could i tune my car to make back fire when letting off the gas peddle

[wesam]

Could i tune my car to make back fire when letting off the gas peddle by increasing the fuel in VE and pulling some timing in the 15 kpa MAP ?
is there any drawback if i do it ?

[DrkPhx]

Why in the world would you want to intentionally make it back fire?

[WeathermanShawn]

Yea, I am not quite sure what you are trying to do..about the only way to ever get it to 'bark' on Decel is to engage DFCO and go really low on the DFCO Timing.

In my state if the car behind you happens to be State Trooper expect to get pulled over if that happens.

I am not sure I would go out of my way to have it happen, but occasionally on cold days it will do it on a rapid DFCO decel.:rolleyes:.

[Taz]

Looking to get flames coming out the tailpipes like they did with Hot Rods in the 1950s ?

That would be an “off road” use only option - at a car show, etc. The “old school” technique was to mount a spark plug in each tailpipe (controlled by a switch), “load” the engine up with excessive fuel, then hit the switch.

I think some of these “nostalgia” kits may be still available - I haven’t seen something like that in a long time.


Regards,
Taz

[wesam]

I don't want it to make flames but in almost all my friends Vettes it will make a sound like it bark when let of the gas peddle and this what i want to do :)

[WeathermanShawn]

1. Enable DFCO
2. Make B3336 all zero's or -10
3. Increase B3334 by 500%..say .5000

Works better when its colder..

Have 'fun'..

[wesam]

Thanks Shawn
but shouldn't B3336 increased so it will pull timing faster ?
if i decrease it it will not pull big amount of timing

[WeathermanShawn]

This is the way I read it..

When DFCO is active the timing will be reduced to this amount until the fuel is cut. So, it should reduce it to that Spark value..

Another Table to play around with would be B5939.

Just log it to make sure...

[mr.prick]

I don't want it to make flames but in almost all my friends Vettes it will make a sound like it bark when let of the gas peddle and this what i want to do :)

Could it possibly be just aggressive exhaust your friends have?

My Camaro used to have the SLP Loudmouth and it would do this. :yucky:

[Sid447]

Could it possibly be just aggressive exhaust your friends have?
My Camaro used to have the SLP Loudmouth and it would do this. :yucky:

Agree,
normally the popping and crackle on over-run is the result of a good free flowing exhaust system, not tune settings.

e.g. A stock CSV R8 here (Pontiac G8 GXP or HSV Clubsport R8 is same) had a stock tune and once the factory exhaust system was changed to 4-into-1 LT's and an aftermarket system, it started popping like crazy.

Also the 2005 & 2006 CV8's (Pontiac GTO) will do it on the factory tune just blipping the throttle in neutral at a standstill when they are fitted with a free flowing after-market exhaust system.

Seems to have more to do with the amount of baffles in the mufflers than fiddling with the tune.

(Would have thought dis-abling dfco from happening is the way of ensuring more unburnt fuel went into the exhaust system. IIRC Vettes had this dis-abled in the factory tune). :cheers:

[Black'Rado]

After a nitrous pass, my truck goes into DFCO and gets that backfire, or popping sound. It scared me at first and i thought i had a stuck solenoid. But is this indeed a good sign of a free flowing exhaust?

[WeathermanShawn]

Who knows. Try a cut-out and see if you get that sound.

With nitrous I would never assume anything.