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Roush 575 and Fuel Octane


Shodan01

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You know I'm joking.

I run 89-91 most of the time. Never 87.

When it's a big 4 day holiday weekend... When it's gonna be a 1.5 tank weekend.... I start with full 93, when it gets down to 1/3 I refill with 89 at a marina.

I actually get better gph using 89-91 than full 93.

I ran a full gas log for 2 summers.

I have a 65gal tank.... 80gal would get me through 98% of my summer weekends. Most weekends I burn 30-45gals over 3 days. 6-8gph average on a 16x15.5

I know - trust me I am not sensitive :-)

I actually like the trailer idea...maybe paint it to match the boat....I can look like the bass fishermen who have tournaments at my launch....

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Question:

Was driving down and found a gas station by my primary house that sells 110 Octane fuel (at a separate pump). Would I be able to fill 5-10 gallons of this, and mix with a 60 gallons of gas at 89 octane to get me to a rough 91 ish? I think it was a "Pumpers" gas station.

Is there any specific items I would need to see on the fuel pump to know if something was to watch for?

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i would imagine if it is 110 octane it is most likely LEADED fuel, you would want to confirm that first.

I missed that on the listing....true. Thank you.

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Question:

Was driving down and found a gas station by my primary house that sells 110 Octane fuel (at a separate pump). Would I be able to fill 5-10 gallons of this, and mix with a 60 gallons of gas at 89 octane to get me to a rough 91 ish? I think it was a "Pumpers" gas station.

Is there any specific items I would need to see on the fuel pump to know if something was to watch for?

Have you been absolutely ignorant to the responses to this thread? Multiple responses to YOUR posting about this concern, not to be salty, but damn... This has been laid out for you multiple times.

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Have you been absolutely ignorant to the responses to this thread? Multiple responses to YOUR posting about this concern, not to be salty, but damn... This has been laid out for you multiple times.

Easy....

Not all of us are mechanically inclined. Personally this fuel..leaded vs unleaded vs e85 vs a 2:1 Mix of 89 and e85 is incredibly confusing. Each of us has our strengths. Some of us are very new to the differences in fuel types and the impact they have.

And please don't give me the...then you should not own a boat speech, that is a silly retort.

Edited by Cipro
  • Like 2
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Have you been absolutely ignorant to the responses to this thread? Multiple responses to YOUR posting about this concern, not to be salty, but damn... This has been laid out for you multiple times.

Wow Badger - Thanks for the reply

My postings were to get specific responses to specific questions, and often times are "thinking out loud". The issue I had was merely a conversation on which was the best option for me in my dock situation. Thank you for your responses previously, however negative responses seem to be more than salty. If you don't want to reply then move on to the next topic and ignore mine...I promise I won't get offended as I have pretty thick skin :biggrin:

I get the 50/50 mix you proposed on Page 1.....I was trying to see a different way to carry less gas down the hill. The E85 option sounds legitimate, however with about 3 hours experience reading up on it, I won't claim yet to be a professional and ready to drop it into my boat.

I appreciate all the input.

Respectfully,

SC

Edited by Shodan01
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Easy....

Not all of us are mechanically inclined. Personally this fuel..leaded vs unleaded vs e85 vs a 2:1 Mix of 89 and e85 is incredibly confusing. Each of us has our strengths. Some of us are very new to the differences in fuel types and the impact they have.

And please don't give me the...then you should not own a boat speech, that is a silly retort.

I love that retort - I have read it a million times.....that would be like me saying to a patient.....well, you don't understand how the medication works so you shouldn't take it..... :lol: No worries....

I get it: Many would opt for the 440.....some would opt for the gas trailer and re-fill at the local launch, and others would just drop the 89 octane in and see what happens......I prefer to ask the questions and see what others have done to gain experience from this forum

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I get the 50/50 mix you proposed on Page 1.....I was trying to see a different way to carry less gas down the hill. The E85 option sounds legitimate, however with about 3 hours experience reading up on it, I won't claim yet to be a professional and ready to drop it into my boat.

I appreciate all the input.

Respectfully,

SC

Keep the E85 away from your boat!

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I looked all over the net for GM's octane recommendations for the 5.7L Vortec EFI V8. I found that GM recommends "Regular" and not less than 87 octane. Indmar recommends 89 octane. Why the difference? Perhaps Indmar just figures lots of boaters will have old gas in their tanks or they are being super cautious and know boat owners are less sensitive to fuel cost than truck/car owners?

Has anyone else looked at the octane requirements of their engines in automotive use?

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Easy....

Not all of us are mechanically inclined. Personally this fuel..leaded vs unleaded vs e85 vs a 2:1 Mix of 89 and e85 is incredibly confusing. Each of us has our strengths. Some of us are very new to the differences in fuel types and the impact they have.

And please don't give me the...then you should not own a boat speech, that is a silly retort.

I didn't mean to sound like you shouldn't own a boat... Anyone who wants a boat (and can afford a boat), should have a boat. Spending time on the water is something everyone should have a chance to do.

And sorry for sounding off a little bit. Not trying to offend anyone here. I definitely understand not understanding the fuel types and its importance, and my apologies for sounding off again. I just feel like the issues had been laid out and proposed solutions had been given, just my two cents.

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JMHO.

You can not deal with detonation! it will destroy your engine. That is a fact.

If it has cat's you can not use leaded fuel.

If you use a lot of ethanol you are going to use it faster. More GPH.

If you need to go threw a lot of effort just to fuel your boat you will likely find yourself using it less with less enjoyment.

My experience.... 65 years.. 30+ of internal combustion gas engines from mowers to Record holding and national event winning race cars.

Chose wisely grasshopper!.

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I looked all over the net for GM's octane recommendations for the 5.7L Vortec EFI V8. I found that GM recommends "Regular" and not less than 87 octane. Indmar recommends 89 octane. Why the difference? Perhaps Indmar just figures lots of boaters will have old gas in their tanks or they are being super cautious and know boat owners are less sensitive to fuel cost than truck/car owners?

Has anyone else looked at the octane requirements of their engines in automotive use?

Could be because of timing/fuel differences in the engine mapping.

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I didn't mean to sound like you shouldn't own a boat... Anyone who wants a boat (and can afford a boat), should have a boat. Spending time on the water is something everyone should have a chance to do.

And sorry for sounding off a little bit. Not trying to offend anyone here. I definitely understand not understanding the fuel types and its importance, and my apologies for sounding off again. I just feel like the issues had been laid out and proposed solutions had been given, just my two cents.

Absolutely no worries - I guess my confusion comes from one member saying to mix E85 (7-8 gallons) with the 89 Octane NON-E fuel 70 gallons to yield an octane of near 91....while another says only "KEEP IT AWAY FROM YOUR BOAT"....

Which is the overall opinion.....I love actual data to back it.

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Why? Details please??

Stoichiometric air/fuel ratios for E85 and and gasoline/E10 are different, way different.

The programming on your engine is set up to look at the O2's for the mixture for gasoline/E10 at maximum.

The correct stoichiometric ratio for regular unleaded gasoline is 14.7:1, while 9.7:1 for E85 (and can be any value in-between for different alcohol/fuel ratios). In newer cars, this means either holding the injectors open longer to get extra fuel into the engine, or running a higher flow rate injector.

You will not get enough fuel injected with E85, end up lean and losing your engine. It has to be programmed and set up to run on E85 from the start. Most of the E85 vehicles I have experience with (turbocharged) have twice the injector size and fuel pump to keep up with the amount needed when tuned properly.

Even if you are mixing, you can easily end up with more than 10% ethanol accidentally.

Edited by 23LSVOwner
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Ok - but what about mixing E85 with E0 Pure 89 Octane?

I added something later.

It is very easy to mess up your mixture and have too much ethanol, especially when you are adding fuel/mixing while you already have an ethanol mixture in the boat. If you were to have an engine issue Indmar will require the dealer to send in a fuel sample for analysis. Over the limit will be an automatic denial.

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I guess my thought on this (Not wanting to risk non-warranty issues) was if E10 (if I understand correctly 10% ethanol) and If I don't please clarify:

If I fill the boat with 89 NON Ethanol fuel routinely and fill, then carry a 7 gallon tank of E85 (85% Ethanol if I read correctly) down, I would be well under E10 as a whole.

UNLESS the E85 and NonE 89 don't mix evenly in the tank with a moving boat.......

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I guess my thought on this (Not wanting to risk non-warranty issues) was if E10 (if I understand correctly 10% ethanol) and If I don't please clarify:

If I fill the boat with 89 NON Ethanol fuel routinely and fill, then carry a 7 gallon tank of E85 (85% Ethanol if I read correctly) down, I would be well under E10 as a whole.

UNLESS the E85 and NonE 89 don't mix evenly in the tank with a moving boat.......

Not mixing evenly and also making sure you have an E10 or less mixture after you still have fuel in the boat and then add more would be the concerns.

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Stoichiometric air/fuel ratios for E85 and and gasoline/E10 are different, way different.

The programming on your engine is set up to look at the O2's for the mixture for gasoline/E10 at maximum.

The correct stoichiometric ratio for regular unleaded gasoline is 14.7:1, while 9.7:1 for E85 (and can be any value in-between for different alcohol/fuel ratios). In newer cars, this means either holding the injectors open longer to get extra fuel into the engine, or running a higher flow rate injector.

You will not get enough fuel injected with E85, end up lean and losing your engine. It has to be programmed and set up to run on E85 from the start. Most of the E85 vehicles I have experience with (turbocharged) have twice the injector size and fuel pump to keep up with the amount needed when tuned properly.

Even if you are mixing, you can easily end up with more than 10% ethanol accidentally.

This, if your motor doesnt have some type of flex fuel mapping then the E85 will throw the calibration way off. If your going to mix then I would stick with some form of unleaded race gas?regular gasoline mix.

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Here is more info. Alcohol in boat gas is never good.

The end result of water in the fuel is phase separation. The fuel separates into two distinct layers: a thick layer of gasoline mixed with a little ethanol on top, and a thinner layer on the bottom consisting of water mixed with most of the ethanol. And it doesn’t take much water for this to happen—phase separation occurs in a gallon of 10 percent ethanol blend with just 3.8 teaspoons of water.

Vented or Closed Fuel Tank?

Not sure whether your British car has a vented or closed fuel tank? You need to know this detail in order to have a feel for how long the gas in your tank will remain good. A sure giveaway of a closed tank is the presence of a carbon canister, which was added for pollution control purposes along with the closed fuel tanks. It’s often located at the back of the engine compartment, on the passenger side. To verify what it looks like and the positioning in your car, look at the diagram of the engine compartment for your car model on the Moss website, mossmotors.com. Note that some aftermarket gas caps are vented, so they can render a closed system open to the atmosphere.

Fuel Phase Separation Problems

What happens to your car and it’s performance when water causes fuel phase separation?

Reduced fuel longevity: A gasoline/ethanol blend absorbs water until it triggers phase separation. The blend has a 90-day product life in a closed tank, but lasts just 30 to 45 days in a vented tank often found in classic cars. With 10 percent ethanol blends, owners are supposed to replace the fuel in vented tanks about once a month by driving or draining, taking into consideration the humidity in the atmosphere and temperatures.

Lower fuel octane: The ethanol in a gasoline blend provides some of the octane rating. When phase separation occurs, the octane rating of the remaining fuel can drop by as much as three points.

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Other people have explained the reasoning but I concur. Running lower than the proper octane is a silly risk. If you're ordering a boat and have to buy fuel on the water get an engine approved for 89.

I've seen what the wrong fuel does to high compression. Auto engines and it's not pretty, or cheap.

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