High octane gasoline

[Sergio]

I was told by some guy to use high octane on my mt that it was better I use regular gas does he know what is he talking about?

 

[Guantanamo Joe]

All I have available here is regular gas... and my MT is an animal... high octane probably does not make much of a difference.

 

[Deluge]

Doesn't make a difference. High octane fuel is mainly used when running a high compression engine, as it resists detonation. I've run 87, 89 and 91. Now I just run whatever is cheaper.

 

[Sergio]

Yeah that is why I use regular and that thing goes man. Cheap gas is why I love the gasser instead of nitro 36 a gallon for nitro. I love my rampage mt.

 

[Guest]

I run high octane only because I have heard that it doesn't have the methonal added to it.

 

[alfred e numan]

i blend up a mix of fuel. ends up being about 95 r-m+2 octane. too much automotive race gas will hurt the top end power, very much so in a 2 cycle engine because they tend to blow out unburnt fuel anyways. There is a type of fuel brewed by Sunoco -100 r-m+2. Non Oxygenated - this brew burns fast- faster even than low octane automotive gasoline. It will build horsepower in our little engines, I am into pouring concrete @ the moment- just took a little break to wolf down food, after i skim, i will go to Sunoco and look it up- There are hundreds of mixes of gasoline, very few are brewed up for high output 2 cycle engines. - gotta go------

 

[GoffeeRedCat]

Yea when I was younger my uncle in Texas used to pour 105 octane on his weed wacker!! He said that it produce more HP!! and it smells good!!

 

[alfred e numan]

Here is my brew. - I mix in small quanities, the same mix is used in the chainsaws also-- dual duty! 10 fluid ounces of 91 octane ethanol free pump gas. - 6 fluid ounces of V-P 110 C race gas, total-16 ounces. Add 1/2 fluid ounce of Klotz super technaplate- spelling-AGG!!! Shake well, add to the gas tank. 16 fluid ounces of gasoline to 1/2 fluid ounce of two cycle oil = 32/1 ratio. No, i have not been to the Sunoco fuel site yet. I mixed up another 50 pounds of fiberglass reienforced concrete and applied vertically on a wall. The damm handle on the 1/2" drill cracked, cut me up. had to keep going- it was my last bag- 3 minutes to mix- and haul ass. It sets up quick. I will find the fuel and post folks- now , i have a bunch of Suzy homemaker stull to do, this is the downside to being alone.-- waaa.

 

[Deluge]

I run high octane only because I have heard that it doesn't have the methonal added to it.

I believe oxygenated fuels are required in AZ. If that's the case, all fuels, regardless of octane rating, have ethanol in them.

 

[Deluge]

i blend up a mix of fuel. ends up being about 95 r-m+2 octane. too much automotive race gas will hurt the top end power, very much so in a 2 cycle engine because they tend to blow out unburnt fuel anyways. There is a type of fuel brewed by Sunoco -100 r-m+2. Non Oxygenated - this brew burns fast- faster even than low octane automotive gasoline. It will build horsepower in our little engines, I am into pouring concrete @ the moment- just took a little break to wolf down food, after i skim, i will go to Sunoco and look it up- There are hundreds of mixes of gasoline, very few are brewed up for high output 2 cycle engines. - gotta go------

Interesting...

 

[rchobby89]

I run 91 ethanol free gas

 

[Guest]

I believe oxygenated fuels are required in AZ. If that's the case, all fuels, regardless of octane rating, have ethanol in them.

You might be right.

 

[xscrick]

isnt most if not all of these engines high compression,,, i would think 14 to 1 to 17 to 1 is high compression,,,but since these engines are alot smaller than there larger counterparts,,, they arent as sensitive,,,heck 17 to 1 or bit higher your into diesel territory,,,,,higher octane does help, runs smoother , burns better,, better throttle response,, and less chances of some detonation,,, melted piston and spark plug and engine failure,,,i have been breaking my engine in on premium,, but plan on stepping up to turbo blue, have a drag strip nearby and some local stations sell it out of the pump...

 

[xscrick]

also read on a motorcycle turbo website about adding toluol which in found at most hardware stores in paint isle by the mineral spirits in proper amount to gasoline will boost octane and prevent detonation as well,,,

 

[Stumpdiggitty]

what if your engine manual says to run 91+ octane? would it be better to run the 91 with ethanol, or 88 octane ethanol free?

 

[Guest]

Ethanol free would be better.

 

[Chief409]

A sticky on LargeScale Online.

The purpose of this Thread is to give baseline fuel/oil requirements from the industry professionals directly to you. Information which is specific to our engines and not based off of other types or sizes of engines or opinions or hearsay. Our engines are unique due to their small size, modding, lack of lubrication surface area and very high RPM range.

I have taken the time to speak with the majority of the Engine porters and Manufacturers in order to compile what in essence is the Baseline for Engine operation. I have also spoken with quite a few 2-stroke Oil Companies to get their input on the situation. The information contained here is from companies in the USA. As I or if I obtain verification from oil companies abroad I will add it but only if it can be documented.

I want to be clear that this information is what is recommended by the industry for best performance and maximum engine life. There are of course going to be different opinions and different combinations used by certain individuals. There is no question that these motors will run on multiple fuel types and oil types and ratios.

Because there are so many variations and so many people using non recommended set ups the intent is to give accurate information based on as much fact as possible. Remember that what works for you in 1 one part of the country or world may not be sufficient for someone else. This is explained in further detail in the Fuels section.

Tuning is also an integral part of performance. A properly tuned engine running the proper fuels and oils will make it's best power. This has been verified by the industry professionals through years of testing and or dyno testing. Odds are if your new engine isn't running properly with the suggested oils and fuels then your tuning is off.

To my knowledge this is the first and only attempt at gaining this specific information directly from the industry as a whole. It is not meant to start or create an argument and is geared towards the new person looking for an appropriate place to start with their new RC.

These are the companies involved with the information being placed here:

OBR (oil preference Maxima Castor 927)

DogPile Racing (oil preference Polaris VES Gold)

ESP (oil preference Maxima Castor 927)

TS (I forgot to ask Trevor his oil pref but will add it when I speak to him again)

Cat 5 (oil preference Klotz R50)

RCMK (oil preference Mercury Quicksilver)

CC Race Engines (oil preference Mercury Quicksilver)

Zenoah

Klotz

Amsoil

VP Fuels

Motul

Maxima

2-Stroke Oils:

Recommended oil ratio of at least 25:1 5oz oil per 1 US gallon (by all industry professionals and manufacturers except for TS who recommends 28:1 in his motors).

This oil Ratio is recommended because of the small size of these engines and the small amount of lubricating surfaces inside of them. The smaller the engine and the higher it revs the more oil it needs to achieve proper lubrication and compression. More oil than 5oz per 1 US gallon will not hurt your engine. Its better to run rich than lean on oil.

What you need to know about 2-stroke oils:

The Purpose of 2-stroke oil is to maintain lubrication, create compression and cool your engine.

Not a single ONE of the oils on the market is specifically formulated for our high RPM stock and modded engines. Most of these oils and blends are designed for RPM operation in the 8-10,000 RPM range. However that doesn't necessarily mean they are not useable for our application. Never rely on what the Oil packaging states for Mix Ratios. Always mix at 25:1 (or what your specific engine manufacturer recommends) regardless of oil type. Just because a package says 50:1 or 100:1 mix doesn't mean that it's specific for our engine types. Engine life and performance is greatly affected by the quality of oil you use.

Oil types:

Natural petroleum based- This oil performs well in most stock and modded engines and blends well with most any gasoline/fuel type. This would be the type of oil supplied with the cars from Losi or HPI.

Castor (Vegetable) Blends-Although castor oil is an extremely good lubricant it can be the cause of carbon buildup, specifically if not mixed with the right type of fuels. Ethyl blended fuel and castor oil will create a situation where build up is more prominent. Certain Castor blends such as Maxima's Castor 927 use a de-gummed form of Castor which is very good performing oil. If you are dead set on running castor oil make sure it's de-gummed.

Synthetics and Blends- Are a great option for running in stock or modded motors. There is however some new evidence that full synthetic oils may be causing blowback into the crankcase in extremely high RPM engines causing bearing failures this is due to the oils superior lubrication properties. If running extremely high RPM engines over 17,500 you may want to stay away from full synthetics. I will add more on this once I do some more research. These types of oils can also be used during break-in for Stock and Modded motors. Although be aware that these oils can be affected by the type of fuel you are running. The consensus from the Oil companies is that the Oil Ratio of 25:1 does not need to be adjusted when synthetic oil is used. Stay away from Ethyl fuels when running synthetic blends.

Reliable Proven oil Brands used by and or tested by our engine builders:

Maxima Castor 927 (de-gummed castor/synthetic blended oil)

Klotz R50 (full synthetic)

Amsoil Sabre (full synthetic)

Motul 800 (synthetic/esther)

Polaris VES Gold (full synthetic)

Mercury Quicksilver (TC-W3 certified Oil based)

Fuels:

Pump Fuels-

For the purpose of establishing a baseline and proper oil ratio mixtures, fuels used should be Non-Ethyl (containing no Ethanol). Octane ratings of 87-110 can be safely used in most of our RC engines. With 87-94 Octane being the most suitable for optimum performance depending on what is available where you live. Octane levels over 100 require higher compression as do fuels such as alcohol and or methanol.

If you have to use Ethyl fuel do not run Castor Oil or synthetic Blended 2-stroke oils as this will create gumming and carbon buildup. Do not store your RC with any fuel left in the tank or Carb.

There is another factor when using Gasoline designed for automobiles which are the different additives and oxidizers used by different oil companies and in different parts of the country and different times of the year. For example East coast gas and West coast gas are not the same nor is summer gas the same as winter gas. These additives can have adverse reactions with certain types of 2-stroke oils and is something to be aware of. Purchase small quantities of fuel at a time to make sure it blends well with the oil you are using and doesn't need to be shelved for long periods of time.

All pump fuels will have some degree of contamination either water or unhealthy particulates from the ground tanks. Always use a plastic sealed Gas Can for Storing unused fuel.

Alternative fuels:

Race Fuels high octane 100+

Methanol

Alcohol

Coleman fuel (55 octane) Everyone laughed when I brought this up and for good reason. Sure an engine will run on this fuel but it's power output is greatly reduced.

For the sake of a baseline in engine performance these fuels should only be used by experienced engine tuners racers as it's a bit tricky to get the tune perfect to reap any benefits from it.

For the Racer:

Now the above information is the Baseline which most people can use to expect high performance and long life out of their RC engine. For racers things can be changed a bit.

Heavily modded motors or purpose built motors can run on Oil ratios of 32:1 or 40:1 (although not recommended by any engine builder) but keep in mind these motors will need to be rebuilt more often and more damage (Can) occur. Running higher (leaner) oil ratios will also require retuning of the engine for proper performance. Do not assume that you can change ratios or octane levels significantly without retuning. For someone who is rebuilding a motor after every few races this isn't an issue. For the backyard basher and guy who doesn't want to be rebuilding motors it is advisable to stay away from the higher Oil Ratios.

Purpose Built Engines such as Trevor Simpson Engines:

Trevor Recommends an oil ratio of 28:1 and a Leaded Race Gasoline in his engines for optimum performance. Trevor also spoke about Oil ratios and said that More oil is not a bad thing and wanted to remind people that 2-stroke oils purpose is lubrication and to create optimum compression. Less oil= less compression= less power!

Special Warning from OBR:

The Guys at OBR wanted me to bring this to your attention. When switching carbs or buying a new carb do not assume that the Carb is pre-truned. OBR has seen a rash of motors come back from people slapping on new Carbs and running the car without re-tuning. Always readjust Carb settings on new carbs prior to running!

Doug at ESP makes a good point in stating that any time you tear down an engine you should find a liberal amount of oil on the piston and inside the motor. If you do not you are running too lean of an oil ratio or running a poor quality oil that isn't supplying enough lubrication. Doug recommends buying a quality oil from a motorcycle or power sports store rather than department stores. And use a good quality "Tacky" foam filter oil.

Doug also suggests that if you change the cylinder or pipe, you will want to retune the carb also. He has seen engines run great with perfect plug color with one pipe, then seize with a different pipe bolted on with the same carb and settings, on the same day. Any time you do something to your engine to change your engines performance, it is a good idea to start off rich, and dial back in.

 

[Chief409]

Best bet, keep the mix at 25:1 (5 fl oz per gallon), use a good quality 2 cycle oil you can find at the local motorcycle shop, and avoid Ethanol if you can. I'm in California, so I use 91 octane just because. Another source for info is DDM, he recommends 91 octane for all our engines. I found a $1.00 measuring cup for oil at the local grocery store. Just had to make sure the Wife didn't grab it for the kitchen after I used it! Something about shi**ing like a Goose comes to mind!

 

[Guest]

Yes. I believe it's best to stay at 25:1 or higher oil ratio. When you power tune or lean the fuel-air mixture you need the extra oil for cooling and lubrication.

 

[Sprint 77]

I run 100 LL avgas with saber amsoil in all my 2 stroke rv and weed eaters. Runs great starts great.