Can someone educate me about running E85 on this car and in general.

[solidONE]

I'm from the old school when it come to hotrodding sports compacts, before E85 was popular and twin scroll turbos etc. Actually before all this "JDM helleflush" crap for that matter... Now that getting back into it I see how running E85 is all the rage, and especially after seeing what Fullblown was able to do with the stock block of this car while running E85, my interest is seriously piqued to say the least (raging hardon).

So where can I look for reading material online and offline to educate myself on this subject? Also, specific to the new 86 running E85 tunes, are you guys pumping E85 into the same fuel tank, or is there an auxiliary tank and pump seperate to the main gas tank? How does this work?

[Craig]

[jamesm]

It's just corn fuel. Ethanol mixed with gasoline 85/15. Goes in the same tank as the regular gas. There isn't anything else required for an NA car beyond proper tuning. Older cars may need updated fueling system components (lines and stuff) but nowadays even regular gas is e10, so nothing to worry about there (alcohol wont mess up anything).

E85 makes more power because it's crazy high octane (resists detonation) for pump gas. This helps a even more when you have a turbo, as it allows you to turn up the boost with less risk of detonation causing catastrophic engine failure. In NA cars, it'll allow you to run more timing, and make a bit more power.

Ethanol does not, however, contain more energy than gasoline as some assume. Actually it's far less. This is why you get worse gas mileage on e85.

[solidONE]

I understand that E85 is just fancy corn booze, what I dont understand is how you can simply add it to the same tank of conventional gas and have a fuel and ignition map run optimally. Is there a sensor that can gauge how much ethanol content in the fuel at any given time and adjust the maps accordingly? Or, is it like an on/off type deal switching from E85 map to conventional premium gas map?

From what I understand is that if you have residual conventional petrol in the tank then you fill up with E85, the fuel will mix and you end up with something closer to a E70 gas than a E85. What has to be done to the car to compensate for this?

[Turdinator]

Originally Posted by solidONE

I understand that E85 is just fancy corn booze, what I dont understand is how you can simply add it to the same tank of conventional gas and have a fuel and ignition map run optimally. Is there a sensor that can gauge how much ethanol content in the fuel at any given time and adjust the maps accordingly? Or, is it like an on/off type deal switching from E85 map to conventional premium gas map?

From what I understand is that if you have residual conventional petrol in the tank then you fill up with E85, the fuel will mix and you end up with something closer to a E70 gas than a E85. What has to be done to the car to compensate for this?

At the moment i believe you have to have descrete pump gas and E85 maps. Visconti is releasing a flex fuel kit at somepoint that will detect the ethanol content and adjust the maps as required. I believe this won't be a cheap option however.

[reeves]

Originally Posted by solidONE

From what I understand is that if you have residual conventional petrol in the tank then you fill up with E85, the fuel will mix and you end up with something closer to a E70 gas than a E85. What has to be done to the car to compensate for this?

Some gas stations lower the ethanol content (to E70-75?) during colder months too from what I've read.. so filling up on E85 with a small bit of regular gas left in the tank isn't too much to worry about.

[Xdragonxb0i]

I car components are modern enough to run e85 without any upgraded. But you will need a new tune. Search ecutek e85. And the flex fuel kit. The ffk is a luxery that isn't needed but its nice to have

[DTS]

Originally Posted by Turdinator

At the moment i believe you have to have descrete pump gas and E85 maps. Visconti is releasing a flex fuel kit at somepoint that will detect the ethanol content and adjust the maps as required. I believe this won't be a cheap option however.

FA20 currently has a Flex Fuel Kit. Just got his Tune honestly so I cant say anything more about it, but I hope to get it soon.

[solidONE]

Originally Posted by reeves

Some gas stations lower the ethanol content (to E70-75?) during colder months too from what I've read.. so filling up on E85 with a small bit of regular gas left in the tank isn't too much to worry about.

That's the thing tho... This mean the map to run e85 must not have been optimized. Some sort of safety margin in the ignition timing and/or fueling must be programmed into the map to account for the inconsistent fuel supply.

Say if the fuel in your tank came out to be closer to e60 for whatever reason and the map was optimized for much higher ethanol content, you may risk damage to the engine, no? Or something will cause the ECU to retard the timing to account for the lower ethanol content?

[Gary in NJ]

Originally Posted by solidONE

That's the thing tho... This mean the map to run e85 must not have been optimized. Some sort of safety margin in the ignition timing and/or fueling must be programmed into the map to account for the inconsistent fuel supply.

Say if the fuel in your tank came out to be closer to e60 for whatever reason and the map was optimized for much higher ethanol content, you may risk damage to the engine, no? Or something will cause the ECU to retard the timing to account for the lower ethanol content?

The knock sensor is the safety net. If the ECU detects knock (detonation) is rolls back the ignition timing until the knock is gone.

[Mars2]

some reading for you:
http://forums.nasioc.com/forums/showthread.php?t=803341

[arghx7]

There is a non-linear relationship between ethanol % and effective knock resistance. That in and of itself creates a safety margin. Basically, for purposes of this application the ~E50 up through E85 have a negligible difference in knock resistance (Research Octane Number).



That's a huge summary/simplification of the issue, but it applies enough to answer your concern. See Kasseris, "Charge Cooling Effects on Knock Limits in SI DI Engines Using Gasoline/Ethanol Blends," 2012 . Dr. Kasseris is at MIT's Sloan Automotive Laboratory.

[reeves]

Someone please sticky this thread! We need an E85 sticky for all relevant info related to fr-s/brz's.. plus its impossible to SEARCH for "E85" because 3-letter words are too short to use on a forum search.

[jdogi]

Originally Posted by solidONE

That's the thing tho... This mean the map to run e85 must not have been optimized. Some sort of safety margin in the ignition timing and/or fueling must be programmed into the map to account for the inconsistent fuel supply.

Say if the fuel in your tank came out to be closer to e60 for whatever reason and the map was optimized for much higher ethanol content, you may risk damage to the engine, no? Or something will cause the ECU to retard the timing to account for the lower ethanol content?

I doubt that there is very much difference between a timing map optimized for e85 vs e70. Plus, as others have pointed out, the ECU is pretty sensitive to retarding timing to avoid knock.

The bigger issue is that your mixture will be a little rich if you're feeding in e70. But that really shouldn't be a huge issue. Just keep filling with e85, and you'll get to true e85 eventually. Of course that's assuming that you're getting "real" e85 out at the pump. As others have also stated, in cooler climates, they pump their ethanol at various levels between e70 and e85 during cold months.

Some of the tuners hawking e85 EcuTek tunes also have e70 optimized tunes.

Be more careful running an e70 tune with e85 fuel since you'll be a little lean. Chances of any knock even in this condition is probably low. But don't forget about the added heat of running lean.

This is all theory. It's your engine, so I'd say be careful and watchful of your engine's vitals.