Finished my front mounted exhaust system and first start!

[AA-ron]

I thought you all might get a kick out of seeing my finished exhaust system in my Roadster. I finished it over Xmas vacation and actually did my first start a few days ago. I wanted an undercar exhaust look and function, but couldn't tolerate any loss in ground clearance; also I'm running IRS which would seem to make it even harder to do. Sooooo.... so I did it this way (see pic). Out of necessity I also had to make my own muffler. I couldn't be happier with the way it sounds. It's actually pretty quiet, in fact a bit too quiet, so I might be diving back into the muffler to make some adjustments (I made it tunable). The exhaust tips will exit just above where the side pipes would normally exit-- just no side pipes. If any of you are interested in seeing more of the exhaust and muffler build you can see it on this link, it's a two part video (build 13 and 14).

https://www.youtube.com/channel/UCgXOGfrufuCWGcelzGecm1Q

Enjoy!

[Jeff Kleiner]

Bravo!

:eek:

Jeff

[CaptB]

Amazing skills.

[Straversi]

Love the creativity and execution. Can’t wait to see the finished project. Great job.
-Steve

[BradCraig]

Nice! I'd weld that O2 bung in, those clamped ones leak and cause AFR issues.

[egchewy79]

very cool concept. I've not seen anyone do this before. wonder if it'll significantly increase your under-hood temps. are you going to put any downturns on the ends of the pipes? you mentioned maybe putting a "Y" connector at the ends. Or maybe direct the hot air out the side vents?
wasn't sure if the heat over time blowing directly into the underside of the body would affect the paint job down the road.

[AA-ron]

Hey thanks for the advice. I will indeed weld the bung in-- didn't know they were a problem.

[AA-ron]

The exhaust tips will indeed exit through the sides of the body, protrude by about 3 inches, and vent away from the car. I'm making a stainless flange where they exit to keep it clean looking and to keep some of the heat away from the surrounding fiberglass/paint.

[Jessew]

Nice! Where’s the start video?

[AA-ron]

The start video is coming! I'm guessing next week. Editing these videos is a bit of work :) And sometimes I forget i actually have a day-job...

[rich grsc]

Thats been tried before. I hope you have good luck with it, the big problem was way too much heat in the engine compartment.

[Cutter 54]

Awesome job on the exhaust. What a craftsman! Ditto the “holy sh**” grab rails. Are you concerned about poor UV protection by the polyurethane? I used marine varnish on my own dash wood veneer but prefer the high gloss finish on the poly. Any thoughts?? Ed Klein.

[Kbl7td]

Lol the heat will be fine. Anyone heard of a mid engine car? Hell you could even go as far as jet coating the internal component, bigger fans, more shielding, lots of options.

Love the videos. Especially like all the customization that you do.

[GTBradley]

I’m impressed with the innovation! Nice work. Have you given any thoughts to running exhaust tubes inside the 4” frame rails? Crazy I know, but if the exhaust pipes entered and exited at the end caps you could potentially have true rear exit exhaust with no loss of road clearance. The frame rails are big enough that an exhaust tube could be surrounded with fiberglass insulation.

Unfortunately, this all looks heavy. What does your muffler weigh? Will it weigh more than the typical side pipe set up?

[Jeff Kleiner]

Unfortunately, this all looks heavy. What does your muffler weigh? Will it weigh more than the typical side pipe set up?

Pair of sidepipes weigh 48 pounds.

Jeff

[Rdone585]

I agree - the exhaust you have created is awesome and original work. And because you created it, it will be tunable as needed in the future. I recommend, you should not locate your battery near that heat source, or it will reduce the life of whatever battery you choose to use. Near the end of your build I suggest borrowing or purchasing a set of scales to balance your build. The end result will be well worth it. Your choices could impact ride height, bump steer, shock choices, or other details should you choose at some point in the future to optimize the performance of the car.

I'm sure this will add weight in the front. That's not always a bad thing. Compared to a typical build weight be moving from the center to the front. Many of our builders move the battery from the trunk to the front passenger side and see improved balance in their cars. I played around a lot this past year moving weight around in an attempt to reach the perfect 50/50 ratios. Every build is different, but I was looking at having to add about 100 lbs centered in the frame between the front wheels to get balanced. I did not want to add that much weight to the car, so I did what I could in other areas. Unfortunately, I do not have room for the battery in the engine bay. The most noticeable improvement was when I converted from a gel cell battery behind the driver, to a lithium battery (costly but lost almost 30 lbs in a critical area) located behind the passenger in the trunk. This allowed me to get within 1.5% of the 50/50 goal. Remember, when corner weighting your car always account for fluids, driver weights, and any other weight typically present (or absent) in the car during performance driving.

[GTBradley]

If you look at some of his other videos you’ll see a really nice fiberglass drop trunk and rear battery installation which allows for removing the battery horizontally.

[AA-ron]

Thanks for all the comments and advice-- this was one of the reasons I wanted to post this.
The muffler weighs 18 pounds including the v clamps and baffling material, and the stainless pipe tips the scale at 11 pounds. So all said and done, I'm under 30 pounds-- which is definitely less than the side pipes. My battery is rear mounted, so I should be in pretty good shape weightwise.
Ah yes, the heat... yes the heat is a concern. I'm half keeping my fingers crossed on this, and also hoping that what I've read and experienced pan out. There are lots of examples where the the bulk of the exhaust system lives very near the engine, and I'm also thinking that I'm running a 302, that it's not as prone to creating as much heat as some of the larger motors. Lastly, if I need to, I can add heat shielding to help evacuate more of the heat out of the exhaust tip and less into the engine bay. I have a heat shield installed on the muffler and have left space to add additional insulation if need be.
I took a long hard look at running the exhaust through the 4" tubes and for some reason, that seemed scarier to me :) Also, trying to navigate around the IRS didn't look fun.

Lastly, the sound! The X-pipe definitely sweetens it up. Part of me wishes for the more classic side pipe sound-- but I can always adjust the muffler to make it louder. I certainly wouldn't want it any quieter, that's for sure! At idle, it almost sounds like a "regular" car...

[AA-ron]

I used a two part marine epoxy that has great UV resistance on the Oh Sh*t handles. I've used this before and it's pretty amazing stuff. I have a few projects where they've been sitting in the sun for years and show virtually no degradation. It's a pain to work with though-- need to expect drips on any surface that's not horizontal. I ended up sanding the drips on the handles smooth.

[Jeff Kleiner]

...I took a long hard look at running the exhaust through the 4" tubes and for some reason, that seemed scarier to me :) Also, trying to navigate around the IRS didn't look fun.



Good call because it's not as easy as simply running inside of an empty tube... The 4" isn't open all the way through front to back. The round tube is notched for 2x3 vertical that creates the front upright for the coilover and X member and that runs through it as does the vertical 2X3 at the rear of the cockpit.

Jeff

[GoDadGo]

By far this is the craziest thing I've ever seen done on a Factory Five. :)

[CraigS]

If you look at standard cars especially exhaust port through and including the cats you see a lot of sheet metal shields. Some wrapped around the pipes, some on the surrounding surfaces. That may not reduce the overall temp in the compartment but apparently they help reduce individual items from getting burned. And help the heat from getting transferred into the passenger compartment. It would be a shame to cover those beautiful SS pipes you have made but may be needed. Also I have found this insulation really nice for shielding things like wiring and hoses that are already installed.
https://www.summitracing.com/parts/dei-010405
https://www.summitracing.com/parts/dei-010405

[AA-ron]

Craig,
Yes, I would love to not cover up my work, but I'm prepared to do so if need be. Like you've noted, I do intend on adding heat shielding in critical places. I already moved my brake lines to put some separation between them and the hot parts of the exhaust. Great call on that heat shielding link you shared (first I've seen that). I'll definitely be placing that order.
Like I've said before, I'm a complete novice when it come to cars-- metal, wood, and fiberglass fabrication is where my experience sits. These past 4 months, I've had a blast applying my knowhow to the car of my dreams!
Once again, I'd really like to do a heart-felt shout out to the talent within this forum. I can't tell you how much I've learned searching the archives and posting questions.

[GTBradley]

When I travel on the interstate with the soft top on I can detect the exhaust in the cockpit. Side pipes just don’t take the exhaust far enough back to prevent it from happening. I’m really hoping you don’t experience this to a greater degree, but you might, considering how far forward the exhaust tips are. I’m looking forward to your first drives to see how it goes.

You could look at this possibility too:
177733177734

[AA-ron]

Bradley,
Oh boy, you just got my creative juices flowing with those images. BTW, that's a beautiful car, what is it? I've not seen that before.

[JeffP]

Bradley,
Oh boy, you just got my creative juices flowing with those images. BTW, that's a beautiful car, what is it? I've not seen that before.

Looks like an Alfa Romeo 8c, but i haven't seen one with that exhaust.

[GTBradley]

Bradley,
Oh boy, you just got my creative juices flowing with those images. BTW, that's a beautiful car, what is it? I've not seen that before.
2010 Alfa Romeo Zagato TZ3 Stradale. It had a Viper engine to boot!

I think about this stuff all the time, but don’t have the skills to get most of it done. That’s why I’m filling your head with crazy stuff:o

There’s a little less than 2” space from the bottom of the square tubes of the floor pan and the bottom of the 4” frame tubes. I would think and oval shaped exhaust tube traveling underneath wouldn’t affect ride height much.

[Avalanche325]

.... in an attempt to reach the perfect 50/50 ratios.

Sorry in advance, but you pushed my rant button.

There is nothing perfect about a 50/50 weight ratio. That is automotive journalist and marketing BS. You do not want to move weight forward in these cars. These cars are rear biased for a reason. Notice how far back the engine sits? There is a ton of room to move the engine forward. It would have been easy for FFR to get 50/50. But it is pushed back as far as they could to get the weight to the rear.

Look at the weight ratios of race cars like F1 and LMP, super cars, the new Corvette etc. Almost always rear biased. Here are a few:

Lotus Exige : 38/62
Porsche 997 C2 : 38/62
Porsche 959 : 40/60
Mclaren F1 : 42/58
Porsche 991 C2 : 42/58
Lambo LP560-4 : 43/57
Ferrari F430 : 43/57
Porsche Cayman : 45/55
F12 Berlinetta : 46/54

[rich grsc]

So glad you posted that, exactly my feelings and experience. :) But when I say anything like that, I get blasted.:eek:

[MB750]

You guys got me reconsidering my front mounted battery now.

[Railroad]

Until I aggravate my friend to use his scales, what are some of the wt balance ratios of various Mk IV combinations.
ie coyote, late model IRS, rear battery, etc.

Just kicking the tires, thanks,

[Jeff Kleiner]

Until I aggravate my friend to use his scales, what are some of the wt balance ratios of various Mk IV combinations.
ie coyote, late model IRS, rear battery, etc.

Just kicking the tires, thanks,

How much gas in the tank? Full vs nearly empty will change the car’s total weight by 3-4%, all of it at (actually behind) the rear. That’s enough to notice!

Jeff

[GTBradley]

Until I aggravate my friend to use his scales, what are some of the wt balance ratios of various Mk IV combinations.
ie coyote, late model IRS, rear battery, etc.

Just kicking the tires, thanks,
Coyote, late model IRS, front battery, single roll bar, ¾ tank, no driver.
48% front 52% rear
This is why I didn’t hesitate to move the battery forward.

[rich grsc]

Moving the battery changes things such a small percentage it isn't worth worrying about. Put it where it's easy to get to.

[Bob Cowan]

I'm really impressed at your skills. No way could I do anything like that.

I would be willing to bet you'll get a lot of exhaust fumes in the cockpit.

[GTBradley]

Moving the battery changes things such a small percentage it isn't worth worrying about. Put it where it's easy to get to.
And with the new light-weight batteries that’s especially true but, moving the heavy, lead-acid battery forward and down can have an effect on autocross performance. To me, weight ratios really only matter if you are pushing the car to peak performance, ie, racing.

With a shorter cables you get weight savings and with a lower battery cg you get better cornering. Plus, not adding to the rear weight bias is a good thing, in my opinion. I will admit though, the single biggest reason for my moving it forward was ease of access, but every little bit goes toward the total.

[Mike.Bray]

All this talk about weight, did i miss the start video? LOL

[GTBradley]

All this talk about weight, did i miss the start video? LOL
Ha! This is what we do. Hijack, redirect, tangents, until we get the start video we’re all waiting for…

[Avalanche325]

All this talk about weight, did i miss the start video? LOL

We are still trying to figure out how to get you to spend money. That is what most threads do.