"Backfire" On Gear Change

ok so tech section is down otherwise i woulda checked there first but im getting sometimes fair bad backfires (or something sounding like it) sometimes during gear change, i cant remember whether its on clutch in/power down or clutch out/power up but i will pay attention properly next time it happens... any ideas?

 

If twin-turbo car and your running ATMO blow off valves, driving on boost and then clutching in will cause your engine to pump to much fuel in and 'pop' from the exhaust.

Its nothing to worry about..

 

twin turbo and blow-off valves but dunno which ones lol, ill jack it up tomorrow and check
thanks in advance if this is it XD

 

ATMO is a brand isn't it? lol

 

"ATMO" means that your blow off valves vent to atmosphere, as opposed to plumback versions.

 

:bash::bash: ahhh lol, how do i tell the difference?

 

You will see when you find the BOVs... They will be either plumbed BACK INTO THE SYSTEM or just sitting there on the pipe which means that they are ATMOSPHEREIC BOVs

I wouldnt stress about it, its nothing but unburnt fuel

 

youll hear it ,pshhhhhhhhhhhhhhhhhhhh

 

My blow off valves are plumbed back into the system and my Zed gives the occasional back fire when changing gears because it's running too rich. So you may have either problem.

Cheers,
Dave

 

I can get a "pop" or more like a low thud on demand pretty much by changing gears just after 3k rpm in every gear....Im running stock twin plumb back BOVs with twin turbos (GTR ) and 800cc injectors...basically the turbos are just starting to get serious about producing boost around 3k and the ECU starts pumping in more fuel through the large injectors but I change gear so it has an excess of fuel which gets burnt off in the exhaust....In this case I don't think you have anything to worry about, if its a really big loud back fire that cracks and scares the grandma 3 cars back then Im pretty sure that is NOT good as I think it will severely shorten the life of your turbos.

Basically it comes down to your tune and how your ECU handles A/F (air/fuel) ratios. Well thats what I figure anyway, wait for the gurus to comment

Cheers!

Craig

 

I get the occasional 'pop' on gear change. While my car was running rich with an O2 sensor issue it was more frequent, but it was never a full-on backfire.

(I remember a few times that my old falcon backfired in the carby...scared the sh!t out of me...haha)

And yeah, BOVs and TT over here...