NyteFall

Hello,

I recently came across this video:
Stating you can use an e85 blend with 91+ Octane to achieve about e30 without any flex fuel sensor or tune to the ecu. The video actually shows dyno graphs and I was just wondering how accurate/safe this was. Does anyone have any input or experience with this?

Would greatly appreciate it.

Avanti

I think I've leave it to the "influencers," since I've seen nothing to recommend it (as I understand it without watching the click-bait).

NyteFall

It's not click bait, it was actually a pretty informative video. He goes on to show the timing and everything of the car and the actual dyno numbers before and after the e30 blend. From what I can gather, it seems to do just as he is stating.

Travlee

and how will you know if you are at E30 without a sensor or analyzer?

NyteFall

You buy a test tube tester kit and test the pump e85 to see what the e content really is then do some basic math to figure out how many gallons of each will dilute it to e30. I used to do this all the time on my Kia Stinger.

9sec

the stoich between pump gas and ethanol are widely different as is the timing to run ethanol properly. this is a way to effectively hurt the motor. do not do it

Travlee

meh, let him do it

NyteFall

I'm not saying I'm going to do it. All I was asking was how accurate that video is. As the guy says he has been doing this with his car for years as well as a few others in the comments and have seen no negative impact. The answer I'm looking for is not no don't do it, that's bad because that's the way it is. I want to know why. His video shows a lot of good information and timing and dyno charts. So I'm looking for someone to explain to me why this is bad. As it's seemingly working.

Travlee

I know here e85 varies between 52 and 71% depending on the gas station, it's not consistent so manual calculation would be off

NyteFall

It wouldn't be off if you test it every time you fill up. Sure it could still be off by 1 or 2

Travlee

It would, because if you fill up with say 12 gal of 93, and then varying e85, you would have no idea until you get home and test. I have stated variety levels at different stations, its a crap shoot and not worth the cost of an engine...but hey, you do you

NyteFall

You don't wait until home to test. You pump the e85 right into the test tube with the small bit of water and shake and it will tell you what percentage the e is. Then from there you can calculate how many gallons of e and how many gallons of 93 or whatever else your pumping.

Travlee

It won't be accurate until it mixes in, I know it takes about 5 miles in my car before my inline analyzer catches up... but hey, be cheap and not get analyzer and tune, not my car

NyteFall

Okay that's no different than if you have a sensor or now. What I'm getting at is his video is showing the stock untuned ECU is adjusting timing enough to work without a tune.

Travlee

@Internets_Ninja helped me alot when i had e85 questions

TJay74

This will not hurt the engine, granted from what I have seen in the factory ECU calibration E30 will be a little outside of that the STFT/LTFT can adjust for you can run E20 all the time with zero issue. Running E20 on 91 octane will take 91 and move it to around 98 octane. The ECU wont use the E85 timing values, it will allow the ECU to stay in the high octane gasoline table which will help the ECU not to pull timing which will reduce power.

jglassmaker

It's not that expensive or difficult to do a proper sensor install and tune. I have done it all myself.

Will this work for everyone's car, not very likely. Will this potentially damage a rather expensive engine, likely over time. Ask yourself, is it worth it to you to take the shortcut.

(for those of you who will likely jump all over me about this not damaging an engine, look into tuning for E85 and what the car is trying to do. Put a little too much Ethanol in it one day or it doesn't mix very well and you will damage the engine. It won't suddenly explode, instead over time it's going to detonate a little here or there which will do a number on rod and crank bearings... then one day you will start seeing metal in the oil and maybe even some engine knock that won't go away)

TJay74

I guess I will be your Huckleberry then, It wont hurt a thing at all. I ran E20 for 1.5 years before installed the full round of mods I installed. Manual even says up to E15 is fine. The fuel trims are plenty capable on the stock calibration to adjust for up to E20. Not only that on the stock calibration the WOT/PE tables are on the fat side of things and can handle the change as well provided there are no issue with the fuel system. These engines are known to knock on 91 octane and on 93 octane. Running some E20 on a 91 or 93 octane mix will help insure the vehicle isnt detonation and will help keep the ECU from dropping down into the low octane timing tables.

jglassmaker

Haha, love the Huckleberry reference!

I think you are correct with E20 being fine, the stock fuel trims being fat enough, and the manual saying E15 is fine so E20 isn't that much farther into the potential danger zone. I can also confirm my car would sometimes knock with 91/93 octane as you state.

My focus is on the fuel leaning out too far. I think even E30 would be reasonably safe if always at E30 mix. However it's those rare instances when you are at a higher mix than you realize or the fuel didn't mix properly yet. Accidentally pushing E40+ and with no sensor to tell you not to go WOT until you can adjust the mix... that is where I think you are risking your motor's life.

The big tuners will even specifically adjust tunes so that you can't run past a certain amount of E to prevent major engine damage, I know LMR (Late Model Racecraft) will do this for their performance packages (saw it in a video). I don't know how they do it, but guessing they take a lot of timing out at certain E% content (there is a table for adjusting timing based on E%).

bc928

Any increase in ethanol will improve the stock operation of the lt4 in the vette. Adding a few gallons won't hurt anything, and even doing half and half only gets you to e50 (tune needed) So half of that is 4 and 12.

I proved with data that the car is in detonation under most non idle conditions on crap California 91 and it goes away with only 3 gallons of real e85 (I say real because there are other ratios that come from e85 pumps across the country)

car simply - was not made to run on 91 and make even stock power.