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Power corrupt LBZ tune!

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Hello everyone,

Yesterday, a good friend called me to check out his LBZ-swaped Hummer H1 (Bone stock LBZ hardware, stock H1 exhaust with behind the axle muffler). He told me the ECU calibration was stock as well. We went for a ride and.... man, the thing hawls! I have almost no experience with the 6.6 Duramax, but right off the bat, I told him, this heavy 8000+ pound truck is too fast and too smokey on spool to be stock (under full boost, it blows minimal, decent, smoke). I read the ECM with HP Tuners to check out the tune. I spend a couple of hours analyzing this wicked tune. No EGR, 3600 RPM limiter and TCM tune, 14 psi extra boost, lots of extra duration, hacked diagnostics (some mandatory for the swap, other I see no reason for...), high torque limiters, etc.

Nick, in the worked example, you do a Stage 1 on a Duramax. Very traditional remap procedures with added efficiency and driveability refinements (kudos for that). But this tune on my friends truck, it´s beyond my experience and technical judgement. I am sharing the injector duration map, which I found the most outstanding in terms of aggressive changes.

Best,

- Angelo

Attached Files

Angelo,

I've got a bit of experience with high HP H1's myself -> [url=https://www.youtube.com/watch?v=ZwZRwMC__NM]https://www.youtube.com/watch?v=ZwZRwMC__NM

One more for fun-> [url=https://www.youtube.com/watch?v=CH-De1ZS4sM]https://www.youtube.com/watch?v=CH-De1ZS4sM

I can tell you that the PW map you've posted has enough fuel in it for nearly 500HP if the turbo and intake are sufficient. Many of the conversion Hummers I've seen and tuned use poorly designed intakes that restrict flow and also artificially inflate the reported MAF signal due to their narrower-than-stock pipe diameters.

Also note worthy is the amount of inflation to the PW graph even at modest fueling rates. There's no reason I can think of to inflate the factory PW map at 20mm3 unless you're looking for more smoke or running a smaller than OEM injector nozzle.

You could probably make a lot of progress cleaning up the tune by taking a more calculated approach to the PW table and adjusting the mixture limit (B0795) table. Add '.1' lambda at a time until the smoke cleans up then fine tune.

Hope this helps,

Nick