Alright I Have An 04 Gmc Sierra Rcsb Z71. I Ran It At The Track The Other Weekend And It Kinda Dissapointed Me On The Top End. My 60' Time Was 2.20 Which Is Fairly Good For A Stock Truck Except A K&n Fipk. But My Final 1/4 Time Was 15.70 @84.89. I Have 3.73 Gears And My Weight Was 4900 # With Me In It And A 1/4 Tank Of Gas. Is It Slowing Down That Much On The Top End Or Am I Just Thinking That And Also What Can I Do To Help It If It Is?

 

that's a pretty good 60' for a big Z. i think the best i pulled was 2.21, anyway i don't know what to tell you about the top end. i'm sort of new to the truck scene but my chevelle with 3.08 gears had a slow 2.05 60' ran 13.30's and a high mph @104. with 4.11 gears had a better 1.78 60' ran 12.90's with the same mph@104. i'm guessing it has to deal with your weight and gearing. just my $.02

 

did you have that nelson tune when you ran the 15.7?

sounds like you should be faster with the tune and CAI. i am guessing low 15's. i was running a 15.7 with exhaust, CAI, and HPP3. and that is with an EC. after the TC, i was getting 15.3

your 60' time is pretty good. better than what i can get.

headers and exhaust should help you some.

 

Your mph is about right, maybe just a little low. But not much. I think you need exhaust to let it breath on the top end. The only way to increase mph a lot is more horsepower. A better 60' is going to increase ET.

 

seems good for a 4x4.

 

All of these times can be brought down significantly with more $$$$$. That's still pretty good for a mostly stock truck.

 

I wonder what my truck weighs..

 

probably low 5k

i programmed my G-tech with a weight of 5400 lbs for a 4WD EC

 

Yeah, that seems like a pretty good time to me for that truck.

 

I've ran 15.0 with my '03 rcsb Z-71. I've got HP Tuners, ls1 fans, aem brute force intake, edelbrock shorty headers, corsa cat back, shift kit, and ported polished throttle body.