Racing fuel

[CNT]

I have two 55gal. drums of racing fuel, one is C-921 RT, and the other is VP-2B. Both are VP racing fuels. Can I use either one of these mixed with pump gas in my Merc. to get some octain boost? They are both 110 octain.

[Travis Fulton]

i have always been told not to mix fuels, tooooooo many variances

[Jay Smith]

You can blend any Racing Motor Gasoline to Super Unleaded to bump the octane ! We do it all the time when pump gas simply does'nt have enough octane to support higher compression that is not safe with pump gas !100 to 105 octane is safe @ 190-200 lbs compression , becarefull not to over octane a 2 stroke as it will hurt performance ! The 2 cycle needs only 1 point above the point of detonation to achieve the most power.

[David_L6]

Not saying that is a good practice, but I've done it numerous times.

I don't need a lot of octane, just something that will pass inspection. In the past, when we were running a lot of classes, I'd mix 3 gallons of VP C-12 with 2 gallons of "pump gas". Never had any problems.

[CNT]

I want to run with about 150#'S comp. and I just want to boost the pump gas (92 oct.) a little for a lttle insurance . How much Racing fuel to pump gas should I mix to get a little extra ass and prevent detonation. Also, I believe that the rasing fuel that I have is leaded, will it harm my motor?

[O/B Dude]

150 psi will run fine with 91 octane...I have been doing that for years. BUT....it gives you no margin for error though, in case you buy 91 octane but actually get 87 octane. 1 part 110 octane to 3 parts 91 octane will get you 93.25 octane. 1 part 110 + 3 parts 87 octane is 92.75 octane. I blend 87 or 91 with 100 avgas all the time. No problemo. :D

[O/B Dude]

I just realized I missed one of your questions...lead. Nope, wont hurt anything. Lead damages catalytic converters on cars and is toxic. Thats why pump gas is no-lead. Won't hurt anything on an outboard motor.

[CNT]

Is leaded racing fuel ok to mix wth pump gas and run?, and how about oxygenated fuels?

[O/B Dude]

You must have been typing this question as I was pressing "submit reply". :D

See my post above.

[Jay Smith]

We ( JSRE )target for no more than 140-45 at 91 octane from a major gas station ! EXXON , CONOCO, CHEVERON, SHELL etc as they have enough traffic to keep fuels stabill and fresh , motor gasoline has a short shelf life from the time of refining till its burned , me working in the largest refining facility in the world I see product sitting sometime too long in vessels before shipping !The difference between the 145-140 numbers and 150 can sometimes cost you a piston and a worlds of greif and the 5 - 8 lbs compression difference ain't worth the risk ! Also if there is a "glich" in your system clogged jet , weak injector, switch box triggerlittle messed up , flywheel magnets off, timing off ect .....
I could go on for an hour, that will cause to slip over that edge and dotinate, just ain't worth a motor !( Least not to me and my customers ! )

Your motor and your call..........

Happy boating,

[O/B Dude]

150psi on 91 octane leaves no margin for error. Works fine as long as your motor is in proper tune/condition and the fuel is fresh. Myself and several of my friends all run 151 psi on 91 octane. Have for years. (We all get 151, never 150 :D ) But we keep our motors in top condition. Also, you can richen up your motor a bit to benefit from "latent heat of evaporation". This means the extra fuel coming in serves to cool the piston and stave off detonation. Main reason I run on the rich side is for the extra lubrication, but cooling is a side benefit. Merc ignitions are so strong they fire an over-rich mixture easily. I am not talking about drowning the motor with fuel, I just run my motor a bit rich. My 2 cents.

[imq707s]

Speaking of Octane..........................


What about octane boosters from autoparts stores? Do they really work? Is it possible to get a true 100 octane fuel from 91 pump gas and octane booster?


Does anyone have a formual for mixing race gas and pump gas as far as how much of each gives you what octane? I have access to Torco 110 octane race fuel and 93 pumps gas. Just wondering what would be cheaper to get 100 octane. Either mixing the race fuel with the pump gas, or octane booster with pump gas.

[vishus]

read the Autozone/Check Auto "Octane boosters" when they are talking about raising the octane by 4 points, they actually mean .4 so your 87 Octane will not be 91, but in truth you have 87.4......

You can buy some TRUE RACE CONCENTRATE for your gas, but why, I would do as Jay and OB DUDE suggest, play it safe with your compression. If you do run high compression buy AVGAS/RACE GAS and MIX....

[Jay Smith]

I would mix Racing Motor Gasoline with super unleaded to bump octane ( Alot cheaper if your doing large quanitys ! ). I don't like av gas either it has additives that is not suited for 2 cycle oil. Stick with Racing Motor Gasoline and Gasoline for an automobile from your pump.

[vishus]

if you search the web, most sites will still claim that something like super 104+ will give you 104octane (when used with 98octane fuel) / 91octane (when used with 87octane fuel).

but IF you search and find out the TRUTH.....

if you want the same results as 104+ for less....

Formula #1 - Toluene
R+M/2.........114
Cost...........$2.50/gal
Mixtures with 92 Octane Premium
10%...........94.2 Octane
20%...........96.4 Octane
30%...........98.6 Octane



Notes: Common ingredient in Octane Boosters in a can. 12-16 ounces will only raise octane 2-3 *points*, i.e. from 92 to 92.3. Often costs $3-5 for 12-16 ounces, when it can be purchased for less than $3/gal at chemical supply houses or paint stores.

I go to Firebird and watch the boat and car drags all the time, I have NEVER seen anyone using 104+ octane. I take that back, on street drag night, some of the posers are pouring 104+, hairspray, coors, budlight, whatever they think will help into their tanks...


BUT GAS experts will always point to the RACE fuel and mixing if needed.


sid

[O/B Dude]

CNT, I was told a while back that av-gas has deicing agents and other additives that make TCW3 turn to gel. After some research, I learned only the av gas intended for higher altitudes has those additives. The standard 100 octane av-gas for your typical piper cub is fine for o/b motors. The 130 LL stuff for high altitude is overkill in an outboard anyway so no need to find out if it will gel 2-stroke oil. I get 100 av-gas at my local air field and sometimes at gas stations that offer it. Havasu has it at most gas stations and lots of people run it. I have never had a problem using it. If you want to run 150 psi compression, why not just drop it to 145, run 91 or 92 pump premium, and not worry about it. The extra 5 psi isnt going to provide any noticeable performance increases.

Vishus is 100% right on the octane booster deal. Great marketing ploy, eh? "raise your octane by 6 points!" Thats what it says on the bottles. Nothing but deception to make you think 6 full octane points. Some manufacturers tell you the truth in small print, some say nothing at all. Home Depot sells toluene. I've never tried the stuff. I now have my compression set at 146 psi and just use 91 octane pump premium. The way gas prices are going, I think I may switch to 2 parts 87 octane and 1 part 100 av-gas, for 91.33 octane.

Good luck.

[O/B Dude]

imq707s....... I forgot about your question on mixing for octane. Just guess at a mix, such as 3 to 1, plug the numbers in the calculator, and average them out.

Example: 3 parts 87 and 1 part 100 octane.

87+87+87+100 = 361
Divide 361 by the 4 total parts = 90.25 octane.

Thats not enough for 145 psi, so try 2 to 1. 87+87+100 = 274 divided by the 3 total parts = 91.33 octane.

[O/B Dude]

I can't find my Merc brochure but I recall it shows fuel requirements for the F1, Champ, and S3000 as 100 octane av gas. Its only the av-gas for high altitude that has the additives that don't work with TCW3.

[vishus]

Not to start up the AVGAS issue again, but check out the F1 site...

http://www.f1boat.com/technic/dac_boat.htm

and Larry Peto down in Tucson, AZ recommends/uses it for years on his BIG DOLLAR Blown BB CHEVY motors...

I have known many MODVP racers that have used it for years. I am NOT an engine builder, just a bass fisherman, lake racer type guy... I just know that it works for most people. If money is no object, I would go with the RACE fuel anytime; if money and the ability to get it at 1000s of small airparks and many gas stations is convienent....

[vishus]

interesting...

[heliopilot]

100 LL = blue in color
130 LL = purple in color

these fuels are rated and blended for this octane at 10,000ft AGL.
at sea level you will find their rating to be a little higher.

It makes no difference to the aircraft using 100LL if their flying at 2000ft AGL (above ground level) or 16,000agl.
The same is true for aircraft whose requirements are 130LL.
( By the way very few aircraft require 130 LL now that the military use jets and the days of barnstorming and the 11 and 13 cylinder radial engines are almost a distant past.

I believe the anti icing additive you are all thinking of is reffered to as "Prist" it is only added to jet fuel.

if you can still find 130LL at your local airport or warbird fuel,and your motor REALLY needs it, go for it, mixing it with outboard oil will not cause jelling.
100LL will support much higher compression than 95% of you are running in your outboards.
LL stands for LOW LEAD

ps at my local airport 100LL is 2.35gal.

[mendo]

OK Jay, my new jeep dealer showed me in the manual where it says "do not use premium in this vehicle" he said it is because of the additives that would do more damage than good. You have said that the best for 91 octane pump gas is 140-145 lbs. Do you mean the super unleaded? The outboards don't have all of those plastic parts that I think he thinks would be damaged. That is all I can get here in Air friendly Ca.

Thanks for all of your advice!!

How could I get some of your stickers?

Mendo

[O/B Dude]

Vishus and Heliopilot....thanks for the info.
:)