Octane boosters
 

No marinas sell anything higher than 87 octane here. I'm looking for a quality and quantity octane booster. I'm tired of buying small, ineffective bottles. Anyone have any suggestions about buying quantities larger than the small bottles and better quality as is typically available at local O'Reilley's/Auto Zone type stores.

Thanks

The bottles of octane booster at the auto stores are useless. What octane do you need for engines???? Best option is to mix in high octane race fuel.

i agree with griff on the race fuel. i do mix toluene with my pump gas for my high compression snowmobile. you might want to look into that. it bumps 91 up to around 105-108 but i am using it on a 2 stroke snowmobile so im not sure how it would do on your boat.

what is your engine compression

A good discussion of octane boost is here.
http://www.offshoreonly.com/forums/g...ane-boost.html

Toulene or Xylene seem to be the best suggestions, but don't mix it over 20% or so.

might consider avgas from your local airport. its 100 oct and contains lead. it has worked well for me in my dirt bike for many years. usually mix it 50/50 with super (93)

isn't avgas mostly alchohol and dryers to prevent icing?

Octane boosters
 

My compression is 10.5 I believe. I was told by builder to run better than 87 octane. I do have a trailer but trailering a 38ft boat with a crew cab dually and then getting into a gas station can be a bit of a challenge.

It looks like I just need to suck it up and hit a gas station every so often at a time when they're the least busy.

Wish me luck !

Aluminum heads or iron?

Octane boosters
 

Iron heads with a little flow work, most of the usual stuff. Inconel/stainless valves, little bit aggressive cam, roller rockers, good springs, good pistons, parts overall pretty nice. Not a race engine by any means. Started life as a stock 502EFI. Bored + .030. Some computer mods, other engine mods as above, Stainless Marine long risers.

They've been great motors for almost 500hrs with one complete overhaul about 100hrs ago. I just don't want to have problems. Two marinas here used to sell 93 but no longer do.

If you had 10.5CR with iron heads, I doubt it would be alive right now without running at least 93 octane.

That's what I've always been told. I know some guys that were running it in their race cars and they had problems with it. Maybe mixing it with regular gas helps, but I would tend to think that you'd be better off using a Torquo 108 or something like that, opposed to an airplane fuel that has additives that aren't needed in a marine application.

NO.....ethonal or alcohol are not present in AVGAS, that would be a big problem, as they would boil at altitude causing fuel starvation problems, not a good thing at 5000 ft. Its actually a very good alternative to race gas if you dont need over 100 octane. It does have a small amount of lead in it, and will screw up any 02 sensors if you are running them. The subject has been beat to death on here, whether its ok to run. I have run it in many motors 2 and 4 stroke and never had a problem. The problem is buying it. Not every airport will sell it to you.

10.5 to 1 and steel heads combined with 87 octane=blown motor/burnt pistons.

With that high of a compression ratio and steel heads, you should use nothing less than 93 octane.

So back to the oringinal question, what to do??

Fill up BEFORE you get to the ramp !!!!!!! :confused::confused:

Good answer. But for arguments sake, like here and other places, I can't fill up on the road, what's to do??

The only concentrated octane booster that would be relatively simple to carry on the boat is the Torco Accelerator. It is very expensive though. It looks like 64oz would give 40 gallons another 4 octane points.
http://torcoracefuel.net/pro-accelerator.html

If the boat is in the water and you will need something on a regular basis, I would get 55 gallon drum of race fuel or Toluene. 32 gallons of 87 octane and 8 gallons of Toluene(114 octane) will get you about 92.5 octane.