Hondata

I'm very underqualified for this... and I think I may be doing it wrong, or right, or at the very least, I'm confused. Initially I was following the kit's chart that said for around 300hp (flywheel) you would be running around 2135 ml/min of fuel and at 350 you would be running around 2526 ml/min at peak power. I'm going to guess I will be around 330 at the crank or so just as a rough figure let's say that it would be around 2330 ml/min fuel. My 225ml/min nozzle at 150psi actually flows around 285ml/min and that would put me at 285/2330 = 12.23% mixture to fuel.

That somewhat differes from what I saw with how I had to adjust a/f -- adjusting a/f, I end up removing 175/3850 fuel units (4.5% fuel) to return my a/f to 11.65:1 where it was originally for this round of tuning. Given that the stoich for methanol is 6.4 and petrol is around 14.4 or so I have been calculating that it would take 2.25 times as much methanol as fuel to make that big of an a/f impact. That seems to suggest that I'm just at 10% methanol to fuel, and with my 40% methanol/water mixture, that would put me at 10 * 2.5 = 25%.

I have been a bit worried to try a bigger nozzle given that the change in fuel would seem to suggest I'm already at 25%.

How can I determine how much fuel I'm pushing (ml/min)? I tried a few things with the injector ms and the injector flow ratings at 50psi and even tried some stuff with calculating based on duty cycle bla bla and I really don't know how to get a good idea of how much fuel I'm providing to gauge what nozzle/pressure to use.

Any help in this area would be greatly appreciated.

Wayne

It could be that you 2330 ml/min estimate is high. Re-calculate the fuel flow based on injector size, fuel pressure and duty cycle. Most injectors are tested at 40 or 43 lbs, so a 550cc injector will flow more at standard fuel pressures. However, with the in tank regulator, I see a big pressure drop at high fuel flow (10 psi), since the regulator is in the tank. Also, remember that injectors flow less under boost due to the lower pressure differential.

RC injectors are tested at 43psi.
Duty cycle is 63% off spray at max.
Flow rate of 650cc injector @ 50psi is Sqrt(50/43) * 650 = ~700cc.
Flow rate of 650cc injector @ 40psi is Sqrt(40/43) * 650 = ~627cc.
Total injector flow capacity is between 2550 and 2800cc.

2550 or 2800 @ 40psi vs 50psi
1606 or 1764 @ 63% duty
~18% or ~16% @ 285 ml/min spray

Seem about right?

I hope that's right as I'd love to be right at 16 - 18 % ;).

I'm guessing that the remaining difference between 16-18% and 25% estimate based on fuel tuning is due to displaced atmosphere in the form of water and half as powerful methanol.

My check valve is suposed to arrive tomorrow. Perhaps then I will be able to keep the tank filled up. Nothing I like more than coming into the garage in the morning and finding my car has drooled all night out of the cai ;).