My motors are just freshened 9.6 to 1 zz572/620 motors. Been reading up on e85 and seems like good choice to high compression high horsepower 11 or 12 to 1 motor if you have easy access to it. It's octane around 108 and runs cooler. Just wondering if anyone has done this on an offshore powerboat?[ATTACH=CONFIG]541370[/ATTACH]

I think the big issue is that alcohol tends to absorb water, which is in plentiful supply in the moist air around a boat.

Yeah I've read that and also it's longevity, Good water separator and not let it sit I don't see any issue. Suppose to run cooler also.

Remember, it also requires ~30% more fuel consumption to make the same power.

1.89 comes out to $2.46 adding 30%. Definately more filling up but if you trailer your boat cost seems relatively cheap for bigger hp or since it runs cooler one would think great for supercharged motors?

No doubt, there is some serious HP being made with E85,

Agree with every comment above, besides water being a big issue. Yes alcohol attracts water, but when your talking E85, E100, M100 "Methanol", vs the E15 blend typically found in gasoline today, it's not a big issue. Small amounts of water stay suspended in high alcohol blends, will pass the filters, and still burns fine. However when you only have 15% alcohol and 85% gasoline [as all US road fuel], that water can fall out of solution and gets caught in the fuel filter, cause corrosion and other issues. I'd be more concerned with fuel evaporation in a boat.

I've preached E85 to several very high HP offshore guys for years with no takers. Tuned right alcohol will turn a 800hp blower motor into a 1200hp monster changing only a pully, timing, and jetting. High compression naturally aspirated also works great. Finding E85 or Methanol on the water is a whole different topic.

Only one way to find out. Try the E85 and report back.

We've run E85 in my brothers boat for the last 3 years without a problem. Procharged 615 a little over 1200hp, performs better accross the board. The boat is trailered everywhere so getting the E85 hasn't been an issue. I don't know if it matters but he doesn't run offshore just lakes and rivers.

I've been running e85 with twin turbos a little over a year now. The motors were 10:1 for about 6 months running 12lb of boost until a waste gate broke and pushed the boost to 20+ on one motor blowing a head gasket. I'm now at 8:1 running 20lb. The boat never sits in the water more than one day but it was on a trailer with full tanks over the winter for about 3 months. I've never had fuel related problems. My only issue is its hard to get real e85, it is anywhere from e60 to e80 in reality here so you need to account for that if you run hard