Nice gains. I've had my Westers 89/93 for a year and it STILL makes me smile I everytime I drive it !!! I'm about to upgrade, too ?!!? Whoo-hoo !!!!!

Wester knows his stuff .

 

I wonder why your truck dynoed so low, my truck with just exhaust put down 240hp and 352 tq. Granted I have the 4l80 and you have the allision but the numbers shouldnt be that far off.

Alex
yours stock 8.1/4l80e 240 rwhp 352 tq exaust
mine stock 8.1/ally 245 rwhp 299 tq airaid

this is probaly about right your exaust probaly freed up about 25 to 30 extra highend lbtq and your 4l80e prob is less restrictive on torque than my allsion by 15 to 20 lbtq.

also your truck has 3.73'S TO My 4.10'S That could cause a little difference in torque. not sure which way but it would cause some difference

if your truck has the 10.5 rear diff that could factor in as well mine has the 11.5 diff

Did you dyno on the 285's in your sig or on the stock size tires? that could cause more difference than any thing my dyno was done on 285's

 

the allison and the larger rear diff are enough to chop the nuts off your numbers. not bad considering the parasitic drag.

 

It had 245's on it when I dynoed it. Ya there definitley are alot of factoras I didn't weight in. Any ways I thought only the dmax trucks had the AA 11.5" rear end, my truck does have the 10.5".

Alex

 

I have the 2002 k3500 with the 8.1/allison and the specs from the factory are 340hp@4200rpm/455lb-ft@3200rpm
It seem from this that the driveline loss is more than the 26% ??

 

I think the factory specs on the h.p. are 330 h.p. for the 8.1, thats what my 2001 is. if you take my dyno number of 246.23 using the division method
246.23 h.p. divided by .74 percent = 332.74 h.p. at the crank

the torque does seem a little off though

299 tq divided by .74 percent = 404.05 tq at the crank so the torque loss is more like 30 percent

 

the specs for the 01 to 03 8.1's are 340hp and 455tq. 04 and up 8.1's are 320hp and 450tq due to some programming changes and adding pre cats.

Alex

 

Can any of you that have dyno'd post your graphs. I'm looking at the rpm that the max values were achieved at and can't fit these with the factory specs. I'm trying to get a feel for the best rpm to tow at. I beleive this would be somewhere near peak torque (455lb-ft at 3200rpm).
thanks Sam