[1stockbmw]

Hey guys so I was wondering if my car was supposed to be backfiring from updating to the ISO firmware. I know it is supposed to have the gurgling sound but the backfiring is new. Here is a video for reference. The motor is the N55 and this is already warmed up.

[mashimarho]

Hmm... I can't imagine why. I wonder if mine sounds like this...
I don't have ISO though.

[E90Company]

That sounds badass! Who cares lol

[Dark_Knight_335]

My Dinan exhaust does that- pretty badass, and normal- for my exhaust at least.

[jsmonet]

Just FYI, that's afterfire, otherwise known as little pockets of unburnt fuel igniting in the exhaust. Backfiring is a far more serious issue usually requiring, at the least, a new intake manifold after it happens

Overrun/afterfire is no big deal.

[sA x sKy]

Originally Posted by jsmonet

Just FYI, that's afterfire, otherwise known as little pockets of unburnt fuel igniting in the exhaust. Backfiring is a far more serious issue usually requiring, at the least, a new intake manifold after it happens

Overrun/afterfire is no big deal.

Your definition of afterfire is backfire...

Backfire happens when you run too rich and unburnt fuel ignites in the exhaust..its perfectly normal and fine if you're catless. Just have to be careful of the O2 sensors.

[PR3CI5N]

You have your mufflers deleted?

[1stockbmw]

Yup mufflers are deleted. I just love the sound haha. Oh and also I still have the stock downpipe so I am not running a catless set up, its just the muffler delete.

[madmanhiker]

I noticed the same issue - I emailed Terry about it already as well. Let him know, this may be a characteristic of the new firmware in certain configurations. I did NOT backfire nearly as much prior to the ISO, and I know my car inside and out.

[SfValley335i]

look at this way, now you can shoot fireballs from your muffler

[BMW_Belgier]

Just like the PPK...

[335iBoii]

i like it.. lol