Went to the dump with the truck - more to weigh it than anything else....
Its got porky... 500# more than the last time I had it on the scales. 4375# !
Guess the biggest adds were the 4L80e and the dana 60.
A bit more from the last dyno session... The boost peaked at 18# @4500 holding until 5200 then tapered off to 15 at 5300 holding steady until the end of the pull at 6200 rpm..
Max torque (wheel) was 608 Lb/ft and 605 hp at 5200 - the torque fell off with boost. Figure 15% drive train loss. Darn close to 3 HP(flywheel/cu_in) This is on M100 - 5* of added timing made a big jump in power (40 HP). I checked the turbo map - its maxed out...
The dyno operator has tuned a lot of high HP cars (2800+ hp 10.5" tire cars etc..) figures if the boost held at 18# we would get close to 710 RWHP...
At 8# its already making 450 RWHP at 4000 - peaks at 510 at 9.5 - this is on 94 octane pump gas.
I have some plenum work to do and get the GT4570 installed. Before the end of the year we'll make another trip to the track..
Old Jimmies don't die they go faster (GMC 1/2 ton)....
Last edited by efi-diy; 06/17/1312:54 AM.
51 GMC 4.2 turbo Can't solved today's problems using the same technology/thinking that created them
