Exhausted

[Daves]

Reading for hours about the length of the exhaust primaries for a 600 cc 4 cylinder engine has frustrated me. It sounds like whether we use a 22" primary length or a 34" primary length, the peak horsepower will be the same, albeit with the 34" providing more low-rpm power. Are the long pipes really worth it? Going with short pipes would save much weight and make packaging easier. After all, Wollongong used a relatively short header in 2003 and they scored well in design.

My sources so far have been a webpage by Birmingham, a webpage by Penn State, Scientific Design of Intake and Exhaust Systems, and an SAE paper by Lawrence Technological University.

http://www.letu.edu/formula

My Formula Photos & Links (http://what3542.5u.com/dave/fsae/formula_photos.html)

[C Z]

I have a copy of a header design article from carcraft (dec 2003 issue). If you'd like to get a copy then e-mail me at zellersc@hotmail.com

[gus]

our virtual 4 stroke numbers always crank out about 22" primaries as the optimal (good peak, decent throughout the torque band)

Gus Aramayo II
Iowa State Cyclone Racing
Engine Team Co-Captain

[Bam Bam]

Redefine your problem dude.
your exhaust will depend on your intake, transmission, final drive ratio, driver, gear shifter, and the race course you intend to run.

Power train comes as a package man.

Ask yourself what do I want this exhaust to do. Where would it be faster to have more torque and WHY?? With more emphasis on the why than the more torque.

If you don't know go back to testing your old car and figure it out.

Then screw around with some telescoping tubes on a dyno, learn an engine simulation program or develop a best guess based on previous torque curves from your team taking into consideration your theoretical intake and exhaust tuning points and the shortcomings of these equations.

If all of these seem like a great deal of work and you'd rather just put the numbers into an equation and then differentiate to minimize weight then your probably better off to just paint last years exhaust pink and consider your contribution to the team as being you didn't screw anything up.

Good Luck

[Daves]

Who sells 1 3/8" tubing in the United States?

I have decided to have two different-length headers built and tested. Then I will choose one.

http://www.letu.edu/formula

My Formula Photos & Links (http://what3542.5u.com/dave/fsae/formula_photos.html)