How to run E85 on stock 86 BRZ FRS with OFT tune

[steve99]

Originally Posted by Shutter

Just pulled off 318 miles with e85, daily driving(90% freeway) with a handful of wot pulls

I was gonna get gas at 250, but I realized that I forgot my wallet at work...so I did the "I think I can get to work with the gas light on" gamble.

Yes, my tank was practically dry lol

adjust these tables below and you will get a bit more

full description
http://www.ft86club.com/forums/showthread.php?t=83945

[steve99]

Originally Posted by Td-d

Has anybody actually tried using the table cryptically called "Table_Fuel_Multiplier_Display" ?

@Td-d

Thanks
tested that and it seems to work well

DI pressure multiplier was upped 30% over petrol

so upped the Table_Fuel_Multiplier_Display values by 30%

seems reasnobly accurate after a tank.

I do run a lot of DI on E85 and little PI
not sure if PI display scaling is adjusted but the Displayed value in dash seems a reasonable approximation of actual economy on E85 now.

[DC2R]

Originally Posted by steve99

@Td-d

Thanks
tested that and it seems to work well

DI pressure multiplier was upped 30% over petrol

so upped the Table_Fuel_Multiplier_Display values by 30%

seems reasnobly accurate after a tank.

I do run a lot of DI on E85 and little PI
not sure if PI display scaling is adjusted but the Displayed value in dash seems a reasonable approximation of actual economy on E85 now.

So should we follow the link our just up that value to 30%¿

[steve99]

Hopefully your rom definition has the table
Table_Fuel_Multiplier_Display defined

if you have it then yes up the values in that table by 30% and your in dash display should read correctly for E85

what link are you talking about ?

[DC2R]

Originally Posted by steve99

Hopefully your rom definition has the table
Table_Fuel_Multiplier_Display defined

if you have it then yes up the values in that table by 30% and your in dash display should read correctly for E85

what link are you talking about ?

The E85 changes link. Sorry I was too lazy to read the link. Read it now. Disregard.

[steve99]

Originally Posted by DC2R

The E85 changes link. Sorry I was too lazy to read the link. Read it now. Disregard.

Table below

[jaf89f]

@steve99 Would you advise that I rescale my MAF considering I have a Grimmspeed Intake on my car? (I thought I read something in a different thread suggesting not to since the MAF in the Stage 2 EL e85 tune was 1:1...)

If so, can I simply use the MAF scaling from the 91/93 Stage 1 Tunes provided by Shiv (which I was previously running while on 91/93), or should I rescale it based on e85 data logs given the change in power, and I'm assuming air flow as well.

Thanks!

[phrosty]

Originally Posted by jaf89f

@steve99 Would you advise that I rescale my MAF considering I have a Grimmspeed Intake on my car? (I thought I read something in a different thread suggesting not to since the MAF in the Stage 2 EL e85 tune was 1:1...)

If so, can I simply use the MAF scaling from the 91/93 Stage 1 Tunes provided by Shiv (which I was previously running while on 91/93), or should I rescale it based on e85 data logs given the change in power, and I'm assuming air flow as well.

Thanks!

Changing the MAF scaling on the E85 tunes is fine if you have one that's already made on the 91/93 tunes.

What you can't do is calculate the scale using the E85 tunes, because the same data you use in calculating is also used to adjust for variable E% and thus won't be useful in finding the MAF error.

[steve99]

Originally Posted by jaf89f

@steve99 Would you advise that I rescale my MAF considering I have a Grimmspeed Intake on my car? (I thought I read something in a different thread suggesting not to since the MAF in the Stage 2 EL e85 tune was 1:1...)

If so, can I simply use the MAF scaling from the 91/93 Stage 1 Tunes provided by Shiv (which I was previously running while on 91/93), or should I rescale it based on e85 data logs given the change in power, and I'm assuming air flow as well.

Thanks!

Grimspped intake maf scaling is pretty close to stock but its always benificial to do yourcown custom scaling.

As phrosty said on e85 you have the added complexity of the changing e% also effecting the fuel trim readings when on e85.

The oft e85 tunes are scaled for average e% arround 75 so this is where your fuel trims will be lowest as e% rises your fuel trims will trend positive as ecu adds fuel to compensate for higher e% as e% goes lower than about 75% then fuel trims will trend lower ie negitive as ecu pulls fuel to keep afr correct.

I rescaled maf on our e85 here as its a consistent mix about e90 so i always had high positive fuel trims.

If your going to transfer your grimspeed scaling to an e85 tune monitor your fuel trims and your wot afr and make sure they are ok.
You can scale maf on e85 as long as you have a cnsistent mix and its best to scale maf for the everage e% you get in your area.

[ronboogieon]

Do I just do the following steps to go back to regular gas (substitute E85 in the steps to 92 Octane):

Run tank down till low fuel light comes on
Fill with E85
Plug in OFT to monitor fuel trims (leave petrol tune in at present)
Drive slowly below 3500 rpm no WOT or hard acceleration until you see STFT rise rapidly followed by LTFT and stay high, this indicates that the petrol is now out of lines and the E85 has made it through the lines and pumps, this generally takes 2 or 3 km
Pull over and turn off car Flash E85 tune with OFT (Stage 2 EL E85) for stock car or car with EL headers or Stage 2 UEL E85 if you have UEL headers.
Start car and drive slowly again below 3500 no hard acceleration for next 10 to 20 km until your fuel trims LTFT/STFT stabilise below about 10% while cruising and idle, this allows ECU to learn the E% of your E85 mix.
If you do flash the E85 map at the pump on switchover the learning process will take longer as the E85 tune will try to learn petrol then when the E85 gets into the system it will need to learn E85.

[steve99]

Originally Posted by ronboogieon

Do I just do the following steps to go back to regular gas (substitute E85 in the steps to 92 Octane):

Run tank down till low fuel light comes on
Fill with E85
Plug in OFT to monitor fuel trims (leave petrol tune in at present)
Drive slowly below 3500 rpm no WOT or hard acceleration until you see STFT rise rapidly followed by LTFT and stay high, this indicates that the petrol is now out of lines and the E85 has made it through the lines and pumps, this generally takes 2 or 3 km
Pull over and turn off car Flash E85 tune with OFT (Stage 2 EL E85) for stock car or car with EL headers or Stage 2 UEL E85 if you have UEL headers.
Start car and drive slowly again below 3500 no hard acceleration for next 10 to 20 km until your fuel trims LTFT/STFT stabilise below about 10% while cruising and idle, this allows ECU to learn the E% of your E85 mix.
If you do flash the E85 map at the pump on switchover the learning process will take longer as the E85 tune will try to learn petrol then when the E85 gets into the system it will need to learn E85.

yes just swap petrol for e85 in proceedure.

[SamGam]

Can all these trims be adjusted with the standard OFT software or do you have to get some add on software?

Thx!

[phrosty]

Originally Posted by SamGam

Can all these trims be adjusted with the standard OFT software or do you have to get some add on software?

Thx!

RomRaider or some other tune editor is needed. All OFT software does is manage the OFT.

[SamGam]

Originally Posted by phrosty

RomRaider or some other tune editor is needed. All OFT software does is manage the OFT.

Thanks for the tip!