JOE LEEN

Hi Lads,

This is a bit from the norm, I'm working at the University of Limerick in Ireland and at the moment I am developing a simulation code that predicts the pressure wave motion within an exhaust system.

Here's the funny bit - you see exhaust fumes leaving the tail pipe, but there are also pressure waves travelling down the pipe and when they happen upon a sudden expansion these waves turn around and travel up the exhaust, but they also change sign. That is the pressure waves begin life as a compression wave travelling at approximately 450 m/s down the pipe, hit an expansion in area, then they become a suction wave and travel back up the pipe to the exhaust valve. This's what tuned pipes are all about, getting the reflected suction or expansion wave to arrive at the exhaust valve at the correct time during valve overlap and also having a low pressure at the exhaust valve prior to exhaust valve opening. Well me model is coming along but I need Honda S2000 flow bench data to move on.

The flow bench data must cover as wide a pressure differential across the head as possible, changing the valve lift, which each corressponding pressure, until full valve lift is acheived (VTEC system implemented). I esentially require the exhaust valves to be flow tested in both directions - from port to cylinder with various valve lift and pressure differential, and similarly from cylinder to port for various valve lifts and pressure differential. From these tests it is the raw data I require - I will convert the data to flow coefficents my self.

Can any one help me out ...

Turtle

Try contacting Joe Alaniz.

http://www.alaniztechnologies.com

There's some flow data posted on the site, but nothing like everything you're after. Worth contacting Joe, to see if he has the data you're after, and is happy to give it out.

-Brian.

twohoos

Again, not everything you want, but:
http://www.vtec.net/articles/view-article?...0&page_number=1

Road Rage

Good stuff - good luck with your studies. The flow dynamics of an exhaust are often misunderstood - such as the bigger is better theory, which fails to consider the tuning you mention, as well as the benefits of maintaining exhaust temperature to help maintain exhaust velocities, and other variables. When you say sign, i assume you mean positive or negative wave pressure, is that right? BTW, is this a Helmholtz tuning function, ro a different one? If diff, could you post the equation? Thanks!

vapors2k

cheers

http://www.e30m3performance.com/tech_artic...low-1/index.htm