Fuel System and Ethanol

[z28quetzal]

Re: Fuel System and Ethanol

Hi guys!

Just read this thread and found it very interesting. I want to share with you all some info:

I have made a 3.4V6 swap into a Triumph TR6. I am using the T5 tranny also. The engine has headers and larger injectors and new valve springs, but basically it is stock. I saw some E85 at a local gas station the other day, noticed it was 115 octane and decided to give it a try. I had about 3 or so gallons left of regular fuel, and the tank will hold about 14, so this ended up being a blend.

Results and comments:

1. When I first started the engine it coughed and sputtered a little. It did not run very well but that was solved in about 5 or so miles. I guess the computer compensated for the higher o2 in the exhaust. After a few more miles, the engine ran perfectly. It pulled off the line very smoothly and had very good throttle response.
2. Since I have larger injectors on my 3.4; I guess this allowed for a little extra fuel in the mix.
3. I noticed the engine temp went up a little. Not by a huge amount, but it went up slightly.
4. The exhaust smell was awesome! It certainly did not smell like 'carbon'. It had a different smell entirely.
5. Power and mpg? This one is up for debate. I did notice a little degradation in power, but I can certainly live with it. I guess mpg might have decreased slightly but I did not measure this in a very accurate manner.
6. I syphoned just a little fuel out of the tank. I wanted to feel what it was like. It has a different 'feel' than fuel. It is strong smelling and it is much 'colder' than fuel.
7. Did some research. Yes, a 50/50 mix is acceptable to run on non-FlexFuel engines. Also, from what I have read, Ethanol contains 2/3 the power that gasoline fuel offers. Therefore, mileage will decrease.

I found another fuel station closer to home. I hope soon to try another 'mix' tankfull and see what results I get. In the conversion I made, the tank was changed and made from aluminium. All fuel lines in my car are a high grade rubber so I think I'm good.

joe

[Stock98camaro]

Re: Fuel System and Ethanol

How much did it cost per gallon?

[z28quetzal]

Re: Fuel System and Ethanol

E85 was about 30 cents per gallon cheaper than regular. Of course that was a couple of weeks ago and I'm sure this has changed by now.

[AZ3.8Camaro]

Re: Fuel System and Ethanol

I have tuned a racing engine on both gas and E85.
Again, I wouldn't run more than the 10% blend in a gas car.
No camaro is designed as a flex fuel vehicle.
E-85 is NOT cheaper than gasd right now. Per gallon it is, but like I said, you need over 1.5 gallons to get the same power and same distance as gas.
Mulitply the price by 1.5 or so, then you will get your real cost.
As growers produce more corn, grains, etc. it will go down in cost.

Again, don't run E85 without a tune specifically for it. Its a waste of time and money.
Your car will not compensate for it properly. Just because it runs doesn't mean anything.

[z28quetzal]

Re: Fuel System and Ethanol

You mention you have tuned specifically for E85. What is involved in doing so? I realize you probably ran a specific engine management system and so forth, but what is the difference between tuning for E85 vs fuel?

I am simply asking. Your comment about 'just because it runs doesn't mean anything' leads me to believe you probably know what you are talking about. Enlghten me...

[AZ3.8Camaro]

Re: Fuel System and Ethanol

Nothing is different in the way you tune for ethanol, except the desired A/F ratio changes. You can find out what your engine likes by using a dyno and altering the A/F ratio to make great power. Ethanol can be ran considerably on the rich side without losing power, unlike gas, so you always start rich, and look for plateau in power. Tuning for economy would be different of course.

Although the methods of tuning are the same, the fuel maps would be different. The shape would remain the same for the most part, just be off by a scalar. The stoich. a/f ratio for gas is 14.7 but for ethanol is 9, so you need more fuel per unit of air coming in.
The stock computer cannot compensate for this on its own, as it aims for 14.7 or whatever target it is set to for that throttle/load section. Even if it did, you might run out of injector, or at least run high duty cycles for long periods of time.
Also, running at 14.7 parts of air per part of ethanol puts you on the lean side, not a safe place to be.

[slow6]

Re: Fuel System and Ethanol

The stoich. a/f ratio for gas is 14.7 but for ethanol is 9, so you need more fuel per unit of air coming in..

9 and 14.7 is a HUGE difference
very lean

[BobbyZ72]

Re: Fuel System and Ethanol

i topped my tank off a few weeks ago with e85, i added like 5 gallons to my tank. I just could not resisted when i was in the area were it was for sale. Basicly my testing was the same as z28quetzal. After filling up, i drove a few miles and the engine started getting a taste of the new fuel, when comming to a stop it would run ruff. After a few miles the computer figured it out, and it ran fine. I wont lie, if we had a station closer to me, its all i would buy. I would rather support american farmers then other countrys.

[AZ3.8Camaro]

Re: Fuel System and Ethanol

The computer runs from about 12.5:1 to 14.0:1 target AFR stock, so it really doesn't have a lot to "learn" it uses your O2 sensors to try and find the AFR listed in the table. Those values don't change, only your o2 readings do.
At even 12.5:1 your lean on ethanol.
Furthermore, around 9:1 where it needs to be, stock narrowband o2 sensors wont work for ****.

[BobbyZ72]

Re: Fuel System and Ethanol

I have bosch, are they the right ones to have? Are they better then delco's

[slow6]

Re: Fuel System and Ethanol

i heard delcos were better than bosch.
stock narrowband sensors can only read from 0-5v.
so, they cant read very far off from 14.7:1 (stoich)
(i forgot the exact range they are able to read in AFR)

[Digiphaze]

Re: Fuel System and Ethanol

I'll have to find a link again, but there was a brazillian company that sold a module to easily convert the car to E85. Not sure what it does, proabably compensates for the right A/F mixtures. Dunno how it handles the fact that you really need larger fuel injectors though.

p.s If your running ethanol now, you may want to keep an eye on that fuel filter. I hear ethanol cleans out the tank of dirt and grime.

[camaroman1181]

Re: Fuel System and Ethanol

I have bosch, are they the right ones to have? Are they better then delco's

both the bosch and the delcos are narrow band O2 sensors. you will not get wide band O2's at most parts stores... almost all cars that I am aware of came factory with narrow band O2's.

I agree with AZ3.8Camaro on this... All of you running higher concentrations of E85 on a factory tune with factory O2's and factory fuel systems are taking a risk. I would highly suggest not doing that. I too would much rather support this country's farmers then some mid east country, but i wont do it until my car can handle the different fuel. If you really must ignore our warnings and start running high concentrations of E85 with no mods for it, do not drive the car hard, as you will really be testing its longevity by running at that A/F ratio. BE CAREFUL!!!!

[AZ3.8Camaro]

Re: Fuel System and Ethanol

Yeah guys, I am not saying this is a bad idea. I am thinking about converting over when I get a wideband. This can be done.
Things you need:
Possibly larger injectors
Wideband o2 setup
Computer Tuner (HPTuners etc).

I am simply saying that it is a bad idea on a stock, non flex fuel car.