Gas mixed with Race Fuel ?
 

My marina only has enthonal free 90oct and I can get 102oct race fuel ,just trying to do the math and want to come up with the correct mix to make 93oct gas. So 1 gallon of 90oct to ? 102oct.

Here ya go

http://ranney.com/mjr/fuel_blend.html

to get to 93 octane, use 25 gallons of 102 for every 75 gallons of 90

Ok got it, Thank you.....

If I did the math right, 3 gal of 102 + 7 gal of 90 = 93.6

Is the 102 a bulk tank fuel or is it 55gal drum qty? If it is, might check with the supplier and find out the specific gravity of the 102. If its a branded fuel like "turbo blue" or something, it may be a little lower SG than the 90. It will initially mix up just fine for about 7-10 days then will definately stratify (seperate layers)...

Not an expert, just a chemical blender familiar with SG's and blending..

If your engine is designed to run on 93 octane and you mixed the fuel and ended up with a higher octane say like 95 or 96could it actually hurt anything?.....would it hamper performance?

I was just going to pick it up from Sunco station and fill a big 20 gallon fuel tank up and the put the 90octain in at the marine.

Call down to the station and find the name of the fuel. Sunoco lists all their SG's in PDF form..

Dont worry Mark......you still have them covered this weekend at JOTJ's. The V's anyway.
Seriously, higher octane than you need just ends up as carbon on your transom. Wont hurt anything, just doesnt burn completely. Hot air temp's and high humidity will make your motor lay down more than higher than needed octane. I have heard some folks say because of the incomplete combustion of the higher than needed octane you are not getting as much horsepower as you would with lower octane fuel burning more completely. Never noticed it in our 700's though.

It would idle really good, but under load or higher rpm performance would suffer. Higher the octane number, harder to burn. The opposite of detonation. Low octane fuels explode before piston is in optimum position of stroke. Higher octane -harder to explode. Hope that helps maybe not the best description but that how it works................................Rjr.......... ...............................

So it's better or safer to run higher octain fuel then lower?

Octane less than needed by the motor and well...big check writing time may rear its ugly head! The higher the octane, the safer the motor. Octane greater than needed for the motor, the lower the power...but I doubt I could actually feel the difference in the boat's performance. In reality, buying too much octane is money that needs not to be spent...but it isn't "bad" in the sense of damaging a motor. On the flip side, if some claims higher octane than needed will increase performance...well, get a second opinion!

That said, the ratings on fuel pumps is not absolutely nescessarily an iron clad guarantee. So, I gladly err a bit and buy slightly higher octane than the motor needs. Especially if the motor is going to see tough duty. For example, when I fuel my tow vehicle that "needs" 89 octane, I will put in higher octane fuel if I know I'm going to tow a large/heavy trailer with that fuel.

On ocassion, I have been forced to buy 89 octane for my boat motors that "need" 92 octane. On those occassions, I avoid letting the blowers develop much boost for any length of time. Ditto for burning off a tank full of stablized fuel that has been in the boat during winter storage.

thanks Randy and Robert Jr......I am little suspect that the "mishap" that I experienced on the Jammin run last year may have been the result of less than rated octane fuel....I was considering adding some 102 aviation fuel to insure against this happening again.....sounds like if the mixture was a little high on the octane side it may hamper performance slightly but at the same time provide a little insurance....am I reading this right?

Yes and no..... If your in the ballpark, it shouldn't really cost you anything powerwise if your a little over on the octane, say 96~98 when your after 93. Now if your running 112 in your 89 octane motor, your probably leaving a bit on the table with the slower flame front (gas burns, it doesn't explode if the octane right).

The piece of mind is worth much more the miniscule loss of power, especially if your running hard

True "aviation Fuel" is formulated to burn at altitude not sea level. Check With AED Performance on J.D. Pike at willis rd.Richmond,Va They sell 102 and 106 octane race gas by the barrel. Blend it 3:1 3 parts pump gas to 1 part race gas will keep you safe. In other words don't buy it at the airfield!........................................R jr...................................

Exactly. A 1:3 ratio will give you a solid 93 octane. The 90 octane is minimum octane it can be(as long as you trust them). Most likely it is more like 90.1-90.5 octane

AV fuel will be fine as long as its mixed with some gasoline.

Nothing wrong with AvGas. Pump it into 55 gallon drums right at the airport. Not going to start the AvGas war, its been beat to death already. Ran it straight in 2 strokes and 4 strokes, also blend it with regular gas. Runs fine. If you want to know what octane you are
blending, you can go here.
www.bazellracefuels.com/Calcs/OC1.htm

LOL. I've been running 33% AvGas in my boat for the past 3 and a half seasons with no issues whatsoever. It is very important to add 2 ounces of Marvels mystery oil to every 5 gallons of the AvGas. ;) Runs good and smells even better :D

I also run it in my lawnmower, Gator, My wife's Honda Ruckus, my old Corvette and everything else that can get messed up from the ethanol getting old. :)

I also treat every ounce of 93 octane fuel that goes into all of the above with the valvetect additive....the price of it seems small when chit isn't blowing up!!! :D

also, 100ll avgas is rated different. The ll=lowlead, but compared to most race fuels, it is actually high lead. Also, gas you see at the pump is rated as (R+M)/2, where as 100ll is just the motor octane I believe. 100ll avgas is actually quite a bit higher than a 100octane auto rating..... It's also "more" consistent than alot of the gas you buy at the local gas station.

I agree with Sax. 100ll is a higher rating compared to auto fuel as said before, its designed and rated at elevation where it is primarily consumed not at sea level. Stuff smells great though. :lolhit: Always loved smelling dads Bonanza idle by. :coolcowboy:

Pump gas octane numbers are "minimum" octane. I have tested 50 + brands and octanes within the brands. The octane in each case is 1.0 - 1.8 octane higher than what the pump says. 93 octane is really 94.5 for instance. I have also test 3 local potomac river marinas pumps each is 1.0 octane higher than what is written on the pump.
Ethanol remains 9.5 - 11.5%

This is true. 100LL would be around 105 on the (R+M)/2 measurement system. The Research number is usually around 10 points higher than the Motor number when they are around the 100 range.

Yes, that is the bottom line. No matter how many ratios, mixtures, & combinations you read or discuss, the piece of mind, and "cheap insurance" you're paying for by having higher octane, is priceless to me.

Our marina carries 87 octane, & 110 octane at the pump for us. My engines are allegedly set to run 93 octane, but since day one, I've been running straight 110 octane through them. I haven't experienced any loss of power, or any other fuel related problems from running straight 110 octane race fuel. When I've been out of town with the boat, I have mixed 91 into the 110 that was already in the tank without any issues, since the mixture was still safely over the required amount of octane they needed.

I found out the hard way on a boat I owned years ago, that its motors required 95+ octane fuel, after they BOTH detonated. Since I didn't know this, I had been burning 93 octane fuel. All it took was roughly a 2 octane deficiency to smoke them both. Ever since then, I've tried to have a little higher octane fuel in any engines I've had, just to be sure.

When I'm on another lake, I'm always a little leery about pumps on the water, just because you never know how much of a specific fuel, especially premium, they are actually selling. If the marina is seasonal, and they don't typically sell enough premium fuel to require their tanks to be refilled with fresh fuel very often, it's tough to know how long the fuel has been sitting in their tank. Or, you never know what's been added to their fuel, like octane boosters, stabilizers, etc. The actual octane of the fuel they are refilling the "93 octane" pump with is also a concern, since it could be 87 octane that the marina is selling as 93.