nitrous_nate

Finally got all my pieces together to start on my kleemann headers and custom exhaust install. Gonna be fabing up from the header flange back with 2.5" pre bent mandrel exhaust pieces into 2- high flow 300 cell metallic converters then into a 2.5" Dr. Gas x-pipe then into 2- Borla boomers series mufflers. Hope to gain around 50 rwhp and a good clean deep sound without any droan. The whole exhaust system came off a whole lot easier than what I thought. Guess I will have to change my sig soon, the sickness has already started And this was gonna be my daily driver that I was'nt gonna mod hahahaha

blkamgsl55

Why would you be going with 2-1/2" piping when the oem stock pipes are 70mm(2-3/4")?????

jangy

I am also wanting to replace from the headers back. Where did you get the pieces? Are they custom bent from your car? I'd pay for a set in nice stainless from shorty headers all the way back to muffler. I want to keep the OEM mufflers, but I may punch them out. I'm not after sound, though.

Jakpro1

Don't mean to rain on the parade but 50rear? Should pickup some from the headers, but from everything I have heard, exhaust, (after headers) no matter how large does almost nothing for the 55. Not sure why. Just a sound issue so you should be lovin it.

Have also heard that men have gone nearly insane with the drone from setups like yours. Keep us updated bro and good luck!

jangy

I'd assume he has no headers now, so adding long headers and full exhaust COULD give him decent gains with proper tuning and other goodies. I'm only replacing the tubing because I want a cleaner look. I scratched mine up a little with Cyn a year or so back. I'm also going to experiment with backpressure (where and how much). I wonder if I can run race cats and NO X or H pipe and use just the mufflers for back pressure. I know that would drop TQ now, but maybe now when I have finished getting the car modded.

nitrous_nate

2 1/2" pipe will support 600 hp or so, and 2 3/4" is way too hard to find. Plus not wanting to take the chance on opening it up too much and killing low end torque. With the headers and high flow cats and high flow mufflers, I feel like I am increasing the flow a ton to compensate the very minor pipe size diff.

nitrous_nate

From what I have researched and talk to alot of people about, a good set of headers (not shorties or log style) is worth 35rwhp - 40rwhp in itself along with deleting primary cats about another 10rwhp = 45 - 50 rwhp. The high flow cats and x pipe and mufflers might gain a little 3 - 5 rwhp but just after sound from there on. I think 50rwhp is not out of the question with this setup but we'll see I guess

nitrous_nate

Jangy, I will have to check my email to see exactly where it was I got the mandrel pieces from. We have used them alot building the exhaust for our race cars and it really turns out good with smooth clean bends. We are gonna try to keep up with what we used when we mock it all up and I might be able to jig something up to make a mid pipe section from headers to mufflers, lemme know what you think? I started to use the stock mufflers too but I opted to just do a complete new exhaust system with nice borla mufflers. I have used them before on my C5 Z06 and really liked them. Hopefully its not too loud with any droan or I will have to start adding stuff back in hahahaha

dsc

I think that's being a little too optimistic. The exhaust from the primary cats back doesn't really restrict. The best you can really do is headers; remove the primary cats and maybe an X pipe. I don't want to sound negative but I would be very surprised at 50rwhp. Good luck though.

nitrous_nate

I was under the impression that with a good set of headers it was worth 35 - 40 rwhp and deleting the primary's another 10rwhp. I know the rest of the stock system is supposed to flow really good, but a x pipe in place of a more restrictive resontor and 2 higher flowing muffles got to be worth a little even if its 3-5 rwhp, thats at least the way I was thinking Maybe not, but man this exhaust design has some major potential with all the mandrel bends and higher flowing pieces in place I am gonna use.....I'll keep everyone posted with the results and pics

dsc

I think the closest claims met by tuners for hp gains are on pulley with programming. Not many people have experienced the gains claimed on a mod when they had a dyno done. This has been a long term concern about the tuners claims.

I'm trying to be realistic here and wish you the best. Are you going to dyno before and after? I would love to see the numbers. Believe me if you hit them, I'll be knocking on your door to help with my car.