E85 and MPG monitor

[brillo]

currently running e63 and was seeing MPG on the car that seemed too high (high 20s low 30s) as I was cruising at 65-70. Does the ECU adjust the MPG readings for the e85? I figure it would know as its pushing more fuel.

[Detroiter]

Originally Posted by brillo

currently running e63 and was seeing MPG on the car that seemed too high (high 20s low 30s) as I was cruising at 65-70. Does the ECU adjust the MPG readings for the e85? I figure it would know as its pushing more fuel.

I would assume any amount of E over E50 in these cars would be impossible to see anything near 30 as I see high 20s on 93. I don't have experience with ECUTek but with OFT you have to go in and change the average mpg's multiplier in order to have it represent the correct mileage. With a flexfuel kit I'm not sure how that would work though.

[brillo]

On 93 I typically average 31-32 mpg at 70. I would agree that my mileage should be down in the low/mid 20s based upon the mix. I'll check with Moto-East on that.

[MurderousPandas]

I know for OFT E85 tunes, you have to change the gas gauge readings by 30% through Romraider, why the tunes didn't come with the proper reading is strange. On E85(probably more like E70 where i'm at), i get roughly 28mpg, mostly highway driving above 60mph.

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[Jaden]

Unless the tune has the multiplier changed, you can't go by the built in mpg indicator.

If you want to know if it's changed and reading accurately. fill up your tank, reset the trip odometer, reset the mpg indicator and run it till just below the quarter tank on the gas gauge. Then it should fill up with right about 10 gallons. divide your miles by ten, or however many gallons it took to fill it up again and that's your true mileage, if it's within about 3 % of your mpg indicator, then it has the multiplier changed, if it's 25-30% off, then it doesn't.

Jaden

p.s. If you're running flex fuel, I don't see a way that they could have it read accurately, unless in ecutek they use a custom map that changes the multiplier based on e85 content percentage.

[DustinS]

Originally Posted by Jaden

If you want to know if it's changed and reading accurately. fill up your tank, reset the trip odometer, reset the mpg indicator and run it till just below the quarter tank on the gas gauge. Then it should fill up with right about 10 gallons.

Off Topic. but just below 1/4 tank for you is 10 gallons?

For me on stock car. Empty was 10 gallons, and after my LS swap, 10 gallons is at the 1/4 mark but I run out of gas just below the 1/4 mark.

[jasonojordan]

Originally Posted by DustinS

Off Topic. but just below 1/4 tank for you is 10 gallons?

For me on stock car. Empty was 10 gallons, and after my LS swap, 10 gallons is at the 1/4 mark but I run out of gas just below the 1/4 mark.

Shouldn't be running out. Fuel capacity is just over 13gals

[MurderousPandas]

Originally Posted by jasonojordan

Shouldn't be running out. Fuel capacity is just over 13gals

This. And because i use E85, this has helped a lot too. If a quarter tank is roughly 3 gallons, i need to fill half a tank at roughly $2 a gallon(standard E85 price here), that's $12 right there. So easy to pay for gas and be mostly spot on, everyone that rides with me thinks i'm some mad scientist lol

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[Lantana frs]

My oft power block tune showed 21 mpg on the dash. Always felt doggy up top. E85 tune shows 21as well. Who knows?

[steve99]

Ecutek e85 or flex tunes the fuel display sgould read correctly as ecutek tuners usually use a fuel multiplier that takes into account the in dash display.

Oft adjust the injector scalar and this requires a corresponding sdjustment to the fuel display metering scalar. Its an easy fix see tune tweaks below

[Silver Ignition]

FYI MPG readout on the gauge cluster has nothing to do with fuel flow or consumption rate. It's literally just an estimate that goes by the throttle %. It's an MPG coach

[moliver]

Originally Posted by Silver Ignition

FYI MPG readout on the gauge cluster has nothing to do with fuel flow or consumption rate. It's literally just an estimate that goes by the throttle %. It's an MPG coach

Do you have a source to back up that statement? That is different than I would expect.

[yelsew]

Originally Posted by Silver Ignition

FYI MPG readout on the gauge cluster has nothing to do with fuel flow or consumption rate. It's literally just an estimate that goes by the throttle %. It's an MPG coach

The mpg dash display is based on a table that references fuel rail pressure and a multiplier. This is how it is adjusted in romraider, by adjusting the multiplier at varying fuel rail pressures.
This is also why e85 does not change the mpg reading, even though more fuel is flowing, the fuel rail pressure does not change accordingly.

for examples/images/more info, http://www.ft86club.com/forums/showthread.php?t=74754