Ok I got a 2000 gmc 5.3 excb with the base sts kit, 43# injectors, nelson tune, Meth inj,high low boost controll,373.posi. This truck ran a 16.20 on my g-tec stock before my posi. Now at 5.7 lbs boost I can only hit a 15.60 at 91mph. Somthing has got to be wrong! Shoulden't it be alot faster than that?
I haven't tried the meth or the high boost since it's probaly not running it's best. What should my truck mph be shifting outta 2nd at, and what should the rpm be? Thanks in advance. Mike

 

Any help or should I post this somwhere else. Thanks

 

THE TRUCK SHOULD BE SHIFTING OUT AT ABOUT 5400RPM STOCK AND ABOUT 81 MPH ROUGHLY. I HAVE THE NELSON TUNE AND IT IS SHIFTING AT 5700 RPM AND 85MPH ROUGHLY. AND YES THERE HAS TO BE SOMETHING WRONG BECAUSE I AM RUNNING A 15.39 WITH A K&N FIPK AND A NELSON TUNE WITH 3.73 GEARS AND A POSI, IN A RCSB 4WD!

 

get a dyno tune

 

Something is definatly wrong. I ran 15.90's before the STS and 14.77 @5psi and this was before i put the injectors,ic, fuelpump and 02pcm. I hadn't made it back to the track but i should be in the low 14's. and this is a 2500HD. You need to put it on a dyno and get it tuned.

 

Thanks guys

 

Take it to a track

 

Yeah or can Nelson help you with it. I ran 16.12 shifting manually at 5,700 and was right about at the end of the 1/4 at the top of 2nd. My friend hit 15.56 in his 00 rcsb,5.3,3.55 peg,FIPK Silvy in the other lane. Good luck!

 

wow, that's pretty shitty! I ran a 15.0 in my truck with the stock rims, tune, long tubes, and exhaust.

 

14.7's with drop in K&N, flow pro muffler, HPP3, and descreened MAF is what i was running 2 years ago.