Latest episode of Engine Masters (flex sensor)
 

I found it interesting .
Quick Summary :
They used a flex sensor and various amounts of alcohol (E85) mixed with 91 octane , then straight E85 (76% alcohol in this example) on an NA motor . 9.3:1

49% alcohol used 14% more fuel
76% alcohol used 30% more fuel yet no power gains.
Raising timing 4* on E85 had a decent power increase.

The small line of a GM flex fuel sensor wouldn`t support my HP so I found something that supports a -10AN

https://www.motionraceworks.com/blog...thanol-and-e85


and some tuning :


Theres already 10% alcohol in pump fuel , another 40% would be nice for cooling and octane increase, just another safety margin..without the negative affects of 100% E85? .... with a fuel sensor I could mix and match any amounts.


thoughts?

I ran my gm flex fuel sensor on my return line. It wouldn't even support my flow on the return line so I had to tee it in. At the time there were no other options like today. No issues for the last 14 years. I'm running 220lb injectors. What are the negative affects of 85 over say 50? If I had the choice I would run 85 over 70, although you can make just as much power on 70. Most will say you can run full power on 60. My engines have always ran smoother on higher ethanol. It amazing while the engine was running and going from pump to e85, you can actually hear the engine run smother. On a boat, I can see the advantage of running lower ethanol to give you more miles or if a tank. I have my ecu programmed to start pulling timing at e70 and lower (just a precaution) and also start reducing boost, if the ecu calls for it. I know people that have ran 60lbs of boost on pump e85. On the dyno I got to 30lbs on my 9:1 sbf on pump e85 (84% ethanol on that batch). I had more left in the turbos but had a crank trigger issue and stopped there. My plan for the dyno was to go as high as the turbos could go. Probably 35ish lbs. My convertor wasn't happy with boost 25lbs and above lol. Zentroics sells an ethanol % display that gets wired into the flex fuel sensor. It makes it real easy to see what's in the tank.

We run the GM flex sensor tied into the ECM along with a dash mounted gauge in a boosted application. The gauge let's us know how far we can push it on a particular tank of fuel, the ECM does the rest. The motor runs smoother and more consistent. The sensor is T ed off of the return line.

I like where this is going!
What do you guys use for hose, the standard AN hose okay?
Lower ethanol content would give boaters more miles per tank and if I run out and fill with 91 it`s not a problem.

Return line would work too , I like it .

Would temperature be an issue, cold heads? E85 gas mileage goes to crap in the winter.

Very interesting I looked into E85 a little when building our engines and the fuel consumption ruined it but the flex sensor may be the ticket, along with just the right percentage of ethonal for most power and most mileage. You are on to something!

One of my concerns is water in the fuel and phase separation with an open vented to atmosphere gas tank.
Id install one of these on the fuel vent to start
Attachment 577500
and a good water fuel separator.
At the end of the season I`d run straight 91 as usual for lay up .

Put boat in air conditioned / dehumidified garage when it’s parked ?

SB , it sits outside under a roof. It`s the moisture that builds up in the tank as temps vary that is also an issue, Thats why a full tank is recommended. It would take a lot to dehumidify an entire garage,


My fuel pumps are at the edge of being undersized if I were to use only E85 .. marginal with a 49% mixture. Might have to upgrade those

GPH=(max hp x bsfc) /7
I need about 101gph

I have the dominator 1200 and at 45psi it`s about there .

https://cimg4.ibsrv.net/gimg/www.off...0a4e713bbf.jpg

In my opinion, it's only worth running E85 in a high compression or boosted application. The price difference between it and racing gas even burning an extra 35 to 40 percent still seems worth it.

I'm not sure what hose is made that is coast guard approved. I have to look again what hose I'm running(street car). It's the black nylon an hose. I do get some smell in the garage, not terrible, but it is there. IMO a lot of incorrect info about e85, usually from people that never ran it. Not sure why e85 mileage would go to crap in the winter? It should actually be better than summer (in general) because it will probably be e70, more btu's per gallon. I had my car out in 0-5* air temps. If the a/f is to rich, I've had misfires (10.8:1 on very low boost). I did have to add a degree or 2 in the very cold start coolant temp table to help it light off easier in very cold temps.

You don't want to skimp on the fuel system. How much hp are you looking to go? What injectors are you running?

I made just shy of 1100rwhp and my 220lb injectors were at 85% duty cycle. Fp was just starting to drop on my last 30psi pull. I'm running a Bosch 044 pump full time and I have a weldon 2035 pump with a boost a pump on it turned on at 1psi. On the dyno I had the boost a pump turned down/ off. After the last pump I raised the pump to get the flow higher. I'm running-10 feed/-8 return.

Pump e85 is about the same price per mpg as premium, by me. Comparing it price wise to race gas isn't even close.

I only had one issue with the e85. The one time I didn't run alcohol lube, I removed the engine and the injectors were sitting for about a year. 6 were stuck closed when I went to start it. They were able to be freed without buying new$1800 injectors, thank God lol.

I never had any issue with moisture/ water in the fuel. My car would sit for months at a time during the winter/ bad weather. I would just turn the key and go. Never worried about old/stale fuel. You shouldn't run paper filters. Run stainless mesh. They go down to 10 micron and lower now. Not sure what mpg or gpm you do will burn. As a rough rule every 10% ethanol will be a 3-4% difference in fuel burn. Will going from e50 to e70/85 make that big of a mileage difference where you won't make it home?