The thing is.... There's no need to run that much timing... Use Michael's pw vs CA degrees spreadsheet and see how much duration is needed for a 3000 us pulse at 4600 rpms It will blow your mind. 82.8 degrees of duration!
So if you subscribe to the 50/50 theory then you need 41 degrees of advance to make that happen. Not an ideal situation...
Shorten up the durations by using a larger injector orifice and you'll be able to run less timing and get the injection duration down to 30 degrees or so. This will decrease heat, increase power output per fuel used and be easier on the motor.
At 1500us duration you only have 41 degrees of total duration, which is roughly 20 degrees of advance for a 50/50 shot.
In JNeals motor we've targeted 12 ATDC for EOI which equates to 26 degrees at 2000us. This has proven to make some very good power on an otherwise stock motor, single pump, w/ cheetah. The truck runs dead clean after spool up and only runs 1450 going down the track with 40,000lbs behind it.
Using Michael's spreadsheet, at 4500 rpm we should use 42 degrees of timing advance for an EOI at 12 degrees ATDC. We're not loading the motor up there though, we just use that for inertia getting off the line. The truck carries around 3400-3000 rpm going down the track, and this is where the spreadsheet tells us we should be running, you guessed it 2000us and 26 degrees advance
Just something we've learned and proven on the track. I really need to get some CP data from the truck. I think it would be interesting.
Brayden
