exhaust flames - how and why???
A mystery to me is why some racing cars have flames licking from the exhaust on the overrun. I don't mean turbos, but NA racing engines. And I'm not talking about the short sharp spits of flame (my 105 used to do that), but long slow big licks of flame - think V8 SuperTaxis and you'll know what I mean .
Now my questions are:
Firstly, how and why does this happen
Secondly (and I know this is childish and I SHOULD KNOW BETTER), but can I get my V6 to belch flame on the overrun?
So engine gurus - what is the go with this?
Now my questions are:
Firstly, how and why does this happen
Secondly (and I know this is childish and I SHOULD KNOW BETTER), but can I get my V6 to belch flame on the overrun?
So engine gurus - what is the go with this?
Jason
1983 GTV6 2.8 litre
1983 GTV6 2.8 litre
Turbo charge it..run decent boost,rich mixtures,serious ign . advance on light load and viola !!
lurid flames on over run !!!!
or activate the anti lag on the Haltech ecu...spectacular !!
lurid flames on over run !!!!
or activate the anti lag on the Haltech ecu...spectacular !!
French cars are shit and shit expensive to service and bloody awful and unreliable and expensive and friends don't let friends drive french cars and you wait years for parts.
Re: exhaust flames - how and why???
Easy peasey.GTV27 wrote:A mystery to me is why some racing cars have flames licking from the exhaust on the overrun. I don't mean turbos, but NA racing engines. And I'm not talking about the short sharp spits of flame (my 105 used to do that), but long slow big licks of flame - think V8 SuperTaxis and you'll know what I mean .
Now my questions are:
Firstly, how and why does this happen
Secondly (and I know this is childish and I SHOULD KNOW BETTER), but can I get my V6 to belch flame on the overrun?
So engine gurus - what is the go with this?
The engine tuner sets the engine managment system to add alot of fuel on over run/trailing throttle and either cut spark or massively retard it.
The excess fuel pumping thru the combustion chambers helps to cool them. The fuel passes thru the combustion chamber unburnt or mostly unburnt and then it ignites in the hot exhaust. The flame you see out the pipe is the end result.
If you realy wanted your v6 to do something that silly, you could try some sort of dodgy fake airflow meter signal that you send to the computer when on closed throttle above a certain RPM.
Using a closed throttle switch, a variable RPM switch, they close a relay that sends a voltage that coincides with a high engine load to the ECU.
Prolly won't give you the desired results tho.
Realy stoopid and will wreck your cat. converter (which converts cats into less harmful gasses .
Not really a serious proposition for my GTV6, just suggested as a hypothetical as to how this would occur.
Thanks for the explanations - the fuel for cooling on over-run and hot exhaust hypothesis sounds plausible. Must 'waste' a lot of fuel though- which could be an issue in an endurance race (or any race with a fuel stop for that matter). Suppose it does allow extra HP, so is all in a good cause.
Thanks for the explanations - the fuel for cooling on over-run and hot exhaust hypothesis sounds plausible. Must 'waste' a lot of fuel though- which could be an issue in an endurance race (or any race with a fuel stop for that matter). Suppose it does allow extra HP, so is all in a good cause.
Jason
1983 GTV6 2.8 litre
1983 GTV6 2.8 litre
Re:
GarthW wrote:Yep just boost it! hehe haha har
I'm quite fine with naturally aspirated
http://www.youtube.com/watch?v=gpmzGiviCJw
- Rookie ROX
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Re: exhaust flames - how and why???
That pales in comparison to this mean beast
http://www.youtube.com/watch?v=_VKq8922 ... re=related
ROCK ON
R~R
http://www.youtube.com/watch?v=_VKq8922 ... re=related
ROCK ON
R~R
Re: exhaust flames - how and why???
I think most factory ecus shut off the injector if the throttle position goes to 0. The ecu will only supply the pulse to turn on the injectors again when it reaches some RPM value like say... 2000 rpm. I did the same for mine. On the street it pops and crackles too much if you don't turn off the injectors on overrun.
Dr. Alban
Re: exhaust flames - how and why???
It's scarey how sad some people realy areRookie ROX wrote:That pales in comparison to this mean beast
http://www.youtube.com/watch?v=_VKq8922 ... re=related
ROCK ON
R~R
Re: exhaust flames - how and why???
Some here say that you should have a big ignition advance, an another says that you would need the spark cutted or retarted big time. Which one do I want?
And what is heavy advance, ~40 degrees?
Much retard, what is that, ~0 degree, -20 degrees?
And what is very rich mixture on overrun? Is 11.0 -> 10.0 AFR enough?
This one I have to try
And what is heavy advance, ~40 degrees?
Much retard, what is that, ~0 degree, -20 degrees?
And what is very rich mixture on overrun? Is 11.0 -> 10.0 AFR enough?
This one I have to try
Re: exhaust flames - how and why???
Tested some now. And the only setup that would pop and bang on overrun was -10deg and ~17afr.