LT4 - What octane fuel is required?

[jjackkrash]

You are going to be much better off in the long term if you can figure out a residential gas tank / fueling station solution and having it filled by a commercial truck periodically.  I would consult with a pro before writing off feasibility.  

[justgary]

30 minutes ago, jjackkrash said:

You are going to be much better off in the long term if you can figure out a residential gas tank / fueling station solution and having it filled by a commercial truck periodically.  I would consult with a pro before writing off feasibility.  

Or talk to the local gas dock and beg them to start pumping 93.  I can see how they would be reluctant if they only have one tank and everybody is OK with 87.

A fella could get set up with a 500+ gallon tank at home for about $2000 or so, then have a service like JROP bring fuel to your tank.  Depending on the amount you use, you might even get a discount.  The trick would be getting the tank situated where the truck hose could reach from the area where he can drive.  That might be a long distance, even over 100 feet.  Your hose from your tank could then run the remainder of the way, or you could keep it on a reel and roll it out when you need it.

[familyfun]

I may look into that to see if over time it saves me any money compared to marina gas prices.  Of course it may be feasibility, but not realistic.  There may be too many compromises.  With a on site tank you now may have to worry about storage time and octane reduction.  Manageable, but more complicated.

To some extent in my case it is a moot point since I already ordered with the M6.  For the OP maybe a storage tank is an option.

[RCorsa]

This is an interesting idea I might consider.   I was thinking most of my outings are 2-3 hours  so I could fill the boat up at the gas station at the beginning of the season and keep 15gallons at a time at home and just top off each time?  However this idea is certainly interesting.  Anyone know how I would set up or who I would call to estimate 

[PNWoke]

I would try to get your marina/s to stock 92+, if they won't, I'd find a new marina to do business with or just plan to keep your boat at home rather than paying marina fees.  Even my buddies who own fishing boats with outboard Honda/yamaha/suzuki's run 92+ in them exclusively.  I'd be willing to bet that there are no boat manufacturers out there that recommend 87 grade fuel.  I have had 409ss motors in both my 23lsv's (2014, and 2015) and both of them threw/throw codes when anything less than 91 was/is used.  If you think playing mad scientist with octane boosters is a good idea for the long run you should probably be ready to buy a new set of cats in the next 3-5 years (which is about as expensive as a new MTC screen last I checked).  I'd write a few letters to your marinas and leverage your local yacht clubs to help you.  Fuel is already expensive at gas docks, an extra .50-.75/gal isn't going to hurt them at all.  My local marina only offers 92+ ethanol free gas, and diesel.  I help 20+ visitors fill up there every summer and have never once heard a complaint that we didn't have 87 octane fuel.  On the contrary you can regularly find locals who don't even own boats coming to fill up their gas cans for their lawn equipment at the dock (in order to get non-ethanol).  After cleaning my previous boats bilge and finding remnants of many octane boosters, then buying that boat a new set of cats, I simply will not compromise when it comes to the fuel I put into my tank.  That was pretty painful.  It would have been so much more satisfying to have a shiny new MTC screen that I interact with every few minutes rather than cat's that I barely ever even see. Just my 2 pennies, good luck to you guys dealing with this issue!!

[Surf4FamFun]

No communication from BOOStane today.

I did check with Mercury and Yamaha outboards online.  For the Mercury 87 is all that Is required for the models I checked.  For the Yamaha 87 was good until you get to the much larger motors which are not docked on the lakes we go to.  I did talk to one of the Marina's and their comment was that he was on the pontoon end of the lake and there was no need for higher octane fuel.  I am not hopeful but will try on the other Marina. 

[Surf4FamFun]

I did reach the BOOSTane tech support on the phone.  I was assured there is no lead in any form in the mix (the off road only product says in writing on the web site the there is no lead in the product, the off road only designation is from other additives).  They do require much less additive by volume than other MMT based octane boosters.  I asked why that was and he stated that it had to do with the chelated carrier they used.  They have a Marine blend that they say has fuel stabilizers in it but he said for long term storage I still would need a fuel stabilizer.  This was an easy opportunity for him to increase the value of his product by claiming the stabilizer was good enough for storage and he did not claim the win.  That did give me more confidence in the rest of his answers.  I was very blunt in my talk with the SE that this was a very expensive blown marine application and would be 100% dependent on their product.  He did not flinch.  

Of note it takes more than double the dose of BOOSTane to get from 6 octane numbers (87 to 93) to 7 numbers (87 to 94) and after that it takes progressively more.  Octanium is another product but going from 87 to 93 gets well into the range on their chart that says it will harm O2 sensors and cats.  Torco says it is safe for O2 and cats mixed to jump from 87 to 92.  Both of these products say you have to put a lot more in by volume in than does BOOSTane and so are a LOT more expensive to treat with.  If you are looking at cost on BOOSTane the cost goes down about 20% in the individual cans is you buy a bunch at one time, even more if you buy the 5 gallon can.  No one burning gas like these boats do will be buying singes so might as well take the discount.

it seems that any MMT product will leave an orange residue in the combustion chamber, BOOSTane says this normal and you should expect a 70k mile plug to need to be replaced at around 50k.

The guy I talked to said he went back to working on the original formulation and his narrative matched what was on the web site and some posts I found going back to 2014.  Guess my point is that if it is BS it has held up for 7+ years.  He mentioned high performance marine as their origins and I found a thread from 2014 backing that up.

While I did find many online with the opinion that the orange residue could not be good and so they would not use (insert MMT based product name here) I did not find any first hand reports of actual damage from the orange other than plug life.  There was one post from a guy that had to replace the cat's on his used boat, he attributed used the bad cat's to the cans of octane booster he found in the bilge.  Not counting that one since it was speculative, not supported by other's experience, and there is no way for him to know if the previous owner followed the product mixing chart.  From way too much reading on the topic it seems like there are a lot of people that "just" put in a bottle, you don't see people talking about how big their bottle is or charts much.

BTW if you want to feel good about Malibu prices the Merc 1,350 offshore racing motor they were talking about was over 200k list in 2010 with outdrive.  Assume they are installed in pairs.

If I end up with the LT4 I will try to find 91 or better fuel and use BOOSTane Professional or Marine when I have to. 

Edited November 17, 2021 by Surf4FamFun
added some info on cost vs volume of purchase

[justgary]

9 hours ago, Surf4FamFun said:

I did reach the BOOSTane tech support on the phone.  <snip>

Thank you for posting your research here.  I still think that something is up with their dosage chart.  Most likely the smaller dose doesn't really give you the octane number they say, but settles knock for most users at a lower dose.  After all, most users aren't really asking for anything close to full power from their engines.

I like your choice of starting with 91 and bringing it up from there.