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Author Topic:   single or dual exhaust?
dode
Member
posted December 26, 2002 03:37 PM
Ok...here is the deal. Our rules say that you have to run a maximum of 2.25" exhaust pipe. You can either run true duals, or a y pipe and a single. My question is this. Brezinski's site claims that especially with log type manifolds, the Y pipe is better, but they are talking about using much bigger pipe. They claim a 30 hp gain on one of their systems. Are brezinski's claims believable, and is this going to be true with my rules, which limit any pipe size to 2.25"? Anyone with insight on this? By the way, we aren't allowed to run a balance pipe or anything like that either.

John

dirtracer50
Member
posted December 26, 2002 06:32 PM
I'm no expert but I don't think I would try to run a single 2.25 inch exhaust. I would think that a dual setup would be a much wiser choice.


dode
Member
posted December 26, 2002 06:37 PM
Well what brezinski suggests is running like a 48" pipe from each manifold to a Y pipe, and then like 12" of pipe after the Y. We run fairly small motor with 9:1 comp with flat tops and cast iron intake and exhaust manifolds.

John

superdave
Member
posted December 27, 2002 02:41 PM
If it's legal and you can afford it run a two into one racing muffler. The type with a 2 into 1 Y pipe on the input and a 3.5 or 4 inch output. Don't run any pipe after the muffler. The extra scavenging is worth it to pull the exhaust out of the manifolds.


dode
Member
posted December 27, 2002 02:53 PM
hmmm...interesting...now that's the gray areas of racing. I hadn't thought of that one. Thanks!!

John

outlawstock17
Member
posted December 27, 2002 03:56 PM
superdave is right. i've been running an "x" pipe for the last couple of years and it does perform better. sounds better too.

remember an engine is an air pump. if you can suck a little more air out of a cylinder when the exhaust pulse is negative(during valve overlap) with the positive exhaust pulse of the other cylinders, you can pump more air through it.

pulling the spent exhaust out instead of it getting pulled back into the engine to contaminate the incoming charge will make more power.

runllm2
Member
posted January 06, 2003 06:24 AM
Heres one if you have way to much time go and get a vacume gage automotive type. place the gage in the car where you can see it and run the hose under the car. keep moveing it untill you find a negitive pressure (witch will exsist)area under the car. You have to do this with the car at the race track. Once you find this place you would put the end of the exhaust there. Just a crazy idea from aerospace. I have never tried this I don't know if there is any gain in reality but in thoery OMG its big!! If anyone tries it let me know!! Mike


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