running out of room on ve table

[racerron]

i running methanol on my 410c.i. windsor 98mm turbo. my ve table is max out by 6200 @ 150 kpa. i have my required fuel at 8.2. i know i have to raise the req fuel. the question i have is how high should raise the required fuel enough to make it to 300 kpa and once i adjust req fuel is there some formula to re number the ve table. because im running methanol my afr's are in the 9 to 10 to keep the egt below 1200 degrees Fahrenheit.
i attach my msq

new10adj.msq

[Paul_VR6]

Are using 6:1 afr in the reqfuel calculator?

[racerron]

Are using 6:1 afr in the reqfuel calculator?

no. if i lower the required fuel to 2.9 (410c.i 8 cylinders 450 lb injector 6.1 afr) my billet atomizers are actually are 500 lb but that is @ 90 psi of fuel pressure. i run my bace pressure @ 60 psi. it hits 255 even earlier.

[billr]

Have you flowed the injectors at your pressure, with your drivers? The req_fuel being so far from calculated, and the VE table being so far from reality makes me think you haven't. I gotta ask, does this engine make the 2500-3000 hp implied by that injector size?

[kaeman]

Have you flow tested your injectors at 60 psi? If they flow 500lbs at 90 psi, I would be surprised if they flow 450lbs at 60 psi, what kind of horse power are you making with this combination. In looking at your msq I noticed that your cylinder trim ranges from 5 to 40 depending on the cylinder, how did you come up with those numbers, egt measurements?

[Paul_VR6]

Are using 6:1 afr in the reqfuel calculator?

no. if i lower the required fuel to 2.9 (410c.i 8 cylinders 450 lb injector 6.1 afr) my billet atomizers are actually are 500 lb but that is @ 90 psi of fuel pressure. i run my bace pressure @ 60 psi. it hits 255 even earlier.

Strange. You have "multiply map" and "incorporate afr" on in the fuel calculations menu?

[jamies]

i think your stoich afr for include afr target is wrong..(you have 2.8?) if your using petrol scale, with methanol this should be 1 lambda or 14.7
also why the 37% difference in fuel trims between cylinders?

[racerron]

i guess i have a few things to work on. i do have egt's thats why im add fuel to the cylinders to make them more even in temp. my temp range is within 200 degrees now. im using methanol and at 14 psi im at 54% duty cycle. so you need more fuel with methanol. im shooting for 1500 hp.

[racerron]

Have you flow tested your injectors at 60 psi? If they flow 500lbs at 90 psi, I would be surprised if they flow 450lbs at 60 psi, what kind of horse power are you making with this combination. In looking at your msq I noticed that your cylinder trim ranges from 5 to 40 depending on the cylinder, how did you come up with those numbers, egt measurements?

What is your guess on the injector flow @ 60 psi? 400 lb per hr.?

[racerron]

I just talked to jack at billet atomizer and @60psi injector flow would be 402 lb per hr.

[billr]

Is that pounds of methanol, or pounds of gasoline? Are they using drivers exactly the same as yours?

[jamies]

they are a low impedance injector

[racerron]

they are a low impedance injector

Yes they are low impedance injectors and I'm running a peak and hold injector driver

[racerron]

Is that pounds of methanol, or pounds of gasoline? Are they using drivers exactly the same as yours?

I don't know

[Paul_VR6]

Most injecors are flowed with iso octane or gas but methanol specific gravity is close enough that it will work fine. Its only when you have wild fuels it drifts off.

[racerron]

talk to a guy on the forum and we concluded to try and change the stoichiometric AFR from 2.8 to 6.0 while the engine is running and watch the pulse width. at 900 rpm the pw is 1.727. it should go up by .2 when i change the stoich AFR.

[racerron]

Most injecors are flowed with iso octane or gas but methanol specific gravity is close enough that it will work fine. Its only when you have wild fuels it drifts off.

ok

[Rick Finsta]

Ron, I got a chance to look at it this morning, and here's what I get. With Incorporate AFR, you are adding a multiplier which is your inputted Stoich AFR (in the general settings tab) divided by your target AFR. I've never looked this far into the fueling calculations so I could have some things wrong here.

So right now your AFR Target modifier (at idle) is 2.8/10.5 which is 0.27.

If you change your stoich to 6.0, then it will be 6.0 / 10.5 which is 0.57.

However, it will also change your req_fuel down to around 3.0 or so. The math works great at idle - drop your VE down to around 50% (which is reasonable) and you end up with about the same 1.8mS through the calculation.

Problem is it doesn't seem to scale at your WOT with the numbers you gave me yesterday. So I think what you need to do is:

Change Stoich to 6.0-6.5
Re-calculate req_fuel (should be around 3 using the 402lb/hr @ 60psi and 6.5 for stoich)
Then, scale req_fuel by an arbitrary amount. Say multiply by 1.3. Then scale your whole VE table by 0.7. Basically raise one 30%, drop the other by 30%. You're losing resolution that way, but gaining top end on your VE table. So in my example you'd have 3.9 for req_fuel and then your 255kPa bins would change to high 170s, which should give you plenty of room for more boost/fuel. You'd be down in the 20-30s at idle after retuning.

Someone catch me if I'm screwing something up. I'm concerned that the math works at idle based on the change in the Incorporate AFR factor, but not up top on the table. Something seems off.

[racerron]

Ron, I got a chance to look at it this morning, and here's what I get. With Incorporate AFR, you are adding a multiplier which is your inputted Stoich AFR (in the general settings tab) divided by your target AFR. I've never looked this far into the fueling calculations so I could have some things wrong here.

So right now your AFR Target modifier (at idle) is 2.8/10.5 which is 0.27.

If you change your stoich to 6.0, then it will be 6.0 / 10.5 which is 0.57.

However, it will also change your req_fuel down to around 3.0 or so. The math works great at idle - drop your VE down to around 50% (which is reasonable) and you end up with about the same 1.8mS through the calculation.

Problem is it doesn't seem to scale at your WOT with the numbers you gave me yesterday. So I think what you need to do is:

Change Stoich to 6.0-6.5
Re-calculate req_fuel (should be around 3 using the 402lb/hr @ 60psi and 6.5 for stoich)
I see what you're saying. Thanks mike
I get what your saying. You explain it in layman terms. Thanks Mike.
I get what your saying. That's for the info mike. I like the way you explain things. Like layman terms
Then, scale req_fuel by an arbitrary amount. Say multiply by 1.3. Then scale your whole VE table by 0.7. Basically raise one 30%, drop the other by 30%. You're losing resolution that way, but gaining top end on your VE table. So in my example you'd have 3.9 for req_fuel and then your 255kPa bins would change to high 170s, which should give you plenty of room for more boost/fuel. You'd be down in the 20-30s at idle after retuning.

Someone catch me if I'm screwing something up. I'm concerned that the math works at idle based on the change in the Incorporate AFR factor, but not up top on the table. Something seems off.

[racerron]

I see what your saying. Thanks Mike. You explain things in layman terms.