Racing exhausts

[jsceash]

Those racing Boxster's any class, what exhaust configurations are you running. I'm thinking of switching out my exhaust on track weekends looking for something that works, and won't break the bank.

If you could show a photo that would be great also.

[rastta]

Mine is a purpose built racing exhaust consisting of tubular headers - I think they are FVD going into custom made three inch pipes - each with a Borla race muffler and existing out where the license plate used to be. I added heat shielding to the pipes where they go by the inner CV's. I will try and post better pics (close ups) that I currently don't have access to.

[j.fro]

I just got this finished:




The mufflers are Full Boar single chamber; the tubing is 2.5" mandrel bent stainless from the cats to the mufflers, and from the mufflers out.

The older cats and headers are are 100 cell Mandrel Bend Solutions cats welded into Fabspeed bypass pipes. The headers are the cheapo Chinese ones.

For the mufflers and pipes, I paid $165 from Performance Curve in Roanoke VA. A local muffler shop welded it up for $150.
This setup replaced a Borla Boxster S muffler. After just a couple of days of listening, this setup seems quieter but deeper at idle, quieter with less resonance at highway cruising speeds, but louder/deeper at WOT. Hopefully I can get some dyno numbers with the new system.

[911monty]

Nice work J.fro! Just curious why you painted the exhaust in flat black. I understand it is best at transferring heat, but this will transmit a lot of heat into an already hot engine compartment?

[j.fro]

Funny you should mention that. I've cleaned the tips back to stainless.
The main reason for the black is that the whole car is silver and black. I know what you mean about black, so I'm hoping this isn't making too much difference.

[spendy]

Most spec boxsters in my area run straight pipes. I couldn't stand the noise (even with earplugs) so put together a home made system that resembles this one:
Exhaust Muffler Silencer Set with Cat Bypass - 986 BSR - Boxster Spec Racing By Patrick Motorsports Porsche & Mid Engine Performance Specialists

Mine uses a couple of magnaflow 4" round straight thru mufflers 14" long. The pipes with the flanges are from a factory exhaust and the output tubes I had bent up at a muffler shop.

[911monty]

Originally Posted by j.fro

Funny you should mention that. I've cleaned the tips back to stainless.
The main reason for the black is that the whole car is silver and black. I know what you mean about black, so I'm hoping this isn't making too much difference.

Yeah I would like to murder out my triple black box. So besides the heat into that already challenged engine compartment, black also transfers heat out of the exhaust. This slows exhaust velocity and reduces scavenging. A good reason to run ceramic coating. Since you're running 2.5" pipe your velocity may already be a little low. Just thinkin' outloud.

[thstone]

My exhaust from engine back: stock exhaust manifold, FabSpeed cat delete pipes, Top Speed Pro 1 catback muffler. 100% bolt on solution. Affordable, adds a bit of extra power at the top RPM's (I did before and after dyno tests), and sounds great on the track.

[itsnotanova]

It would be great If you guys could shoot some video so we can hear what it sounds like? I've thought about building something like what you have J.Fro. I have the Chinese headers already and was thinking about building the secondary pipe with some 996 exhaust/cat I have. It would wraparound into two mufflers just like what you have. I have a dansk sausage muffler right now and it's not loud enough at all. Only weighs 3 lbs lighter too.

[rastta]

A few more pics - thought I had others but this appears to be it.







Thermotec heat shields

[911monty]

Originally Posted by rastta

A few more pics - thought I had others but this appears to be it.







Thermotec heat shields

Top notch job Rastta!

[rastta]

Originally Posted by 911monty

Top notch job Rastta!

Thanks - but the design was already done - but had small resonators which were way too loud. I blew sound at Thunderhill which has a limit of 103dB's and I hit 107! Had a shop in Sacramento put the Borla's in place of the resonators using the existing pipes and mounting. They did a great job. I'm at 97dB's now and with supertrapps installed can pass sound with lifting at Laguna.

[j.fro]

I finally got a vid of my car with the new muffler setup:
https://youtu.be/hyFjYMGXCcc
sloppy day of AX in the wet, but good noises nonetheless.

[itsnotanova]

Sounds good!

[jsceash]

I guess I'm surprise. I thought that most the straight race cars ran some sort of straight pipe or a cross pipe to tip, without mufflers. You guys have some nice setups. Thanks for the photos.

[rastta]

Originally Posted by jsceash

I guess I'm surprise. I thought that most the straight race cars ran some sort of straight pipe or a cross pipe to tip, without mufflers. You guys have some nice setups. Thanks for the photos.

All the tracks I run have sound restrictions. Laguna is the worst - but Sonoma/Sears is now more strickly enforcing their 103 dBa limit and it's the same at Thunderhill. I blew 107 with what were essentially straight pipes.

[j.fro]

SCCA autocross db level is 95. With headers, no cats and the 986 Borla muffler, I was way over. With my new set up, headers, 100 cell cats, 2.5 tubing, and the single chamber mufflers, I think I'm right on the limit at WOT.