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LT4 - What octane fuel is required?


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Just as the title states, trying to plan multiple several-day trips for this summer to different lakes but some only offer 87 octanes.

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From the RTFM playbook...  

Whenever possible, use 93 octane gasoline! Admittedly, there are locations where only lower-grade fuel is available, but to ensure long-term, high performance, the use of 93 octane is strongly recommended. Boats equipped with LT4 engines should use 91 octane fuel at a minimum. For other engines, in such instances where the highest-grade gas is not available, boaters may use 87, 89, or 91 octane fuel, but no lower grade. (Boaters outside the U.S. and Canada should confer with their authorized Malibu dealer to determine the correct fuel grading, as it is often graded differently in other countries.) Malibu strongly recommends the use of the above-mentioned fuel grades. With continued use over a period of time, the lower octane fuel could damage the engine, and such damage is not covered under warranty. Again, if the customer chooses to use a lower octane fuel than recommended, and it causes damage or failure, then warranty claims may be denied. Malibu reserves the right to have the fuel tested.

GM, as of 2017 stated 91 is fine.  87 is kinda low in my books.  And FWIW, it is nigh on impossible to get 87 on the water up here.

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1 minute ago, Eagleboy99 said:

From the RTFM playbook...  

Whenever possible, use 93 octane gasoline! Admittedly, there are locations where only lower-grade fuel is available, but to ensure long-term, high performance, the use of 93 octane is strongly recommended. Boats equipped with LT4 engines should use 91 octane fuel at a minimum. For other engines, in such instances where the highest-grade gas is not available, boaters may use 87, 89, or 91 octane fuel, but no lower grade. (Boaters outside the U.S. and Canada should confer with their authorized Malibu dealer to determine the correct fuel grading, as it is often graded differently in other countries.) Malibu strongly recommends the use of the above-mentioned fuel grades. With continued use over a period of time, the lower octane fuel could damage the engine, and such damage is not covered under warranty. Again, if the customer chooses to use a lower octane fuel than recommended, and it causes damage or failure, then warranty claims may be denied. Malibu reserves the right to have the fuel tested.

GM, as of 2017 stated 91 is fine.  87 is kinda low in my books.  And FWIW, it is nigh on impossible to get 87 on the water up here.

I appreciate it man. I haven't got my boat delivered yet so no handbook to reference.

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1 hour ago, gorenation said:

I appreciate it man. I haven't got my boat delivered yet so no handbook to reference.

All on line.  Google is your friend.

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4 hours ago, Eagleboy99 said:

From the RTFM playbook...  

Whenever possible, use 93 octane gasoline! Admittedly, there are locations where only lower-grade fuel is available, but to ensure long-term, high performance, the use of 93 octane is strongly recommended. Boats equipped with LT4 engines should use 91 octane fuel at a minimum. For other engines, in such instances where the highest-grade gas is not available, boaters may use 87, 89, or 91 octane fuel, but no lower grade. (Boaters outside the U.S. and Canada should confer with their authorized Malibu dealer to determine the correct fuel grading, as it is often graded differently in other countries.) Malibu strongly recommends the use of the above-mentioned fuel grades. With continued use over a period of time, the lower octane fuel could damage the engine, and such damage is not covered under warranty. Again, if the customer chooses to use a lower octane fuel than recommended, and it causes damage or failure, then warranty claims may be denied. Malibu reserves the right to have the fuel tested.

GM, as of 2017 stated 91 is fine.  87 is kinda low in my books.  And FWIW, it is nigh on impossible to get 87 on the water up here.

On the lake we go to the one marina has unmarked pumps, I found out who the distributor is, talked to them, is 87.  Curious how much higher you are finding.  

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8 hours ago, Surf4FamFun said:

On the lake we go to the one marina has unmarked pumps, I found out who the distributor is, talked to them, is 87.  Curious how much higher you are finding.  

We only have premium  - 91

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16 hours ago, RyanB said:


I keep this in my boat  my LS3 requires premium and I can’t get it on some lakes.  And I have had knocking if I don’t use the octane booster.

Lucas Oil 10026-PK12 Octane... https://www.amazon.com/dp/B001OZL9OQ?ref=ppx_pop_mob_ap_share

I was going to suggest getting a bottle or two of Race Gas Concentrate.  https://www.amazon.com/Race-Gas-100032-Race-Concentrate-Octane/dp/B015HRK7ZS

 

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47 minutes ago, 23LSVOwner said:

Just make sure you read the mixing instructions on the cans.

Your boat has a MUCH larger fuel tank than your car.

It would take a little math and watching how much fuel you are adding to the tank.  But, if you can start with (say) 91 octane, as you top off the tank, you simply add the correct amount of additive to the tank to maintain 91 octane based on the amount and grade of fuel you pumped in. 

The only disadvantage (if you can even call it that) would be that if one goes to a higher elevation, they might have a higher than needed octane fuel.  But as soon as you drop back down to lower elevations, you're ready to rock.

Pat and Mike on Engine Power have dynoed some seriously high HP engines using this stuff.  Seems its all they use currently, instead of keeping jugs of various octane VP race gas.

Edited by Texan32
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The cheapest option for octane boosting is most likely by buying toluene in bulk.  Toluene has an octane rating of RON 121 and MON 107, giving an (R+M)/2 rating of 114.  To bring 87 octane gasoline to 93 octane, you will need (per gallon):

T = (93-87)/(114-93) = 0.286 gallons per gallon of gasoline, which is 36.6 ounces per gallon.

To bring 89 octane to 93, that would be:

T = (93-89)/(114-93) = 0.190 gallons per gallon of gasoline, or 24.4 ounces per gallon.

Five gallons is about $83 or so including shipping.  https://skygeek.com/toluene-5-gallon.html

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  • 5 months later...

So I am getting really close to pricing an LT4 in an M220 for use on a lake where all the dock pump gas nearby is 87 octane.  Have calculated that using BOOSTane Marine (have asked them to confirm this is the right product for a blown 10:1 motor, cost will go up if the racing blend is needed but don't think it will be) buying 20 cans at a time will add 36 cents per gallon to get from 87 to 93 octane which is less than the spread at the local pump between low and premium fuel.  Anyone have practical experience with this approach?  

We are near sea level and I know the LT4 is not "needed" but looking to see if anyone has gone the octane boost route and regretted or loved it.

BTW I have eliminated brining gas to the boat as an option or trailering to fuel.  Mix of factors for both, they will just not work.

 

 

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8 hours ago, Surf4FamFun said:

So I am getting really close to pricing an LT4 in an M220 for use on a lake where all the dock pump gas nearby is 87 octane.  Have calculated that using BOOSTane Marine (have asked them to confirm this is the right product for a blown 10:1 motor, cost will go up if the racing blend is needed but don't think it will be) buying 20 cans at a time will add 36 cents per gallon to get from 87 to 93 octane which is less than the spread at the local pump between low and premium fuel.  Anyone have practical experience with this approach?  

We are near sea level and I know the LT4 is not "needed" but looking to see if anyone has gone the octane boost route and regretted or loved it.

BTW I have eliminated brining gas to the boat as an option or trailering to fuel.  Mix of factors for both, they will just not work.

So you made me go look at BOOSTane Marine.  Well, I tried to look at it.  They don't publish an MSDS for it.  That seems very odd.  Before you use it, note several things:

- They recommend 0.43 ounces per gallon to bring 87 to 93 octane.  That is a ridiculously low amount.  Suspect that something is up.

- They state that it is not street legal.  Take this as a hint.

- They claim a "proprietary chelated carrier" as an ingredient.  Chelation is the act of binding a metal with a hydrocarbon.  Guess which metal works really well as an octane booster, even when used in very small amounts?  Yup, lead. 

I guess I don't blame them for not letting their cat out of the bag.  I'm not prepared to do a chemical analysis on the stuff, but be warned that adding lead to your gasoline will very likely damage your catalytic converters.  I'm not sure that I buy in to all the overblown health concerns about lead and other heavy metals, but you also risk breathing lead vapor in the exhaust.

I wouldn't use it.  Don't take my word for it though.  Call BOOSTane and ask them directly if it contains lead, and if so, will they guarantee your catalytic converters after using your product?

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I will ask them about lead.  It says CAT and O2 safe and I thought that lead would ruin at least the CAT.  I did notice that going from mixing 87 to 94 rather than 93 more than doubles the amount needed.  Since all I will be trying to do is be sure the octane Is in the range where the Engine Management system can work normally this is a pretty low demand application.  I am not going to be playing with timing and fuel profiles and swiping for a different size pulley on the blower trying to get MORE.  Reading on different product Web sites they read pretty differently considering that the consensus is that they all use MMT to add octane.  More research and reading to follow.

 

 

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The main problem is that BOOSTane won't publish an MSDS, so you really don't know what they are selling you.  Whatever it is, I seriously doubt that a few drops of the stuff will get you to 93 octane.

MMT has its own set of issues, and it wouldn't surprise me to learn that it will plug your cats with manganese if used in high enough concentration.  Your case may need a high concentration.

Also keep in mind that if the can says it will boost your octane "10 points" it means 10 times 0.1, or 1.0 octane.  Gotta love marketeers.  By their count, you need "60 points" to get from 87 to 93 octane.

Note as well that even though you aren't playing with timing and fuel profiles, your engine is.  If you don't get all the octane you should, the engine will hopefully just retard the spark for you.  If you are seriously low on octane for a while, you could still risk damage from detonation and other fun oddities.  I know that hauling gas is no joy, but in this case I'd probably do that and haul the 93 to the boat.

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19 hours ago, justgary said:

So you made me go look at BOOSTane Marine.  Well, I tried to look at it.  They don't publish an MSDS for it.  That seems very odd.  Before you use it, note several things:

- They recommend 0.43 ounces per gallon to bring 87 to 93 octane.  That is a ridiculously low amount.  Suspect that something is up.

- They state that it is not street legal.  Take this as a hint.

- They claim a "proprietary chelated carrier" as an ingredient.  Chelation is the act of binding a metal with a hydrocarbon.  Guess which metal works really well as an octane booster, even when used in very small amounts?  Yup, lead. 

I guess I don't blame them for not letting their cat out of the bag.  I'm not prepared to do a chemical analysis on the stuff, but be warned that adding lead to your gasoline will very likely damage your catalytic converters.  I'm not sure that I buy in to all the overblown health concerns about lead and other heavy metals, but you also risk breathing lead vapor in the exhaust.

I wouldn't use it.  Don't take my word for it though.  Call BOOSTane and ask them directly if it contains lead, and if so, will they guarantee your catalytic converters after using your product?

I would be willing to bet that all their formulas are the same.  Here is the SDS for one.  Section three, all solvents and MMT.  (Asking for a MSDS is like asking for a type writer....  GHS changed all this.)

https://1ddf4b1b856a39e33863-d785dc0e3b62b5e0ef07f55db00b0659.ssl.cf2.rackcdn.com/BOOS Tane/BOOSTane Shot_SDS.pdf

@justgary I am with some of what you are saying.  And mostly, I wouldn't be buying a LT4 and trying to take octane up with lead or MMT (or toluene...LOL).  There is a reason that all engine manufactures, API & NMMA advise against this.  I would be willing to bet (ALOT) that adding lead or MMT voids your warranty.  Google cat converters after lead or MMT usage....  You'll get a bunch of pics from China where they still use MMT to boost octane in some of the more rural areas.  

And for what is worth - this should be coming:

http://www.nmma.org/press/article/19496

fuelsandlubes.com/nmma-launches-gasoline-protection-program-cqa/

6 hours ago, justgary said:

I know that hauling gas is no joy, but in this case I'd probably do that and haul the 93 to the boat.

Yep....  

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On 11/6/2021 at 1:24 AM, Surf4FamFun said:

So I am getting really close to pricing an LT4 in an M220 for use on a lake where all the dock pump gas nearby is 87 octane.  Have calculated that using BOOSTane Marine (have asked them to confirm this is the right product for a blown 10:1 motor, cost will go up if the racing blend is needed but don't think it will be) buying 20 cans at a time will add 36 cents per gallon to get from 87 to 93 octane which is less than the spread at the local pump between low and premium fuel.  Anyone have practical experience with this approach?  

We are near sea level and I know the LT4 is not "needed" but looking to see if anyone has gone the octane boost route and regretted or loved it.

BTW I have eliminated brining gas to the boat as an option or trailering to fuel.  Mix of factors for both, they will just not work.

 

 

I was in the exact same situation you are in.  I really wanted a LT4 for our 2022 25LSV, also close to sea level.  Our lake only has 87 and the boat stays on the lake so no trailering or nearby gas station.   Carrying gas in also was not an option.  I also considered BOOSTane.  While I suspect it might work, my concern was if it does cause a problem, and I have to stop using it, then I have a very expensive boat and motor that I can not get the needed gas for unless I carry it in.  I am just not willing to do that, will be too hard and take too much of the fun out of it.  So no good "plan B".  I opted out of the LT4 and just went with the M6.  It was worth the peace of mind for me.

Oh and I did all the same research and came up with everything you also mentioned.  Likely MMT etc.  From what I could find it appears that it works, but it could also cause problems.  I could not find anything conclusive.  Just that it may work, but consequences unclear.

Edited by familyfun
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3 hours ago, Five Cent Worth said:

or toluene...LOL

Toluene (C6H5.CH3) is also known as methylbenzene and phenyl methane.  It isn't just some add-on paint thinner, it is a clean burning hydrocarbon that is already in your gasoline.  In fact, you can use it at just about any as concentration you want, up to 100% (with a few potential vaporization issues as noted below).

From Wikipedia: "Toluene can be used as an octane booster in gasoline fuels for internal combustion engines as well as jet fuel. Toluene at 86% by volume fuelled [sic] all the turbocharged engines in Formula One during the 1980s, first pioneered by the Honda team. The remaining 14% was a "filler" of n-heptane, to reduce the octane rating to meet Formula One fuel restrictions. Toluene at 100% can be used as a fuel for both two-stroke and four-stroke engines; however, due to the density of the fuel and other factors, the fuel does not vaporize easily unless preheated to 70 °C (158 °F). Honda solved this problem in their Formula One cars by routing the fuel lines through a heat exchanger, drawing energy from the water in the cooling system to heat the fuel.[24]"

If I had to treat 87 octane gasoline to make it 93 octane, I'd use Toluene.

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I considered toluene for all the reasons mentioned above.  I decided against it simply because if I read the info I found correctly it takes a LOT added to 87 to raise the octane to 93.  I am going by memory so the numbers are not right but it may have been something like 10 gallons (or more) of toluene for each tank full.  I don't remember the exact numbers but pretty sure it was gallons not ounces needed.

Edited by familyfun
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6 minutes ago, familyfun said:

I considered toluene for all the reasons mentioned above.  I decided against it simply because if I read the info I found correctly it takes a LOT added to 87 to raise the octane to 93.  I am going by memory so the numbers are not right but it may have been something like 10 gallons (or more) of toluene for each tank full.  I don't remember the exact numbers but pretty sure it was gallons not ounces needed.

That sounds about right.  You'll end up adding about 29% toluene.  That's my point about the stuff that claims to do the job with a few drops of magic proprietary additive.  If it doesn't take much additive, they are probably using metals to do the job.

Octane is basically a detonation retarder that allows the engine to advance ignition timing enough to optimize the delay between the spark and the flame development during the power stroke.  Boosted engines have a much higher effective compression ratio, so they need higher octane to keep the fuel from detonating (or dieseling) before the spark initiates the flame.

As for fuel hauling, is your main drawback a hill, distance, or just that it seems like a pain?  Toting a 55 gallon drum of fuel isn't the worst exercise routine you could have.  If you make it seem fun enough, the neighbor kids will pay you to let them have a turn.

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43 minutes ago, justgary said:

As for fuel hauling, is your main drawback a hill, distance, or just that it seems like a pain?  Toting a 55 gallon drum of fuel isn't the worst exercise routine you could have.  If you make it seem fun enough, the neighbor kids will pay you to let them have a turn.

In our case it is all the above and then some.  The shore line is steep (which makes for nice deep water off the dock) so we have a good slope/hill plus stairs plus a section of a few steps of natural irregular rock stairs.  Makes getting even something light on wheels difficult to maneuver down.  There is one section of grass slope that is steep enough that rolling a 300lb+ drum would be hard without slipping.  Losing control of it would be possible.  It would take major dirt work/construction to be able to gen a drum down.

I though about getting a drum just to the top of the steep/stairs section, but then I would need a good 150' of hose to reach the end of the dock.  Then you have heavy hose and safety issue there plus I might run afoul of some regulations since our lake is a reservoir.  Plus of course we would still have to get the drum off the truck.  A lot of times it is just my wife and I so getting a 300lb+ drum off a truck is not trivial.  And if I were to pump from the truck we are looking at a good 250" of hose.  Then it is also a 40 min round trip to the nearest gas station.

I just have not been able to come up with a good way to get large quantities of gas to the dock.  I wish I could.

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