Why do people have cars that backfire..?

Some attention seeker just drove past ours with a car that seems to backfire every time they change gear. It’s like a shotguns just gone off and now my dog is going crazy and my kid is awake.

Why would you think that’s a good idea.

It’s probably a 1.1 corsa that would struggle to outrun my old pickup truck!

Drives me mad.

If you’re in Chester it’s probably a WRC. Or a kid in a 1.1 Corsa.

Because race car.

It basically means it’s running rich and overfuelling, so a bit of petrol escapes into the exhaust where it subsequently catches fire and makes a popping noise.

With custom race cars getting the fuel mixture right is a bit of an art, hence the popping, or if you have a 1.2 corsa, you can make it run a bit rich to make it ‘sound like a racing car’.

It’s usually anti lag on the turbo cars 🙂

Keeps the turbo spinning whilst your changing gear so no loss of boost – you could run multi maps on Mitsubishi evos and have one wiv anti lag and one without with the later Ecus and switch it on or off.

Not sure if it’s particularly usefull on a road car TBH other than for shits and giggles.

Kids also fit things into the exhaust to make their cars sound fast.

Kawasaki ZX9R, at a constant 7000 rpm and just flick the cutoff for a split second while going through the Dartford Tunnel

Certainly wakes up all the tin tops 🙂

its a thing, you can have you car mapped with a “crackle n pop” map, extra Morrison’s car park points if it spits a flame.

It’s a bedwetter early warning system.

“look at me am ‘ard as **** with me backfiring Nova, Staffy n’ 15 year old gf.”

It’s a cultural thing.

Load of bollrocks. Just extra noise that we don’t need. Why do you need your nova/ corsa to not lose too much boost? It’s a 30mph zone through here.

It’s a thing, yes, but it can have a purpose. Tuned engines, or any engines for that matter, don’t like to run lean (not enough fuel for stoichiometric combustion). At all. A lean running engine can “knock” and a lean running tuned engine will break very quickly. Rich running engines (more fuel than required for stoichiometric combustion) don’t have this problem, and so pretty much any tuned engine will run rich. The downside is sometimes that extra fuel doesn’t combust in the cylinders (or rotor housing 😈 ) and instead combusts somewhere in the exhaust system, creating pops and bangs that wake kids and annoy dogs.

I also associate it with aggressive cam profiles, racing cars used to sound gorgeous on the overrun, all popping and banging. Dunno how the audio is on this vid (in the sticks, shocking connection so can’t check) but you could hear it great on the elevated shot of Depailleur’s P34 on the original vid.

When I was in high school our Austin Maestro had a hole in the exhaust which used to make it backfire.
Dad used to love it when the bus was dropping off at the same time…

This used to be a pleasing byproduct of highly tuned rally/race cars in days gone by. Some modern high performance cars, particularly turbos are tuned/fettled in such a way as to do this deliberately to add a bit of character and excitement into what might otherwise be a fairly anodyne experience.

Pops ‘n’ Bangs remap yo!

My old clio 16v used to bang a bit on over run and gear changes if it was canned after I had it mapped
Old tech I guess as remap was a solder new chip job. It struggled at idle too after the cam swap.
But for a 1.8 na engine it went very well and liked to rev.

But never in town.thats just daft

Only car I regret selling

yoof innit

Probably an engine mod for youfs to feel cool, but I’m sure one of my old friends learnt how to do big exhaust explosions in any standard car, a trick he learnt from other employees when working for a rental car company delivering and picking up rental cars. Something I think he said you wouldn’t want to do in your own car as it knackers the engine and/or exhaust eventually. Probably as stated above, somehow pumping petrol in the system and then igniting it, I never bothered asking him to elaborate altho he did do it once or twice when I was in a rental car with him.

I had a Cavalier that did it once.
Frightened the hell out of some women leaving work.
I was told not to bring it back on site.
It was quite funny when it did it though.
It would choke up, splutter & let off what sounded like a shotgun going off.
My brother banned me from his street. 😀

If you catch it just right my 500 does it in every gear. Sometimes twice in succession. It’s possibly a by-product of an over-cautious rich map, but more likely a deliberately immature decision by the manufacturer. I like it. I can see why some people don’t. There’s better things to worry about.

It gives you fantasy streetracer cred.

Quite a few modern cars do it on purpose. Things like the Audi RS cars ace little injectors specifically to squirt drops of fuel into the exhaust to make it pop and bang in certain situations.

The pops and bangs in the F Type are engineered in and very very raucous.

I heard an Audi A3 RS drive pass the other night, it too popped and wheezed.. car was 16reg too.

Seems like a very strange thing to me to do to a car.

There are quite a few off the shelf expensive sports cars that now do it. Boys and toys….

My motorbike pops and crackles on downshifts when the engine is in dynamic mode. Sound fab!

So, girls and toys, too. 😀

Rachel.

I’m totally hypertuning the S-Max today.

Yes Mindmap. I think there was a fairly new Aston which did too. Little mist of petrol in the exhaust system on down changes.

My car makes fire at high revs and full boost. It runs rich at that part of the map to help prevent Det. It’s a highish compression turbo engine from the eighties. The only time anybody will hear it is if I’m overtaking or on a track.

It also used to have a vent to atmosphere blow off valve but it sounded like the car had a cold and had to go.

I’m guessing none of these cars can have a functioning cat, apart maybe from the dafter ones which deliberately inject fuel downstream in the exhaust just to make a noise?

Quite a few modern cars do it on purpose. Things like the Audi RS cars ace little injectors specifically to squirt drops of fuel into the exhaust to make it pop and bang in certain situations.
The pops and bangs in the F Type are engineered in and very very raucous.

See, this sort of thing really bugs me. Basically, older, pre electronic engines needed an excess amount of petrol to ensure they had enough fuel in all situations for stioch stocicall effective ignition, and to avoid pinking. Now, computers and engineers are clever enough that engines can be made just as powerful, but much more efficient by precisely metering fuel in all situations, so no popping. Then Mr marketing cheaply comes along, and points out that they will sell more cars if they can engineer back in popping in the exhaust because mr midlifecrisis likes it to sound ‘sporty’. So we get a ridiculous situation whereby a fairly amazing bit of engineering gets spoilt by having an extra injector in the exhaust manifold of a remap which runs just a little bit too rich on the overrun, so pointlessly burning fuel and money. It’s just wasteful and impure. Heaven forbid Mr Midlifecrisis watching German DTM and wanting six foot flames coming from side exhausts; there will be some eye watering helmet cam commuter videos then…

Sound fab!

Only to you, pre-teen boys and older males with the learning age of a pre-teen boy.

v8ninety

See, this sort of thing really bugs me.

The alternative is fake engine noise piped into the cabin. Or no noise at all.

So we get a ridiculous situation whereby a fairly amazing bit of engineering gets spoilt by having an extra injector in the exhaust manifold of a remap which runs just a little bit too rich on the overrun, so pointlessly burning fuel and money. It’s just wasteful and impure

It’s also controllable via driving and exhaust modes. The only question is does it make the car sound better or worse? Does it add or detract? There are a lot of cars out there so vote with your wallet and buy a diesel.

Press the ‘Dynamic’ mode button in the latest RS4 and when it slows down its more of a Woof than a pop! Great on a race track, but a bit out of place on the A24!

Only to you, pre-teen boys and older males with the learning age of a pre-teen boy.

Counter-position: not to you, and the yoghurt-knitting, peacenik, social-justice-pinkos that share a hemp-weave, vegan-friendly stuffed beanbag in your NIMBY echo chamber 😉

I just want a quiet life. Life’s noisy enough already.

There are quite a few off the shelf expensive sports cars that now do it. Boys and toys….

Yep always amazed when the stuff people complain about on modded cars ends up as standard.

The f type jag seems to be a noisy beast not sure how they got that by the evil EU regs for drive by noise levels.

Another thing on the long (maybe infinite) list of things STW members don’t like about other peoples’ cars.

Much more fun is the bark a Merc C63 AMG makes when you fire it up! And the noise a V8 makes generally, it doesn’t need artificial pops and bangs.