E85 tuning

[RacerX9623]

    Since I have my detonation under control. And had great success with the new nitrous system. I am going to
begin using E 85. I will only use race grade E85. It is more consistent than pump E85. Plus it has corrosion inhibitors. Though I will flush it out after each race.

I know with streight alcohol it would be a 100 % increase in volume compaired to gasoline. But I am getting advice with E85 to use between 40%and 80%. To me that is a big swing.

I am going to be converting the carb. Pilots and main jets then adjusting the float.( it will sit higher in the E85)
And I will be using it with nitrous.
Am I correct thinking the 40 to 80 % is a safe starting point? And should really be looking at an air fuel ratio around 8.5 to one on e I am on the dyno?

[Dean Los Angeles]

Gasoline has a stoichiometric ratio of 14.7
E85 has a stoichiometric ratio of 9.765
It is a big swing.

E85 typical power air/fuel ratios can run as high as 6.9, mostly to control detonation. Octane ratings are around 100-105 for E85.
Racing gas or pump, you don't have any idea what the gasoline percentage contains.

[fredvance]

From what I have been told 40% would be a safe starting point. AFR 8.2-8.5.

[RacerX9623]

I am just looking for a starting point. I will be starting on the dyno and being as careful as I can. I have a whole lot of jets and a nice set of jet reamers. I don't like to use them.  But if Ihave to I can.
I am goin to use Rockett racing fuel E 85 and stay with that brand. I want to try to keep it as consistent as I can. I will start at 40% and just get it running than go from there. Thanks for the advice.   

[Hellcat Customs]

Ok I'm starting the same adventure into e85 and I'm seeing the same afrs etc here... my question is what is the afr seen on a wide band o2 gas sensor...Will the sensor still read the exact same or if it reads a lambda value of 1 does that mean the e85 is running a afr of 8:1....

Never played with anything but pump fuel and race gas so I'm trying to have a full understanding of what the sensor will see to help eliminate chances of error

[LandSpeed-DSM]

You can use a Wideband set for gas scale AFR to tune E85, and tune it like you would on gas.

The Wideband reads in Lambda. Lambda 1 is going to be a stoich burn on any fuel, as it relates to the oxygen ratio

14.7:1AFR Gas = Lambda 1.0

9.76:1 AFR E85 = Lambda 1.0

So if you are running E85, and seeing 11.0:1 on the Wideband gauge, it is actually

11.0/14.7 = Lambda ~0.75

0.75 * 9.76 E85 Stoich = ~7.3:1 AFR for E85.

[LandSpeed-DSM]

As a quick follow up:

{[(11.0-7.3)/11.0]+1} will tell you that you'll be consuming ~35% more fuel than pure gasoline at the same Lambda ratio

[RacerX9623]

What would a good exhaust gas temp be with E 85?

[LandSpeed-DSM]

Are you NA or Turbo/Supercharged?

My only EGT experience is on turbo applications and don't know that I would feel comfortable running out for 3-5 miles at WOT with much more than 1350*F EGTs pre-turbo.

Post-turbo EGTs should be about 100-200*F cooler under light load and as much as 450* under full boogie, depending on how much energy your turbine takes from the mass flow.

Hoping to have more data on that after this year.

Maybe someone more experienced can chime in?

 

[RacerX9623]

I am NA carb with nitrous. My motor only EGT was 1165 and the engine was turning 12250 rpm. With nitrous it was just over 1200 deg. And turned about the same rpm (. Different gear and 14 mph faster) . Will E 85 run cooler exhaust temp. 

[Hellcat Customs]

You can use a Wideband set for gas scale AFR to tune E85, and tune it like you would on gas.

The Wideband reads in Lambda. Lambda 1 is going to be a stoich burn on any fuel, as it relates to the oxygen ratio

14.7:1AFR Gas = Lambda 1.0

9.76:1 AFR E85 = Lambda 1.0

So if you are running E85, and seeing 11.0:1 on the Wideband gauge, it is actually

11.0/14.7 = Lambda ~0.75

0.75 * 9.76 E85 Stoich = ~7.3:1 AFR for E85.

Thanks bud that's exactly what I was looking for! So now using the same sensor I can write a formula for mlv specifically for e85 to help me tune the bike out proper!

[Steve Cole]

One thing to remember is the great White dyno runs a corrected altitude of 4000 - 9000' depending on the day your there! Setting fuel mixture on a dyno at home is a good start but make sure you check things on an easy pass first at the salt unless you have a bunch of spare parts with you.

[RacerX9623]

I race in Ohio. So I can tune very close on the dyno. Then I test at the 1/4 mile track just before the one mile runs. I use a wizards of Nitrous system. The nice thing is I can program in 0-100% power and make easy passes. Then turn it up as things go well. And turn it down if say the clutch slips or something seems off.
 I not only bring the power level up in stages. I also slowly increase the duration. First spraying the last 1/4 mile of the track then spray for the last 1/2 mile. And also spraying in lower gears if all goes well.

[LandSpeed-DSM]

One thing to remember is the great White dyno runs a corrected altitude of 4000 - 9000' depending on the day your there! Setting fuel mixture on a dyno at home is a good start but make sure you check things on an easy pass first at the salt unless you have a bunch of spare parts with you.

I'm running an EFI turbo setup, and my ECU is MAP/IAT based (Speed Density) so I'm hoping that'll more or less adjust its' self with respect to relative air density.

It will change where I sweep through on the turbo's compressor map though. So I'll have to see for sure just how much that 4000-9000 or more effective altitude is going to play with my IAT's if it pushes me into less efficient islands because I have to run a greater PR to make the same boost.

I plan to have a weather station handy by the time I make it to the salt, and a RAD gauge in the dash, if not datalogged as well.

[Hellcat Customs]

One thing to remember is the great White dyno runs a corrected altitude of 4000 - 9000' depending on the day your there! Setting fuel mixture on a dyno at home is a good start but make sure you check things on an easy pass first at the salt unless you have a bunch of spare parts with you.

Thanks Steve... we do data log constantly. A very talented sort also suggested an alternate map sensor to try on our ongoing project. Well be switching tuner systems next year as well.