Interesting study on backpressure vs exhaust length

BurtonF166 · 09-12-2009, 5:04 AM

This is an article published by The Japanese Society of Mechnical Engineers (JSME) and studies the affect of exhaust length of a 2 and 4 stroke engine on exhaust temperature and backpressure.

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***All rights go to JSME (This is _NOT_ my work)

BurtonF166 · 09-12-2009, 5:05 AM

The link still works, just has strange characters in it!

bladeracer · 09-12-2009, 6:49 AM

Quote:

Originally Posted by BurtonF166

The link still works, just has strange characters in it!

Can you simply upload the PDF here?

Doesn't work for me.

"http://nels.nii.ac.jp/img/cinii/s.gifELSC0501: Error is occurring in displaying full Text PDF file.
Because PDF file may be displayed normally, please act bellow.

1. Search again because of the case of the close of the session.
2. Change your browser's setting to accept Cookie because of the case that your browser doesn't accept Cookie."

BurtonF166 · 09-12-2009, 9:37 AM

You're right!! It worked fine earlier, here is the pdf short version.

Attachment 38836

bladeracer · 09-12-2009, 9:44 AM

Thanks :-)
Interesting stuff.
One thing I've wondered about for many years is why nobody has ever developed a telescopic two-stroke expansion chamber. There must be a simple reason.

BurtonF166 · 09-13-2009, 7:15 AM

Yeah, it is interesting. I'm just starting to peak into the world of exhaust theory and know not nearly enough to support or disagree with the concept of a telescopic chamber.

I just read about the most basic chamber used, a cone or megaphone-like pipe. The reason I'm curious about this is that we're going from '01 F4i engine to a YZ 450 for the UW Formula SAE car and though its four-stroke, we're looking at applying a basic form of expansion chamber instead of just using a slip-on muffler...we'll see how it goes!

bladeracer · 09-13-2009, 9:58 AM

Here's a bit of variety including a model exhaust that adjusts its length according to gas pressure. I'm not into the hardcore physics explanations. I prefer more the "if you do this, this will happen" explanations :-)

Exhaust and Intake Tuning

page2

Exhaust Length,exhaust pipe,induction

BUKU Self-Tuning Exhaust System Review

Exhaust Tuning Theory and System Design - Sideways-Technologies Forum

BurtonF166 · 09-13-2009, 10:06 AM

Awesome!
Thank you!

jdugen · 09-13-2009, 3:09 PM

I thought that was the job of the EXUP valve (as Yamaha called it). I notice no-one is using it on the latest models.

To get really technical, an I.C. engine only gives max power at one certain RPM and max torque at another certain RPM. Trying to spread power over the whole RPM range is the problem. I still think linking an engine to an hydraulic pump is a far better idea. Run the engine at its most powerful / economic RPM and modulate the hydraulic drive. Better than an electric motor, much lighter for one thing.

bladeracer · 09-13-2009, 3:25 PM

Quote:

Originally Posted by jdugen

I thought that was the job of the EXUP valve (as Yamaha called it). I notice no-one is using it on the latest models.

They aren't?
I thought they all had them.
The '08 GSXR1000 and R1 still had it.

Charles486 · 10-08-2009, 10:41 PM

Quote:

Originally Posted by BurtonF166

Yeah, it is interesting. I'm just starting to peak into the world of exhaust theory and know not nearly enough to support or disagree with the concept of a telescopic chamber.

I just read about the most basic chamber used, a cone or megaphone-like pipe. The reason I'm curious about this is that we're going from '01 F4i engine to a YZ 450 for the UW Formula SAE car and though its four-stroke, we're looking at applying a basic form of expansion chamber instead of just using a slip-on muffler...we'll see how it goes!

Hey Burton, with that restrictor your exhaust tuning is going to have a very minimal effect, i did the intake design for mizzous car last year and we saw almost no changes in power with the exhaust vs huge changes with intake. Most of what you would worry about is out anyway since with a single you dont have to worry about interference from the other cylinders

BurtonF166 · 10-08-2009, 11:11 PM

^^Thanks for the response!
Im assuming youre on fsae then too?
We just rolled our '09 car....destroyed.

Charles486 · 10-09-2009, 12:07 PM

was...i work for boeing now. Wow, thats a serious bummer... any hope of salvaging/rebuilding for competition?

BurtonF166 · 10-09-2009, 1:52 PM

Good for you!
What major were you?
The only thing salvageable are the Ohlins shocks (better be!), pedal tray assembly, steering rack, fuel system and basically everything stucked in under the seat.

The roll hoop did its job though, driver walked away after rolling 3 times

Charles486 · 10-09-2009, 2:48 PM

The major was "mechanical and aerospace engineering" but it was really just mechanical

Glad to hear the driver walked away, are you guys still going to try to compete this year?

BurtonF166 · 10-09-2009, 4:54 PM

I wish UW would smash AA and ME together, I'm just starting my third year in ME.

We competed this summer (May - Detroit and July - LA), didnt go as well as we thought.
The 09 car is done. Complete new build coming this year

jbond4321 · 10-10-2009, 4:26 AM

Real interesting stuff

Charles486 · 10-10-2009, 2:30 PM

Quote:

Originally Posted by BurtonF166

I wish UW would smash AA and ME together, I'm just starting my third year in ME.

We competed this summer (May - Detroit and July - LA), didnt go as well as we thought.
The 09 car is done. Complete new build coming this year

Sometimes competition ends up more luck than skill. Good luck with the new car

BurtonF166 · 10-10-2009, 2:42 PM

Thanks, hope your career keeps moving the way it is