NASTYC7

I know it's taboo on here. It has been stated many times... YOU CAN'T USE E85 AS AN ADDER WITHOUT THE CONVERSION KIT... THE COMPUTER WON"T KNOW AND RUN LEAN!!!!

I went against everyone's advice.. Now I am paying the price.... I did it once to cure bad gas, then did it 5 more times just to make sure I really screwed up things. The first time I added 5 gallons to my 5/8 tank of bad gas that was making the car fall flat on it's face. I ran that gas out at average driving speeds.

Then I did the unthinkable.. I added 3 gallons to fill it up with 91 ( California's Premium) did spirited driving.. Man o Man did the car come alive!! The next tank I added just 2 gallons.. Same fun..

Did this for 3 more tanks so far.... What a huge improvement.. MY CAR IS ALIVE!! I am betting the 91 fuel is knocking off at min 120 HP. My car runs 8-12 degrees cooler ( just filled up with 91 again because I was nowhere near the E85 station and ran hotter again)

So to all the Nay Sayers…. The car runs perfect on a few gallons of E.. I did not notice any difference between 3 gallons vs 2 gallons added per tank.

Now before all of you that study your logs and feel you know all.. Let me tell you. I tested in real life and you are wrong! I went through 6 tanks in my testing and will do another 100 if needed....

No codes were thrown...
Engine temps were down 8-10 degrees...
Increased Horsepower....
Taken to long runs tapping the redline in each gear and hitting over 165 MPH multiple times for a distance further than any track would allow. Ya, I'm that *** on the freeway you all hate....
Stop light to stop light like I was running the 1/4 mile...
I truly believe there Is more damage done to the motor running 91 than what I have tested.

I am just giving real life experience and I am not recommending anyone to do as I did, but if you only have 91 available.. Your car is most likely down on power and its a lot more fun on E..

I only have one station that carries E. So to make sure I don't over saturate the fuel with multiple fill ups. I run the tank low and add 4-5 gallons of Premium ( depending how far away from the station I am) I try to get there with 50 miles or less on the tank.

Z06Brucey

Sub'd....

pewter99

any data logs showing air/fuel? knock ? codes??

C7/Z06 Man

All stock or do you have some mods?

Rdubfalco

subieworx

A couple gallons won't hurt and is well within the ability of the ecu to adjust using fuel trims.

Say you put in 13 gallons of 91 and 2 gallons of e85 (assuming it is actually 85% ethanol) that would bring your effective octane to roughly 92.87.

It takes roughly 30% more e85 by volume to equal the energy of gasoline. If we assume your car was running at 0 fuel trim all the time (very unlikely) then adding 2 gallons of e85 would create an add to the fuel trim of about 3.9% which is well within the realm of adjustment of the ecu.

davepl

When I was 16 I was an idiot junior chemist and tried to make all kinds of special fuels for my car from my Dad's hardware store. I found xylene and toluene were good for octane and ethanol was good for leaning a motor that was too rich. Nitrogen did nothing. Muriatic acid burned the nose hairs.

So all you did was run a little lean for a while, and even then the computer was running at its compensation limits. Unless you spent a lot of time at WOT with that lean burn I wouldn't expect a problem.

I'd say stop doing that if you can, though.

BUCKNERBUCK2

As a disclaimer, I am a GM engineer, engine focused and I am assigned to our IndyCar program that runs e85.

The amount of bad information/assumptions in your post are too many to address.

The fuel system in an LT4 is meant to run 91-93 octane e10-e15 fuel. End of story.

subieworx

That has to be fun!

sammyv

Thanks BUCKNERBUCK2!

BUCKNERBUCK2

Indeed it is! We are quite disciplined in our approach and do not just randomly mix fuels to achieve performance.

3 Z06ZR1

Might want to change your oil you may have considerable alcohol in your oil.

NASTYC7

What's your proof? Because you said so? Got any data what I did is hurtful? Do you not offer 100 Octane tune? Are there not E85 conversion kits available?

NASTYC7

Just a Filter and Mamo TB..

NASTYC7

Never mind

BUCKNERBUCK2

100 octane tune is on a fuel with similar stochiometric ratio, which is 14.2 for sunoco 100 octane where typical pump 93 octane is 14.6, so the fuel flow rate required is similar to 91-93 octane. It is also a tune that enables additional spark to take advantage of that octane.

e-85 has approximately 2/3 of the thermal energy as typical e15 fuel, so you will eventually reach the limit of the fuel trims. Long term durability is also greatly compromised as valve seats will not withstand the higher cylinder pressures combined with the volatility of e85.

You are negating years of development and durability testing carelessly. Committing to a conversion kit is one thing, playing splash and dash with incorrect fuel is another. Good luck.

AORoads

remind me not to go looking at used z's in blue in the area....

mig1980

Good info here. BUCKNERBUCK2, what are your thoughts on octane boosters like Torco and Boostane as it relates to performance gains as well as potential harm to the vehicle for those of us in California living with 91 octane?

Jnape

Also curious. I bet the same applies. Keeping your mix accurate and don't OD it trying to get to 95+ octane your fuel trims are consistent with the stock tune.
You are still using the same potential energy fuel (gas) and not using a lot of Alcohol.

6Speeder

BUCKNERBUCK is right. You are running your engine too lean. Check it with a wideband O2. Don't run E85 or a mix of 91 octane gas and E85 without a retune and a conversion kit. You will blow it up sooner or later.

As for torco, yes it works. With the stock tune I was getting 5 degrees more timing with torco and 91 octane gas (the best we get in Albuquerque) than with 91 octane gas alone, and no KR