I was reading my December DIESEL POWER magazine and saw a article called DIESEL VS. GAS Chevy Engine Shootout. They dyno tested the Duramax and came up with these numbers. MAX POWER 303 hp at 3200 rpm. MAX TORQUE 507 lb-ft at 2700 rpm. I thought that was a big loss of torque , a loss of 153 lb-ft. Just thought I would share the info.

I was reading my December DIESEL POWER magazine and saw a article called DIESEL VS. GAS Chevy Engine Shootout. They dyno tested the Duramax and came up with these numbers. MAX POWER 303 hp at 3200 rpm. MAX TORQUE 507 lb-ft at 2700 rpm. I thought that was a big loss of torque , a loss of 153 lb-ft. Just thought I would share the info.
I saw another test at 295hp and 520tq, to the ground. You can expect large losses with large drivetrain pieces. Think of the huge tq converter, all the massive parts swinging around inside of the Allison all of which are on bearings and bushings with their own frictional losses.

Then, a heavy two piece driveline (well, in my case anyway) with carrier bearing.

Then, a huge ring/pinion set, thick axles and big rotors, all on bearings also.

Lots of friction. That's where synthetics come in. You can gain SOME of that back by making things more slippery where metal meets metal - at the same time being thinner for the parts to swing around in.

I was reading my December DIESEL POWER magazine and saw a article called DIESEL VS. GAS Chevy Engine Shootout. They dyno tested the Duramax and came up with these numbers. MAX POWER 303 hp at 3200 rpm. MAX TORQUE 507 lb-ft at 2700 rpm. I thought that was a big loss of torque , a loss of 153 lb-ft. Just thought I would share the info.

What were the numbers on the Vortec Max? (I'm assuming thats what they were testing).

Thats right about where I figured it would be based on how a stock LB7 dyno'd. 15 - 20 % loss thru an automatic tranny drivetrain I've alway been told to expect.

What were the numbers on the Vortec Max? (I'm assuming thats what they were testing).

6.0L

What were the numbers on the Vortec Max? (I'm assuming thats what they were testing).
6.0 Vortec LY6
Rated at 353 hp / 373 lb.ft.
Dyno at 279 hp at 5900 / 263 lb-ft at 4800rpm

Honestly the problem I have with these tests is who is monitoring the soot content in the DPF before the run? My truck really feels boggy when the DPF is full, and without forcing a regen (which the stock software doesn't permit) I just don't know how these guys are getting accurate numbers out of these trucks. In fact I would wager there's a 10% difference in power from a squeaky clean DPF to a full one right before a regen.

To back up my thinking I recently read a Chevy vs. Ford review where the Duramax made more power on the rollers, and then got beat in the quarter mile by the Ford. Having driven and raced several stock Ford 6.4's, I can tell you this is just BS (they are heavy and slow). My guess is that the system did a regen while conducting the quarter mile tests. But who really knows?

+1 on the clogged filter idea...

I was reading my December DIESEL POWER magazine and saw a article called DIESEL VS. GAS Chevy Engine Shootout. They dyno tested the Duramax and came up with these numbers. MAX POWER 303 hp at 3200 rpm. MAX TORQUE 507 lb-ft at 2700 rpm. I thought that was a big loss of torque , a loss of 153 lb-ft. Just thought I would share the info.
4x4turbo,

Our LMM with the converter clutch locked put down 302 HP @ 3200 RPM and 541 Ft-Lbs @ 2350 RPM on a load barring Super flow AWD dyno. I would assume that the magazine did not dyno with the converter clutch unlocked and or didn’t use a dyno that could provide the proper load to spool the turbo. Both of which would affect the TQ numbers.

thought i read somewhere that the allison takes 90hp to spin

That seems pretty high. Maybe all drivetrain from a standing start, but that would be more torque than HP.

I sure wish I would have made a stock run with mine before all the mods. I am convinced that the difference in the #'s are just the different dyno's the trucks are run on. I ran mine on Kennedys super flow