[Cloud9...68]

Does anybody who has messed around with different exhaust configurations know how much, if any, top end, full throttle power is to be gained with an exhaust set-up if you are willing to sacrifice low-end and mid-range torque altogether? In other words, compared to the best known exhaust set-up (which would appear to be RS Barn's full header/high flow cat/catback set-up), would, say, a set-up with larger diameter tubing (or any other combination of magical bends) provide any additional ultimate power at full throttle, high rpm? Depending on the responses, I'll explain why I'm interested. Thanks.

Partial Post: Please Login or Register to read the full post.

[flash]

so far, it looks that, to get any further gains, the displacement would need to go up, as would the intake size - that or the power band would need to be abnormally high



there is a good article here that is just enough to make you dizzy:



http://popularhotrodding.com/enginemasters...ore/0505em_exh/



what do you have in mind?

Partial Post: Please Login or Register to read the full post.

[Cloud9...68]

Thanks; looks like a very informative article. The reason I asked the question is sort of two-fold. I just did my first DE this weekend, and while the VAST majority of my room for improvement lies with refining my ability to take corners, it would also be nice to have a little more oomph when blasting out of the corners leading to the long straights. In addition, there's an interesting thread on 968.net about a "variable diameter" exhaust, which utilizes a butterfly valve located in the exhaust stream that's actuated by a combination of throttle position and engine rpm.



So, I thought, analogous to conventional knock sensor-driven spark timing, where the engine is allowed to run right to the threshold of detonation, why not design an exhaust system that's tuned for absolute maximum rpm, wot, low-end-and-midrange-be-damned power (which I assumed would entail tubing diameter somewhere in the neighborhood of 3"), and let the above-described valve throttle things back for around-town running. Since the position of the valve would be driven just by rpm and throttle position, it doesn't seem like it would be all that complicated to integrate.



But from your response, it sounds like exhaust may not be the limiting factor for this engine, so this scheme may not be worth the trouble.

Partial Post: Please Login or Register to read the full post.

[flash]

it's not as limiting as other factors, though what you are talking about may ultimately provide more room up top - the control mechanism would be the key to it - it would have to sense not only rpm and throttle position, but engine load as well - likely not the most economical way to get there, but interesting idea nonetheless



never know until somebody tries it

Partial Post: Please Login or Register to read the full post.