nitrous backfire?

[juiced347]

was at the track on monday made a good nitrous pass on one stage, went up to the line second time, did the burnout, purged the system, boomed the first system 125 hp hit, worked fine boomed the second system 225hp hit and had a nice lil backfire that blew out the burst pannels and wrecked the carb.... any ideas on what would casue this, fuel pressure was fine and bottle pressure was normal 975psi i called my builder and he said on the promods he tunes on cold days they have to hold the throttle a lil higher around 3500-4000 rpms or they will have back fires, i had the pedel at around 2500.... any one have any imput on this.... i am using a wilson 2 stage plate system,check the fuel pressure bottle pressure was good and thats it i am out of ideas! btw on the 2nd system i was pulling 10* of timing PLEASE HELPPPPP

[69chevydr]

I would never boom any system (even a small one ) below 3k rpm could pinch the rings. As for the backfire in cold weather the system is going to be lean due to more oxygen concentrated in less humid cooler air,you should probably add about 1/2 lb fuel pressure and maybe take out a degree or 2 of timing on the bigger hit when its cold out or even just drop your bottle press. about 50 lbs. Just my thoughts

[Pyott Racing]

I bring mine upto around 3200 or so before I bump it through the engine.Just so you know, bumping it is hard on part no matter what rpm you do it at and many say it is unnecessary and purging is enough.I have begun to agree with this.also, especially on cold days make sure youe engine is up to temp before you spray it!! cold eng. and the go juice are a recipe for backfires!!

[mrhockey]

I am a little late jumping in on this one but I always used to bump both stages into my motor before a pass and never had any issues. The beginning of this year I mentioned it to John Balinsky and he said he never purged a fogger into the motor so I decided to give it a try. I went this whole year and just purged into the air to adjust the bottle pressure and didn't have any back fire issues and didn't notice a difference. I think it can clean the motor out because you can feel it get crisper if you burp it more than once but I was trying to keep the power down off the line to prevent wheel spin so that didn't matter.

[adamsvega]

i always arm it and let it flow just as the tires start to drag the motor down below 4200 in the burn out. it flares up and let of the line lock off. it rolls out hard and the throttle switch closes it off - the purge is only for second stage if it breaks loose rolling on first pass i never purge again. if it spins outta the hole i wont arm till after the burn out . just me , never back fired and never spun more than once .they dont give us alot of chances on raceday

[cmracing]

I've never had a backfire yet. When I first started using nitrous I had a BIG problem being too rich and running too little timing. I was trying to do my liscense passes and the car was stepping into a wheelstand like it was walking up a ladder! It would pop and fart out of the exhaust and you could see the car making small steps up, I could feel it in the car too, absolutely crazy! Never came out the intake though. I eventually found the right people to talk to and got it right. No more problems. Now when it leaves it smoothly pulls the wheels up and smoothly sets them back down, really amazing how gentle it is, even with the front end 4 feet off the ground!

Sorry, can't help you with the backfire issue.

I also hope that you aren't one of our Wedneday night guys that I just love to see at E-Town for the test-n-puke sessions! I love the guys that purge about 2lbs in the air, then bang it through the motor, go to the line, and every once in awhile launch the hood scoop 40ft in the air with a HUGE fireball! It's a good show for us in the stands whil eating our burgers though.