OK, I went to the dyno today. Had a few problems. 1. Hit the rev limiter 2. Hit the speed limiter. I guess my Tahoe limits at 5200 rpm or so at WOT. The speed limiter, which I had raised to 130 mph, was still not high enough. At WOT I earned 230.9 hp and 284.6 tq. But as I said, I hit the speed/rev limiter. On the 2nd and 3rd runs, holding in second gear, I got 236.4 / 283.9 & 236.4 / 348.4 respectively. Still hit the rev limiter on the last 2 but the speed limiter wasn’t a factor.
1. Why is my torque so different between the 2nd and 3rd runs? Must be a typo because the graph doesn’t show anything over 250.
2. Why are my numbers so bad?

I have a Westers 93 hot tune and a cat back exhaust and still a guy with a completely stock 2004 Silverado 5.3 posted better numbers than me by 10hp. What gives? Doesn’t Chevy claim 285hp on these engines? Am I really losing 50 horses through the drive train? I attached the dyno sheet.
Chris

 

24 views and not 1 reply. You guys need some coffee or something?

 

I think your results are within reason. My '01 Silverado rolled 240rwhp and 275tq. Yes, the driveline saps torque and therefore hp. When are you installing the Radix?

Richard

 

you can figure 17%-18% for drivetrain loss....also, the 24's are NOT helping you AT ALL because it takes ALOT of HP to turn those steamrollers, If you dyno it again do it on the stock size tire....I'm willing to bet you pick up 20hp

 

Maybe you should have got the Nelson tune. You would probably gain another 20hp over the 20 additional hp with the stock wheels.
Jim

 

#'s dont sound to far off at all considering the mods on your truck which is a tune and wheels, tq looks good to, im talking about the 284, im sure that 348 was a typo or just a tq spike for whatever reason.

 

I'm with the others who think that your tune and tires and wheels are what's hurting you. Westers tunes are known to be conservative and I bet those 24's are pretty heavy.

I tried to dyno last week in 3rd gear (speed limiter issues like you) and got 231/297. In 2nd I got 260/279. All with my 20's which are actually 4lbs lighter than my stockers. Put your stockers back on and you'll be right there.

 

Thanks for the inputs. The Radix goes on tomorrow. That's why I did the dyno yesterday, to get a baseline. I will do another run with the radix and 24's to see the difference it made. The I might put the stock wheels back on and dnyno just to see the numbers. Any suggestions on where I shouls get the rev and speed limiter set?
P.S How much a Nelson tune? Do they ship you a hand held programmer or, like Westers, do they send you another computer with the tune installed?

 

he will send you a tuned pcm.he also has pulleys for the radix as well

 

I think like everyone said, the power that chevy claims is at the flywheel, not the wheels. So I think that you are about right. I dont know about the other chevy that got 10 horses, maybe cause he got in some good runs...did not hit the limiter.