exhaust back pressures...
Turbo Mini Forums

on a normal 5 port mini i know you need a bit of backpressure for best performance. but on a turbo is this different...

etc can you run a straight through pipe with no silencers without harming performance on a turboed mini?...

just wondering how its stands on a turbo regarding backpressure.

i have used search but couldnt find anything...

i love the idea of asking maniflow to make a me a back box without the backbox in it and having a nice 2" rolled end :)

thanks. :)

well first off the "you need a bit of back pressure" is a bit of a misnomer, a decent sized NA exhaust allows an extraction effect (vacum)

anyway...

turbo's work by the pressure diferential across the turbine, so you want the minimum back pressure possible, mike race runs just a pipe on his car.

ah ok. so a straight pipe wont harm the performance that much? ive got a maniflow 2" single box system at the mo so if there is not much difference i will probably use that, if not them ill give maniflow a ring to construct a pipe lol

i guess mikes the man to ask then?

thanks for the extra quick reply

i ran a straight pipe in the past and will do when my alloy one turns up next week....lol,
tad on the noisy side,

i want the noise... the neighbors are getting petty and and have started to take the piss by taking all but 1 of the parking spots at the back of our house, but my mini will be parked in the garage thats conveniently under there house lol. so noise is a bonus

If you want my advice, speak politely to your neighbours and sort it out like adults. Once you fall out with them it can only ever get worse and worse.

If you want to do any trackdays then fit a silencer. I personally think anything with a totally open exhaust sounds shite, and will just cause you grief from the local plod. A free flowing silencer will stop all the hassle and probably make a very small if at all noticeable difference to your performance.

Tom has a point, theres no point in pissing them of futher,

yeh. suppose

so a freeflowing backbox will perform better i have a maniflow 1 at the moment?

Now I must ask...

I have always thought that the exhaust pressure is needed. Even when you have a normal turbo then you have exhaust pressure at the exhaust side.
As the supercharger is under the pressure it is more difficult to implement. I carried it out with exhaust manifold, after that the exhaust gases to flow freely again be the big pipe.

Am I now totally wrong?

Jani

1399cc, Eaton M45 supercharger, N2O system, compression ratio 9.23:1, boost pressure 0,8bar/11.6psi.

http://www.garaget.org/?car=176816

You don't need back pressure, what you need is something that maintains gas velocity. On a turbo this is not as big deal.

1399cc, Eaton M45 supercharger, N2O system, compression ratio 9.23:1, boost pressure 0,8bar/11.6psi.

http://www.garaget.org/?car=176816

Tom i run a free flow no box exhaust with no issue, its not that loud tbh. I even went to MOT with it as it is and he didnt bat an eyelid. There are far more chavved up corsas ect that are much more noisier than mine. It just sounds like a well sorted stainless N/A system. all be it with a little hint of whistle.

1/4 Mile 14.3secs 96Mph Terminal 10psi of boost.


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