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flames from exhaust?



Ive ran cam2 112 and 116 blue and never had flames. Also ran plenty of Octane boosters, never had flames either. Id say your cars pig rich. Whats the wideband say?
 
Wideband is reading 11.5 so I don't think thatd be rich enough... I might see tonight though what its saying while I'm pulling out of wot to see if is shooting rich or something...
 
Could be hot fumes that just ignite when they get enough oxygen too. A backfire out the exhaust wouldn't worry me as much as out the intake.
 
Just took it for a spin and have narrowed down when this is happening...

1. It only happens when I let out above 6K rpm...

2. Doesn do it letting out of first at all....

3. When I let off the wideband jumps to around 10 (couldn tell cuz it was so fast)

So I dunno maybe brians right but I'm still pretty convinced the toluene plays a part in it a little too...

Oh well ill just kinda see what happens...
 


When you let off the throttle, it starts to go into deceleration enleanment, it pretty much cuts spark, then fuel. You may be getting raw fuel into the exhaust, and the heat from the headers after running it up that hard might ignite the fuel when the clean air comes through.

Just a theory, but it sounds cool, don't it?
 
Bio248 said:
otherwise, speaking of 3800s in general, most backfire at least a small amount when they let off the throttle completely after going heavy into it. mine always did.
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That is your answer right there...mine had massive backfire with resonator and muffler delete, I had to put a glasspack :)
 


Floating valves...with stock springs...last I checked Jarred shifting much of anything over 5800 on stock springs is asking for a unhappy valvetrain.
 
Also a chemical compund that is found in a lot of other things... Very stable do to the 6 member ring it forms. Therefore increasing its flash point as the higher temp is needed to break the double bonds in the stable ring.
 


Reptile said:
When you let off the throttle, it starts to go into deceleration enleanment, it pretty much cuts spark, then fuel. You may be getting raw fuel into the exhaust, and the heat from the headers after running it up that hard might ignite the fuel when the clean air comes through.

Just a theory, but it sounds cool, don't it?
Click to expand...

It is IMPOSSIBLE to cut spark on a 3800.

You can get very low timing, but it will not ever cause flames in the exhaust, although it may help transfer some flames into the exhaust.

The real trick here is the fact that the transmission does not instantly "disengauge" at high speeds/rpms, so the trans will push the motor quite a bit, and it usually makes for a dead spot in the intake where fuel swirls strangely. I can usually get a really nice pop backfire when I put it in 2, and let out at almost any RPM, in my completely stock DD with a short exhaust.

I have yet to shoot a visible flame on my turbo car to my knowledge, and I am running many many devices that would help that happen (race gas, extreme timing mods, antilag, etc).

My buddies UGR TT lambo would toss a pretty decent flame out the back on shifts, and he was running meth injection and a fairly short exhaust.
 
SilvaMan61 said:
umm may i ask what toluene is? ive never heard the term, unless im misreading it
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Almost Tri-Nitro-Toluene, but not quite as much fire hehe

Had a buddy with a 02 TA that had really free flowing exhaust with a couple bolt-ons and he loved to rev it up to bounce off the limiter because itd shoot flames out, nothing major like the 2F2F cars but a couple puffs of pretty bluish-yellow fire

If your motor is really handling shifting over 6k with no problems, and your exhaust is that free flowing, and the race gas additive is working right, when you just let off the throttle at peak rpms you would be putting enough fuel thru the exhaust to do what Reptile suggested. Id say if your scanner isnt showing anything abnormal, your fine... enjoy it... wow people with it... back up to a cop and scare him with it :th_king-evil: j/k don't do that
 
gtpsleeper said:
Just took it for a spin and have narrowed down when this is happening...

1. It only happens when I let out above 6K rpm...

2. Doesn do it letting out of first at all....

3. When I let off the wideband jumps to around 10 (couldn tell cuz it was so fast)

So I dunno maybe brians right but I'm still pretty convinced the toluene plays a part in it a little too...

Oh well ill just kinda see what happens...
Click to expand...
My question is, how are you driving it AND checking for fire out the back at the same time? :th_laugh-lol3:

tayl5645 said:
Also a chemical compund that is found in a lot of other things... Very stable do to the 6 member ring it forms. Therefore increasing its flash point as the higher temp is needed to break the double bonds in the stable ring.
Click to expand...
That alone makes it sound awesome. :th_winking:
 
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