Turbo Cars and exhaust popping!

[Ceirwan]

Everyone else with turbo cars knows the score, you down shift and you get lovely burbling noise with the odd pop from the exhaust...
And every now and then you get a really loud one, not a bang but a really loud burp or pop, it can happen on either the up or downshift.

I've been experimenting with different throttle settings and the way I change gear and I can't seem to get the secret of doing it when I want it to, it just seems to be random.

I know its when unburnt fuel hits the exhaust but it'd be ace to be able to do it at will! (Not for any particular reason, just for the hell of it!)

Does anyone know the secret..?

 

[Ed]

Its quite often random its a combination of lean un-burnt fuel and retarded ignition of over run.

If you have a Cat on your car that's one way it almost certainly will not happen.

 

[Ceirwan]

Ah ok cheers.
I guess this means my cats pretty knackered then...? As i get pops etc pretty regularly and i don't have a De-Cat, this sounds like a potential emissions failure next MOT lol!

 

[Baz]

It's hilarious when the st does it as there no way to predict it, although it usually happen at low revs when taking it easy and you come off the throttle

 

[Ceirwan]

Yeah, i've noticed that much! Your going really steady so as NOT to sound like a cock with your loud exhaust and out of nowhere you get a big bang!
Must be awesome coming from the ST.

 

[ollyc98]

I used to do it with my non turbo fiesta, cos it had a wasted spark ignition you could rev it hard and turn the ignition off then on again and you'd get a big bang and some sparks out the exhaust. This is cos the exhaust valve was open when it sparked, of course if the exhaust is hot enough it'd do it anyway. Richen up your mixture a bit

 

[Ceirwan]

I thought the 'On-Off' technique is only useful on a carbed engine..?

 

[joesouthgate]

yer it is, although you have to be careful, I blew up the backbox on my landrover doing it lol

 

[Baz]

Yeah, i've noticed that much! Your going really steady so as NOT to sound like a cock with your loud exhaust and out of nowhere you get a big bang!
Must be awesome coming from the ST.

Thats it exactly man(Y)

 

[LifeOfALegend]

De cat it, bring the revs up and down quite a bit, and turn the ignition on and off while ur doing it, or drive it up the revs in 1st or 2nd gear and as its coming down turn it on and off!! My starlet sounded unreal!!!

 

[mrogers]

get this on my 300zx TT when changing gear at high revs, even pops a flame out of the back (not a biggie) mine is due to fitting an ECU from an auto car to a manual car, whcih does not cut the fuel delivery between gear changes. not a problem, looks good at night though

 

[Ceirwan]

My cat must be totally wasted then since my friend claims that when following me down a hill I was getting flashed from the exhaust on overrun.

 

[Baz]

get this on my 300zx TT when changing gear at high revs, even pops a flame out of the back (not a biggie) mine is due to fitting an ECU from an auto car to a manual car, whcih does not cut the fuel delivery between gear changes. not a problem, looks good at night though

Cool , a friend of mine has a Toyota soarer and it does the same, but as far as I know it pulls back ignition timing on gearchanges and you get a weird burping sound and then a flame:laugh:

 

[jowley]

my old red car pops and spits flames i love the sound when it does it tho

 

[jim_bling]

mine pops when i down gear and just oddily on the up gear but if i take it to the limit in second gear and then let it run down the rev range and just tap the throttle it will pop but sounds terrible with the janspeed mani and the janspeed de-cat/sports cat

 

[Rimski1688]

^^ yeh i thought you could cause it by revving hard and lifting off and letting it run down

 

[Glen]

you could get a bee-r which would alow you to pop

 

[jim_bling]

^^ they are so kool

 

[Glen]

plus they give you launch control

 

[John_G]

Mine doesnt (stand system) but my saxo did with a SS 2" it sounded unreal, i miss that noise!

 

[superls]

my k10 used to do it quite alot when i had the bike carbs and 4-2-1 on last year, quite funny for the first few weeks but can be quite annoying when you dont want it to do it, for instance when working on site and having to leave the house in the early hours of the morning lol.

 

[Willenium]

Mine pops and burbles a bit every time I come off the gas. Think the main reason for is there isn't a second silencer to dampen the blow.