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how to avoid nitrous backfire ?? any basic infos ??

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Old 05-25-2009, 09:47 AM
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Default how to avoid nitrous backfire ?? any basic infos ??

well ,

i'm runing two wet stages on my 02 T/A
1st stage 200hp
2nd stage 100hp

and i already had belw up a 92mm F.A.S.T intake before "twice"





actually it happes only when hitting both stages on the 5th gear
i didn't have any problem hitting the 1st stage (200hp) to the end of the 5th gear before and i already used to do that many times without any problems

also i didn't have any problems hitting both stages on 3rd and 4th gears , so my only problem is just when hitting them both on the 5th gear

my new intake is F.A.S.T 92mm opened to 96mm and ported by vengeance racing with F.A.S.T burst panels



















so i paid alot for dat shitt and i'm looking to not blow it up like my last intakes

that's why i need to know What causes a nitrous backfire and how it can be avoided ??

one more thing , A/F ratio with n2o was little rich bt i can't remember now how was the A/F exactly , but all i can remember that my tuner said it's o.k and no matter to make it little rich for more safty

any openions will be highly appreciated
Thanks

Last edited by alharbi; 08-09-2009 at 11:01 PM.
Old 05-25-2009, 10:05 AM
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Don't spray fifth.If you've still got a stock t56 it's overdrive, that's usually a no no. Also, are your kits comming through the front or DP? If they are both plates or plate/nozzle, that's alot of gas comming through the front, and may be causing issues
Old 05-25-2009, 01:10 PM
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Agree with above. Is it a DP or plate. You should only spray from 1st to 4th and your run should be over in the 1/4. I would not be doing that much spray unless you have a D.P. Or it will puddle or lean out the back.
Old 05-25-2009, 03:44 PM
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How much timing is in the engine on both kits? It's possible that maybe the engine is loading up when in fifth gear.
Old 05-25-2009, 04:39 PM
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Originally Posted by jdiddyws6
are your kits comming through the front or DP? If they are both plates or plate/nozzle
1st stage : TNT plate
2nd stage: HSW nozzle
Old 05-25-2009, 04:43 PM
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Originally Posted by dnkynrbk
Agree with above. Is it a DP or plate. You should only spray from 1st to 4th and your run should be over in the 1/4. I would not be doing that much spray unless you have a D.P. Or it will puddle or lean out the back.

so it's better switching to DP for the 1st stage ?? is that all ??
what about tune ? how it must be you think ?
what about decreasing the chance of runing rich when nitrous on ?

Last edited by alharbi; 05-25-2009 at 04:52 PM.
Old 05-25-2009, 04:50 PM
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Originally Posted by WE TODD DID
How much timing is in the engine on both kits? It's possible that maybe the engine is loading up when in fifth gear.
timing 21 degree
and i'm feeding the fuel solenoids from my stand alone fuel system which contain 125 octane VP racing fuel


Originally Posted by WE TODD DID
It's possible that maybe the engine is loading up when in fifth gear.
would you please clear that .
what you mean exactly by loading up ??

Thanks
Old 05-25-2009, 05:00 PM
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as others said dont spray in 5th,at the level of spray your using I would go direct port.Then you can hit it with a 400 shot on the street
Old 05-25-2009, 05:35 PM
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Originally Posted by alharbi
timing 21 degree
and i'm feeding the fuel solenoids from my stand alone fuel system which contain 125 octane VP racing fuel




would you please clear that .
what you mean exactly by loading up ??

Thanks
5th gear is probably bogging the engine somewhat, which can cause fuel and nitrous to load up in the cylinders. There is far too much load on the engine in 5th gear. I would suggest, like the others, to not spray in 5th.
Old 05-25-2009, 05:37 PM
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Remember, 5th gear is over driven, so the engine is actually spinning slower than the wheels.
Old 05-25-2009, 06:43 PM
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agreed with above is there anyway you can NOT spray in 5th
Old 05-25-2009, 07:51 PM
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Originally Posted by alharbi
1st stage : TNT plate
2nd stage: HSW nozzle
Yeah, seems like you're overloading the front. If i had the money, I'd go dp with a progressive, and DON'T spray in fifth, it's bad news
Old 05-26-2009, 07:58 PM
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Ok thanks everybody I appriciate the help.

so no more N2O in 5th

ok i just was reading this in ls1.com and some one there had wrote ...

a nitrous backfire occurs when the motor's ability to rpm upward is too slow or stops. the intake manifolds fills with nitrous and fuel, but has nowhere to go. at some point, one of the intake valves open and unburned combustion enters the intake (called reversion) and ignites the mixture inside the intake.

Also timing retarded too far,usually happens from someone trying to be overly conservative trying not to hurt a motor


** is there any method can be done to minimize the chance of (reversion) ??
what if i incresed the exhaust flow like going to bigger headers like the 2" kooks or a cutout to increase the flow so no more (reversion) accures
or improving cam specs for more exhaust flow
i'm runing a custom camshaft which has specs. 254/258 624/624 114LSA

** what about 21 degree of timing ? is that o.k with 300-400 hp nitrous mixed with 125 octane racing fuel ?

Last edited by alharbi; 05-26-2009 at 08:07 PM.
Old 05-27-2009, 06:25 PM
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Originally Posted by robsquikz28
agreed with above is there anyway you can NOT spray in 5th
actually some times i have to race for long distance here where i am
and i have to spray in 5th to reach the 1/2 mile as fast as possible especially when racing with bikes
Old 05-28-2009, 06:04 PM
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damn thats alot of nitrous
Old 05-29-2009, 11:50 AM
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Originally Posted by blackls1ta00
damn thats alot of nitrous
this doesn't help
Old 05-29-2009, 12:56 PM
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You should be logging your runs. i will bet that the rpms are way to low in 5th gear for the amount of spray and added fuel you are spraying. Like has been stated, likely you are experiencing fuel drop out due to low air speed. If you find your self really needing to spray in 5th gear to win a race, I would log a run and find out what RPM you will be running. then you might be able to add a small hit? I would not even try if it were my personal car. So like has been stated, don't spray in 5th and you should be good to go, unless there are other problems. even a DP and that size hit is a no-no in 5th gear, IMO, the motor will be lugging to much. have you ever seen a dyno graph of how much tq there is with that size hit, and down low in the rpm band it has a much more likely chance of causing damage even with no back fire. Why? Because it causes such a large increase in cylinder temps and pressure and stays there longer per revolution and thus a greater chance of damage.
Robert
Old 05-30-2009, 07:32 PM
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Originally Posted by Robert56
You should be logging your runs. i will bet that the rpms are way to low in 5th gear for the amount of spray and added fuel you are spraying. Like has been stated, likely you are experiencing fuel drop out due to low air speed. If you find your self really needing to spray in 5th gear to win a race, I would log a run and find out what RPM you will be running. then you might be able to add a small hit? I would not even try if it were my personal car. So like has been stated, don't spray in 5th and you should be good to go, unless there are other problems. even a DP and that size hit is a no-no in 5th gear, IMO, the motor will be lugging to much. have you ever seen a dyno graph of how much tq there is with that size hit, and down low in the rpm band it has a much more likely chance of causing damage even with no back fire. Why? Because it causes such a large increase in cylinder temps and pressure and stays there longer per revolution and thus a greater chance of damage.
Robert
that made sense to me , and i really appreciate your help ..

any more openions about minimizing the chance of (reversion) ??

Thanks,
Old 05-30-2009, 07:37 PM
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Originally Posted by alharbi
that made sense to me , and i really appreciate your help ..

any more openions about minimizing the chance of (reversion) ??

Thanks,
go FI (turbo supercharger)
Old 05-30-2009, 08:13 PM
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way to much timing for that big of a hit and thats alot of spray to put thru a tb you should use a direct port, and what plug are you running?
Originally Posted by alharbi
Ok thanks everybody I appriciate the help.

so no more N2O in 5th

ok i just was reading this in ls1.com and some one there had wrote ...

a nitrous backfire occurs when the motor's ability to rpm upward is too slow or stops. the intake manifolds fills with nitrous and fuel, but has nowhere to go. at some point, one of the intake valves open and unburned combustion enters the intake (called reversion) and ignites the mixture inside the intake.

Also timing retarded too far,usually happens from someone trying to be overly conservative trying not to hurt a motor


** is there any method can be done to minimize the chance of (reversion) ??
what if i incresed the exhaust flow like going to bigger headers like the 2" kooks or a cutout to increase the flow so no more (reversion) accures
or improving cam specs for more exhaust flow
i'm runing a custom camshaft which has specs. 254/258 624/624 114LSA

** what about 21 degree of timing ? is that o.k with 300-400 hp nitrous mixed with 125 octane racing fuel ?


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