61 replies to this topic

[Cooperman]

Can't understand why anyone would want their car to do this. Very strange. It's best if the car runs properly, surely.

I'm pretty sure even if a car is running properly, it can still pop through the exhaust.

As mentioned, fuel injected cars don't do it as much as carb'd cars.


I suppose, on a standard mini, it probably 'shouldn't' do it, but its not really a problem or anything IMO.

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.

[mike.]

When I was younger, we used to make the mini's backfire. Basically, rev the engine then flick the ignition off and back on. As you flick the ignition off, "blip" the throttle.

I've heard of people doing this before, but I've never understood it. If you turn the key off and back on again isn't the starter motor going to engage and damage the motor or starter ring?

[me madjoe 90]

When I was younger, we used to make the mini's backfire. Basically, rev the engine then flick the ignition off and back on. As you flick the ignition off, "blip" the throttle.

I've heard of people doing this before, but I've never understood it. If you turn the key off and back on again isn't the starter motor going to engage and damage the motor or starter ring?

Not if you only flick it one notch so ignition turns back on, Not that this is in any way a good idea for any engine.

[MiniAlex]

Since i've put my fletcher dtm on (still got the catylic convertor on) going down a hill in my mini, it gurgles and pops a bit. sounds very nice!
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

[Sprocket]

I would like to point out, that in no way was I suggesting that my engine runs like this merely pointing out the conditions that will result in pops and bangs during over run that be low advance and rich fueling with high manifold vacuum. I would be very suprised if you can get a dizzy to give low advance at mid rpm with a high vacuum irrespective of its setting at idle

[Sprocket]

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.

[danrock101]

My 1275 stage 3 ish head, 1.5.1 rockers, SW5-07, hif44, cooper freeflow manifold used to pop all the time even after I got it set up at a local old skool rolling road, I got it set up at smart performance when on a RR day and I was plus power and the popping was gone, no matter what I tried it wouldn't do it, I did miss it but I could live with it due to the way it drived after

[Cooperman]

Sprocket is absolutely right.
Now this is a strange thread. A Mini, or any other car come to that, should not backfire unless there is an intermittent ignition fault, so if one does, it should be properly set-up to stop thjis happening. Surely no-one actually wants this to happen? If anyone does, then this is probably not the right Mini forum for them as we like our Minis to run properly and some of us try to helpothers to get their running right. Please don't come on here and say, in effect, "my Mini is running fine, but I want it to run badly and backfire. How do I do this?"

[samsfern]

When I was younger, we used to make the mini's backfire. Basically, rev the engine then flick the ignition off and back on. As you flick the ignition off, "blip" the throttle.

I've heard of people doing this before, but I've never understood it. If you turn the key off and back on again isn't the starter motor going to engage and damage the motor or starter ring?

Not if you only flick it one notch so ignition turns back on, Not that this is in any way a good idea for any engine.

also, youll get bore wash, which is where the unburnt fuel washes the protective layer of oil off of the bores, not good at 6k rpm. A friend also manage to literally blow his exhaust up when he done it on his old fiesta as we were "driving" along the coast, i laughed out loud, and laughed even more when i saw the exhaust!


I started my new 1330, piper race 649+ cam, modified head, for the first time today, it idles real lumpy, but you can hear the engine note change when it gets on cam, it was popping and banging out the exhaust, sounded pretty cool, neighbours didnt seem to like it, but ******* them, lol, but a lot of it is due to it not being set up properly yet.

Edited by samsfern, 17 October 2010 - 05:40 PM.

[project mini chris]

used to do it with my step dads 1340, rev to 6k with choke out then release foot and as the revs drop it should pop, but i only did it on cold days

[Team Loxley Racing]

When my 998 engine was pretty standard (Just had an RC40), it used to pop all the time. Now its been rebuilt, with stage 3 head 1.5 rockers maniflow exhaust, lightened balanced bottom end it doesn't pop at all. I think its been set up properly now though...

[Cooperman]

When I was younger, we used to make the mini's backfire. Basically, rev the engine then flick the ignition off and back on. As you flick the ignition off, "blip" the throttle.

I've heard of people doing this before, but I've never understood it. If you turn the key off and back on again isn't the starter motor going to engage and damage the motor or starter ring?

Not if you only flick it one notch so ignition turns back on, Not that this is in any way a good idea for any engine.

also, youll get bore wash, which is where the unburnt fuel washes the protective layer of oil off of the bores, not good at 6k rpm.


I started my new 1330, piper race 649+ cam, modified head, for the first time today, it idles real lumpy, but you can hear the engine note change when it gets on cam, it was popping and banging out the exhaust, sounded pretty cool, neighbours didnt seem to like it, but ******* them, lol, but a lot of it is due to it not being set up properly yet.

I remember when I started my 1071 'S', which had a 649, etc., for the first time. It was so lumpy below 3200 rpm, then, wow, it really came on-the-cam right up to 7500 rpm. I built it at 1071 in order to win the 'up-to-1200 cc' class, which it did on an event in Belgium shortly afterwards. That was one heck of an engine, but really horrible in any sort of normal road use as it would not stay on the cam. Mine was very lumpy and did 'pop and bang' a bit until it went on the rollers, then it was a truly superb historic rally car. It now lives with my friend in California, but the cam has been changed to a 286 and it seems even better overall in competition use.

[tuf998]

The popping sound on decel is an indication that the car is running rich

dosent matter whether carby or efi, if you have a decent aftermarket exhaust on any car thats manual you will hear the sound if its running a bit rich. My ford falcon xr6 does the same and i know its running rich lol

[GreenMini17]

Is this a serious question?!!!

[jake cooper]

Could also end up with a Section 59: Vehicles used in a manner causing alarm, distress or
annoyance.