[C5Natie]

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, 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.

[Vettezuki]

E85 is great stuff, especially for boosted applications. Just be careful with the AFR, get it wrong and you'll have a melt down. You'll have to adjust your readings for the fact a percentage of your fuel has a much lower energy content. As a result you'll note that while E85 is cheaper than race fuel, you'll burn more of it for the same results (energy content by volume again). Also, ethanol is less corrosive than methanol, but not non-corrosive.

While not exactly legal, you can make your own ethanol very cheaply depending on scale. That's all your doing; making your own gas/ethanol blend.

http://running_on_alcohol.tripod.com/id1.html


I run Torco in my slightly higher than 11:1 CR engine. Slight addition in cost (about $6 a tank), no change in mileage.

[C5Natie]

Yeah, so far its working. AFR at idle is at mid 13 and wot is 12.5 avg. Thats seems to be pretty good for a 30% e85 mix. Results seem good so far.

[C5Natie]

Car loves to rev on the e85 mix. Messed around with my crappy cell camera and taped a quick wot 1-2 shift from 30-90mph. Tires arent gonna last. Lol.

YouTube- LS1 Vette on 30% E85

[Vettezuki]

Originally Posted by C5Natie

Yeah, so far its working. AFR at idle is at mid 13 and wot is 12.5 avg. Thats seems to be pretty good for a 30% e85 mix. Results seem good so far.

My concern is that you may be pushing lean a touch at WOT.

Talk to corn fed, he thought he was rich enough too on his trubo E85 setup until he melted a piston. The problem is that ethanol and gasoline have different stoichiometry by a lot.

gas = 14.6
ethanol = 9!!

As a simple average of your ratios 30% of 85% E = 25.5% E and 74.5% Gas overall.

That means your mix has an adiabatic point of 13.2~ (I think.) What was your AFR on pure gas at WOT? If you were running rich on gas to be well tuned, 12.5 on your mix is almost certainly too lean.

TANGENT
That's if it's as simple as average the amounts together, and I'm not completely sure about that. It certainly isn't so simple in averaging octanes together. That is 10 gals of 90 and 10 gals of 100 does NOT necessarily give you 20 gals of 95. Different subject though.


Don't get me wrong, and I'm not trying to sound like a know it all (I'm certainly not), but I'd hate see your experiment result in melted bits.

[C5Natie]

^^
Well on gas that car ran fine but it was on the rich side, in the low 13 afr area. So I noticed that a 5-7% increase increase in fuel is what I needed for the ethanol mix. I might be wrong and Im open to suggestions. That percentage I increased it was across the board and I dont seem to have any lean spots. I figured I would noticed it leaning out in certain area. As for the octane mixing, its just a way to get me into a general area. Still, Im new at this so thanks for helping, Im deffinately listening.

Heres an example of my botched math,
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.