Not sure what you mean by DC? I am a bit limited in injector choice due to fuel. I have almost 3000cc per cylinder available 
in general the injectors I am using are less of a stream and a little more of a cone shape.
Best would be some close injectors for low speed and far ones for high, but who has the budget for that.
In reply to Paul_VR6 (Forum Supporter) :
sorry, DC=Duty Cycle. That was the variable that seemed most important to hp, but only when injection timing was tuned.
I have a couple data sheets that I can't share a lot of detail from because they are not mine, but low/high placement was 1-2% more for high, while long/ short DC for these 2 was 3-4%. Uncontrolled is the spray pattern becasue injectors changed to change the duty cycle and it looks like low/high placement was only tested with short DC on both engines so there are holes.
Ah I will be tuning for max power anyway and can log it all as I go. I will just give it what it wants for max power avg, even out afr/egt per cyl and see what happens.
I would assume as the mixture prep gets better the DC for a desired afr would go down all else being equal.
In reply to Paul_VR6 (Forum Supporter) :
That all sounds right....but if charge cooling is involved as I believe it is then as you dial in the injecting timing both hp and DC should increase to maintain the AFR. All I have to look at is best tune results for each condition and I wasn't there so I don't know what all they changed to get to best tune. I also don't have enough data or discussion data points to really know the best DC. I know from the couple dyno sheets that going from 80ish to 35ish DC helped. I know from another source that going from 85ish to 60 helped....different shops, very different engines though so where optimal is I really don't know.
True I was thinking that the primary method of "more power" would be from the increased atomization, so you would need less total fuel for an ideal mix. I will already have some pretty meaty cooling effect (testing on methanol) so likely it won't be a huge change compared to other fuels that will change more with dwell in the port.
The fun part about this is you can argue it all about 10 different ways but once you hit the rollers the winner is the winner and you just need enough data to explain the why to make the next leap.
In reply to Paul_VR6 (Forum Supporter) :
You can get maximum cooling with methanol. And probably best power.
One problem. You're restricted to the size of your fuel tank or a chase truck filled with drums of methanol.
At least with E85 it's far more accessible.
My fuel cell is only 2gallons, it only needs to run for a few minutes at a time.
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