E85 and 93 octane mix


May 26, 2001
Looking for some fact based opinions here. I plan on running 116 octane at the track at around 26# boost, mid 20's on timing. Heading to the chassis dyno soon and plan on doing a strip and street tune. What I'm wanting to do is run a 93 and E85 mix for the street so I can run more than 16#'s with the timing around 18*. Just looking for less of a wimpy street tune and not burn $12 a gallon 116 or mix it w/ 93 for that matter. I like the feel of the car on the street at 20-22#'s and 18-20* timing on 100 octane, 11.8 a/f. Please keep in mind I want to be safe here and have absolutely no detonation. Currently no knock retard on the tune above.
Here is the set up.
Stock fuel lines, adjustable regulator, 255 lph pump, hot wired, 60# injectors, TT chip v6.xx wideband, power logger, AEM wideband o2, Bison turbo (basically a TA60), rpm won't exceed 5k.
Thinking run 25% E85, 75% 93, to raise octane to 96 or so......
Can my fuel system keep up?
Concerns on rubber fuel line components?
Can I run more than 25% E85?
If this is possible start the a/f ratio around 10.5?
Or is this a totally bad idea, and I should live with a super safe tune on the street?
All comments welcome! Thanks, Jeremy.
I fully agree NOT to mix fuels as there are way too many variables involved? :confused:

You are going to use 93 octane gasoline, but can you verify it is really 93 since octane will degrade after only 3 weeks?

How are you going to mix to the proper ratio, in the tank or in your garage?

Then you will be experimenting with A/F ratio and timing and boost for an optimum tune at what level, and is that level a given, or will it be variable?

I also do not think your fuel system in not even up to E-85 standards, much less with some unknown blend of fuel?

If you change your thought process to first state a given performance goal and build around that, it would be a better place to start. :)

There are many experienced owners that have been down similar paths with excellent results, so that should be a better path to follow. It is good to come up with new ideas, as this is how we learn, but mixing fuels, even just injecting alky, requires a proper method and supporting parts. Even this learning curve has been difficult over the years developing the blend of parts and tuning.

The path you are on will usually lead to some mishap along the way, and just hope it is not an expensive one. :eek:
You're looking for trouble, big time. If you got E85 available just upgrade you're fuel system (plenty of info here on that, much debated) and tune for it. Alternately you could run 93 and inject alky. Many do that.
Question answered, thanks guys!
This is a street car with the occasional trip to the strip. I should have stated I don't want to switch over to full E85, that is not my intent. Just wanted to run an aggressive 93 octane tune and be safe by using a bit more octane using E85.
I'll stick with a 93 octane tune for the street and put a couple gallons of 116 in with my fill ups for some extra insurance. I have 116 for my na race car, just not wanting to go burning it all up cruising on the street in the Buick.
As far as my goal goes, I'm going to run 26#'s on 116 octane with safe timing of some number 26*ish? And the car is going to make and run whatever it does at the track. As for the street you guys helped me answer my questions, it will be a 93 octane tune that is safe, and it will make whatever power it makes.
Thanks, Jeremy.
Why don't you just use the tried and true Alky set up for these cars?

Mixing fuel is a recipie for disaster.
The 116 is leaded and will kill your O2 sensor(s). You could go with a straight 100ul tune too. BTW, there is no such thing as an "aggresive tune and be safe".
I have a similar setup to yours, but a 340 pump. I had Eric burn me an e85 chip for 60's and am running 18psi. All is good, and i am happy to daily my car at 18psi with cheap gas. An e85 chip is similar to an alky chip, whereas timing is more aggressive than a street chip so even at the same boost as a street chip, the 85 chip pulls a lot harder. Might be something to consider, 100% e85.
Why run race gas? For the money you spend on race gas, you can easily pay for a set of 120's and a double pumper. then you can run 26lbs of boost all day long on E85.
At some point I may go with an E85 setup. I'm actually looking at picking up another TB (wish I could have picked up that white WO2 that was Jeremy's!) and it will most likely be an E85 conversion. I have been running race gas because I buy a barrel every year for my 15:1 sbc race car and it sitting in the gargage and readily available to pump into the GN. I should have gone E85 to begin with, but at the time I told myself not to be stupid and mod the hell out of the GN since I have a race car. But as you all know, once you find out how fun and relatively inexpensive it is to make some descent power with the TB's things change! Also, I consider heated o2 sensors to be like spark plugs, replace them every spring (waste of money or not thats how I think about it!) Thanks again for the comments!
the lnf guys have been big into blending e85 and pump gas for many years , turbo cobalt ss .etc... if you still have interest this thread will walk you from that platforms infancy with e85 blending though dialing it in pretty well , pitfalls , trials & tribulations and sucesses.I live 3 states away from the nearest e85 station and dabbled with blending a bit and tuned a buddys 3800/sc rock crawler thats been running e30 for a couple years now , in his case easy enough to bring a couple jugs of e85 home and bump octane not practical to swap with no availability in state.

I do have to agree though with how dialed in some guys on here are with full e85 swaps if you have it local why wouldnt you...

Murph, the closest for E85 around here is in Boston. Wish someone in the Lowell area would start selling it.
yep Burke oil right by logan airport by the hanger with the x ray view of a plane inside it lol , thats where I got it to mess with when I commuted to Mass for work , been 2 years since I got a job closer to home and been patiently waiting , would be nice to at least see it in NH along 95 , still couldnt justify converting anything but would do some blending again
You won't see it in NH unless the legislature gets it's head out of it's ass. They banned the sale of E85 here. All I can hope for is something near the boarder.
I mix in 4.5 gallons E85 with 93 octane in my supercharged regal. It runs much better wot...no knock! I use it as an octane booster. I would mix it with my GN, but I'm just converting it full boat. E85 is like Viagra!
I mix in 4.5 gallons E85 with 93 octane in my supercharged regal. It runs much better wot...no knock! I use it as an octane booster. I would mix it with my GN, but I'm just converting it full boat. E85 is like Viagra!

It's good for limp dick?.........................:confused::p