bsly

i was wondering if any of you guys know where i can get a down pipe mde for my car. it would be great if it was in norcal but if not oh well. a good one, i only use the best.

Closer

comptech headers and downpipe.

bsly

comptech does not make a downpipe, i just got the email back from them and they said that they wont even release a high flow cat for the cls.

scalbert

And what do you assume a downpipe is, normally it is a replacement plumbing between the exhaust manifold and the catalytic converter. The Comptech headers include both the new exhaust manifold and the A-Pipe which, for all intents and purposes, is a downpipe.

So I would assume you would want to keep the stock exhaust manifolds and then just replace the A-Pipe?? If so then I would say it would be a wast of time, most of the restriction appears to be in the manifolds.

Stock and Comptech

Caddy©

Good Pics for Comparison !

Thanks Scalbert

typeR

i wanna crack pipe!!!

Bluto

From the pics, it looks like Comptech could get buy with just selling the headers, and not the A-Pipe. The headers would be a lot cheaper without the A-Pipe.

Is there much difference between the stock and Comptech A-Pipe?

Bluto

I took a closer look. There is a difference in the length of the headers. So a new A-pipe is needed.

bsly

what i ment was, i want a straight pipe, i would like to get rid of my cat and just have the headers run right to the exhaust. i want some to tell me where i could get on custom made.

Ricka220

That is a good comp pic

scalbert

Why?? I believe they have visual inspection in your area which would negate this idea.

Other than that, what about the HO2S2?? Without a cat in place you will have a permanently lit SES light unless you get one of the devices to trick the PCM but I am unaware of any for our range of O2 sensor output. Not to mention the pollution issues, just get some nitrous, the power is there when you need it and the rest of the time there are no emissions issues.

The next aspect is the irrelevance of doing this. I know people claim to 'feel' more on the highway but yet no one ever tests it. Geez, If I had a $ for every time I have heard someone claim to have gotten more power from a mod without any evidence. Just wishful thinking...

However, there is power to be gained on removing the cat. But this is minimal, about 4 - 6 HP at best. I have been involved in some of the flow tests of our catalytic converters and even built a life cycle test stand for an OEM provider of exhaust systems (cycle between 800 and 100 C with a constant flow of 100 CFM for weeks or until failure). Based on the flow tests there is about 4 - 6 inches back pressure at 350 - 400 CFM which is about what we will see at peak HP. For every inch reduction in back pressure you can expect about 1 HP gain. So as you can see the amount gained is limited.

Add to this that it takes at least a 5% increase in power to begin to feel a difference. 5% on a stock motor is 13 HP, a far cry from the about 5 HP that could be gained showing that anything someone claimed to have felt was just optimism.

As an aside here is some of the sound test data on our exhaust: Ear Sound Levels

Closer

Removing your cat or resonators also makes your exhaust sound like a$$.