My E85 as a Octane Booster Experiment
05-20-2010, 08:49 AM
#1
My E85 as a Octane Booster Experiment Just thought I'd share this in case it can help someone.
I have a heads/cam LS6 with a 12:2 compression ratio in my vette. For the last few months Ive been messing with it here and there trying to see how much timing I can put into it without detonation or pinging. Well, Im in CA so 91 pump gas sure doesnt help. My first idea was a methanol and water injection system. I pieced one together with a Snow Perf pump and a Summit RPM window switch. It worked good but on hot days I still noticed some lugging when loading up 4th on the frwy (its an A4), like partial throttle at highway speeds. Now with 100 octane being $7.99 a gal I didnt want to spend $120 on a full tank of gas so I did some research on e85 which I knew was about 105 octane. A few problems arose, first, what was the availability of e85 and, what mods are needed to run e85?
First, CA sucks at e85 availability but luckily for me theres a Chevron with e85 three blocks from my house. Still, I didnt want to be dependant on one gas station with the nearest one being in Beverly Hills 45mi away. So I decided, based on octane calculations, to use a 30% mix of e85 to 91oct. This would yield me an octane of about 95.4 which is more than enough for my application and the percentage of e85 wouldnt be too high so that I can fill up with all 91 if I had to and the car would only run a bit rich but it wouldnt hurt anything.
Then, what would I need to run e85? NOTHING. If your car is newer than 1988 I wouldnt worry about corrosion problems. Methanol is the alcohol that eats everything up not ethanol, you'll be fine. All i had to do was richen the fuel. Since I have bigger injectors, it took about a 5-7% increase in fuel throughout the fuel curve. The AFR at WOT is now 12.5-8, right on the money for this percentage of ethanol.
Results, well I havent put it on a dyno but idle feels a lot stronger, it revs up quicker and pulls like a freight train up top. I have it at 26* of timing right now which is quite a bit for this high of a compression. So far Im very happy but I have yet to drive it more and go to the 1/8mi track next week. So, if youre close to an e85 station and youre a FI or high cr N/A car you should really consider using e85 even if its just as an octane booster. Theres some info on full e85 conversion but almost nothing on partial percentages like myself and on how to tune them. Its a learning process but just experiment till you get the right AFRs and you can add more timing with no detonation problems. E85 is good stuff, safe, clean, creates more torque and cost 40% of race fuel. To get 95.4 octane I use 10.5gal of 91 to 4.5gal of e85. 15gal for a full tank equal $46, cant beat that.
I have a heads/cam LS6 with a 12:2 compression ratio in my vette. For the last few months Ive been messing with it here and there trying to see how much timing I can put into it without detonation or pinging. Well, Im in CA so 91 pump gas sure doesnt help. My first idea was a methanol and water injection system. I pieced one together with a Snow Perf pump and a Summit RPM window switch. It worked good but on hot days I still noticed some lugging when loading up 4th on the frwy (its an A4), like partial throttle at highway speeds. Now with 100 octane being $7.99 a gal I didnt want to spend $120 on a full tank of gas so I did some research on e85 which I knew was about 105 octane. A few problems arose, first, what was the availability of e85 and, what mods are needed to run e85?
First, CA sucks at e85 availability but luckily for me theres a Chevron with e85 three blocks from my house. Still, I didnt want to be dependant on one gas station with the nearest one being in Beverly Hills 45mi away. So I decided, based on octane calculations, to use a 30% mix of e85 to 91oct. This would yield me an octane of about 95.4 which is more than enough for my application and the percentage of e85 wouldnt be too high so that I can fill up with all 91 if I had to and the car would only run a bit rich but it wouldnt hurt anything.
Then, what would I need to run e85? NOTHING. If your car is newer than 1988 I wouldnt worry about corrosion problems. Methanol is the alcohol that eats everything up not ethanol, you'll be fine. All i had to do was richen the fuel. Since I have bigger injectors, it took about a 5-7% increase in fuel throughout the fuel curve. The AFR at WOT is now 12.5-8, right on the money for this percentage of ethanol.
Results, well I havent put it on a dyno but idle feels a lot stronger, it revs up quicker and pulls like a freight train up top. I have it at 26* of timing right now which is quite a bit for this high of a compression. So far Im very happy but I have yet to drive it more and go to the 1/8mi track next week. So, if youre close to an e85 station and youre a FI or high cr N/A car you should really consider using e85 even if its just as an octane booster. Theres some info on full e85 conversion but almost nothing on partial percentages like myself and on how to tune them. Its a learning process but just experiment till you get the right AFRs and you can add more timing with no detonation problems. E85 is good stuff, safe, clean, creates more torque and cost 40% of race fuel. To get 95.4 octane I use 10.5gal of 91 to 4.5gal of e85. 15gal for a full tank equal $46, cant beat that.
05-20-2010, 12:51 PM
#3
Good to know I am running rich as it is because I am in AZ and have the same issues you do with octane and any time I want to run hard/N2O its either race fuel or Torco with 10G of 91 the good ol 102 mix. I am going to try this I am running 28* of timing and my CR is 10.5:1 so I am sure I will be ok but I can feel when I am running a higher octane the better street mannerism. Thanks for the info
05-20-2010, 01:28 PM
#4
Yeah, it deffinately runs smoother and accelerates smoother. I know AZ weather can be rough on a car too but this ethanol seems to be doing the trick. Its been cool here so im waiting to see its behavior in warmer conditions. If it still runs hard and shows no signs of detonation when its hot or has been in traffic then itll really pass my test.
05-20-2010, 03:01 PM
#5
05-20-2010, 03:43 PM
#7
When it first came out, they made a big deal about E85 and its been how many years now and its still hard as **** to get...another good job by the govt.
Nice findings about your setup. I personally cant believe you got it run good at all with that compression on only 91 octane.
Nice findings about your setup. I personally cant believe you got it run good at all with that compression on only 91 octane.
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05-20-2010, 06:36 PM
#8
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isnt stoich for e85 9.6 :1 instead of 14.7 for gas. so even though you can use bigger injectors or tune to compensate, dont you need to recalculate your "ideal" afr.
05-20-2010, 11:48 PM
#10
Yes, you have to find that sweet spot depending on your ethanol percentage. Im still playing with mine but mid 12s afr at wot seems to be good for 30% e85, which is actually about 25% pure ethanol in my tank. Like I said, theres no real guide lines for percentages of e85 so you just have to do some math and use the wideband to find where the right afr you want is.
05-20-2010, 11:57 PM
#12
This is a crude example but itll get you in the ballpark. The stoich of e85 is 9.6 and gas is 14.7. Thats a 5.1 difference. Now since Im at 30%, 30% of 5.1 is 1.53. 14.7-1.53= 13.17. So at idle you can start by aiming for 13.17. Its going to be richer, needs to be, at wot so, so far Im noticing that a afr reading of 12.5 seems to work. This isnt an exact science and Im open to suggestions but it seems to be working so far.
05-21-2010, 12:09 AM
#13
When it first came out, they made a big deal about E85 and its been how many years now and its still hard as **** to get...another good job by the govt.
Nice findings about your setup. I personally cant believe you got it run good at all with that compression on only 91 octane.
Nice findings about your setup. I personally cant believe you got it run good at all with that compression on only 91 octane.
Well with the right cam and good tuning it was done.
05-21-2010, 01:16 AM
#14
Just for fun I took a (crappy, sorry) vid of a quick full throttle after tuning for the e85 mix. Sorry it sucks a bit but I only had one free hand. 
It was to see the aggresive timing kick in at 4500rpms, just a quick 1-2gear shift, I let off at about 90mph, too much traffic lol. So far so good. The vid was longer but didnt look good. I did wot runs from about 60mph and you can really feel the car use that timing after 4500rpm. Since Im 12:1 cr I have the more aggresive timing table up top to avoid detonation at partial throttle.
http://www.youtube.com/watch?v=tQeaZEHbwhQ
It was to see the aggresive timing kick in at 4500rpms, just a quick 1-2gear shift, I let off at about 90mph, too much traffic lol. So far so good. The vid was longer but didnt look good. I did wot runs from about 60mph and you can really feel the car use that timing after 4500rpm. Since Im 12:1 cr I have the more aggresive timing table up top to avoid detonation at partial throttle.http://www.youtube.com/watch?v=tQeaZEHbwhQ
Last edited by C5natie; 05-21-2010 at 07:44 AM.
05-21-2010, 09:58 AM
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From wikipedia
E85 has an octane rating higher than that of regular gasoline's typical rating of 87, or premium gasoline's 91-93. This allows it to be used in higher compression engines which tend to produce more power per unit of displacement than their gasoline counterparts. The Renewable Fuels Foundation states in its Changes in Gasoline IV manual, "There is no requirement to post octane on an E85 dispenser. If a retailer chooses to post octane, they should be aware that the often cited 105 octane is incorrect. This number was derived by using ethanol’s blending octane value in gasoline. This is not the proper way to calculate the octane of E85. Ethanol’s true octane value should be used to calculate E85’s octane value. This results in an octane range of 94-96 (R+M)/2. These calculations have been confirmed by actual octane engine tests."
E85 has an octane rating higher than that of regular gasoline's typical rating of 87, or premium gasoline's 91-93. This allows it to be used in higher compression engines which tend to produce more power per unit of displacement than their gasoline counterparts. The Renewable Fuels Foundation states in its Changes in Gasoline IV manual, "There is no requirement to post octane on an E85 dispenser. If a retailer chooses to post octane, they should be aware that the often cited 105 octane is incorrect. This number was derived by using ethanol’s blending octane value in gasoline. This is not the proper way to calculate the octane of E85. Ethanol’s true octane value should be used to calculate E85’s octane value. This results in an octane range of 94-96 (R+M)/2. These calculations have been confirmed by actual octane engine tests."
05-21-2010, 10:00 AM
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Most widebands have 2 outputs that output different voltages. 1 will read something like 11.0-19.0 (5-10v)and the other will read 7.0-21.0(.0-5.0v)? Most gauges work off of the 11-19 area so if you are really at stoich it will read 14.7. If you have HPtuners or another logging software that can read the other output it will actually read the true AFR ie 9.xx. I have a AFR gauge and it reads 14.7-14.9 and the HPtuners will read 9.6.
05-21-2010, 10:04 AM
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From wikipedia
E85 has an octane rating higher than that of regular gasoline's typical rating of 87, or premium gasoline's 91-93. This allows it to be used in higher compression engines which tend to produce more power per unit of displacement than their gasoline counterparts. The Renewable Fuels Foundation states in its Changes in Gasoline IV manual, "There is no requirement to post octane on an E85 dispenser. If a retailer chooses to post octane, they should be aware that the often cited 105 octane is incorrect. This number was derived by using ethanol’s blending octane value in gasoline. This is not the proper way to calculate the octane of E85. Ethanol’s true octane value should be used to calculate E85’s octane value. This results in an octane range of 94-96 (R+M)/2. These calculations have been confirmed by actual octane engine tests."
E85 has an octane rating higher than that of regular gasoline's typical rating of 87, or premium gasoline's 91-93. This allows it to be used in higher compression engines which tend to produce more power per unit of displacement than their gasoline counterparts. The Renewable Fuels Foundation states in its Changes in Gasoline IV manual, "There is no requirement to post octane on an E85 dispenser. If a retailer chooses to post octane, they should be aware that the often cited 105 octane is incorrect. This number was derived by using ethanol’s blending octane value in gasoline. This is not the proper way to calculate the octane of E85. Ethanol’s true octane value should be used to calculate E85’s octane value. This results in an octane range of 94-96 (R+M)/2. These calculations have been confirmed by actual octane engine tests."
Point???
05-21-2010, 10:22 AM
#20
From wikipedia
E85 has an octane rating higher than that of regular gasoline's typical rating of 87, or premium gasoline's 91-93. This allows it to be used in higher compression engines which tend to produce more power per unit of displacement than their gasoline counterparts. The Renewable Fuels Foundation states in its Changes in Gasoline IV manual, "There is no requirement to post octane on an E85 dispenser. If a retailer chooses to post octane, they should be aware that the often cited 105 octane is incorrect. This number was derived by using ethanol’s blending octane value in gasoline. This is not the proper way to calculate the octane of E85. Ethanol’s true octane value should be used to calculate E85’s octane value. This results in an octane range of 94-96 (R+M)/2. These calculations have been confirmed by actual octane engine tests."
E85 has an octane rating higher than that of regular gasoline's typical rating of 87, or premium gasoline's 91-93. This allows it to be used in higher compression engines which tend to produce more power per unit of displacement than their gasoline counterparts. The Renewable Fuels Foundation states in its Changes in Gasoline IV manual, "There is no requirement to post octane on an E85 dispenser. If a retailer chooses to post octane, they should be aware that the often cited 105 octane is incorrect. This number was derived by using ethanol’s blending octane value in gasoline. This is not the proper way to calculate the octane of E85. Ethanol’s true octane value should be used to calculate E85’s octane value. This results in an octane range of 94-96 (R+M)/2. These calculations have been confirmed by actual octane engine tests."
I read the same quote followed by many saying other wise. Thats the way they have to calculate the octane for sale. Seems like the e85 website is the only one to state that but Im sure they dont want theyre fuel associated with racing when theyre trying to sell it as a envirnmentally friendly substitute. Fact is ethanol alone is 110+ octane, even your wikipedia states that. If you have a fuel thats 85% 110oct and 15% 87 how do you only get 94-96? Itll be closer to 106oct (unofficially) This is just another type of gasohol, or alcohol + gas. Alcohol, ethanol and methanol all have high octanes.