10 replies to this topic

[simdhillon]

what is the best exhaust system for my mini? im after a system that will improve performance and i want it to be loud

[newdawn1st]

Rc40 seems to get good press for both, just get the right size bore about 1.7"internal all the way thru I think (edit: for 998), cooperman seems to enjoy these topics so he should be one to ask

Edited by newdawn1st, 23 July 2009 - 09:33 PM.

[camp freddy]

mine.

[newdawn1st]

mine.

ah I see modesty is one of your strong points

[camp freddy]

mine.

ah I see modesty is one of your strong points

well known for it LOL

[Cooperman]

I run competition Minis, so the one thing I don't want is for it to be too noisy. We are noise-tested at the start of each event and the old adage that it's no use having the most powerful car which was not allowed to start is always in my mind. Real competition cars are not really noisy. In fact, the most noise my Cooper 'S' makes comes from the straight cut gears and drop gears.
Anyway, the best diameter exhaust for a big-bore engine (that's 1275 and over) is 1.75" internal diameter from exhaust manifold to the end of the tailpipe. For a 998 it is 1.625" int. dia. It is important to keep the diameter constant right to the very end to maintain the velocity of the molecules of exhaust gas and get the best extraction effect. Those cars which go to huge outlet pipes, or twin outlets are sacrificing power. I call them 'noise boosters and power sappers'.
With regard to silencer boxes, the Maniflow is excellent and can be fitted with one main box only or with an additional 'cherry bomb' to make it a bit quieter. The RC40 is also vey good, not quite so well made as the Maniflow, but a bit quieter. I have a twin-box RC40 on my rally 'S' with special strengthening and skid plating and it seems to pass noise tests without any problems.
Race cars are allowed a slightly higher noise level than rally cars and can run with a single box system.
On really high-revving race engines, say revving to 8000+ rpm, a larger exhaust pipe is sometimes needed as there is more exhaust volume to be got rid of in a given time, so a 2" or even 2.25" is sometimes used. I've even seen 2.5" pipes on racing Minis with large engines (over 1400) and very high-overlap cams. But then, they have no real power under 4500 rpm, but pump out a lot of exhaust gas.

[simdhillon]

are these cherry bomb silencers any good?

Attached Files

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[Bungle]

i run a stainless steel single box RC40 on my mini

it's been on there now for around 15 years with no problems

[shorty]

rc40 twin box system..nice noise when needed..but nice and quite for when coming home late at nite (well not that quiet but its enough)

[Mr Joshua]

what is the best exhaust system for my mini? im after a system that will improve performance and i want it to be loud

Mine!

[sambarnes]

I have this exhuast: http://www.minisport...fo_PHBPPS1.html

I put it on to replace the standard one, and OMG the difference in performance was crazy, and it sounds soo nice (especially high revs).

i know its not stainless and what not, but for the price its worth it.

sam