Loud popping sound under hard acceleration? Noob here.

[AnArmyOfJuan]

Hey guys, I haven't had a turbo car since the mid nineties, so maybe this is a normal thing. Earlier today, I had a Cobb RMM installed, and when I got on the car hard afterwards, there was a loud pop sound that came from under the hood when I let off the throttle. Is this just the BOV or something? No lights came on, and everything ran fine afterwards, but it freaked me out enough to ask here.

 

[me32]

Maybe you didnt tq it down all the way cause if the pop wasnt there before then all signs point to install

 

[AnArmyOfJuan]

Maybe you didnt tq it down all the way cause if the pop wasnt there before then all signs point to install

ModBargains did the install. I don't think I've come off the throttle that hard before, either. I'm guessing it was just the diverter valve making its presence known for the first time. I figure it would have happened again or my car would have thrown a code if something bad happened, right?

 

[Hijinx]

Catless down pipe?

 

[AnArmyOfJuan]

Car is bone stock save for the RMM and pedal spacer.

 

[dyn085]

I definitely wouldn't attribute a 'pop' sound to the dv as I don't recall a single other person ever describing it with that word. I agree with me32-if the sound wasn't there pre-install but was then heard post-install...

If you're not hearing it anymore I wouldn't be overly concerned though. If it comes back up I would double-check the install.

 

[D1JL]

If your still coming on the drive with us today we will have others listen to it.




Dave

 

[Boro]

Could it be just a little pop from when you lifted off the throttle? when I decelerate from high rpm, my car pops a little (mbrp exhaust, stock downpipe). Sometimes even when I lift off throttle at 4k rpm or so, in that short moment of no load, it'll pop now and then.
I thought this was something to do with backpressure on turbo cars, or the throttle snapping closed really fast at high rpm and fuel mix gets a little leaner for a sec?

I'm a noob too, I probably do not know what I'm taking about..

 

[AnArmyOfJuan]

Could it be just a little pop from when you lifted off the throttle? when I decelerate from high rpm, my car pops a little (mbrp exhaust, stock downpipe). Sometimes even when I lift off throttle at 4k rpm or so, in that short moment of no load, it'll pop now and then.
I thought this was something to do with backpressure on turbo cars, or the throttle snapping closed really fast at high rpm and fuel mix gets a little leaner for a sec?

I'm a noob too, I probably do not know what I'm taking about..

Yeah, I think it was just a backfire. I've never had one happen before in a car that wasn't 30 years old, so I was likely just making a mountain out of a molehill.

 

[dyn085]

Back-fire would be combustion that went past the intake valves and back out the intake. What you're thinking is after-fire, and I can't think of any instance where it's been noticed or reported on a stock exhaust. I'm not trying to shoot down all of your possibilities, honestly. Again, I wouldn't worry about it unless it happens again and/or becomes more frequent.

 

[BeansNCornbread]

Mine has done this since day one similar to my rotaries though definitely not as often. It's unturned fuel in the exhaust from the sudden lean condition of letting off the throttle same as competition cars throwing flames out the pipe under down shift. Your CAT just keeps it from getting that far. I'm bone stock but at altitude.

 

[Hijinx]

Back-fire would be combustion that went past the intake valves and back out the intake. What you're thinking is after-fire, and I can't think of any instance where it's been noticed or reported on a stock exhaust. I'm not trying to shoot down all of your possibilities, honestly. Again, I wouldn't worry about it unless it happens again and/or becomes more frequent.

I considered this but threw the idea out the window when OP answered he didn't have a catless exhaust. I'd be concerned about the cat if he were able to get some after-fire popping (pun-intended).