reg or prem fuel ?

[HT32BSX115]

Re: reg or prem fuel ?

I would agree with that except for one thing. Ethanol has a nasty tendancy to attract water. Lets set aside that fact that the boat is operated in the water and just consider the amount of time between fill ups and the storage time vs. a regularly used automobile. I waste a lot of fuel by regularly draining my boat tanks to clear them of accumulated water. You would be suprised how much is sitting in the bottom of a tank after a long lay up. I was always under the assumption that Stabil or a similar product would prevent this but I've found that to not always be the case.

I may be a bit over cautious but the way I figure it, it's easier to fund a new tank of gas than a new motor.

If you have a LOT of water in your fuel, you should look elsewhere for the source.....the most common sources of water intrusion are the vent, fuel fill opening and the fuel supplier itself! NO amount of snake oil will mitigate that water in the tank. If you have more than a teaspoon or so in any recreational boat fuel tank, it's not from condensation.

Condensation is not a big source of water in any fuel tank.

http://www.yachtsurvey.com/myth_of_condensation_in_fuel_tanks.htm

 

[markheck1]

Re: reg or prem fuel ?

Also there is no more power in 92 gas than in 87
the higher octane is needed in higher compression engines to prevent detonation or pre-ignition,
The misconception comes from mostly muscle cars because they have to use the higher octane because of the compression ratios...
the theory comes that if they are using it a muscle car then it must make more power.
Newer engines can combat this with computer controlled ignition timing and knock sensors but only so far

This begs the question, who's 383 crate motor are we talking about here?
one that is a stock compression ratio?
Or one that has higher compression, as most people build the stroker to get more power,

Edit: I just reread the original post that it's a crate motor from Merc.
I would have to assume normal compression, but would find out to be sure.

and Yes ...we had 3 tanks at the station, from 3 seperate compartments on the tanker.....
And here's a little jewel....the higher octane comes off the refining tower first, you actually have to refine it more to lower the octane level.

 

[HT32BSX115]

Re: reg or prem fuel ?

the higher octane comes off the refining tower first, you actually have to refine it more to lower the octane level.

Actually the octane levels are controlled by introducing very specific additives.

Tolulene, Xylene, and Tetraethyl-lead are octane boosters as is methanol, ethanol and some others...

Tolulene is a major octane booster in AVGAS since they reduced the level of "lead" in recent years. The plan is to eliminate it altogether. Tetraethyl-lead was banned for motor fuels but AVGAS 100LL continues to have an exemption as does certain off-road/racing fuels and additives.

 

[Brewman61]

Re: reg or prem fuel ?

Minnesota requires gasoline to be oxygenated for pollution control reasons. Used to be seasonal, now it's year around and has been for years. Since the former oxygenator (MTBE?) was found to be harmful, they now use 10% ethanol to oxygenate the fuel.
Some fuel sellers sell non oxygenated gas, and the pump must be labeled so. It's not to be used in passenger class vehicles, only small engines, boats, etc..... The only octane grade of non oxygenated gas in my area happens to be premium. I have not seen any 87 octane non oxy gas for sale in my area. Probably just a profit thing. Premium grade gas costs around $0.20 or so more per gallon and at least that much more per gallon to be non oxy. Except for the monopoly on our lake, which only sells non oxy premium, and for about $1/gallon more than the ethanol containing 87 octane.

Premium grade gas doesn't have more power, it has greater resistance to detonation, which some high performance engines need due at least in part to their higher compression, which would cause problems with gas of lower octane.

Ethanol does per gallon have less BTU's than gasoline, so gasoline with 10% ethanol has slightly less energy than straight gas, and therefore may deliver a bit less MPG.

This is why vehicles that run on E85 get lower MPG's than E10 or E0. As much as 30% less, I"ve read.

Sooner or later we here in MN will have E15 (or E20?+) available. Lotsa corn growing in the area, lotsa ethonol plants.

 

[HT32BSX115]

Re: reg or prem fuel ?

Minnesota requires gasoline to be oxygenated for pollution control reasons. Used to be seasonal, now it's year around and has been for years. Since the former oxygenator (MTBE?) was found to be harmful, they now use 10% ethanol to oxygenate the fuel.
Some fuel sellers sell non oxygenated gas, and the pump must be labeled so. It's not to be used in passenger class vehicles, only small engines, boats, etc..... The only octane grade of non oxygenated gas in my area happens to be premium. I have not seen any 87 octane non oxy gas for sale in my area. Probably just a profit thing. Premium grade gas costs around $0.20 or so more per gallon and at least that much more per gallon to be non oxy. Except for the monopoly on our lake, which only sells non oxy premium, and for about $1/gallon more than the ethanol containing 87 octane.

Premium grade gas doesn't have more power, it has greater resistance to detonation, which some high performance engines need due at least in part to their higher compression, which would cause problems with gas of lower octane.

Ethanol does per gallon have less BTU's than gasoline, so gasoline with 10% ethanol has slightly less energy than straight gas, and therefore may deliver a bit less MPG.

This is why vehicles that run on E85 get lower MPG's than E10 or E0. As much as 30% less, I"ve read.

Sooner or later we here in MN will have E15 (or E20?+) available. Lotsa corn growing in the area, lotsa ethonol plants.

Yeah. It's pretty much nation wide now. MTBE (Methyl Tertiary Butyl Ether) and ETBE to a much lesser extent was used in gasoline but banned because of contamination of water........( because storage tanks were leaking into the ground everywhere.......)

I REALLY question that (not the leaking) now.......... since ALL of them (the tanks) have been dug up and replaced with tanks that not only have double wall construction, but also must have leak detection systems..........SO even if we were STILL using MTBE today, the leaks wouldn't be happening..........no leaks, no contamination......... But of course, there's a political aspect of corn based ethanol being pushed then and now. (please, lets not get into that)

In MN, you do have non-ethanol gasoline available in many places. See http://pure-gas.org/index.jsp?stateprov=MN


The difference in price from 87 octane to 91 octane is not really like it used to be.

10-20 cents (more) per gallon is not the huge difference when you're talking $3.50 - $4.50 (and more at some lakes and marinas)
per gallon, like it was when gas was only $1.00 or $2.00 per gallon.


So if it really bothers you, go for the non-ethanol gas. Most of us have run E-10 for many years and not had significant problems.

Buyer beware though........... test your gas to ensure that it REALLY is ethanol free.......It wouldn't be the first time that a supplier delivered fuel that wasn't exactly what the pump said it was.......


Cheers,