69CapriceHDTP

2011 Silverado 2500 6.0 TVS1900 with ported 2300 lower tub and 3.2" pulley. So I got my truck dyno'd and obviously the 3rd gear pull is the 1:1 ratio, he would not do it in 3rd because he says these trucks will lose the driveshaft at the top end of 3rd because they are unbalanced. The truck did 362rwhp in 2nd gear, any way to calculate what that would be in a 3rd gear pull? The number just seems low to me. It was done at 8lbs boost, where under load on the highway I can pull 12lbs.

Vortec350ss

iTrader: (20)

Your truck is actually 1:1 in 4th gear with the 6 speed trans. A second gear dyno is going to read very low as you pointed out. He is right that its common to toss a driveshaft at the top of a 1:1 gear in a big truck.

Interesting that boost was low though. I can see it maybe being a tad low on such a short pull, but 4 LBS is a ton.

ZO6Ted

Think its 1.15. They did mine in 4th. NM its a 2500...

Vortec350ss

iTrader: (20)

Nope you're still right.

69CapriceHDTP

So is there any way to calculate the difference?

SUPERCHRGEDGMC

madmann26

iTrader: (7)

It's not that the driveshaft is unbalanced it's very very thin material.

You need to invest in a built driveshaft before bad **** happens.

smokinlmm

X2... I hit 485 with my 5.3 and 1900. Who tuned it?

smokeshow

iTrader: (16)

Stock cam?

Atomic

iTrader: (42)

Tires make a huge difference as well. That number isn't that out of line for 8psi and 35"+ tires.