Percentage of E85

[wordy1]

What would be a safe percentage of E85 to add to my current set-up without having to change anything to up the octane rating? Been using toluene and have been able to run up to 25% toluene without any noticeable problems. If I am adding E85 instead, will I need to up the fuel pressure?

My car likes 94-96 octane even for daily driving, once and awhile I get knock issues when I get 92 octane as some stations only have 92.

 

[wordy1]

I understand the octane benefits, just do not want to do any harm to anything on the car by trying it without first changing things like fuel pressure, my chip settings, etc. as I know the BTU's are about 25% less and the actual consistency is very thin

I would NEVER consider adding 50% E85 unless I had everything swapped out, (bigger injectors, reprogrammed chip, etc.) And if I were you I'd at least be adding some Heet to the tank as Ethanol retains a lot more water than gasoline and can cause some freezing issues.

All I am wanting to know in this thread, is that I am considering topping it off with say 2 gals for a whole tank to up the octane to limit knock issues instead of using toluene for the moment and am wondering if I can without changing anything.

And in the future I am contemplating converting the car to be able to run a 50/50 mix of E85 (mainly because I don't want to have to go to a double pumper fuel pump or MUCH larger injectors, I am going with 60#ers in the spring) and want to try some E-85 before the winter hits to see if it makes any difference before I decide on what I want to do in the spring.

Can I take a direct scan reading to see if there are any changes before and after.. and if everything is "ok" can I keep increasing the percentage with my current set-up?

Its always best to start small. I did the same thing with toluene, but its harder to find and more expensive. And yes I will be upgrading to ALKY in the spring and would like to run a mix of 50/50 E85 on top of that.

Without boost my car runs NOTICEABLY better with higher octane. I think a 50/50 mix of approx. 100 octane fuel with a spray of ALKY at the right time will turn this car into a completely different animal for all applications including daily driving.

E-85 costs less and if I can expect equal milage with a 50/50 mix what more can I ask for? And if I want to really skimp I can mix a 50/50 mix of E-85 and 87 octane like you suggested. I figure that if I have ALKY backing me up, that when I cannot find an E-85 station, I can just drop the fuel % with Eric's chip and keep on keepin' on ..

 

[Hot Air]

If you are marginal on fuel pump or injectors, don't do it. If you do it, change out the fuel filter before you do it and after a tank or two. Cut them open and see if you have a bunch of "Stuff". I understand that ethanol has a high detergent value and will clean out your fuel system for you. Let us all know how it works.
Conrad

 

[wordy1]

Sure, I decided not to add any today as the car started up sorta funny, and got a bunch of error codes and I had to reset the computer. It was like 25 degrees, so I am hoping that was why. There's nothing wrong now. What would cause virtually every error code to come up? Could I have an issue with the ECM? It has never done this before..

Will be converting the car to ALKY and will tune for a 50/50 mix of E85 and Premium in the spring. The way I figure, when E85 is not available, I will have the ALKY backing me up just in case and will just need to lower the fuel and timing accordingly.

 

[FlaBoy]

And if I were you I'd at least be adding some Heet to the tank as Ethanol retains a lot more water than gasoline and can cause some freezing issues.

I'm pretty sure most of those gas antifreeze products (like HEET) are just methanol/ethanol and a few other additives. While both Methyl and Ethyl alcohol are very hygroscopic as you say, this is why they're useful as gas antifreeze. They combine with any water to form a solution, and in doing so drastically lower the freezing point of any water they combine with. So while E85 has the possibility of holding more water than gasoline (due to its miscibility with water) i'd be surprised if it drastically effected the freezing point (freezing point of ethanol is about -170*F, which is far below the flashpoint of gasoline, and whatever little amount of water might get in there isn't going to raise it that much). And even if it WAS a concern, adding HEET to the tank wouldn't make much of a difference. If you have a 20 gallon tank of 85% ethanol, and add 6 ounces of 100% methanol, its not going to change the alcohol concentration much in that tank, and as such isn't going to have a drastic impact on the freezing point of any water-alcohol solution present.