[mattr832]

There are many mentions of "backfires" across the forum, but it seems like folks mix that term in with the standard burbles and braaappps that occur so I wanted to get some clarity (i.e., what they call a backfire actually isn't).

I recently flashed BM3 OTS stage 1 @ 91 and had a CSF IC installed. Been running 92 which is the best I can get in WA. Also recently upgraded to Bav Motorsport ignition coils and NGK plugs. Running stock gaps since folks seem to overhype gapping down and I have the upgraded coils.

I noticed when downshifting in Sport mode that I get distinct gunshot sounds. About one or two, but much louder and with a bang. Something more similar to a backfire than the standard burble sound. Seems to happen much less in Comfort mode.

Is this standard with the BM3 OTS map given the IC upgrade? It didn't seem to happen when I had that tune before the IC was installed. Should I check the gaps in my spark plugs? Flash back to stock and see if it happens again? Try a custom map and reduce some of the burble stuff?

[ThreeStripes]

You can adjust the length and intensity via Bootmod3. Turn it down to taste.

[Sundinisagod]

I have the MHD tune. It has the option of having your exhaust flaps fully open in sport and sport+ …or you can have them function as per stock. If you have this option it would eliminate a lot of the pops, bangs and burble especially at lower speeds. I drove my car with a sport cat and CSF ic before the tune, much quieter due to the exhaust flaps not being wide open at all times. I’d think your tune has this option as well? I’ve been thinking to go back to stock settings for the flaps myself, the burbles are a bit much for me.