Well pulled twice now, with disppointing results.

Low side 1st gear, tachs out at 5100rpms runs the whole pull at 70% throttle,

or if a try to shift into second slight delay which shakes the sled and truck, loses speed and bogs the motor to 3100rpms (out of where the cams likes it around 3900++)


Last pull truck was bounceing start to finish

I was wondering what would you guys think would happen if I tried hi side 1st. would that be a split between low side second and first ???

OR

I have on my list to build a weight bar and set of traction bars. (I hear that a weight bar tame some boucing)

Any tip or Ideas???:help2:

Thanks again

CT:ro)

Are you holding it in 1st gear? I say leave it in drive and let the computer do what it can and see where that gets you.
What tire size and gear ratio you running?

285 75 r16 with 3.73

Time for 4.10 or 4.56 gears.
If you have your stock tires try a pull with the 245's it may give a few hundred rpm more when it hits second to let it pull in 2nd low

I tried quite a few times when I had my 8.1 to pull in second - never worked. Traction bars or clamps should tame the hopping, and/or more air in your back tires. 1st gear on the high side is faster than 2nd on the low side and your torque converter won't lock up in first gear. I don't think I'd try it, unless you can unlock some major horsepower so it'll pull it. And when the thing bounces off the rev limiter be careful of the motor mount! I broke the left one last year, had a hell of a time trying to figure out why my air intake tube keep coming off when I pulled. There's a huge jump in ratio's between 1st and 2nd, that's why it falls on it's face and won't pick up speed again. You have 3.73, I had 4.10 and still couldn't get it done, (2nd gear low side - that is.) A weight bar on the front is always a good idea.

I'd try to find some smaller OD tires but wider, like 265/60-16 to get a lower ratio.

They need to be a d or e rated tire though.

When I was pulling we had an 84 w/ LS-7 454 (around 600hp) and had a turbo 400 w/ 5.13 lockers in both axles and used 32" tires.
Usually pulled in 2nd gear low side, shifted @7000rpm.

Do you have a programmer where you can run the red line higher? If so, try to run up where's about 5500 that would get you 400 rpm's closer to where you need to be in 2nd.

The hypertech on my 6.0 gasser raised the rev limiter to 6200rpm and it liked to run up there too!!

I thought the Allison didn't like seeing anything over 5k? My 8.1 gasser I had a Diablo programmer, I turned the rev limiter upto 5500 and 6000, as soon as I hit 5000 it would be governed at 5k no matter what. Then I learned it was the TCM overriding the ECM. I think, I never investagated it all that much.

When I had my 8.1 I had the hypertech, K&N fipk, true duals, granatelli mass air flow sensor and the tornado. I kept it in first gear all the time at 6200 rpm. I had a 3 in body lift with 305 claws with the rear end blocked, and bounced all the time. Then I lowered the torsion bars almost all the way down, and put on a set of 285 non aggressive tires and Bingo. I started whooping ass. Plus we can weigh 7000lbs and the weight can only be in the bed of the truck. I hope this helps you to go kick some ass.

I thought the Allison didn't like seeing anything over 5k?

That's true but it's not a concern with a 6.0 since it has a 4L80E.

Do these 8.1's have nuts or what? I have driven the 6.0 a million times but never had the chance to get behind the wheel of a good old GM big block. I was lookin at Hypertech's dyno charts and it adds 50 -60 h.p. to that thing and another 55 lbft. I want to get one now. I have to know. That may be my next truck.

Be prepared to run premium fuel all the time in that state of tune. I did not like the way my Vortec 7400 responded to the Hypertech but to each his own. I did not notice any seat of the pants performance feel either aside from firmer shifts and raised redline. Not that it wasn't faster I didn't make any runs at the strip with it but it was not noticable like a program is on the diesels. They do run like SOB's though even in stock trim. The 6.0 is a dog in the trucks, and horribly so in the 2500's.

I thought the Allison didn't like seeing anything over 5k? My 8.1 gasser I had a Diablo programmer, I turned the rev limiter upto 5500 and 6000, as soon as I hit 5000 it would be governed at 5k no matter what. Then I learned it was the TCM overriding the ECM. I think, I never investagated it all that much.

Really? I turned my 8.1 5500rpm all the time. The problem is that 8.1 valves are heavy and they have weak springs. Combine this with the bigger cam 8100hammer is running and valve float could start showing up at 4500rpms. But this soon will be cured on his truck.

going to trade in my set of nitto terra grappers, for 4.10s gears and 265-75-r16 bfgs mud terr.s , set of long ass traction bars.

I hear "gray max" makes a nice set???