvious. Now think about those 4 legs each having a compression spring on the end. Now the spring on the long leg gets compressed more than the others so there is no gap to the floor and the table feels OK. But, if you put a scale under each leg you would see that the long leg is pushing more of the total table weight onto it's scale. The short leg would have less weight showing on it's scale. So the table is now an FFR and we rely on the fact that FFR built a frame that is correct so the frame mounts for the coil overs are all even. Then we want to be sure that it's 4 'legs' (the coil overs) are all the same length. Front and rear ride heights are different so the front coil overs will be a different length than the rears. But we want the left front to = the right front and the left rear to = the right rear. That is why I said to check that your second coil over matches the first one. A caution. I am not sure what tires you have but the ambient temp these days can have a major effect causing significantly less traction. The 'extreme' or 'ultra high' or 'max' performance and any w/ 'summer' in their description are especially bad as temps drop. Back in 2015 my wife bought a Mustang GT Performance Package w/ 'summer' tires in April. In Oct she asked me to drive it because she thought the tires were slippery. Dang she was right. 2 weeks later we replaced tires w/60% tread with all season tires. Just a thought to say don't test too aggressively.

[AdamIsAdam]

Thanks for the reply. I have a local shop who specializes is race cars (including fabrication), all German cars and is actually building a FFR at the moment, ironically enough. He has the scales and alignment equipment to corner balance the car, which I plan on doing. And yes, I know all about cold summer tires in a big way! I have Nitto NT01's on the Cobra and a 2018 GT350 with Pilot Super Sports that I run all year (but only drive it on sunny days) so I know all too well how extreme summer tires dislike cold temps!

What is a good corner balance weight setting?

[Jeff Kleiner]

What is a good corner balance weight setting?

You want to have both diagonal pairs equal. It isn't a setting per se.

Jeff

[AdamIsAdam]

Sorry, "setting" is not the right term. I mean in general, what's the ideal (or a good starting point) percentage to look for with a small block FFR? 48% front/ 52% rear?

Diagonal pairs equal? Interesting. What's the logic behind that? I would think you want the fronts equal, and the rears equal, and then you want what the car likes best front/rear (ie, if 48/52% F/R was the ideal). This assumes balanced driving and not something like nascar that is only left turns. Again, I'm looking for the most predictability here on the street.

[Jeff Kleiner]

Adam,
You're not grasping the concept and are confusing static weight distribution with corner weighting/balancing and cross weighting. You can't "move" weight with spring adjustments. If the front end of the car has 1,000 pounds on it and the rear has 1,200 pounds that is the static weight distribution and won't change with spring preload adjustment. HOWEVER what can change with spring adjustment is that you could end up with 400# on the LF, 600# on the RF, 700# on the LR and 500# on the RR. The front would still be a total of 1,000 pounds and the rear 1,200 so the weight distribution remains the same but the car is what I call "cross jacked" (some refer to it as "wedged" particularly in the circle track world). If the diagonals are not equal (or equalized as much as possible which is sometimes dictated by driver or component positions) the car will not perform the same cornering left as it does cornering right. A diagonal mismatch will also lead to poor braking with the lightweight wheel(s) locking up prematurely. I mentioned the circle track guys because they will intentionally "wedge" a car for left hand turns but in our case we want our cars to perform the same in both directions and not oversteer one way and understeer going the other!

That's probably clear as mud but the googles are your friend! There is a ton of info out there; check it out :)

Jeff

[Railroad]

Jeff,
I have the Wilwood 6 pistons on front and 4 pistons on the rear. I have manual adjuster on the master cylinders.
I was just feeling out the brakes to make sure the rears do not lock and cause a panic stop issue.
My right rear and left front slide on a hard stop.
It sounds like the car balance is off. I set the ride height by ground height, 4.5 inches all around.
I am sure it has settled some and needs re setting.
I doubt I will ever competitively track the car, but would like to have it at its optimum balance.
Your last post is telling me I need to balance the car before adjusting the brakes??
I can probably get on a set of scales of a local racer.
Sorry to interject brakes with handling, but they surely overlap.
Just wanted to glean as much info and apply before calling it done.
thanks for listening, to OP and others.

[AdamIsAdam]

Jeff,
I'm actually understanding what you're saying. But I will disagree that you actually can shift weight front to rear the same as you are shifting left to right in your example. 1000 lbs up front but 400# LF and 600# RF is doing the same thing as shifting it front to rear if you adjust the springs and ride height. I assume you would need much great adjustment settings to make changes since the center between front/rear is further from the wheels than is the center from left to right wheels. I'm not silly enough to think all cars can be made to be 50/50, because as you said, if a 911 has hundreds of lbs over (and behind) the rear axle, no amount of adjust is going to get that car to 50/50. But I think it could have an effect to some extent. Which is why I was asking if there's an attainable goal to shoot for.

If I understand your thought, it's to just make sure left/right are about balanced with each other, which would also make the opposing diagonals equal. That sounds easy enough to do.

I'll do more reading on Cobra suspension tuning. Coming to these forums is part of my homework, and I'll try more searching than posting. I'm just trying to understand the nuances of the Cobra specifically.

But I do appreciate your and others sharing your vast knowledge and experience. Honestly.

Weather was too crappy to take the Cobra out for a longer ride today. I selected the car with a roof instead :(

[rich grsc]

Jeff, sometimes it's just hopeless

[AdamIsAdam]

Hey, come on now. Play nice.

[Jeff Kleiner]

Jeff,
I have the Wilwood 6 pistons on front and 4 pistons on the rear. I have manual adjuster on the master cylinders.
I was just feeling out the brakes to make sure the rears do not lock and cause a panic stop issue.
My right rear and left front slide on a hard stop.
It sounds like the car balance is off. I set the ride height by ground height, 4.5 inches all around.
I am sure it has settled some and needs re setting.
I doubt I will ever competitively track the car, but would like to have it at its optimum balance.
You last post is telling me I need to balance the car before adjusting the brakes??
I can probably get on a set of scales of a local racer.
Sorry to interject brakes with handling, but they surely overlap.
Just wanted to glean as much info and apply before calling it done.
thanks for listening, to OP and others.

You're locking opposite diagonals which is a classic indicator that your cross weights are off with the RR and LF being light. I'd bet that your LR and RF adjusters are cranked more than the RR and LF. If this is the case change them (either up with one, down with the other or some of both) so that both fronts have the same number of threads showing. Now do the same with the rear. Note that the front and rear will not show the same number of threads. We want both fronts to match and both rears to match but the fronts won't match the rears. You may wind up with a bit of ride height variance, probably <1/4" but I bet it will solve the uneven braking. I've set the cars I've built up using this method and when scaled they were so close to dead on that they either needed no change or less than 1/4 turn.

Jeff

[AdamIsAdam]

That's probably clear as mud but the googles are your friend! There is a ton of info out there; check it out :)

Jeff

You were right. This article explains it well:
https://www.elephantracing.com/tech-topics/corner-balance/#:~:text=Corner%20balancing%20is%20the%20process,a djusting%20the%20suspension%20spring%20height.

and this

https://youtu.be/0uCUk30lP0s

[NAZ]

Adam, some candid tough love for you to consider.


These light weight, short wheelbase vehicles are not as forgiving as your standard passenger car. And they have little in the way of modern safety features and absolutely no nanny devices to prevent you from driving beyond your limit and ending up in a ditch or wrapped around a pole. It’s easy for an inexperienced driver to get in over his head – and that can have serious consequences. These cars are not for everyone and need to be treated with respect – they can kill you in a heartbeat.


To drive a performance vehicle near its limit requires knowledge, skill, and experience. To set-up a chassis on a performance car to make it handle optimally requires knowledge, skill, and experience. Adam, you seem to be short on KSE and are having trouble following the good advice of more knowledgeable folks. And you seem quick to dismiss their recommendations or even debate the advice given.

The best advice anyone here can give you is to take your poor handling car to that race shop you mentioned, open your wallet, and have the shop set-up your car to ride smoother with a neutral balance.
And while the shop has your car, go take a performance driving class so you’ll be better prepared to drive that car safely. These cars have gotten owners killed because they got in over their head. A high power to weight, short wheelbase car with loose handling is not something to take for granted.

[GoDadGo]

Adam,

These cars are a handful and learning to drive and adjust them takes time especially if you didn't build the car.
Ride height, corner weights, tire air pressure all need to be understood before spring rates get changed.

Please Do Your Best To Take It Slow So You Don't End Up Like This:
https://www.copart.com/lot/33551180/2017-shel-cobra-la-baton-rouge

Just know that the fellows on the forum are like family and they are always here to help especially those who want to be helped.
For me, my friend Phil will soon be riding shotgun in Redbone after I learn the basics of my car and its abilities along with my own.

Steve

Phil's Gone A Bit Faster Than I Have!
https://youtu.be/hsvEx4vDVdg
https://youtu.be/zm2RdZ-FJmA
https://youtu.be/YTPvLRlmp7E
https://youtu.be/uFm3CM8_Zf8
https://youtu.be/JhR21Q24xHU

[AdamIsAdam]

I'm being very misunderstood and totally mischaracterized.

The Cobra is new to me, as is this forum, so I always try to come off as humble rather than conceded, especially since I am asking for knowledge and advice from those who know more than I do, which I appreciate. In fact, the selection of those springs was the advice of both FFR cobra builders and my local race car builder. And yes, he'll be aligning and corner balancing the car as originally planned. Please don't mistake humility for a lack of KSE.

[CraigS]

What I have found is that our FFRs are hard to get the corner balance as perfect as we would like. This is mainly due to the 150-250# driver sitting in the left rear of the car. The empty car is rear heavy by 2-3% but w/ the driver you end up w/ a car that is rear heavy and left heavy. If you try to get the front tires equal (which would be best for braking) you end up w/ the left side more rear heavy than the right side. My goal is to have about the same front to rear difference on both sides. I will fudge that a little to get the fronts a bit more equal.

[Railroad]

You're locking opposite diagonals which is a classic indicator that your cross weights are off with the RR and LF being light. I'd bet that your LR and RF adjusters are cranked more than the RR and LF. If this is the case change them (either up with one, down with the other or some of both) so that both fronts have the same number of threads showing. Now do the same with the rear. Note that the front and rear will not show the same number of threads. We want both fronts to match and both rears to match but the fronts won't match the rears. You may wind up with a bit of ride height variance, probably <1/4" but I bet it will solve the uneven braking. I've set the cars I've built up using this method and when scaled they were so close to dead on that they either needed no change or less than 1/4 turn.

Jeff

Jeff,
Thanks for the info, sounds easy enough. Does driver weight 240# undo this balance, or does it need to be done with driver/passenger ?

Rich, I understand, added wt will not change the thread setting, in case you are reaching for the keyboard. LOL

[Jeff Kleiner]

Jeff,
Thanks for the info, sounds easy enough. Does driver weight 240# undo this balance, or does it need to be done with driver/passenger ?

Rich, I understand, added wt will not change the thread setting, in case you are reaching for the keyboard. LOL

In an ideal world the car would be corner weighted with the driver in the seat (unless it one of those new fangled self driving things) but when that isn't possible simply setting the springs as I described in the earlier post will get you pretty darn close.

Jeff

[Rdone585]

There is a lot of good information being shared here, so I'm watching, reading, and learning myself. I have the car corner weighted with salt or sand bags to simulate myself driving. I also have the tech simulate a passenger with extra weight in the passenger seat so I know what the balance will be if I allow a passenger to ride along at the track. Sometimes there is a compromise between the two if I know there will be passengers. I also make sure to have the gas tank between full and 1/2 full of gas. If I plan to run my cool suit I have the cooler mounted and 1/2 full of water. I'm trying to get to the point where I can do this myself in my garage. I have most of the specialized equipment already, just need to find out when I can borrow a set of scales from my friend in the neighborhood.

[Railroad]

Jeff,
My rear spring adjusters were 3 turns different. The front was 1 turn different.
The rear now match side to side, as do the front.
Thanks for the help.

[Jeff Kleiner]

Jeff,
My rear spring adjusters were 3 turns different. The front was 1 turn different.
The rear now match side to side, as do the front.
Thanks for the help.

You had a real good teeter-totter there! I bet your braking will be even now :)

Jeff