GTI-R34 said:
Hello guys i have a question
wich exhuast is best for bhp gain, performance gain?i did search the forum and found out almost every one is using mongoose , but does it really give a bhp gain?what about the fujitsubo and the other ones
which exhuast can give you more gain ?
thanks in advanced
Myron
I have a custom 3" elbow and downpipe that tapers down to 2.5" as it goes to the decat pipe. The idea behind this, is to keep gas velocity up. It has a small straight through 2.5" silencer where the cat pipe was and a fairly small 2.5" rear silencer.
With that, a blitz filter and boost at 1.1bar, mine made 318bhp (249 at the wheels) and 293 lb's/ft of torque (around 230 at the wheels).
So, I'd say it works quite well.
What you're trying to do is get the gas out as quickly as possible and if you do that correctly, it will pull the new cylinder charge into the cylinder, as it exits the exhaust valves.
To help this, you need to have a large enough pipe, with as few a bends as possible. And if you have bends, these should be as mild as possible. Lagging the exhaust will help maintain gas speed too.
I think the minimum you should go for is a system similar to mine, with the most important part, being the 3" elbow and downpipe. It's not just the bore of the elbow thats important. The stock elbow has a lot of obstructions inside and, isn't smooth. A fabricated stainless elbow will be smooth and have no obstructions.
If I had the choice again, I'd go for a full 3" system, from turbo back.
