Alcohol ladden gasoline

[widowmaker]

I've noticed a drop of 200 rpms and 3 mph this summer since doing prop testing in cooler weather back in April. I think, but I am not sure, that I have some alcohol ladden fuel on board. I spoke to my engine builder this morning and he gave me some information about an alcohol/gasoline issue. Testing that he was involved in last December resulted in 98 mph in a Fountain 35 that was equipped with HP525s. That boat, with no changes other than using alcohol ladden fuel, runs 8 mph slower in the present hot and humid conditions. A consult with Mercruiser engineering by the local Fountain dealer revealed that the HP525s develop around 75 hp less using alcohol ladden fuel in these weather conditions. Does anyone else has any information on this subject? Thanks, in advance, for your thoughts.

[RedDog]

I don't know, but I have lost around 200 RPMs as well. I hadn't thought of it maybe being a fuel issue.

[VetteLT193]

If tuned for Ethanol the engine should make more power. But since they are not tuned for ethanol a drop in power makes sense. Ethanol is not as efficient regardless, so you have to burn more.

[Last Tango]

How does one "tune" a stock 350 Mag MPi for ethanol fuel addatives?

I have also noticed the lower performance of my boat since ethanol was added to fuels. Summer temps and humidity have an effect, but the ethanol really makes it far worse. I'm actually thinking of having my prop recurved back to stock since there is less horsepower to work with.

[tommymonza]

I have noticed just recently also the lack of power coming out of my father inlaws 350mpi in his stingray. A couple of weeks ago i was down 2-300 rpms and thought maybe he bent the props. I checked it and every thing looked good.

Went skiing the other day and the boat was struggling to get on plane with the duoprop and thought to my self Wow this thing needs plugs already at 300 hours.

You would think there would be less alcohol in the fuel with the current low oil prices.

[VetteLT193]

How does one "tune" a stock 350 Mag MPi for ethanol fuel addatives?
I have also noticed the lower performance of my boat since ethanol was added to fuels. Summer temps and humidity have an effect, but the ethanol really makes it far worse. I'm actually thinking of having my prop recurved back to stock since there is less horsepower to work with.

it might be possible to tune it custom, but you would have to always run E10. The GM flex fuel vehicles have a sensor that figures out the ethanol mix and the computer figures it out. The higher the E content the less MPG and more HP you get. I can tell you that my father in-law's Flex fuel Avalanche doesn't seem to lose much of any MPG on E10 because whatever the computer is doing, it does it properly Vs. a standard gas only computer that doesn't 'know' enough to make it work exactly as it should.

[JimG]

Check your local marina. If they are selling Valvtect fuel you are in luck! It has no ethanol, and is made for marine engines. My friend Mike has a Formula 31 with twin 6.2's and picked up 300rpms on the stuff. My Donzi loves it, too! And it has a one year shelf life...

I've been wanting to run some in my P-car and see if I pick up any more power...

[widowmaker]

While I do not customarily believe in "snake oil" additives, I'll give this Valvtect product a try. I'll get back with my results.

[JimG]

Not the additive... it's a pump gas...

http://www.valvtect.com/marketing04.asp

[widowmaker]

Rats! Poodle, you're right. Reading further, I see that the claims for the fuel are not duplicated for the additive. I thought that I had a potential solution to this problem. Doing further research on the Valvtect web site, I find that there is no North Carolina fresh water marina carrying the fuel. I guess the real question is has anyone knowingly used this fuel product and realized an improvement in performance or otherwise.

[JimG]

I would have to guess that if there is ethanol in the fuel, you might be able to add something to mitigate the effects (absorbing water, etc) but will not be able to capture the lost volumetric efficiency. If you can't find Valvtect fuel, you might want to try aviation fuel. It's expensive, but also contains no ethanol and has an even longer shelf life.

[widowmaker]

Over the years, I've learned a lot by asking what may appear to some as being a dumb question. The following is likely another one. Does all highway gasoline contain ethanol these days. On occasion, I see a sticker on gas pumps indicating that the fuel contains ethanol. Is that sticker mandatory on pumps that dispense alcohol ladden fuel? Also, do different sections of the country have different restrictions on percentages of ethanol allowed? I await responses from more learned individuals.

[RedDog]

Stickers on the pump around here say "may contain up to 10%." My assumption was that it could vary from none to 10.

Good question - if there is no sticker, does that mean the fuel is 100% gas?

[VetteLT193]

I had another random thought as I drove home from work yesterday....

Normally you can make more power with Ethanol because the octane is higher. E85 is about 105 octane. Ethanol straight is around 115 octane. so, higher octane you can run more timing to make more power, and higher compression if it's really built for it.

Here's my thought. Every time I get E10 the car gets crappy mileage. So I'm assuming if they say 'up to 10%' it's probably pretty close to 10% every time. I'm wondering if the real savings for E10 on the manufacturing side is less refining work. It costs more to make higher octane gas. But, if you can mix in 10% Ethanol @115 octane you don't have to refine the gas as much to make 'the grade'.

So, we're probably getting screwed from both ends.

[Tom Smith]

When I lived in NY all gas stations were required to post if it had ethanol in it's gas or not, but here in NC there is no such law. We have a Mallard gas station nearby that advertises 100% gas. No ethanol. I bought this gizmo on line that tests the gas for ethanlo content. Darn thing really works. Cost me $25 if memory serves me. I tested the gas in several local stations and Mallard always comes up as having 0% ethanlo, where the other stations show 10% every time. Guess where I buy my gas. My Prius looses 5 mpg on ethanol. Tom

[BUIZILLA]

My Prius looses 5 mpg on ethanol. Tom kinda makes you wonder if the CAFE numbers aren't fake anymore.... if they used E10 like we are required to use, 'ol Oby will be real pissed about his zapper plan...

[Last Tango]

Huh. So...
I may be talking out my a$$ here, but it seems to me that if ethanol has an Octane rating of 115, then it is not actually usable by most cars or boats because they run compression ratios that are very low these days (8.0 to 10.3). Since Octane refers to the ability of the fuel to resist pre-ignition in the cylinder, then an engine built to fire 87 Octane without pre-ignition may not be able to fire off the 115 Octane, so it just dribbles through the system and maybe burns up in the catalytic converter on a car. There being no cats on most boats, it just burns after the compression cycle. So you really aren't getting anything out of it but heat after the fact.
My 350 Mag MPi owners manual says NOT to use any fuels over 87 Octane because you can actually lose power and performance since the engine was designed and built specifically for El Cheapo regular and nothing more. My engine was manufactured in late 2005, well before the Federal ethanol mandate in automotive fuels. That also means the PCM555 running my motor has never been programmed to "understand" ethanol.
So along with absorbing water at a high rate, and causing regular gas to lose its octane rating quicker, and less volumetric efficiency, it is just pouring through my motor unused at the point it most needs to burn. May as well be straw filler.

Maybe someone knows how to reflash the PCM555 to "teach" it what to do with ethanol, and also some sort of additional sensor so it knows how to read the fuel for ethanol content.

Just me running on what has already been said by others before me on this thread.

[DC18]

Huh. So...
I may be talking out my a$$ here, but it seems to me that if ethanol has an Octane rating of 115, then it is not actually usable by most cars or boats because they run compression ratios that are very low these days (8.0 to 10.3). Since Octane refers to the ability of the fuel to resist pre-ignition in the cylinder, then an engine built to fire 87 Octane without pre-ignition may not be able to fire off the 115 Octane, so it just dribbles through the system and maybe burns up in the catalytic converter on a car. There being no cats on most boats, it just burns after the compression cycle. So you really aren't getting anything out of it but heat after the fact.
My 350 Mag MPi owners manual says NOT to use any fuels over 87 Octane because you can actually lose power and performance since the engine was designed and built specifically for El Cheapo regular and nothing more. My engine was manufactured in late 2005, well before the Federal ethanol mandate in automotive fuels. That also means the PCM555 running my motor has never been programmed to "understand" ethanol.
So along with absorbing water at a high rate, and causing regular gas to lose its octane rating quicker, and less volumetric efficiency, it is just pouring through my motor unused at the point it most needs to burn. May as well be straw filler.

Maybe someone knows how to reflash the PCM555 to "teach" it what to do with ethanol, and also some sort of additional sensor so it knows how to read the fuel for ethanol content.

Just me running on what has already been said by others before me on this thread.
My owners manual says the same thing and from talking to the service manager at the local Donzi dealer, if you run over 87 octane, it will not help performance one bit. I have been adding Marine Stabl every time I fill-up. There are other stabaslizers that help controll or stop the affects of the ethanol. I haven't noticed any decrease in performance using it and the boat continues to perform well. Here in ILL ALL gas has to have ethanol in it (at least in the Chicago area). I use BP gas. Haven't had any problems with their fuel. There are a few stations in the area that still sell 100 or slightly higher octane fuel. Too bad we can't use it.

[chip w]

Besides that alcohol absorbs water, here are a couple of other things to consider. E10 has a shelf life of 30 to 45 days in vented tank and 45 to 60 days in a sealed tank like what you have on your car or truck (unlesss you're driving a clissic car). If you don't run through a full tank in that time period you'll start getting water building up in your tank. An additive may help and keeping the tank full with delay the process too. I use Stabil too as I'm frequently out of town for long periods and I may end up with the boat sitting for a while (old gas). I also have this problem with the classic cars and bikes I own.

[tommymonza]

So Ethanol is serving pretty much as a CUT or Filler in todays gas that really is not producing any energy or very limited amounts of energy in a motor that is not designed to utilize the benifits of high compression.

How will the ECM help you gain hp out of the ethanol by advancing the timing? Does increase or decrease the fuel also?

[BigGrizzly]

It is only a profit thing for the government and oil people.

[BUIZILLA]

So Ethanol is serving pretty much as a CUT or Filler in todays gas that really is not producing any energy or very limited amounts of energy in a motor that is not designed to utilize the benifits of high compression. couldn't have said it any better myself.... then the Guvmint can say we are using 10% less gas consumption...

[RedDog]

I found a dealer near me that sells 100% gas. My tank is pretty empty now so next outing I'll get the 100% and see if my RPMs come back up - unfortunately it will be a couple of weeks before I can try it.

[BUIZILLA]

I picked up about 200-250 rpm using the Jamestown Valvetect premium over the crap we get here...