I am looking to make my 2006 997.1 C4 competitive in the stock H class over time as I do more DE days and eventually earn a racing license. I already have a fabspeed cold air intake so thought I would first look at an exhaust upgrade to take advantage of it. The rules allow pretty much anything for exhaust, but without flashing the ECU. Given this, what is a good exhaust set up if performance is all I care about. I have new performance headers on the way, but am not sure what to do after that. I was considering an x-pipe without cats and straight pipe after that w/o mufflers, but maybe that is going too far without a ECU reflash. I realize I may want some kind of mufflers if I can't take the noise, but I can deal with that if there is some real performance gain. Anyone have experience with this? I haven't seen many posts for stock class race cars. Thanks in advance.

 

I think the general consensus, is that most mods for these engines, are for sound, without a tune, I don't think you're gonna get much.... if there is any, opening up the input and output is the pathway.... lots of discussion on x-pipe vs standard crossover... don't believe if there is a true answer.

Cw.

 

Thanks for the response. I kind of got that impression too, although lots of manufacturers like fabspeed advertise decent gains (10-20 hp) and to me logic would say there is back pressure that should be holding back performance. Add that to all the weight savings at the back end where the car is inherently heavy and it seems worthwhile. I would love to know what Class H racers do for exhaust, but cant find that kind of detail online. Maybe I will have to just do some careful observation at the track events this summer.

 

Recently purchased an H stock 997 built by a very experienced shop. It has a Part no RES 997 100 80S M and M Race exhaust system. You might investigate that option.

 

Yes!! That is what I needed. I got in touch with FVD Brombacher who sells the part and they are contacting the manufacturer in Germany "M&M" for pricing for my car. I already have a performance header on order so they can get me the end muffler section that will bolt on to my headers. It combines an x-pipe with resonators, which makes a lot more sense to me for racing than a full x-pipe bypass then separate muffler which adds weight and backpressure for no reason. This is perfect and I am grateful for the help.

 

Shawn, Wow, glad this was so helpful. You can go to Autometrics web site and find my car under the cars for sale section. Its listed as sold but there's a lot of info that might interest you.

 

Ha! When I started doing this research I saw your car, but did not know it was for sale so there was limited information. Now I am reading the listing carefully in the cars for sale section as you suggested. This is definitely the direction my car is going. Coincidentally I bought exactly the same MCS shocks about a month ago and am waiting for delivery. After that pretty large investment I am committed to getting the most out of the car for the H class just as the previous owner did for your car. So where do you plan to race? I would love to see you out there one of these days. I am in the NorthEast and am going to Watkins Glen in late May assuming it doesn't get canceled due to Covid (for DE, not ready for racing yet).

 

I am drooling. The car looks great, btw. I saw you have stock intake so maybe my aftermarket isn't allowed, although the way I read the rules I thought it was. I also noticed the stock calipers, which I was pretty sure was an issue for me. I love my big brake kit on the front and I view it as a safety measure as I don't think they stop any better. It is disappointing to me that the rules will not allow a safety upgrade like this. Maybe the rule makers know something I don't. Anyway, with that duct work you have I am sure the stock calipers and rotors are plenty. I just wish I had not bought a brake kit I can't use I guess. Since I don't have a roll bar I am not sure where to mount the rear external MCS reservoirs yet, but probably not a big deal. FYI, if you have any issue with heal toe like I did with my stock pedals, I bought some fully adjustable pedals from Rennline and they work great and are well made.