my set up is a 95gsr, t3/t4E with 3" ehaust, tail WG, 450dsm, with a smc500 to control it...
in fisrt it will run fine then in second and realy bad in third it will strat to hesitage at 55k and at 6k it kinda sounds popcorn poping, but it is a deep sound... i thought it was the timeing, so i retarded it to 8BTDC but it still dose it...???? what is wrong.. i have try goin from -30 to -50 on the smc with no change and everthing in between.. HeLP

 

Did u change out your stock exhaust straight with your turbo install or did you run a while with your stk exhaust setup while boosted and then change out to 3" after?? Reason I asked is when I had my stk system with just HKS muffler and de-cat I was OK, but after I got a custom made 3" straight thru downpipe back I get this popping noise at the top end....I know this doesn't help you much but least I know going to a bigger exhaust has caused this problem....

 

if your fuel is ok, what is your plug gap? what plugs?

 

STOCK PLUGS.. GAPED TO .033

 

Could be detanation, could be that your fuel pump is not able to delive fuel under higher boost levels, could also be that your running a stick plus when in fack yould be MUCH better running the 7 series ngk since its 2 steps colder, it could be tuning in general.

Mine was just on the dyno for over 8 hours in all and it was MINT on the dyno but as soon as I got home and started driving it, its doing things it never has befor But I dont care. Ill see how it goes at the track on mon day. Im going to a better track and im tuned better so I should run better times and if not. Then I know something is up!

Good luck. It sucks when crap us always happening, But listen careful to the sound with windows up and stereo off cause if its detanation you want to have it tuned and checked out cause a blown engine is no good for enyone! That sound to me is how you described it but others like to use marbles in a tin can sound!

 

anyone else???