I have seen a number of posts and remarks with some confusion about what exactly Flex Fuel means. I decided to make a quick thread to help clarify everything for both the ProEFI and E85 in general.

E85 Basics:

• Ethanol is an American-based product that both stimulates local argricultural economy and is a very clean-burning fuel.
• E85 has a 30% lower energy content than regular gasoline and therefore requires 30% more fuel to operate the same.
• E85 has a stoichometric level of 7.6:1 compared to Gasoline's 14.7:1 stoich level.
• E85 will have a less efficient fuel economy due to the increased fuel needs (roughly a 15-25% drop in fuel economy).

Why use E85 in performance applications?

• NEVER buy Race Gas again!! Cars have made well over 1200whp on E85 with the potential to make more.
• Torque! Each turbo car we've dyno'd with E85 ALWAYS makes substantially more usable torque making for a great street car.
• Spool! Expect your current turbo setup to spool ~500rpm's FASTER than it currently does.
• E85 burns cooler than Gasoline further adding to the power increases over Gasoline.
• Most importantly....it's CHEAP!! E85 literally has the capabilities of C16 Race Gas. With E85, you essentially have C16 in the tank for ~$3.00/gallon.

What about changing ethanol contents?

• Yes, ethanol content fluctuates and can be harmful if you have an EMS that doesn't have a true Flex Fuel integration. The ProEFI DOES have this so you're completely safe!
• In addition to the fluctuations that can occur, a "winter blend" is often switched over to E70 (70% ethanol content). This is done so because the higher content of E85 would be much more difficult for vehicles to have an ideal cold start-up.

ProEFI Flex Fuel Integration

• Ignition, fuel, and cold/warm start-up maps are adjusted in real-time based on ethanol content as seen with the ProEFI Flex Fuel sensor. This is also displayed directly on your CAN Gauge or CAN Display.
• ProEFI iBoost includes a 5-position switch to choose your 5 pre-determined boost levels (1 being the lowest or wastegate, 5 being the highest allowed given current ethanol content). The ProEFI will AUTOMATICALLY adjust your maximum boost level and corresponding lower boost levels to give you the safest boost level based on the real-time ethanol content.
• ProEFI firmware allows for an additional 400% increase in fuel for cold start-up maps to GUARANTEE you'll always have enough fuel to start your car in the cold weather (See quote below for more info).
• The internal ProEFI wideband adjusts in real-time for the fluctuating stoichometric measure of your current fuel mixture.

Link below to .XLS file to determine stoichometric level for different blends of Ethanol and Gasoline:

Additionally, here is a quote from last year's winter season. While I was late at SP one night, I had to start an E85 powered vehicle in -2 degrees Farenheit!

Original thread:
http://www.spracingforum.com/forums/...degree-weather!!

 

Sounds great except that the tax credit/subsidy for E85 is due to expire at the end of this year, which will increase prices, but beyond that, puts the entire future of E85 in doubt. Even if it costs more than gasoline it would be worth it to enthusiasts but outside the midwest, it's availability is so limited. If the price is equitable to gasoline, spread beyond the midwest seems unlikely. Envy you Chicago folk...

 

It's already more expensive per gallon than gasoline out here. Given you get much worse MPG's on top of that makes it a pretty big flop for the average person. Cheap race gas it is, but it can't last too much longer on the street at current/future prices.

 

I get 9mpg around town and ~15mpg on the hwy. I love this stuff though. The amount of safety it adds is awesome.

The flex fuel doesnt miss a beat.

My local E85 station still has E85 in the pump, so cold starts are still rough. But I am getting it better and better as time goes on.

Good to see you venturing off SF Reid

 

Interesting read!

 

I have yet to have a cold start issue with mine. Just to test I let it sit outside overnight last week and it was 36* in the morning. It fired right up and idled at 12:1 until 60 seconds of enrichment table was up. Of course i've edited the post start enrichment in my Haltech to fix that issue.

I see low teens on street driving (because i'm usually doing WOT pulls) but when i drove back to indiana on the interstate i got 19mpg. With gasoline I got 24-25 so not too bad of a drop.

I was low 500's on pumpgas and now i'm 650hp on only 22psi with e85. Well worth the cost for the amount of HP and safety I have. I don't care what the price is because it's never going to be the cost of c16. I also can't get c16 from the gas station right up the street.

Reid, your stoich value in the first section says 7.6:1. I think it's 9.8:1 isn't it?

 

They're popping up everywhere here in Long island. I have 3 or so stations within 5 miles of my house. 1 a mile away. Premium here is in the 3.75 -3.90 range and E85 is around 3.23 so its still great for the race gas users.

 

u LI guys are so lucky...
I have 3 all in the same area about 15 miles away....