Flex Fuel Ethanol fuel scale

[ATS_Scott]

Has anyone had a chance to try this setting with a FF tune? I did yesterday, and its pretty cool. It actually allows you to only have 1 VE table on a FF tune. Here's how I used it, and I sort of stumbled my way through it, but i learned!

Tune non-ethanol fuel first, around here its about E10, but this particular car came in with E0 91 octane fuel. Leave fuel factor at 100%. Tune until you are dead nuts on your Lambda targets ( i messed this part up).

Drain pump fuel, and fill with your favorite ethanol blend. If you have FF VE blend enabled thats fine, but copy your entire VE table from pump over to your Ethanol VE table. I use table 1 for ethanol, and table 2 for pump. Make sure your Lambda table for ethanol is already set, and that FF blending for AFR (lambda) is enabled. Set Ethanol fuel scale to about 175, start the car and adjust fuel scale until your idle lambda matches your target, and if you did a good job with pump gas targets, and setting up injectors etc... Then just check your work. I ended up adjusting fuel scale to get Idle/ low load fueling correct, and then i had to go and tune high load areas and adjust lambda targets to get the fueling correct, because i didnt fully dial in to my targets on E0. That means i didn't correctly "describe" VE to the EMU.

Then to confuse the situation further, I dialed in a little exhaust cam retard, and had to go and retune most of the VE table. The really cool thing was, once i adjusted the VE table on E85 and cams, i started testing different ethanol blends, and by the time i got back to E0 my fueling was just where i left it before any Ethanol tuning or cam adjustment.

Huge thanks to Kuba and the rest of the ECUMaster team!

[Jadzwin]

Thanks That was an idea to help you

[Racekid21]

Thank's ! That's a good point for getting FF started.

Greetings

[ATS_Scott]

Thanks That was an idea to help you

It and the EMU worked flawlessly, so thank you!

[samvel]

So it`s kinda enrich% when on ethanol. When You switch back to gas you have to set scale back to 100%?

When i have played with FF 1.time i have made a mistake. I have tuned VE1 for gas and saved file. Then i have readjusted injector size (=base scale), fine tuned same VE1 and saved another file. When i was off dyno i have copy/pasted etahnol file VE1>VE2 and was about to start blending i`ve realized i can not blend because tuned on different base fuel scale. So i had to re-tune my VE2 on same scale VE1 again and after this i could start blending.
At this time Ethanol fuel scale was unavailable.

For me copy/pasting VE and just fine tuning with another scale seems more advanced and saves a lot of time/effort. But i do not want to set scale by hand every time i change fuel. So i think it`d be even more perfect if we could also blend this scale based on FF sensor value.

[ihiryu]

I'm pretty confused about this as well.

I've noticed in all of ATS_Scott's post, he mentions that he uses VE1 just for E85, and VE2 for Gasoline. Why is that? I couldn't find any other reason why.

[RHD]

I do believe Kuba would have allowed the ethanol fuel scale factor to be scaled according to the blend percentage otherwise it would be of very little use!

it is a very good idea to get things in the ball park since in reality the "VE" which is a mechanical constant determined by the engine design, which does not actually change. So an ethanol "fuel scale" brings the ethanol VE table back to basic correlation with the actual mechanical VE of the engine

[Jadzwin]

Ethanol fuel scale factor is scaled by Ethanol content

[samvel]

Good to know. So it`s enrichment % for whole span of FF sensor?
Does it scale only VE or all fuelling (enrichments, cranking etc)?

[ATS_Scott]

I'm pretty confused about this as well.

I've noticed in all of ATS_Scott's post, he mentions that he uses VE1 just for E85, and VE2 for Gasoline. Why is that? I couldn't find any other reason why.

Because there is additional "room" (255% vs 200%)in #1 enrichment tables, and E85 typically needs more enrichment that other fuels. I have not actually needed that much range, but it's available. Most of the cars I tune are planning to stay on E85 as much as possible, so I just prefer to use Table#1 for E85.

[ATS_Scott]

So it`s kinda enrich% when on ethanol. When You switch back to gas you have to set scale back to 100%?

No, it is automatic based on Ethanol content. I'd love to see what the fuel formula is when considering FF scale factor.

When i have played with FF 1.time i have made a mistake. I have tuned VE1 for gas and saved file. Then i have readjusted injector size (=base scale), fine tuned same VE1 and saved another file. When i was off dyno i have copy/pasted etahnol file VE1>VE2 and was about to start blending i`ve realized i can not blend because tuned on different base fuel scale. So i had to re-tune my VE2 on same scale VE1 again and after this i could start blending.
At this time Ethanol fuel scale was unavailable.

You should be able to scale your gasoline VE by the change in injector size to get it close. But you are correct, if you change anything that affects the Fueling equation, it will alter your fueling. I tackle it a little differently by "weighting" the blend table for VE so it will force me 100% to VE1 or VE#2 depending on what i need to tune. You do have to be careful and plan ahead depending on your actual Ethanol content. If your only E70 when tuned, you need to compensate for AFR if later the car is able to get E85, but that is where the FF scale factor comes in. It can do this for you once you have set the VE with gasoline or E10, just adjust the FF scale factor to achieve the target lambda at whatever your current ethanol content is.

For me copy/pasting VE and just fine tuning with another scale seems more advanced and saves a lot of time/effort. But i do not want to set scale by hand every time i change fuel. So i think it`d be even more perfect if we could also blend this scale based on FF sensor value.

If you are using the FF scale factor, you will only require 1 VE table for all blends of gasoline/ethanol. The FF scale factor takes the place of the second VE table AND the VE blend table. If you leave the FF sacle factor at 100% you can do 2 VE tables, and use the VE Blend table. I suppose you can still use the blend tables if you really want to make it more confusing with addition of FF scale factor.

[samvel]

If you are using the FF scale factor, you will only require 1 VE table for all blends of gasoline/ethanol. The FF scale factor takes the place of the second VE table AND the VE blend table. If you leave the FF sacle factor at 100% you can do 2 VE tables, and use the VE Blend table. I suppose you can still use the blend tables if you really want to make it more confusing with addition of FF scale factor.

Yes, by copy/paste i mean they are same and no actual VE2 needed. This is great approach, considerably saving time and effort of tuning.
Does scale factor scales everything fuel related or only VE?