Hello everyone,
I am sort of new to the tunner world and tryin to bag up as much knowledge as possible. I have 93 hatch back sohc si that i am working on, and was wondering if anyone has heard or done a Flex Fuel conversion. A buddy of mine mentioned it to me and it caught my attention only because of cleaner exhaust fumes, a horse power bost, and better fuel milage.

 

good info in here

https://honda-tech.com/forums/forced-induction-16/%2A%2A-e85-thread-%2A%2A-1812349/

 

e85 conversions have been done, as long as you can get the fuel easily it's a good move.

the term "flex fuel" means it can run off either normal gasoline or e85.
Which one is in the tank is selected by a switch via the driver... but be careful running e85 in the normal gasoline mode and the engine will not like you.
This switch between fuels can be handled with the better programs out there. (eCtune, neptune, hondata)

 

i wasnt aware of a switch playing a role between the fuels managment. Thanks for the info!

 

No, there are calculations based on fuel density, and / or oxygen content. There is no switch. That would be impossible if you filled up with half a tank of regular and half a tank of E85. You wouldnt move the switch "half way" or anything.

 

I'm waiting for someone to take some data with a flex fuel sensor so I can add an option into NepTune.

 

I have a GM Alcohol sensor that I am considering using with a DTA S80Pro.

You can download DTA's S-series software (free) on their website and see their alcohol compensation table (ign advance & injector duration).

They are fairly expensive sensors though, I paid $150 at a local junkyard. Ebay they range from $100 - $300 depending on how lucky you get.

 

I was told that you can use a GM Flex Sensor with an AEM EMS, I got both of them now hoping my tuner can get it all tied in later on down the road, if it works it will be sweet

 

Just got done setting up a Flex Fuel sensor on a Vipec V88 for our Supra. If the OBD1 Honda ECU has an available digital input (PWM), this is all the information you need to build FlexFuel capability into Neptune.

GM PN 12570260 or 12568450.

Sensor connections w/GM Pigtail colors:
Pin A: Ground (white)
Pin B: +12 Volt supply (pink)
Pin C: Output signal (purple)

Output signal is square-wave. Frequency = ethanol %. Amplitude = fuel temp.

Frequency Range (Linear):
50hz = 0% Ethanol
150hz = 100% Ethanol

Pulse Width / Amplitude Range (Linear):
1 millisecond = -40*F
5 millisecond = 257*F


You can get away with only using the frequency to build a 2D compensation table. Temperature is primarily used to aid in cranking fuel and post-fuel compensation.

 

Thanks for the info.

 

Does this sound like something that can be done? Are there open PWM inputs on the stock OBD1 board?

I suppose you can always build a small circuit to take in the Flex Fuel square wave and output a 0-5v signal for just the ethanol content... use that on an analog input like B6 or D10, etc.

 

This is very interesting. I would absolutely LOVE to have flex fuel capability on Neptune. Maybe the PWM circuit that you can add for the boost solenoid could be used for the flex fuel sensor instead.

 

A circuit to convert would not be a bad idea, but then the cost and amount of people interested would come into play. A lot of people already had issue with the cost of the Flex Fuel Sensor in the first place and this would be adding to that, at least a little.

 

BAM!

http://www.zeitronix.com/Products/ECA/ECA.shtml

^that + flex fuel sensor = 0-5v output in a nice linear fashion.

 

The sensors could be grabbed from the local pick and pull for peanuts. They came on alot of cars standard.

 

That's what we need. If you want to start a thread on the NepTune forum to see how much interest there would be, I'd be all about it.

 

Will do.

 

ProEFI already does this and has a PNP kit for Honda.. Since the fuel/ignition stratgey was designed with Flex Fuel in mind, its currently the best system out for doing flex fuel that I have seen.

 

There are open PWM inputs on the Demon Boards...

With (2) E85 stations 15 minutes from my shop...I am highly interested

 

Good stuff

 

For E85 you're going to need bigger injectors, a new fuel pump, and you'll burn a lot more fuel, which is costly. I would highly recommend a methanol injection kit instead, so you can still preserve your daily driver economy, don't have to drive across town for fuel, don't have to use special O2 equipment, and won't have to buy a new fuel system.

 

You must live somewhere special! I don't ever recall seeing methanol available at the pump.

For a meth injection kit, you need a tank, pump, injector, lines and control module. Free?