13 replies to this topic

[mikesitalianjob]

just wondering if it is possible to fit a 3" exit magnex back box onto a mini? as i have been offered one for £15 nearly new off a mate i know i can trust but i don't want to buy it and it not fit. any help would be appreciated.

mike

[clubman katie B.F]

i have read in a few places that you shouldn't go above 2" as it causes "back pressure" and will reduce your power....don't know what this back pressure is exactly maybe someone can help here?

[Jordie]

I think its when the flow of gases slow down and cause a build up through the exhaust. Not sure.

U cud fit just the back box using a converter section, available at local motor stores.

[Alex1380]

right, every car needs backpressure in the exhuast to get a decent level of tune out of the engine, stander out of the factory they put too small exhuast on which have to much backpresure and don't let enough gass flow which limits power out put. by putting a larger exhuast on you remove some of the backpresure if the exhuast is to big (a 3" on a mini) you will loose alot of power, so getting the size correct is key to a good amout of power from your engine. really the best size pipe for a mini is around 1 3/4" even on big bore engines don't go above 2".
hope that helps
Alex.

[psycho mini driver]

so really, my car would be quicker and more efficient without the twin dtm on?

[Jackman]

If you change a standard exhaust to a better one what benefits will i get and also will it increase the mpg or stay the same, will be on a standard 998 carb.

[BlAck0ut]

Ive always known it as larger exhaust bore higher mpg,

and Physco Mini Driver 1.75" is the size for optimum performance, i.e. RC40 system.

I will be going for a 2" maniflow system decatted when I purchase my stage one kit.

[Alex1380]

a 2" pipe is way to big for a 998cc engine its to big for a 1380! so yeah psycho if you take off the twin DTM and go to a smaller pipe you will get alittle bit more power but changeing the carb to a hif38 and a K&N filter on a good inlet manifold will give more power. My 998 with that combo pulled 60bhp.

[mikesitalianjob]

thanks guys won't be buying that then.

[TimS]

check this out if uv got a few mins to read

http://forum.maxpowe...?TOPIC_ID=46218

[Jackman]

Quick suggestion, would anyone here recommend removing the standard exhaust? The main problem i have is money, i could afford a better exhaust but if it lowers the mpg loads then it wouldnt be any good because i couldnt afford to fill it up on the ammount of money i get.

[TimS]

it is a good idea as the std exuast it extreemly restrictive to make the car quieter! most modern cars dont have this problem as exhuast baffles and technology has moved on.

If you were to get a new exhuast stick to something small and definatly less than 2" with a twin back box and a small bore LCB if you have a 998 in it and medium bore if you have a 1275

[mikesitalianjob]

that made for interesting reading i will save for a 1.75" bore exhaust or just leave it for the minute its all new so i will apply the simple rule of

"if it ain't broke don't fix it" :grin:

mike

[TimS]

good idea mike, wait untill it needs replacing!