Can anyone explain why the Mopar ECU takes away popping/cracklin from exhaust?

[RMcGuinness]

I have read a few times and experienced it on my own 2009 that with the Mopar performance ECU installed there is no crackling noise from the exhaust...even with out cats...can anyone explain why this happens?

-THANKS

 

[bluesrt]

probably because the mopar ecu fattens up the fuel,wild guess

 

[Viper Specialty]

In order to increase engine braking, the Mopar ECU likely has little to no fuel in deep vacuum, where the street ECU will try to retain Stoich in closed loop, which will cause the popping you hear. I see the same scenario in the Mopar ECU's for the Gen-3/CC where I can actually view the program.

 

[Twister]

Viper specialty did my sct tune and I as well noticed that the popping sound from the xhaust was eliminated..The exhaust even sounds a lil more exotic (custom titanium exhaust with no cats)

just another benifit from the tune that i didnt expect

 

[RMcGuinness]

THANKS GUYS!!!

 

[BlackSnake99]

I love the popping on decel. It's music.

 

[Bobpantax]

The answer is that Dick Winkles does not like popping on decel and eliminated it.

 

[Makara]

probably because the mopar ecu fattens up the fuel,wild guess

More fuel would increase the popping.

 

[SilveRT8]

I have it, but keep it stored in a box because I love to hear the popping more than the extra HP it provides.
Will put it back on before going to the dragstrip or on the Dyno.

 

[mjorgensen Woodhouse]

Mine will still pop and cackle when I drop throttle from high RPM at the track.

 

[SRT Engineers]

In order to increase engine braking, the Mopar ECU likely has little to no fuel in deep vacuum, where the street ECU will try to retain Stoich in closed loop, which will cause the popping you hear. I see the same scenario in the Mopar ECU's for the Gen-3/CC where I can actually view the program.

OK, here's the answer - Dan is partially correct, the Mopar "Off Road" ECU is much more aggressive with fuel cut on decel to provide more engine braking and a slight fuel economy improvement. Anytime you hear popping in the exhaust, fuel is burning after it leaves the combustion chamber. Another big factor is that in addition to keeping some fuel on in order to keep the catalyst hot, spark is also ******** so that late burning takes place to some degree in the catalyst, again to keep it hot (all done for emissions and since the Mopar ECU is off road only and many times without catalysts, this doesn’t matter). This ******** spark timing results in popping and lazy spark/throttle response coming out of the decel. The Mopar ECU has much higher decel spark so that what fuel is there burns where it supposed to (in the cylinder) and provides better throttle response when you tip back in. And you are also right Bob, Dick Winkles hates inefficiency in the engine and that popping sound you all seem to like is an inefficient use of fuel!

 

[gilly6993]

I love the popping on decel. It's music.

so do I....it's my favorite part of the exhaust...

 

[Brian GTS]

I love the popping on decel. It's music.

+1!!! That's the sole reason I haven't installed the Mopar ECU on my car. As inefficient as it may be, it is sweet music.

 

[TrackAire]

I want to thank the SRT Engineers for responding to the question with a very thorough and technical response. I hope to see more of this in the future as it really helps answer questions regarding our cars correctly (and without a lot of "internet experts" bull crap that tends to be put out on the forums).

Thanks again and it is much appreciated.

Cheers,
George

 

[FLL-B/W-GTS]

The popping sound is one of the coolest things about the Gen 4 Vipers.I make mine do it all the time.My ZR1 does it also.


2008 Viper Coupe
2009 Coevette ZR1

 

[Viper 24]

Can someone shoot me the part number for the Mopar ECU? I want to buy one for my 2009 Viper.

Has anyone noticed a change to exhaust tone (stock exhaust) or db level with the new ECU?

Thanks for the help - jm

 

[Viper Specialty]

Can someone shoot me the part number for the Mopar ECU? I want to buy one for my 2009 Viper.

Has anyone noticed a change to exhaust tone (stock exhaust) or db level with the new ECU?

Thanks for the help - jm

I do have one in stock if interested.

 

[SilveRT8]

Can someone shoot me the part number for the Mopar ECU? I want to buy one for my 2009 Viper.

Has anyone noticed a change to exhaust tone (stock exhaust) or db level with the new ECU?

Thanks for the help - jm

On a cold start the Mopar ECU settles down to an even purr of the engine tone much more rapidly than the stock PCM wich seems rough and bucking by comparaison. The DB is the same but the Mopar note seems more refined almost like going from a Carburated Harley to a Fuel injected one.

 

[dtenney]

If you really like popping on decel then pickup an SRT-4 with stage 3 upgrades, run a straight side exhaust, and enjoy.

-David

 

[Smokin' 2]

I wonder if Chevy engineers are checking in on their avid owners' forus and actually answering questions?

SRT rocks!!!

I have the Mopar ECU on my ACR and prefer it. I guess I'm in the minority.