Exhaust Popping Sound - What is it from?

[Mopar Boy]

Technical question here. When down shifting, the exhaust makes the standard Viper popping/crackling sound.

What actualy creates the sound? Is it fuel ignition in the cats (I highly doubt this!) or ??????

I gather a strait piped race car would have flames comming out at this point.

Thanks!

Robert

 

[SingleMalt]

I have been told by all of the tuners and Viper techs that it is lean decel. It can be 'tuned' out (with a VEC or other tuner) by adding fuel when you release the pedal at RPM. I had major pop with my car before adding a VEC2 with tune and it's considerably better now.

Enjoy them or have them 'tuned out' -- either way it's your call!

 

[eucharistos]

good o-post and good answer

that explains the change (in pops and let off idle) after the SCT tune

 

[Dan Cragin]

The pop relates to how much fuel is allowed on decel. We can tune this in or out depending on what you like.

 

[Kala]

AND I Like it like it, yes I do... LOL

 

[mike & juli]

AND I Like it like it, yes I do... LOL

ME TOOOOOOO!!! LOVE the *pop* on decel...wish we could have flames, that would just be PERFECT when it pops~! ~juli

 

[dave6666]

What actualy creates the sound?

It is unburned fuel that when it hits oxygen rich air at the end of the hot exhaust pipe ignites and explodes. As has been explained it can be tuned out by reducing that unburned fuel.

 

[mike & juli]

It is unburned fuel that when it hits oxygen rich air at the end of the hot exhaust pipe ignites and explodes. As has been explained it can be tuned out by reducing that unburned fuel.

Like, DUH!!!!! ~jules

 

[treesnake]

I like the pop on decel.
I also like the flames, since I took the cats out...

 

[dave6666]

Like, DUH!!!!! ~jules

Next lesson boys and girls is the fuel triangle.

Juli? How many sides does a triangle have?

 

[kcobean]

I have been told by all of the tuners and Viper techs that it is lean decel. It can be 'tuned' out (with a VEC or other tuner) by adding fuel when you release the pedal at RPM. I had major pop with my car before adding a VEC2 with tune and it's considerably better now.

Enjoy them or have them 'tuned out' -- either way it's your call!

It is unburned fuel that when it hits oxygen rich air at the end of the hot exhaust pipe ignites and explodes. As has been explained it can be tuned out by reducing that unburned fuel.

eh....so which is it? Too much fuel or not enough fuel?

 

[dave6666]

eh....so which is it? Too much fuel or not enough fuel?

Fuel will burn within a specified concentration. Too lean, not enough fuel to burn. Too rich, not enough oxygen to support combustion.

What is the concentration range that gasoline will ignite in air? Do not know. Or care.

Can you richen the fuel trim so that decel is too rich to support combustion? Do not know. Or c......

But too rich will destroy your cats. And that, I care about.

Dave, with cats.

 

[2001 GTS]

I leaned my VEC out under decel and the popping went away.

 

[dave6666]

I leaned my VEC out under decel and the popping went away.

I would agree that leaning the decel is the way to reduce popping. It would be hard to believe that at the end of the exhaust pipe the unburned fuel could be so concentrated it couldn't find enough oxygen to ignite.

Plus, the fumes from that would make you post like Juli.

 

[mike & juli]

Next lesson boys and girls is the fuel triangle.
Juli? How many sides does a triangle have?

Like, DUH!!!! ~juli

 

[mike & juli]

I like the pop on decel.
I also like the flames, since I took the cats out...

I know, I LOVE your car...we, alas, have to have cats...ME-OWWWW~! ~juli

 

[mike & juli]

I would agree that leaning the decel is the way to reduce popping. It would be hard to believe that at the end of the exhaust pipe the unburned fuel could be so concentrated it couldn't find enough oxygen to ignite.

Plus, the fumes from that would make you post like Juli.[/quote]


Then what is YOUR excuse, Cowboy...HOPS????? ~juli
(bummer on NO popping on decel......)

 

[dave6666]

Then what is YOUR excuse, Cowboy...HOPS?????

I've switched to Sex on the Beach. Or some body. Of water.

 

[mike & juli]

I've switched to Sex on the Beach. Or some body. Of water.

I don't drink, but I 'presume' this is a drink one orders at the bar...presumably a bar IN the water AT the beach?

Like, DUHHHHHHHHHHHHHHHHHHHHHHHHH! ~juli

 

[dave6666]

Sex on the Beach

 

[DAMN YANKEE]

Popping deceleration - excess fuel

Popping acceleration - timing

Popping during deceleration and then acceleration - Drive by Shooting

 

[mike & juli]

Sex on the Beach

Thanx...would sound yummy if I drank likker......juli

DY: TOOO FUNNNY~!!!

 

[2006red/whitecoupe]

This past summer I was at Branerd Int'l Raceway for a track day, riding shotgun for 1 session in a Ford GT; we followed another Ford GT that had a smaller pulley and headers; on his upshifts, big flames poured out and we were right on his bumper; it was quite a sight...i have seen that on on race cars of course many times but never to that extent on a street car.

 

[mike & juli]

This past summer I was at Branerd Int'l Raceway for a track day, riding shotgun for 1 session in a Ford GT; we followed another Ford GT that had a smaller pulley and headers; on his upshifts, big flames poured out and we were right on his bumper; it was quite a sight...i have seen that on on race cars of course many times but never to that extent on a street car.

I'd have loved to see that too! ~juli

 

[Detlef]

Treesnake, what did you do after removing the cats? O2 simms or reprogramming of the PCM to get rid off the CEL codes?

 

[gts_2001]

The pops certainly make for interesting reactions when driving thru the ghetto!

 

[Mopar Boy]

Wow! Alot of responses!

Tune them out? No way! I love them!

Thanks guys and gals!




Like Duh!

Robert

 

[mike & juli]

Wow! Alot of responses!
Tune them out? No way! I love them!
Thanks guys and gals!Like Duh!
Robert

It's Sir SMOTY!!!! Wondered where you was hiding!!!

Like, DUH!!!!!!!!!!!!!!! ~juli

 

[Mopar Boy]

Sir Smoty was out on his knoble steed fighting men in armour....... Like duh!

Actually, this being in a different time zone thing throws everything off!

Sir Smoty

 

[dave6666]

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