I took my truck to the drag strip today and it was slow as crap. Here are my times R/t .866 60' 2.393 330' 6.737 1/8 mile 10.3 1/4 mile 15.8 90.9 MPH my tires did spin a little but I was disguisted with my times.
Does any body got any suggesting.





GMC sierra 2wd. sc 4.8, whipple spercharger 6lbs. of boost, no cats 43lb injectors, K&N intake Nelson tune.

 

yeah something very very wrong with that, ive ran a 9.7 1/8 with my minor mods in 100 degree heat haha you sure everything is hooked up cause that is around what a stock 4.8l should run, sorry i cant be more helpful but damn yeah something is really wrong

 

Do you have a boost leak? Like a hose completly off or something?

 

What elevation are you at?

 

I don't have a boost leak I just think the computer is not tuned right.My boost gauge reads 6lbs. before it shifts. what should the air fuel ratio be?

 

i see you have a nelson tune, everyone here seems to hold him in high regard, but have you logged it ? or dynoed it or had an exhaust gas reading done ? the reason i ask is these whipples seem to all be completely different, i'm having a hell of a time tuning mine, getting really funky o2 readings. an example of this is ryansilverado has essentially the same setup but with a cam and an intercooler, his ifr is set at 5.12, i had to drop mine to 5.00 to get the ltft's close to zero. so what i'm saying is even though you had a pro tune if you have a whipple it might not even be close. oh yeah, do you have a boost gauge ? are you sure you're running full boost or just assuming. i going on the assumption you have all the whipple electronics hooked up, if your bypass solonoid if malfunctioning you may only have 2-3 lbs of boost. these are just suggestions and since i know nothing about your truck they're just guesses.

 

forget what i said about boost, you posted before i finished. but your fuel could still be off. all i know about tuning for fuel is what i've learned here. if you have a way to log get you ltfts in line and the wot should fall somewhat into place mine is much better now. what are your o2's at wot ? if your whipple is like mine these won't help a bit, but i'm curious.

 

sorry to say, but i ran better than that with my stock 4.8 and 3.42 peg leg

somthing is VERY wrong

 

Did you remove the 2 Whipple injectors when you installed the 43 pounders?
Any other mods besides what is in your sig?
What was the weather like? Heat? Humidity?
Forced Induction hates bad weather, especially a non intercooled setup.
I only had a chance to run my 4.8 once before I blew it up, but on it's one and only pass I only managed a 14.5 at 95. The weather was horrible...85 degrees and very,very humid and sticky.
That was with the 4.8, whipple at 6pounds,4.10 gears, yank 3000 stall,dual exhaust dumped,K&N fipk intake,Gibson headers,Predater tune,still runnning stock injectors with the 2 whipple ones.

 

I ordered my whipple supercharger without a computer and electronics and had allen tune my computer for the supercharger with 43lb. injectors. I do have a boost gauge in my truck and at red line it reads 6 lbs. of boost. I'm going to my friends house later to see what all the readings on the cpu are.
thinks for the help I will get the info soon.