As many of you know I have been studying up on converting to EFI.

Can a system such as the Megasquirt II be programed to either sense or be switchable to run different grades and types of gas? Around here E85 is availible in most cities, then we have the good old E10/20, and if I go racing the high octane stuff is availible at the track.

The new vehicles all "sense" if your using E85 and make the needed changes. What about the aftermarket stuff?

Chris

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Chris'
Autobody
Restoration
Service

You can run dual, switchable main fuel tables. I'm not sure how the fuel type sensors work but you may be able to interface it with the MS to make the switch automatically instead of manually.

I believe the target AFR tables are switchable too but I'm not positive. Try looking in www.megamanual.com or ask in the www.msefi.com forums.

Would it be able to adapt with a wide-band O2 sensor? (even a narrow band if you want it at stoichiometric)

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Each fuel has its own stoich point. This is from the innovate motorsports lc-1 wideband manual:

Gasoline 14.7
LPG (Propane) 15.5
Methanol 6.4
Ethanol 9.0
CNG 17.2
Diesel 14.6

I'm not sure where E85 is. I believe you'll have to use wideband or some sort of specialized narrowband. Now I'm not an alternate fuel expert, but I don't think you want to depend on the o2 to make up the difference because depending on how far off the stoich point is from regular gasoline you may hit the o2 sensor trim limit.

O2 sensors measure lambda and don't care what the fuel is ......

As long as your burning the fuel at the stoich point, the lambda of the O2 sensor is 1.0


However, the ECM would need enough control to vary the injector pulse width for the various fuels...............


E85 would be

15% * 14.7 + 85% * 9.0 = 9.855

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

On MEga Squirt you can change the switch over point on the o2 sensor to change the target AF ratio from 14.7 to something lower or higher. If you want it to maintain a richer AF ratio, then you set the switch point from .5 volts to ,say, .6 or .7. Without a wide band, you will not know for sure what that change is producing, but you can make it run richer or leaner with that adjustment. If you set it to switch at .6 volts, then it would allow the ratio to get higher before it cuts the fuel back.

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I really feel that you'd want to tune for each fuel. Yes, flex fuel cars can run from 0-85% ethanol, but they also have a sensor to know what's fueling the engine and adjust accordingly. I'd like to see the code or know the tuning strategy on a flex-fuel vehicle beyond just adding a certain % pulse width as the alcohol content is increased and allowing more timing advance.

Also, you need a lot more E85, and even more M85, than gasoline so the fuel delivery system including the pump, lines, filters, injectors and regulator(s) all have to be upsized. Methanol is quite corrosive too. I wouldn't run methanol if you can meet your performance goals on something else.

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Joshua

The way I understand it, oxygen sensors sense oxygen concentration. Narrow bands will put out 0.5v at stoich for gasoline, when a certain concentration of o2 is reached. When another fuel burns at its own stoich, there will be a different concentration of o2.

Hence 0.5v when using an ordinary gas nb burning gasoline is one thing, but if you use the same sensor when burning another fuel and get 0.5v it will be at a different afr. And since nb gas sensors are only accurate around their own stoich to begin with, they won't give useful info for other fuels. However since widebands are accurate over their whole range, it will provide useful info for other fuels.

Also when mixing fuels I don't think you can linearly compute the afr. Each kind of fuel combusts in its own manner but when mixing them together they may interact together as well as ambient gases.

O2 sensors don't care what the fuel is. The oxygen ratio stays the say depend on the degree of richness or leanness.

For a narrow band it would be .5V at stoich no matter what the fuel (ok, commonly used fuels, get something exotict and I don't know what happens)

http://www.ngk.de/Lambda_sensors.642.0.html

&


"Of course, when running in closed loop, the engine will run at 14.13 AFR instead of 14.7. O2 sensors (incl. widebands) don’t measure AFR, but Lambda. Lambda is defined as actual AFR/stoich AFR. It's a ratio. In closed loop part throttle the engine is just running at Lambda 1.0, regardless of fuel. The same would be true for other Lambda values when running closed loop at WOT using a wideband. The engine would run at the tuned Lambda and everything would be fine. Open loop systems would need to be retuned for alcohol blends though. "

from:
http://www.innovatemotorsports.com/resources/news6.php

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

There has been some work with getting Megasquirt-II to run E85 - AFAIK it's the only standalone that can run a flex-fuel vehicle on a variety of fuel mixtures. And yes, getting it to work does require a fuel composition sensor.

http://www.megamanual.com/flexfuel.htm

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

2 years ago my brother and I switched his Mustang drag car to E85 and there were two things that we had problems with.
The first was that the engine ran so, so, so much cooler that we couldn't get real consitant on each run. At the begining of the day we would just make laps, but as other classes would get involved and other track activities went on the time between runs changed so much. We would litterally let the car run between rounds. (we were just happy to be going rounds )
Second was tuning the carb to ethanol. Once we figured out that gas jets are just too small we bought an alcohol jet kit and played with that for a weekend. We used a O2 sensor and some software on his laptop to get the air/fuel ratio right. Then we started adjusting for the best ET/MPH. We quickly learned that we were using almost twice as much E85 as we were using E10 from the local pumps.
I know that ethanol usage should be left for a different discussion but I am just looking at alternatives and the possible future. Mn is already switching from E10 to E20 next year so I have to make the fuel system alcohol compatible anyway.
At the strip I see alot of alcohol fueled, supercharged rails but I don't think I have ever noticed a turbo/alky combo. Any reason why that would be an issue?

Chris

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Chris'
Autobody
Restoration
Service

The new Mopar Action has an article on this, but for a carb. Might be interesting info for somebody to read.

They used a Thermoquad with huge jets and airbleeds.

The authors main reason (if I remember correctly) was the octane rating of the fuel. He figured that building a motor specifically for E85 (much higher compression ratio) might remove many of the downsides.

He did say he hasn't has issues with corrosion yet, too.

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'15 Chrysler 200S V6
'74 Duster 360, factory 4 speed car

The Drake clan Simca, has a EFI, turbo, alky, slant six. Has turnd a 9.85 in the quarter

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

This suppost to be coming along quit nicely and can be done.


Go to TurboMustangs.com and read this thread it may help you some and even offer some other links that may be helpfull.

http://www.turbomustangs.com/smf/index. ... ic=47094.0


E85 is working out very good for high performance turbo engines. It is something that most of us should get use to because in the year 2008 all leaded racing fuels will be band in the USA and not sold anymore. Now I am sure there will be unleaded race fuels to buy but it may get very pricy by then. There is always the local airport if there is nothing around in your area but E85 is going to be a very good fuel to run for boosted apps.


Jess