Doogie Posted February 19, 2012 Share Posted February 19, 2012 Thanks for the info! Link to comment Share on other sites More sharing options...
ViscousSquirrel Posted February 20, 2012 Share Posted February 20, 2012 Nice well written and organized post. Thanks! Link to comment Share on other sites More sharing options...
.Catalyst. Posted February 20, 2012 Share Posted February 20, 2012 I vote for sticky topic! My spec.B [#163] Project Thread with Pictures Get CryoTuned! Link to comment Share on other sites More sharing options...
dr_sharp Posted February 20, 2012 Share Posted February 20, 2012 Excellent thread, that info is spot on. I'd suggest adding the Avo line of turbos. lol Link to comment Share on other sites More sharing options...
bigjweb Posted February 25, 2012 Share Posted February 25, 2012 Good post man. Link to comment Share on other sites More sharing options...
sumfoo1 Posted February 26, 2012 Share Posted February 26, 2012 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. Link to comment Share on other sites More sharing options...
bigjweb Posted February 26, 2012 Share Posted February 26, 2012 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. Link to comment Share on other sites More sharing options...
fahr_side Posted February 26, 2012 Author Share Posted February 26, 2012 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. Link to comment Share on other sites More sharing options...
mwm5094 Posted February 26, 2012 Share Posted February 26, 2012 great post! Link to comment Share on other sites More sharing options...
bigjweb Posted February 27, 2012 Share Posted February 27, 2012 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. Link to comment Share on other sites More sharing options...
sumfoo1 Posted February 27, 2012 Share Posted February 27, 2012 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.... Link to comment Share on other sites More sharing options...
rapture Posted February 27, 2012 Share Posted February 27, 2012 so i know i've read this else where but all u need is larger injectors for e85 rite? no tune? Link to comment Share on other sites More sharing options...
lordeldor Posted February 27, 2012 Share Posted February 27, 2012 so i know i've read this else where but all u need is larger injectors for e85 rite? no tune? Uhm... You certainly need a tune. Link to comment Share on other sites More sharing options...
Mega Users seabass07 Posted February 27, 2012 Mega Users Share Posted February 27, 2012 Without a tune, you'll simply kill your gas mileage and run ridiculously rich. Why you'd waste your money on 30% more fuel for no reason, I don't know. Link to comment Share on other sites More sharing options...
sumfoo1 Posted February 27, 2012 Share Posted February 27, 2012 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. Link to comment Share on other sites More sharing options...
bmx045 Posted February 27, 2012 Share Posted February 27, 2012 so i know i've read this else where but all u need is larger injectors for e85 rite? no tune? but I thought you knew everything? Link to comment Share on other sites More sharing options...
ChefRacer Posted February 27, 2012 Share Posted February 27, 2012 Not everybody in Philly knows everything Just most of us Link to comment Share on other sites More sharing options...
LosAngelesLGT Posted March 6, 2012 Share Posted March 6, 2012 Without a tune, you'll simply kill your gas mileage and run ridiculously rich. Unlikely to run. Link to comment Share on other sites More sharing options...
Mega Users seabass07 Posted March 6, 2012 Mega Users Share Posted March 6, 2012 (edited) It should run, just not safely. It would definitely idle at least unless it's cold. But I forgot about the fuel trim limitations. Edited March 6, 2012 by seabass07 Link to comment Share on other sites More sharing options...
rapture Posted March 6, 2012 Share Posted March 6, 2012 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. Link to comment Share on other sites More sharing options...
goneskiian Posted March 9, 2012 Share Posted March 9, 2012 Yes, you can easily switch back and forth between tunes with the AP. Link to comment Share on other sites More sharing options...
jasejase Posted March 9, 2012 Share Posted March 9, 2012 Question out of curiousity if nothing more - how empty do you need to run your tank in order to switch between these two fuels (with a map change) without any hitches. Link to comment Share on other sites More sharing options...
spec.B Dream Posted March 9, 2012 Share Posted March 9, 2012 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. Link to comment Share on other sites More sharing options...
jasejase Posted March 9, 2012 Share Posted March 9, 2012 ^^ thanks... DOnt really have the option here in CT... but i always wondered the ease of switching between maps. Still sounds like it takes some logistical forethought. Link to comment Share on other sites More sharing options...
spec.B Dream Posted March 9, 2012 Share Posted March 9, 2012 Yea, it takes some thought, but so do any mods. It really isn't that hard. Most running it here just run it all year round. I haven't ran 91 since a tuning experiment in December. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now