How much extra B.H.P does a full exhaust system add?

BalinJu · Post by **BalinJu** » Sun Jun 19, 2005 11:05 pm

If you change everything including the catalytic converter, maybe you get between 5 to 10bhp maximum. Probably with a good induction system and a good 4 in 1 manifold, you will be closer to 10bhp

BalinJu · Post by **BalinJu** » Mon Jun 20, 2005 11:03 am

does it include a manifold though? I am asking because I think this is the most expensive part of the whole system

david burton · Post by **david burton** » Mon Jun 20, 2005 5:46 pm

it's very varied - e.g. an impreza has 2 catalytic converters, and removing them can gives over 25bhp.

the supra has an enormously restricitve manifold and changing them gives stupid amounts extra,

the polos are so low powered I would work with percentages - perhaps 5% more, possibly 10% doing the whole system but that would be lucky.

and on some of the cars, it's the mapping and heads that decrease the power, so opening up the exhaust doesn't help much because that's not the bottleneck.

i would say on a 60bhp 1.4, it would give about 5bhp.

carmadaaron · Post by **carmadaaron** » Mon Jun 20, 2005 6:53 pm

unlikely i rekon (manifold)

give around 10hp i rekon, depends on how good the system is... low resistance metal (pipes)