tery

I have hard time looking for a header for my CLK. I am thinking if i get a bigger down pipe connect to stock header will this give me a bit more hp and tq ? i have mid pipe, race cat, and rear tip already. if so what will the effect be on the size of the down pipe ?

Fast55

Almost nothing, like the rest of your exhaust mods. There just isn't that much to be had on the exhaust side. An ECU upgrade would almost certainly be worth more RWHP than the exhaust. K&N or some type of cold air intake might do as much too.

tery

I have renntech ECU and intake already and Schrick camshaft that is why i am looking at exhust tunning for now. If there is no other way then i guess i will have to look into supercharge

Fast55

Ah, turned on the sig, I see what you mean. With all that, you might see a little more, but you sound like you're ready for a blower or trading up.

FIAutoSports

How large of exhaust pipes do you have? If you went with larger by about 1/2" or more, you possibly lost horsepower. On NA motors backpressure and exhaust velocity are necessary to keep horsepower. But on FI motors, the less exhaust the better, as the flow properties are almost exact opposite. In fact, on a turbo car, no exhaust is the best exhaust. For supercharged, you do want some exhaust, as a backfire could damage your blower.

Fast55

Right on. As I suggested, if there's anything to be had from exhaust, it's not likely to add up to much, possibly reduce power in his car. Time for FI or a V-8 (V-12)?

tery

thanks for the info. So how dose a header help producing more power ? if a header helps reduce backpressure and more flow.

Steve Clark

http://headerdes********/extras/design.asp

Fast55

Cool link Steve.