E85 on OEM EFI system

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lemons racer
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E85 on OEM EFI system

Post by lemons racer » Sun Mar 24, 2019 2:15 pm

Going to start by saying I have not kept up with any EFI since the 80s, ya I'm a dinosaur!. I picked up a 1992 Dodge Ram 50 (Mitsubishi Mighty Max) 2.4 4G64 for 1/4 mi. dirt track in Placerville CA. The rules are tight, must be stock-OEM but you can run E85, so this is what I'm thinking. A dual overhead 4 valve head from a 4G63 bolts onto the 2.4 leaving the 2 valve pistons yields right at 13-1 comp. The Ram 50 injectors are 260cc but EVOs are up to 450, headers are OK.
Will use the harness & computer from a 95-99 Eclipse(2G) to match the head. Also have to use race E85 not pump or flex E85, can't install a fuel sensor, nothing newer than 03. This is where I fall flat on my face, don't know how to make the system understand the fuel difference.
These are all stock parts, just mix & match, standard circle track practice.
ANY help-anything will be great as I'm dead in the water right now.

Brian P
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Re: E85 on OEM EFI system

Post by Brian P » Sun Mar 24, 2019 7:56 pm

I can not speak for what will happen with the 16-valve head in place of the stock one, but if it were only the fuel difference ... For otherwise equal engines, if you have enough fuel pump capacity, and you make the injector capacity 36% more than stock give or take, you don't need the fuel content sensor. The fuel injection system won't know the difference. Cold starting will be an issue, and if you set it up to run optimally on E85, it won't run properly on straight gasoline any more.

Many unmodified production engines will run on surprisingly high ethanol percentages, much more than the 10% that they are certified for. Not necessarily optimally, but they'll run.

Some older fuel systems contain materials that are not ethanol friendly, might want to replace hoses, and investigate the fuel pump itself.

More reading material for you: https://innovativetuning.com/e85-ethano ... -concerns/

lemons racer
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Re: E85 on OEM EFI system

Post by lemons racer » Mon Mar 25, 2019 2:17 pm

Thanks Brian, read their site & sent them a question, will see what they come back with. However they did talk about tuning which is my concern, don't want to go through all the parts swapping & find out the 95-99 computer can't control it or be reflashed?
This project is just for fun so it's not something I'm going to sink much of money into, run 7-8 times a year.

mekilljoydammit
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Re: E85 on OEM EFI system

Post by mekilljoydammit » Tue Apr 02, 2019 11:47 am

I'm not a DSM guy or anything else so I haven't used it, but check out http://www.ecmtuning.com/

n2xlr8n
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Re: E85 on OEM EFI system

Post by n2xlr8n » Tue Apr 02, 2019 12:17 pm

Questions Off the top of my head:

Has the stock ECU been "hacked" in a way that allows you to modify parameters associated with fueling?
If not, you'll have a harder time tuning it properly.
He who is in me is greater than he who is in the world.

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Re: E85 on OEM EFI system

Post by In-Tech » Tue Apr 02, 2019 3:27 pm

lemons racer wrote:
Sun Mar 24, 2019 2:15 pm
Going to start by saying I have not kept up with any EFI since the 80s, ya I'm a dinosaur!. I picked up a 1992 Dodge Ram 50 (Mitsubishi Mighty Max) 2.4 4G64 for 1/4 mi. dirt track in Placerville CA. The rules are tight, must be stock-OEM but you can run E85, so this is what I'm thinking. A dual overhead 4 valve head from a 4G63 bolts onto the 2.4 leaving the 2 valve pistons yields right at 13-1 comp. The Ram 50 injectors are 260cc but EVOs are up to 450, headers are OK.
Will use the harness & computer from a 95-99 Eclipse(2G) to match the head. Also have to use race E85 not pump or flex E85, can't install a fuel sensor, nothing newer than 03. This is where I fall flat on my face, don't know how to make the system understand the fuel difference.
These are all stock parts, just mix & match, standard circle track practice.
ANY help-anything will be great as I'm dead in the water right now.
Let me see if I can word this correctly...If the efi system is matched to your head flow rate, are the two short blocks similar in cc/cu in? If so, you should just be able put an adjustable regulator after the stock regulator to raise the fuel pressure. The carb guys that have a lot of experience with e85 should be able to give you a percentage of flow required and then use an online calc for fuel pressure increase vs original pressure. This should put you in the ballpark and e85 is going to be much more forgiving on the tune so start rich.
I am not sure that made any sense, perfectly clear in my head but getting it in print can sometimes leave things vague. I guess what I am saying is if the VE of the stock computer matches the VE of your application then all you need to do is raise fuel pressure to compensate for the added need of fuel that the e85 requires. :wink:
Heat is energy, energy is horsepower...but you gotta control the heat.
-Carl

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Re: E85 on OEM EFI system

Post by n2xlr8n » Thu Apr 04, 2019 6:01 am

In-Tech wrote:
Tue Apr 02, 2019 3:27 pm
Let me see if I can word this correctly...If the efi system is matched to your head flow rate, are the two short blocks similar in cc/cu in? If so, you should just be able put an adjustable regulator after the stock regulator to raise the fuel pressure. The carb guys that have a lot of experience with e85 should be able to give you a percentage of flow required and then use an online calc for fuel pressure increase vs original pressure. This should put you in the ballpark and e85 is going to be much more forgiving on the tune so start rich.
I am not sure that made any sense, perfectly clear in my head but getting it in print can sometimes leave things vague. I guess what I am saying is if the VE of the stock computer matches the VE of your application then all you need to do is raise fuel pressure to compensate for the added need of fuel that the e85 requires. :wink:
Carl- you've probably forgot more than I'll ever know about ICE, but I was thinking the same thing re fuel pressure until I saw 13:1 CR. That will certainly change things with respect to fuel and timing.

Lemons: Go on one of the mitsubishi tuner forums and find out if the stock ecu has been cracked (a software interface written to allow custom tuning of the tables in the ecu).

If it has, you're in bidness :wink:
He who is in me is greater than he who is in the world.

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Re: E85 on OEM EFI system

Post by In-Tech » Thu Apr 04, 2019 8:38 am

Yepper, of course it would be better if that ecu is "cracked" and he can tune it. I'm not too worried about the 13:1 compression as he said he has to run "race" e85 from a drum and not the pump e85 which can vary greatly from tank to tank.

If you can't get to a chassis dyno that has a wideband you could always use an Innovate SSI-4 for AFR, RPM, Fuel Pressure and TPS. Along with a PL-1 pocket logger so you can log while going around the track. An Lc-2 wideband finishes it off for plug and play but if you already have a wideband the four inputs can be set for anything 0-5v. It's the cheapest option I've found out there for standalone datalogging. I want to say the last time I looked you can get the SSI-4 and the PL-1 pocket logger for around $200 total.
Heat is energy, energy is horsepower...but you gotta control the heat.
-Carl

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