Backfire during gear change? low rpm, can it be tuned out?
 

Hi guys,
I have a FD with full exhaust from Turbos (hi flow cat installed), Stock airbox modded and Power FC tuned.

During low rpm gear changes (say 3000rpm)... the car backfires... I heard this is normal for a Apexi but wondering if there is anything to minimise it or can it be tuned out?

Thanks.

It is not normal. It is possible that you are running way too rich, however large exhaust leaks are also known to cause backfiring on decal.

Are you running the Apexi base map?

Hi matey, thanks for your reply...

This happened on both the base map and now has been pro tuned & doing the same.

To my knowledge there is no exhaust leak but I will to try check again.... failing this, any other suggestions?

The car runs really well, It made good power and did a good time at the track (114mph), it's just this backfire, on almost every low rpm shift and decel It backfires..... the highers rpm shift changes do not. I am getting a wideband but in a couple weeks time.

Mods: K&N Filter - Modded stock airbox, SMB Exhaust & Tune. 11.5psi

Might be to much fuel in the 3000 rpm - (-80) kpa area of the fuel map. Wideband will be the best way to fine tune out that sort of issue.

In my opinion.

Sounds like you need to do some driveability tuning.

Ok I have installed a wideband..... its more around the 1800rpm-2000rpm shifts and between gear changes the arf can dip to 10.9....

would this be causing the problem?

Also in saying that, if I am cruising in 5th @ 3000rpm I can blip the accelerator afrs hover between 16-14 and it will also do it.....

but it is more between the low rpm gear changes??

suggestions on whatto do now?

Needs fuel tuning at lower vacuum in the lower P row/s just above the cruise points.
Also, what are your 3 fuel cut points?