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What turbo? wiki... with a twist


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e85 helps because the extra fluid obsorbs more combustion energy.

 

PV=nRT where n & r are constant

 

So drastically reducing (T) reduces either pressure (P) or volume (V) (more like flow rate in this case) or both thus making a formerly choked turbine more efficient.

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e85 helps because the extra fluid obsorbs more combustion energy.

E85 works because it has a higher octane rating then regular 91 or 93 unleaded gas. Meaning that it resists pre-detonation (knock) better then pump gas. The need for more E85 then gas is only because E85 has a different Stoich then gasoline. Gas being 14.7 parts air to 1 part fuel, and E85 being 9.7 to 1.

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E85 works because...

 

We were discussing why it that cars running given power levels can get away with running smaller turbines and exhaust housings on e85 than those burning gasoline. The effects of high-octane / low-calorific-value fuels on CR, timing and boost are well-understood. ;)

Obligatory '[URL="http://legacygt.com/forums/showthread.php/2008-gh8-238668.html?t=238668"]build thread[/URL]' Increased capacity to 2.7 liters, still turbo, but no longer need spark plugs.
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We were discussing why it that cars running given power levels can get away with running smaller turbines and exhaust housings on e85 than those burning gasoline. The effects of high-octane / low-calorific-value fuels on CR, timing and boost are well-understood. ;)

 

You were talking about this? - The smaller turbos reach their max efficiency sooner and therefore heat up quicker then larger turbos, but because ethanol burns cooler then gas, the air charge remains cooler and more dense which means more total air molecules.

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E85 works because it has a higher octane rating then regular 91 or 93 unleaded gas. Meaning that it resists pre-detonation (knock) better then pump gas. The need for more E85 then gas is only because E85 has a different Stoich then gasoline. Gas being 14.7 parts air to 1 part fuel, and E85 being 9.7 to 1.

 

 

 

Yes you're exactly right... the by-product is more fuel is more fluid phase changing to liquid. It basically works as an octane boost & water/meth injection.

 

I mean with meth injection do you shoot 30% more fluid in??? nope....

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actually without a tune your car will not be able to compensate the fuel tables enough to keep the car from running lean iirc you need to ATLEAST scale your injectors to 25% smaller then they really are or add more fuel to the entire open loop table.
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thanks guys i wasn't sure... seeing as how i have an ap,would it be possible to save a e85 tune and a 93 oct. tune and switch back and forth? i'm asking because there is only one station within about 100+ miles that even has e85...but i'd like to see what it's like.
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Till the low fuel light comes on. I try to drive a bit more after that, but that's really all you need. I had a shop tell me that they actually pull the drain plug on the tank and drain out all the old fuel. That is unnecessary and wasteful. Most gasoline I've seen at the pump is an ethanol blend anyway, so I see no problem mixing a bit more. Besides, you're going to have some leftover gasoline in the lines anyway even if you completely dump the tank.

 

The low fuel light comes on at 2.5 gallons. Premium here is 10% ethanol. The fuel tank capacity is what, 15 gallons? So 2.5@90% and 12.5@15% becomes 4.125 gallons gasoline and 10.875 gallons ethanol, e72.5. 85% less ethanol than e85. There's a thread where Legend shows that you can successfully run the same tune for both summer (e85) and winter (e70) blends because the ECU can easily correct for ARF swings of 25% in closed loop.

 

Make sure to watch your idle AFR after initial start and not drive until they come back in (usually around 5 seconds for me). Then, periodically check the tune and pull Learning Views to make sure all is still well. Stay out of open loop until Learning View shows AFR D is dialed in.

 

After that, your next tank of e85 will be much closer to ideal. I'd recommend getting your injectors scaled on the second tank (assuming your MAF was well scaled before). Then again check the tune and you're good to go.

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