TurboBerserker

iTrader: (1)

Yes, but not by a heck of a lot. The big amount I show up there is the outside edge. Even the 50/50 mix will be more than 99% of all the cases out there (the examples are with 2 15 gph nozzles spraying at capacity).

trever1t

iTrader: (14)

You should post this up in the tech only section too. Good info.

vanillagorilla

iTrader: (1)

Not to bring up an old post, but I'm not following your calculations here.

You have 8 injectors rated a 96lbs/hr at 43.5psi. At 18psi boost you should see roughly 61.5psi rail pressure at which case your injectors are now flowing 114lbs/hr. That's 912lbs/hr total or 152gph of fuel.

Now you have 2-15gph nozzles flowing 100% meth, with meth being 50% oxygen. So you have 15gph of methanol, which leaves you with a ratio 15/152=.1 or roughly 10% meth. Crunching more numbers says that you should be shooting for 11.45:1 AFR when targeting 11.5:1 AFR without meth.

Correct me if I'm wrong, but that doesn't seem like a big difference to me.

TurboBerserker

iTrader: (1)

Remember that the trucks run on 4bar of fuel pressure, so the 96ers aren't starting at 96lbs (so we have to first convert to the 58psi base pressure, then add 18psi = 76psi).

I'm running late, so I'll have to try to get back to this post

vanillagorilla

iTrader: (1)

Right, I thought you were running a 3bar setup since I thought you're running Megasquirt. It just seems counter-intuitive that you're replacing gasoline with another fuel that has a lower stoich value, and you're target AFR is higher on the guage.

TurboBerserker

iTrader: (1)

Yes, at first glance, it does, but think about it this way:

you are now trying to measure the lambda of a fuel with a lower stoich than what the gauge is calibrated to, so the gauge will read higher than the actual lambda.

vanillagorilla

iTrader: (1)

So at 58psi plus 18psi boost you have 76psi rail, that equates to ~126lb/hr per injector. That's 1008lb/hr total and 168gph.

15gph of meth with 168gph of gas. 15/168=.0893 or 8.93%

8.93% meth and 91.07% gas

.0893*.93*6.4+91.07*1.07*14.7=14.86 mix stoich

14.86/14.7=1.011 gauge calibration discrepency

11.5/1.011=11.37

dhpro

iTrader: (3)

U shud talk with Slowhawk

BlownChevy

iTrader: (20)

More like 40 psi at the rail....the boost pressure is pushing back on the injector.

TrickTurbo

iTrader: (12)

if the regulator is a 1 for 1 boost compensating it should 58psi. You may see 76psi on the rail but as BC said the boost pressure is pushing against the fuel coming through the injector. It all depends on how the regulator is set up.