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.
- 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 9.6:1 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!! 3.0L 2JZ motors have made well over 1200whp on E85 with the potential to make more, especially with larger displacement engines.
- 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:As many people know, E85 cars are incredibly difficult to start in cold weather. This is due to the fact that E85 stops vaporizing at approximately 55 degrees Farenheit and it only gets more difficult as the temperature drops further. Fuel is ignited at start-up by these fuel vapors. For comparison, Gasoline (only about 15% present in E85) does not stop vaporizing until -45 degrees Farenheit which is why it does not have issues starting in colder weather.
With the ProEFI's built-in E85 controls, you are able to add an additional 400% of fuel in your start-up fuel map in addition to firing all injectors simultaneously. Basically, the ProEFI allows more than enough fuel, the Supra got plenty of that fuel, but I was frickin freezing!!