marcucci

Someone posted this earlier, but I couldn't find the article again.

Ever want to know how an exhaust system SHOULD be designed? Ever want to know how to size piping, or how to size an exhaust for a motor?

David Vizard published all of this in a recent Circle Track article. You can check it out here:

http://www.ntpog.org/articles/index.shtml

Here's the summary:

- Pipe size should be the square root of CFMx1.27/FD where CFM is the flow (either for an individual port, primary, secondary, etc.) and FD is flow density @28" of water. The article gives 80CFM as a flow density for race applications.

- 2.2CFM per HP provides optimum muffling and flow with limited pressure drop (< .2psi), providing for optimal scavenging.

There's a lot more info... read the article!

The Reverend

Anyone got time to do the math on this for the s2000??

marcucci

UL did, and found that the stock exhaust is designed properly. The only restriction might be in the mufflers, which might not be quite up to the task. I also think the "Y" and dual setup is probably inherently lossy, but I have no real proof of that.

It's hard to believe that with both mufflers, though, that they wouldn't be able to handle the flow.

racer-rob

with the stock exhaust being designed very well, would it be beneficial to just replace the mufflers? Just a thought. If thats the case I just might go muffler shopping. Has anyone on the board had just mufflers installed?

marcucci

I have been very pleased with the stock exhaust... and I think it is well designed. The mufflers appear very similar to the Mugen "twin loop" muffler design for other vehicles... I would suspect they flow very well.

Someone needs to flow bench the stock mufflers.

j2k

[QUOTE]Originally posted by racer-rob
[B]with the stock exhaust being designed very well, would it be beneficial to just replace the mufflers?

racer-rob

j2k , have you had it dynoed? Does it make the car sound any louder. Better yet what does the buttdynometer read. And if you dont mind me asking, How much did it cost?

sfphinkterMC

i'll be at California Muffler hooking these up saturday.....12 discs per side to start...i may need more......someone do the math! they are rated at up to 250hp per can for normal aspirated.

marcucci

[QUOTE]Originally posted by j2k
[B]
Voila!

j2k

Power gain/loss was pretty much zero... but the weight loss was considerable. And yes... it was quite a bit louder... but louder in a good way.

I also had them make a straight pipe section as well... so if I was at a track with no noise restriction, I could drop the muffer and make some real noise.

If I remember correctly the grand total was about $300.