well i've had this problem for a long time. it happens every once in a while, if i stomp on the gas it will pop through the intake (if im sitting in park just reving it or if i'm sitting at a light and stomp on it). it only does it when its idling: the second you first hit the throttle. this is the main reason i didnt go with a true wet kit. but anyway, i've tried everything from logging my car and different tunes and stuff. my lterms are right where they should be. it did it when i had delco platinums (.050") and its done it with my TR6's (gapped at .033" and .040"). i've been told intake backfires are a cause from the timing being off. it does it with stock timing and now, i've back my timing off quite a bit for the nitrous (most of which is from map value from 50 to 100). i dont have any knock retard anymore on the motor either. so i'm just wondering what else i should be looking at to try to get rid of this. timing at the map value around idle? my fuel pressure is fine, and i have no misfiring at all other than that. thanx for your input.
Ryan

 

1) You dont need to just hit it from an "idle" (2) Make sure you are up on the convertor good or aren't bogging it if you have an m6 (3) if you are up on the converter good or aren't bogging it, program a little more fuel into it in the lower rpm's. This should take care of the problem, been there, busted pistons, etc...

 

i have an a4. and although i dont usually just "hit" it from a stop on the street, it still shouldnt backfire through the intake. and also i just dont want it to do it when i'm at the track because thats when i do hit it full throttle. and it doenst seem to have any problem bogging when i do start hard. thanx again,
Ryan

 

Intake valve too tight, bent, burned?
Leak down ok on the engine?
Compression good?

 

U know hot rod hawk i didn't think about that one. Even ofter 10 yrss of playing with nitrous and building engines i can't believe i didn't think of that.

 

good call. i'll have to test those soon. thanx