fuel

[chuck st romain]

What fuel are you running in zenoah mod motors? Anyone use vp, trick, hi test sonoco?? Just wondering, when I raced 2 stroke cycles it was easy hp..

 

[Ron Olson]

Coleman campstove fuel.

 

[Hydro Junkie]

Most run standard pump gas or, as Ron said, Coleman fuel. Of course, you have to mix in a two stroke oil of some sort.

 

[lohring]

We tested a lot of different "gasolines" in a modified Zenoah. We even cheated with nitro added to ethanol containing gasoline. We tested nitro/methanol mixes as well. The needle needs to be richer as you add alcohol. The bottom line was that with low compression and fixed ignition timing we couldn't see a difference within the precision of our dyno. Different oils didn't make any power difference. We did see that there was a slight increase in power due to break in over the series of runs. Colman fuel is easier on the carb parts, but costs at least twice as much as pump regular. It is still cheap compared to nitro.

Lohring Miller

 

[Dan Pralle]

Did you ever put Coleman on the dyno?

 

[Ron Olson]

I love the Coleman fuel. After trying gas out I'll pay the extra money. No nasty gas smell, no ethanol to mess up the diaphragms in the carbs, a very long shelf life, no additives that you don't need and the list goes on. You can swap between gas and camp fuel and not have to touch a needle.

It's not nitro prices but it has gone up in price, about $11-13.00 a gallon at Wal-mart.

 

[chuck st romain]

Thanks, I'm new to these small motor and just want opinions. Sounds logging has done his homework. I just know on a 250 mx and 1000 road bike the difference was no doubt worth the price on race day. Looks like pump gas it is!

I know hp2 synthetic, but anyone use Castors like maxima 927 or Castrol r. I know in pre power valve motors (like these) it makes them last forever.

 

[Daniel's Racing]

100LL Aviation fuel is clean, non ethanol, consistent and doesn't stink the high heavens.

It runs awesome but it isn't compatible with Maxima Castor 927. It will not mix.

Many oils to choose from. Motul 800 offroad is stocked at all motorcycle shops is great choice and mixes well with 100LL.

Best of all AV gas is inexpensive. It is same as getting race fuel for 1/2 price. Our two strokes have no issues with the lead content.

 

[Hydro Junkie]

My only question would be whether AVgas is legal or not per the established rulebooks?

 

[Ron Olson]

Yes, it's legal.

 

[Hydro Junkie]

Okay, I'll go back to hiding at my desk then

 

[Ron Olson]

No, hide UNDER it!

just messin' with ya Marc.

There were some questions also about the legality of camp fuel when people started using it. The Powers That Be said that it was fine to use.

 

[Hydro Junkie]

I tried to check the rules but the system here at work wouldn't open up the NAMBA rulebook so I figured I'd just ask. BTW, Ron, when aren't you messing with me

 

[JimZaremski]

these engines have 8:1 or 9:1 compression ratios with a quenching combustion chamber (squish band around the perimeter.) Zenoah recommends 90 RON gas (yes, they do, I asked them) for an unmodified engine, which is about 85-86 on the AKI octane rating we use in the US.

So since I live near a lake, I go to the marina gas stations and use ethanol-free regular (87 octane) gas. There's absolutely no reason to use 100LL or anything crazy in these engines, unless that's the only ethanol-free gas you can get.

 

[JimZaremski]

Did you ever put Coleman on the dyno?

coleman fuel is basically 60 octane gasoline (AKI rating, or the R+M/2 method) without any of the other usual motor fuel additives like detergents or water dispersants. it won't affect performance; the burn rate and energy content of gasoline is more or less independent of octane rating. the ONLY problem you'll have with octane rating is if it's too low and you get pre-ignition and/or detonation.

oh, and one other possible problem with Coleman fuel is you've got to be careful where you're buying it and what else you're buying. people might think you're running a meth lab...

 

[Daniel's Racing]

As mentioned Japans RON 90 would be about 85 octane to us.

90 RON isn't the same as 90 octane at the gas pump. It is calculated by the RON + MON/2 method RON might be what they use in Japan but it isn't the same. Straight RON numbers always run higher than RON + MON/2

RON 95/98 is the same as our RON + MON/2 91/93

We aren't running it because it is any kind of requirement of the engine. We run it because it is clean, consistent, non ethanol, leaded, low odor, inexpensive and run's like the dickens and it is readily available.

How many more reasons would one need to realize 100LL is an exceptional fuel for a little two strokes.

You would be hard pressed to find another fuel that compares except for some of the race fuels might but at 3 times the cost.

100LL is not 100 octane by the method used to rate pump gas. It is a MON rating not the RON + MON/2 rating used for auto pump fuel.

People tend to focus too much on what they have heard about running higher octane than you need makes less power and that lower octane fuel has more BTU's of energy than higher octane fuel and while this is true it would not be possible to measure the difference of having more octane than necessary in our engines. Having more octane than needed just doesn't mean jack to us whatsoever.

Look at the extreme octane difference of Colemans versus 100LL. Even though the engine will function on Colemans it will never make measurably more power with it than 100LL. It is probably going to perform a heck of a lot better with 100LL at almost 40 octane higher than the engine could be run on. This is extreme amounts of difference and it isn't measurable so running 100 instead of 90 sure as heck won't be any different.

Then the lead in 100LL is another benefit as it is a lubricating compound. Almost everyone racing 2 stroke motocross bikes are running leaded fuel. A lot run 100LL the rest leaded race fuel.

 

[lohring]

Did you ever put Coleman on the dyno?

Yes, see the graph below. It also shows what happens when you don't richen the needle for alcohol in the fuel. The 92 octane pump gas was 8% ethanol, but the E10 was actually 32% ethanol with our water separation test.

The octane rating is only a measure of knock resistance. It has nothing to do with an engines power output as long as the engine doesn't detonate. I don't know of any way to increase a NAMBA G1 Zenoah's compression enough to require very high octane fuel. That said, running a Quickdraw in a rigger on 87 octane fuel rather than a higher octane fuel dropped the lap speeds down several seconds. Head button engines should definitely need a higher octane fuel. The last time I checked (years ago) the Quickdraw head volume was around 1.8 cc while the Zenoah's was around 2.4 cc.

Lohring Miller

 

[JimZaremski]

How many more reasons would one need to realize 100LL is an exceptional fuel for a little two strokes.

it's leaded so that's reason enough not to use it. you might be fine with inhaling a neurotoxin but don't blast that **** in my face, please.

these engines don't need 100 octane (whatever method you want to calculate) and they sure as hell don't need TEL.

 

[Ron Jefferson]

As mentioned Japans RON 90 would be about 85 octane to us.

90 RON isn't the same as 90 octane at the gas pump. It is calculated by the RON + MON/2 method RON might be what they use in Japan but it isn't the same. Straight RON numbers always run higher than RON + MON/2

RON 95/98 is the same as our RON + MON/2 91/93

We aren't running it because it is any kind of requirement of the engine. We run it because it is clean, consistent, non ethanol, leaded, low odor, inexpensive and run's like the dickens and it is readily available.

How many more reasons would one need to realize 100LL is an exceptional fuel for a little two strokes.

You would be hard pressed to find another fuel that compares except for some of the race fuels might but at 3 times the cost.

100LL is not 100 octane by the method used to rate pump gas. It is a MON rating not the RON + MON/2 rating used for auto pump fuel.

People tend to focus too much on what they have heard about running higher octane than you need makes less power and that lower octane fuel has more BTU's of energy than higher octane fuel and while this is true it would not be possible to measure the difference of having more octane than necessary in our engines. Having more octane than needed just doesn't mean jack to us whatsoever.

Look at the extreme octane difference of Colemans versus 100LL. Even though the engine will function on Colemans it will never make measurably more power with it than 100LL. It is probably going to perform a heck of a lot better with 100LL at almost 40 octane higher than the engine could be run on. This is extreme amounts of difference and it isn't measurable so running 100 instead of 90 sure as heck won't be any different.

Then the lead in 100LL is another benefit as it is a lubricating compound. Almost everyone racing 2 stroke motocross bikes are running leaded fuel. A lot run 100LL the rest leaded race fuel.

 

Does the 100LL require carb adjustments different from gas or Coleman fuel?

 

[FloridaScaleBoater]

As mentioned Japans RON 90 would be about 85 octane to us.

90 RON isn't the same as 90 octane at the gas pump. It is calculated by the RON + MON/2 method RON might be what they use in Japan but it isn't the same. Straight RON numbers always run higher than RON + MON/2

RON 95/98 is the same as our RON + MON/2 91/93

We aren't running it because it is any kind of requirement of the engine. We run it because it is clean, consistent, non ethanol, leaded, low odor, inexpensive and run's like the dickens and it is readily available.

How many more reasons would one need to realize 100LL is an exceptional fuel for a little two strokes.

You would be hard pressed to find another fuel that compares except for some of the race fuels might but at 3 times the cost.

100LL is not 100 octane by the method used to rate pump gas. It is a MON rating not the RON + MON/2 rating used for auto pump fuel.

People tend to focus too much on what they have heard about running higher octane than you need makes less power and that lower octane fuel has more BTU's of energy than higher octane fuel and while this is true it would not be possible to measure the difference of having more octane than necessary in our engines. Having more octane than needed just doesn't mean jack to us whatsoever.

Look at the extreme octane difference of Colemans versus 100LL. Even though the engine will function on Colemans it will never make measurably more power with it than 100LL. It is probably going to perform a heck of a lot better with 100LL at almost 40 octane higher than the engine could be run on. This is extreme amounts of difference and it isn't measurable so running 100 instead of 90 sure as heck won't be any different.

Then the lead in 100LL is another benefit as it is a lubricating compound. Almost everyone racing 2 stroke motocross bikes are running leaded fuel. A lot run 100LL the rest leaded race fuel.

 

Does the 100LL require carb adjustments different from gas or Coleman fuel?

I have the same question, I found today the mentioned fuel IS easy to get and $4.69/GL Think it may be worth a try.

Specially since my wife is getting comfortable with her CT and is asking for MORE speed.

Fill us in Daniel, You ARE the go to guy