Originally Posted by KevinD

thats correct, you do need to account for the manifold pressure when calculating the flow rate of your meth with a given nozzle size.
Just doing a rough est. thats all, but you get the drift.


thats not exactly what i said. i said scaling has no effect on the fuel delivery when you have IDC and the rated flow rate of the injector. the scaling is used by the ecu, injector duty cycle is a percentage of the total open time in a given cycle. if your at 50% duty cycle you are approximately using 50% of the total size of the injector. 100% duty you are using 100% of the size of the injector as it is open continously. the only thing changing the scaling does is change the multiplier for how long the injector is open for. for example, if you have a stock injector and run it with the stock scaling, it will work fine. but if you rescale the stock injector to be 1000cc injectors, the car will run extremely lean (and most likely wont run at all). this is because the size of the injector didn't change but the ecu reduces the pulse width because it thinks it is a way bigger injector. try it, take a stock injector and rescale it to be 780cc injectors. you will have to go through your fuel tables and add about 40% more fuel in order to get the tune the same as before. and you will find your IDC will end up being about the same as before you rescaled the injectors (assuming both tunes are hitting the same AFR). so IDC * by the size of the injector is the max CC used, regardless of scaling factor.
I see what your saying, but I guess it didnt make sense that 9's IDC is so high when it really isnt. I know I have mad math sometimes but hey its was 1:30 in the morning so cut a brother some slack :P


that is also correct (well kinda, you contradicted yourself with the second sentence). for the o2 sensor itself, it doesn't make a difference what fuel is used. lambda will work the same way no matter what fuel is used. but for the case when your wideband will read out in AFR, then you need to rescale the AFR values depending on what the stoic ratio is. i've used some of the most expensive widebands availible (motec), and they would read out in only lambda. it didn't matter what fuel we were using, gasoline, E85 or M85, lambda would always readout about 1 for idling. we had to go in and rescale the output to the laptop though, which would be in AFR.

I was talking about the sensor , then moved to changing lambda I know I can be confusing changes subject so quickly. we have the same points man

right! i have a different target lambda then with gas only. i target .82 lambda and on my gas calibrated wideband (or 14.7 stoic ratio AFR display if thats what you want to call it), that reads 12:1. with gas only i would target .78 lambda or 11.5:1 AFR on the gas calibrated AFR display.

you are making this way more complicated then it is... i use a wideband that reads AFR for gas, of course the meth changes what the scaling for the AFR conversion would be, but i'm not going to change the scaling factor and tell people they are hitting 10.9 AFR when on the wideband it might show 12:1. most people only know AFR in a 14.7 scaling.

SEE why using AFR's can be confusing LOL lambda FTW. Yeah I'll start using lambda for now on. no more AFR's



in your last statement you said why would you set your wideband for a different stoichiometric ratio. now you are saying you set your wideband for 13.3 AFR. you know that ratio is only good at the point you calculated your mixture? unless you actually mix the fuels together and use the same delivery system (i.e. the injectors), the mixture will be different for every RPM and every boost level. if the mixture is different, your stoic ratio will be different. if you are going to that trouble, just say everything in lambda, it will be much easier.

I was saying change your stoich only when your tuning meth since you have a new stoich value, since for normal driving your using straight gas.

i'm not sure what you're trying to say here, but i was tuning the car on a dyno. and since i know how to tune a car (not as simple as adding more timing or more boost), i can assure you that the mixture the AFR was tuned to was optimal. in fact we could have gone even leaner, but since we didn't have EGT's to work with its better to be a little safe. adding more timing induced knock at the boost level we were running. and slowcar ran a ton of meth too....

I didnt say in didnt know how to tune trust me, but slowcar would still be close to gas stoich. So thats why a leaner mixture is better. Maybe the afr was little to lean for that amount of timing. Dont assume that some of "street tuners" dont know how to tune either, I was just giving you an idea bro. I know there is more too it trust me . I would love to due this, would be a dream of mine to have a shop and tune cars or be apart of well known shop. But my first love is the military, and love what I do. Dont get me wrong I tune cars still here and there but trying to find the time with working is hard. I will say this Kevin @ least you like being safe thats a great thing to have, some tuners scare me with these "edge" tunes I call them.

i think we are trying to argue the same point. the only difference is you are saying you target 10.9 AFR with a 13.3:1 stoic ratio, or lambda of .8-.85.

i am saying i target 12.5-12:1 AFR with a 14.7:1 stoic ratio, or a lambda of .82-.85. we have the same lambda which is the important part.

i didn't know you were stating your 10.9AFR with a 13.3 stoic. no one ever changes the stoic ratio when stating AFRs with meth injection. if you specified E85, M100 or any constant mixture fuel it would make sense. but with a mixture that constantly changes it doesn't make sense.

Yeah we are making the same points but in different value LOL. Alot of guys change there stoich value when injecting way more meth than me. Check out the innovate forum MAN thats all those guys talk about lambda lambda meth meth meth LOL

Originally Posted by cfdfireman1

KevinD it's pretty well known that the most power can be obtained from gasoline right at .85 Lambda, for Ethanol is at .75 any idea what that would be for Methanol? Now what happens when we start mixing these fuels at various % at different RPM ranges and then throw some water into the mix?

Forget AFR's and stick with Lambda guys, we Yankees are the only ones that use it and for good reason.

Originally Posted by cfdfireman1

My head hurts.

Originally Posted by KevinD

try changing your mix to a little more meth. you don't need 100% meth, but maybe a 75/25 mix.

Originally Posted by cfdfireman1

Very good thread using 20% H2O and getting big power. 30 degrees of timing at redline with a IX.

https://www.evolutionm.net/forums/sh...ghlight=timing

Originally Posted by bnice01

meth makes its best power @ 4.5:1 so thats .69 lambda since its stoich value is 6.5:1.

Originally Posted by crcain

From this thread I have gathered that 12.5:1 is actually provably the best AFR for gasoline in terms of power / energy production. Any links to this as this is interesting.

And for whatever reason, most of us tune for 11.5-12:1 on gasoline. Let us use 12:1 as an example. 12:1 AFR for gasoline is .82 lambda.

Now bnice01 says best power for meth is 4.5:1.. or .69 lambda.

Let's say we were using 60% gas and 40% meth. Would it be right to say that our ideal lambda technically should be something like:

.69 + ((.82 - .69) * .60) = .76 lambda

That seems odd.... as it seems a bit rich. Tell me what I'm doing wrong. I was just trying to come up with a way to get a lamda in between the two lambdas which was proportional to the fuel used.

Originally Posted by bigric09

my last meth tune... running 50/50....

my pump map i tune for 11.5 to 11.3 by redline...

my meth map i tune for the same AFR, maybe even a little richer, but i add about 3* of timing or so at peak and probably 6 or 7 up top. I picked up 75hp/70tq on our dyno here running this style of meth tuning. Im using an SMC kit, m15 nozzle. Start spray i have set around 14 and full spray around 22 and im running 27 or 28psi.

would you guys recommend a different method of tuning to try ? i hit 499/420 on my tune but personally i think there should have been a lot more there. i was guessing mid 500's. Any ideas as to what i can try ? i dont want to run 100% meth as my car seems to like the water in the mix... but what about running a leaner AFR and less timing ? or a richer AFR and more timing ? i know a lot is trial and error, but what have you guys experienced