Pops / Backfires

[Zebbie]

Ok, I *think* I know the answer, but time to check, before I spend $$ etc

R33 '96 Series 2

T3/4 Hibrid Turbo

FMIC

Stainless Ducting

3" high Flow, all the way through

Mines ECU

Adjustable Fuel Reg

Pod

Etc, Etc.

When I'm using the engine to brake, usually when i've been doing quite a few k's at motorway speeds (100-110), I get random pops/almost backfires. Usually only one or two, when slowing down for a roundabout etc.....

It's noticable to me, but not to an uneducated passenger, so they're not too noisy.

I think it's because i'm running rich atm, and am going to be changing ECU & getting a retune done soon (Which should fix it, and a little more power, I hope)

(IIRC, I was running 12.5's on the mix at the last dyno)

Any other thoughts?

[bless_you]

running rich

[R31Nismoid]

1 - faulty coil pack

2 - ATMO BOV

3 - ECU

[unwritten law]

mine does it when backing off after staying on a constant rev for a little while (eg getting off the hwy). Mine is running very rich, so I have put it down to that. Just a bit of excess fuel

[tang0]

mine does the same mate ...

just unburnt fuel passing into / through the turbo and igniting in the exhaust ...

when you have LOTS of fuel going through, then you get, ahem, nice flameouts ...

slightly more than a popping noise tho when this happens .... a friends rx-7 in the uk used to shoot flames on each gear change ..

lol

[SeriesIIGTST]

not cat converter = pops/flames

[Craved]

mine does it.. shame that it is caused by a leak in the exhaust wore a hole in the botom from being low

pretty sure it would happen on most free flowing exhausts though!

[Beer Baron]

My GTI-R does it. I love it! It sounds great on gear changes. Mine is caused by two things, free flowing straight through exhaust and rich as tune. Don't worry about it too much. Unless of course it has only just started happening which may indicate a problem.

Richard

[BBQ]

Due to your car running rich, the unburnt fuel when you back off the throttle is left in the chamber, So once your throttle body closes theirs no more air only leaving fuel to hit your nice hot turbo. Which ignites and back fires. no mager dreamer, as lots of skylines do it. You should see what happens when you have a 700hp GT3540 and that fuel hits that a full noise. Its pretty awesome flame about 1m long.

Just make sure your exhaust sticks out far enough from your back bumper, other wise it will melt it eventually.

[IOWNU]

I think backfires are normal with turbo skylines.

Also....i often see black smoke coming out the

back of the boosted GTSTs.

[R31Nismoid]

not cat converter = pops/flames

thats more a result of a sh|t tune.

my car doesnt pop/backfire or flame and it has no cat

[Guest RedLineGTR]

The mines ecu is the issue...most of the ones i have used run very bloody rich..And for the main factor they are tuned for Jap fuel and could be tuned for different modification etc.

[MR R33]

mine pops because its a straight through exhaust system. its usually cause there is too much throttle being used well thats why mine does it.

[SeriesIIGTST]

thats more a result of a sh|t tune.

my car doesnt pop/backfire or flame and it has no cat

NOPE, don't think so. mine pops away quite happily on occasion as a result of a very free exhaust and nothing to do with my tune which is near on perfect 12:1 AFR's thanks to PFC.

[R31Nismoid]

i do.

how can not one car here in Vic do it when they are tuned properly.

other guys flame easily. but they are the first to admit thier tune aint 100%

[SeriesIIGTST]

Interesting leg you're standing on. So you're telling me that my car isn't actually tuned properly and every car in victoria is so therefore they don't do it?

Anyway, lets not start a shitfight. Agree to disagree but I can tell you there ain't nothing wrong with my tune :uh-huh:

[hayes_666]

I get mine to pop when driven hard, i wouldnt know if she flames normally as i have a flamer kit installed, i also dont have a cat either.

Nathan

[BBQ]

thats more a result of a sh|t tune.

my car doesnt pop/backfire or flame and it has no cat

I think you will find it has absolutely nothing to do with a sh!t tune. If in fact it’s probably a good tune if your car does pop/ blow out flame.

Because if it does then you know you don't run as much of a risk of leaning out your motor and killing it, as compared to no back fire, were you don't have enough fuel into the engine causing it to run lean.

If you watch the Japan drag racing I think you find just about every one of their cars running any were from GTS-T running 11 to GTR running low 8, pop and back fire every gear change. Because they tune them rich, for reliability.

[(B1) MR_fanny]

i have a dual N1 exhaust and mine pops and burbles all the time down gearing and i can control it with the throttle. i put it down to back pressure. but when i heel toe and get it right i get a nice pop every downshift. i aint complaining:D:D