drivetrain loss

[jason31]

Perhaps a poll should be taken. Some tuners seem to have more conservative numbers than others. What is the real hp of our zo6. 405-50, -60, or -70. These numbers are floated around quite a bit. I don't know whether or not a tuner is incappable of producing good numbers or is just giving a conservative estimate. I know of two vendors who seem to have different views on drivetrain loss (50 vs 70). What do you think.
Thanks,
jason

[case2307]

I use 13%. I think that is pretty close. My car pulled 359 stock...using 13% that would put me at 405 crank. I think it's somewhere between 13-15%.

[RobGrnfld]

MTI calculates a 12% loss with the 6 speed and a 15% loss with an automatic trans...seems to be alot of different measurements depending who you talk to.

[PerforminNorman]

Most GM 6 speeds are about 12% loss. Automatics vary greatly depending on the tranny configuration and the stall converter type. The dynoshop used 22% on my 4L60E with the 2400 converter.

[IT L GO]

For the C5 platform which is more efficient than the C4. Lingenfelter uses 15% for the 6 speed and 18% for the C4.

.

[TTRotary]

Percentage can produce erroneous results. M12 drivetrain loss in HP at stock engine redline is known to be 50HP. If you change cam and you make max power at 6800 rather than 6200, you add 10% friction, so you now have 55HP loss.

The stock LS1 makes max HP at 5600, so the loss was only 45 HP.

Examples for manual cars:

97+ LS1: 350-45= 305 RWHP
01Z: 385-50=335 RWHP
02+Z: 405-50=355 RWHP