61 replies to this topic

[DAVEY_C]

Even with high-overlap cams Mini engines should not back-fire through the exhaust if the ignition, mixture and timing are correct. If my car started to backfire, and it has a 115 bhp 1310 cc rally engine, it would be back on the rollers to be corrected straight away. Any regular backfiring is the sigh of a poorly set-up engine.
[/quote]


is this why any decent rally car, the engine, has to be rebuilt after each weekend of rallying?? are they set up incorrectly or are the supose to sound poppin'... i assume that is the sound he is after

[AndyMiniMad.]

Is this a serious question?!!!

I really hope not!!! I think its just the young boy racer types having a laugh...You know the ones, They think if you have an exhaust back box the size of a dustbin and drive every where with the ICE on full blast the girls will think they are soooooo cool their knickers will literally fly off!!!!

[xtr hardcore]

Get what i had, play mini twin DTM complete straight through. No cat, No silencers oh and maybe a nice new LCB pipe

[Cooperman]

Get what i had, play mini twin DTM complete straight through. No cat, No silencers oh and maybe a nice new LCB pipe

And presumably when you've annoyed enough people with your under-powered but very noisy car and you get an S59 from the Old Bill, you'll complain about it. Even more so when they snatch your car and crush it!

[chipster196]

mine gurgles abit on overrun but i know its running abit rich sounds nice and its how i wanted it to sound. Ive got an LCB downpipe with a single box 2.5" exhaust system

[finch661]

my mini used to pop and burble out the exhaust when i took my foot of the throttle and the engine slowed down. though this was down to a iffy HIF44 carb, that was dumping fuel into the the engine. wasnt a big fan of the backfire! you could go for one like the car in Uncle Buck?

[DAVEY_C]

my last car was a pulsar gtir and it had a straight through mongoose exhaust, walbro fuel pump, and profesionaly tuned to 300bhp and it over ran like a ******* but without it she was loosing boost for some reason....

whereas my mini is so far a 998 and i have just bought a stage3 head, i have a straight through exhaust with single backbox and a downdraft weber for it..... oh and i think i want a small over run..... im no young lad and my miss mightn't like to think of me going out to impress the young 1's but i like it.

oh and there's nothing worse than a car with loads of noise and no go.... is sounds rediculous...... lol

[MiniAlex]

Its not overfueling, as its completley standard engine wise, not messed with it at all. My mates does aswell, same back box as me. Its the unburnt fuel in the exhaust just popping

Thats a contradiction in terms

If it is not over fuelling, then there will be no unburnt fuel in the exhaust.

Well I supose maybe a little overfueling

[CGilmour]

Ever since I fitted my wide Sportex back box it rumbles and pops on over run

Edited by CGilmour, 18 October 2010 - 04:06 PM.

[Cooperman]

Ever since I fitted my wide Sportex back box it rumbles and pops on over run

It probably needs re-tuning to cope with the decreased exit velocity of the exhaust gas molecules which will be causing an increase in back-pressure at the extra wide part of the final exit. This is making the exhaust exit less efficient and not clearing the gas properly. You will have lost a bit of power if the final exit pipe is a bigger cross-sectional area than the pipe from the end of the exhaust manifold.

[samsfern]

well drove mine today, to my mates work to do a bit of setting up, first time on 1330, 649+ cam, single box large, 2" centre exit maniflow system, was popping and burbling away quite nicely on the overrun, it was running rich, and the timing was retarded, timing advanced, mixture set better, still has a bit of a grumble on the overrun, and the odd pop, but thats only really letting off at high revs (+6k). All was going well till the clutch gave in

[GTIAlex06]

How silly

http://www.youtube.c...feature=related

[Cooperman]

How silly

http://www.youtube.c...feature=related

Absolutely.What's clever about that?

[RayBoogs]

I really don't understand why you would want it to backfire, when my MAP sensor failed it was running super rich and would back fire all the time and lose momentum, it was awful. Also a pop isn't the same as a backfire is it? Although i agree none of them are really a good sign, I'd rather my Mini sounded good because it was running well.

[AndyMiniMad.]

How silly

http://www.youtube.c...feature=related

What the hell is going on. Why would anybody make their car do that.. Ive watched The films "fast and furious" And those cars did this kind of thing because they were basicaly race engines for the road. Just because you can make your mini do this does NOT turn you into a film star. STOP IT PEOPLE.

Edited by AndyMiniMad., 18 October 2010 - 05:56 PM.