fuel injector duty cycle and methanol question

mike13 · 10-01-2009, 04:27 PM

Not sure how to word this question, but here goes.

If you have a turbo combination that puts you right at 90% duty cycle on 42lb injectors if you run 100% methanol at 1000cc min what will this approximately drop your duty cycle to if you tune for the same 11.5afr?

The motor is right around 650 crank horsepower

I asked this over in the fuel injection forum but no replies.

Johnv · 10-01-2009, 05:23 PM

I don't think anyone could give you a definate answer to that,
you will need to be more like 11.0:1 afr with meth.

even so you will be able to pull some fuel out of the tune and lower your duty cycle at the same power level.

But if you add more timing and or boost and make more power more fuel will be required.

I have duel nozels and a 250psi pump, at 15 psi boost without meth i am at 11.8 afr with the meth AFR drops to low 10s and thats with an extra 5 deg timing.So i can still pull some fuel, made an extra 45 rwhp.

'Trust' · 10-01-2009, 05:42 PM

You don't ever want to use methanol as a bandaid for lack of injector. Your injector duty cycle will be the exact same with meth, but you are getting more fuel to the motor via the meth kit, it will just make your mixture richer.

MIGHTYMOUSE · 10-01-2009, 07:01 PM

18% of my total fueling is from my meth... on high boost.. exactly

i know because my fuel trim is perfect +/-0 on gas alone and (get this) -18% when the meth is spraying

probably harder to capture that with a stock computer.

cablebandit · 10-01-2009, 10:02 PM

my meth is providing 18% of my total fueling as well
on the street i run 11.5 afr.

Jimmy P · 10-02-2009, 03:02 AM

You guys that have logged the meth is using 18%, what type of meth nozzles do you have? Single or double?

Johnv · 10-02-2009, 04:37 AM

Quote:

Originally Posted by cablebandit

my meth is providing 18% of my total fueling as well
on the street i run 11.5 afr.

IS THE 11.5 afr with meth?

Mine is in the low 10s and i was going to shoot for 11.0:1 with meth.

MIGHTYMOUSE · 10-02-2009, 04:39 PM

i run two snow nozzles, a 625 and 375 both wide open on their high pressure pump

i run different afr's depending on boost, from say 11.5 at low boost up to about 10.8 at high boost

YSILT1 · 10-11-2009, 02:53 PM

Are you guys running 100% meth or a mixed amount with water.

I am trying to see what I should run with 20lbs of boost. i was hoping to run 80lb hi imp. injectors and do the rest with the meth.

MIGHTYMOUSE · 10-12-2009, 06:06 PM

pure meth