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Octane mix for LT4?


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Btown801

Headed to Powell, houseboat has 100gallons of 87 octane. LT4 needs minimum 91. Manual does not recommend octane boosters. I am contemplating taking gas cans full of 100octane to mix with the 87.  Am I wrong?

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3 minutes ago, Btown801 said:

Headed to Powell, houseboat has 100gallons of 87 octane. LT4 needs minimum 91. Manual does not recommend octane boosters. I am contemplating taking gas cans full of 100octane to mix with the 87.  Am I wrong?

100 octane is going to be aircraft fuel, isn't it?  Not sure that 100LL is going to be good for your o2 sensors/cat.

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As long as the 100 octane is un leaded you shouldn't have issues doing that. But be aware a lot of it is leaded which will not be friendly to your cats. 

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Btown801

This is what Christensen oil in Utah lists the fuel as:

100 Octane Race Fuel

An alternate solution to using additives is to use 100 octane Unleaded Racing Gasoline. This is a street legal 100 octane unleaded gasoline that can be used in its pure form, or it can be blended with any street gasoline. You will always know what octane you end up with because we can provide you with a blending chart that helps you to determine that. In addition, if the 100 octane gasoline is used in its pure form, the engine will make additional power due to the "improved burn" characteristics. This is because 100 Unleaded Racing Gasoline contains a very select group of hydrocarbons that vaporize and burn much more readily than those found in conventional street gasoline. When more of the gasoline is burned in the combustion chamber, the engine makes more horsepower. This phenomenon is known as improved combustion efficiency.

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41 minutes ago, Btown801 said:

This is what Christensen oil in Utah lists the fuel as:

100 Octane Race Fuel

An alternate solution to using additives is to use 100 octane Unleaded Racing Gasoline. This is a street legal 100 octane unleaded gasoline that can be used in its pure form, or it can be blended with any street gasoline. You will always know what octane you end up with because we can provide you with a blending chart that helps you to determine that. In addition, if the 100 octane gasoline is used in its pure form, the engine will make additional power due to the "improved burn" characteristics. This is because 100 Unleaded Racing Gasoline contains a very select group of hydrocarbons that vaporize and burn much more readily than those found in conventional street gasoline. When more of the gasoline is burned in the combustion chamber, the engine makes more horsepower. This phenomenon is known as improved combustion efficiency.

Should work.  100 octane race gas - like $20 a gallon?  Is there no premium fuel on that lake?

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Ahhh, another octane thread.

I would use toluene as an octane booster since it is already in pump gas anyway. 

Just keep in mind that a "point" in octane boost speak is a decimal point, or 0.1 octane boost.  You need ten "points" to raise your octane one "number."

I think Sunoco sells drums of 104 octane unleaded for a little over $10 per gallon.

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dizzygti

Adding toluene will raise the octane but will also require more fuel volume to keep AFR's in check, similar to ethanol/E85.     Mixing 100 unleaded with 87 if the cost isn't extreme is going to be the easiest solution.   

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42 minutes ago, dizzygti said:

Adding toluene will raise the octane but will also require more fuel volume to keep AFR's in check, similar to ethanol/E85.     Mixing 100 unleaded with 87 if the cost isn't extreme is going to be the easiest solution.   

It's a feedback engine, so I assume it knows what to do.  Toluene is one of the primary ways fuel vendors raise octane in pump gas.

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12 hours ago, Btown801 said:

Headed to Powell

And to answer the question, this is from one of the many Powell/octane threads:

 

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dizzygti
Just now, justgary said:

It's a feedback engine, so I assume it knows what to do.  Toluene is one of the primary ways fuel vendors raise octane in pump gas.

Well aware, I've mixed it myself before, however there is a volumetric limit and adaptation range of the controls that can be exceeded by extreme blends.    Adding 100% toluene to 87 to get a tank of 91 would be extreme IMO.   

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22 minutes ago, dizzygti said:

Well aware, I've mixed it myself before, however there is a volumetric limit and adaptation range of the controls that can be exceeded by extreme blends.    Adding 100% toluene to 87 to get a tank of 91 would be extreme IMO.   

I think that is definitely more true of ethanol than toluene due to the lower energy density of ethanol.

If I did my math correctly, raising 87 octane to 91 octane with toluene (at 114 octane) requires (91-87)/114 = 3.5%, or 4.5 ounces per gallon.  So one gallon of toluene per 28 gallons of 87 pump gas.

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dshack
1 hour ago, justgary said:

And to answer the question, this is from one of the many Powell/octane threads:

 

I'm pretty sure Halls Crossing fuel dock is closed indefinitely. No premium on the water at Powell. Which is crazy considering how many supercharged tow boats are on the water these days.

 

11 hours ago, Btown801 said:

Christensen oil in Utah 

Do you buy from their provo HQ? Or is this sold by the pump at certain gas stations?

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dizzygti
25 minutes ago, justgary said:

I think that is definitely more true of ethanol than toluene due to the lower energy density of ethanol.

If I did my math correctly, raising 87 octane to 91 octane with toluene (at 114 octane) requires (91-87)/114 = 3.5%, or 4.5 ounces per gallon.  So one gallon of toluene per 28 gallons of 87 pump gas.

I don't think that's right.   I always used this method:  Sunoco mixing octane link. One gallon of 114 toluene in 28 gallons of 87 octane would only net you 87.93 octane.   You'd need roughly 5 gallons of toluene in 24 gallons of 87 octane to get a 91 ish octane 29 gallon blend.   Depending on where you source it from, toluene can be anywhere from $15 to $50/gallon, aka it doesn't make sense to use as bulk octane booster.   

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1 hour ago, dizzygti said:

I don't think that's right.   I always used this method:  Sunoco mixing octane link. One gallon of 114 toluene in 28 gallons of 87 octane would only net you 87.93 octane.   You'd need roughly 5 gallons of toluene in 24 gallons of 87 octane to get a 91 ish octane 29 gallon blend.   Depending on where you source it from, toluene can be anywhere from $15 to $50/gallon, aka it doesn't make sense to use as bulk octane booster.   

Thanks for catching that.  Never do math in public.  You need 17.4% toluene to bring 87 to 91.

Toluene used to be pretty cheap, but now has that "aromatic hydrocarbon" solvent EPA business going on.  It is still in spray paint and paint thinners in addition to gasoline.  I'm pretty sure by the smell that it is a large component of the small engine fuel they sell in one gallon cans at hardware stores these days.

The thing is, if you have 87 octane and need 91 octane, you have to add something.  Adding higher octane means you add less of it.  You would need 44.4% of 100 octane "race gas" to get 91 octane.  The toluene would come out cheaper if it were 2.5 times as expensive as the race gas, which it generally isn't.

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dizzygti
45 minutes ago, justgary said:

Thanks for catching that.  Never do math in public.  You need 17.4% toluene to bring 87 to 91.

Toluene used to be pretty cheap, but now has that "aromatic hydrocarbon" solvent EPA business going on.  It is still in spray paint and paint thinners in addition to gasoline.  I'm pretty sure by the smell that it is a large component of the small engine fuel they sell in one gallon cans at hardware stores these days.

The thing is, if you have 87 octane and need 91 octane, you have to add something.  Adding higher octane means you add less of it.  You would need 44.4% of 100 octane "race gas" to get 91 octane.  The toluene would come out cheaper if it were 2.5 times as expensive as the race gas, which it generally isn't.

Yeah, you can buy it by the gallon at Home Depot.  If you have to buy a 55 gallon drum of toluene to get it at a price that makes sense, I'd just haul the 91 octane with me....    I haven't bought race gas in years, since E85 became available at the pump.   100 octane at the pump near me was $11.99 last I checked about six months ago.   I don't have an LT4 and Costco 93 is about two miles from my regular boat ramp, so none of this affects me.  

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I looked at using Boostane if needed for a Powell trip, but we ended up filling several 55 gallon drums on the back of the houseboat with 91 octane at Antelope Point.  Then we just used a Holley electric fuel pump to pump the fuel from the barrels to the boats.

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Btown801
9 hours ago, dshack said:

Do you buy from their provo HQ? Or is this sold by the pump at certain gas stations?

I plan to buy it from their Provo location if this ends up being the route I choose. I need to find out what the price is. 

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Btown801
11 hours ago, justgary said:

And to answer the question, this is from one of the many Powell/octane threads:

Halls crossing is closed and is at the opposite end of the lake. It would probably be a 6 hour round trip even if it was. Wahweap only has 87. Antelope point should have 91 but that is a 1.5 hour round trip from where the houseboat will be to fuel up. Which is why I am looking to boost the 87 octane in the houseboat toy tank. 

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Btown801

I thought I had read in the manual that Malibu does not recommend octane boosters. But I am not seeing it in there now. Plenty of information on the interwebs mentions harmful side effects of octane boosters. Just trying to figure out if there’s a way to do it without harming my boat. 

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dshack

Just out of curiosity, has anyone actually tried straight 87 in their LT4 at Powell? At 3Kish feet elevation, I wonder if the engine can adapt on its own. Theres a reason you can't get 93 at our elevation in Utah...maybe 87 is still workable here.

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dizzygti
1 hour ago, Steve B. said:

Wondering if there's an easy way to adjust to lower octane? Hotter plugs? Advance the ignition?

Neither will help but DEFINITELY don't want to do the latter.

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Btown801
9 hours ago, SurfNAZ said:

looked at using Boostane if needed for a Powell trip, but we ended up filling several 55 gallon drums on the back of the houseboat with 91 octane at Antelope Point.  Then we just used a Holley electric fuel pump to pump the fuel from the barrels to the boats.

Damn!!! I need an invite your houseboat trip! I will bring the beer!

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