When you lift and revs start to drop, excess unburned fuel is dumped into the header. The fuel ignites in the header instead of in the cylinder - that causes the popping.

 

Yep.

 

engine is prob going to blow soon. take it to the dealer and complain asap!

 

mmm I think not. (@jode since flylow posted already....btw...trollololol!)

The 3.8 only really pops when its cold. Doesn't do it hardly if at all once the engine is up to operating temps which is when the headers would be hottest.

I would venture to say that the pop is from the expansion of gas after transitions in the exhaust, namely the pressure gradients before/after the cats. You're causing a massive backpressure wave once you let off the gas and the throttle plate closes. That wave is going to repeatedly propagate the length of the primary and to a lesser extent, the downpipes. The cats contain the majority of the wave, and you get a big pressure gradient across the converters. Once the system heats up there's not as much of a pressure gradient since the hot exhaust is helping to keep EGT therefore velocity higher and it stops popping so much.

Could be wrong... but throttle lift isn't going to cut spark, so I doubt there's much unburnt fuel going into the headers in the first place.

Bottom line is, it's completely normal, don't worry about it. You don't hear it on most cars because of the stock exhaust system. Any car with an open exhaust pops a lot.

 

Your explaination works for the stock exhaust system... I forgot it was only like that when cold. In addition, as the block is warming up, our CVVT allows a LOT of cam overlap on the exhaust valve - very much contributing to the build-up of pressure gradients before & after both sets of cats.

Having aftermarket headers and a tune, mine only pops AFTER the whole system has warmed up, and only after some aggressive driving in the upper RPM range - prior to the tune, I was running a little richer and had a lot more popping... the tune has quelled that to some degree but it's still prominent (and sexy as hell) when you stomp on it for a bit, lift and coast down from 5000RPM. It immediately stops when the injectors shut down, and I can restart the fury with a tiny tap of the gas pedal

 

Put a Flowmaster super 80 muffler on and then you'll hear some pops haha. Sounds awesome.

 

Helped me out too. I bought a used 2013 3.8 and I thought it was jacked up. Thanks for the thread.

 

beans in the exhaust

 

3.8's run on popcorn.

Scent via Glade Air Freshener.

 

hamsters in the engine bay with alien technology. the popping sound is made when they open a portal to another dimension.

 

Its the sound of your car sighing/growling becuase you're teasing it.