Backfire After WOT

[JaBoT]

I helping my friend tune his new motor and we're having a strange problem.
After Running wot when you let off the gas the car backfires through the exhaust loud. Sounds like a cannon went off under the car! The longer your at wot the louder and longer the backfire is.
The o2's are 800 and egt's are at 1530.
The car runs fine and pulls hard otherwise.
He is running a very large cam, a little over 230 if i remember with fully ported heads.
te-44, 40 lbs inj, maf translator w/ 3.5 maf, turbotweak alky chip and an smc dual line kit.

Thanks

 

[next_level]

sounds like it's loading up on gas ans some unburnt fuel is getting into the exhaust....cant help ya with a reason though...im new to these cars

 

[turbotwister]

it can do this for various different reasons.for starters,if the exhaust has a leak it will suck in cool air under deceleration and cause this.if the exhaust has no back pressure it can cause this also.another thing i have found is if the cam sensor is out of adjustment enough it will cause this also.probably becuase of unburned fuel entering the exhaust.

nick,

 

[RKturbo6]

Its funny you should mention this because this happened today. I later found out my IC-TB hose had popped off. I hope this was the reason and not the result.