When I ran the Rotax I’d run BP or Shell Premium gas with no Ethanol if I didn’t have the VP fuel available. It ran just fine. You shouldn’t have to change the jetting much or at all from what you normally run. I used 6oz a gallon of redline oil. I’ve even when as far down as 3oz castor to a gallon. And normally around a 154-155 main jet.
If you think you need something better than pump gas get the Sunoco stuff.
I’m not really concerned about the performance (theoretically the ethanol should make more power, correct?). I’m more concerned about the ethanol degrading the seals and gaskets.
Drain your carb after each weekend (which you should be doing regardless of fuel) and you’ll be fine. No one is running rubber fuel lines here.
I would just pull the fuel line off the pump and run the engine out of fuel. Then drain out the float bowl. Squirt some WD40 into the pump and fuel inlet on the carb and your done.
Biggest issue ethanol. Motor doesn"t like to run on fuel with ethanol as it is very hygroscopic.
If you can find ethanol free fuel should be good to go.
I tried to run my Iame x30 on small amount of premix made with pump gas with ethanol just to do a system check before a race. It ran but ran terrible. Swapped fuel at track idle perfect.
We’re taking about two different things. I’m not talking about a specific oil ratio per fuel type or the ratio changing depending on the fuel.
I’m talking about a specific oil ratio per driver/tuner when you are comparing jetting. If the oil ratio is not the same in both cases, then the same jetting may not apply. You should ensure that you are comparing notes for jetting that the oil ratios in both cases match.
This stackexchange thread has some good chemistry talk on the first reply:
Ya’ll are about to see someone on the internet admit he was wrong. Here’s the concerning part I didn’t know about (or maybe I slept through that chem class):
In the presence of water (pulled in by the ethanol) and oxygen, sulfur naturally forms sulfuric acid by a variation of the “contact process”; it oxidizes easily to sulfur dioxide, then more slowly to sulfur trioxide, which when dissolved in water becomes sulfuric acid. This reaction, specifically the formation of sulfur trioxide, is sped up in industrial processes by heat and by contact with catalyst metals such as vanadium oxide (hence “contact process”), but it will also happen on its own without any special treatment (i.e. acid rain).
OK OK lets calm down. First of all there is very very little sulfur in tier 3 gasoline (10 parts per million).
Secondly phase separation of water in any gasoline is most likely with (liquid) water being mixed with gasoline. Most water in gasoline is drawn from water vapor in the air (unless you are pouring water into your fuel tanks). This does not cause phase separation and therefore is fine. The ethanol in the fuel actually makes water in the fuel less of a problem. I’ve copied the conclusion from an EPA document below, you can read the rest of it in the link.
Conclusion
Water phase separation in any gasoline is most likely to
occur when liquid water comes in contact with the fuel. (Water
in the form of moisture in the air will generally not cause phase
separation.) Water which is in solution with gasoline is not a
problem in any engine, but as a separate phase it can prevent an
engine from running or even cause damage. Since oxygenated
gasolines, however, can hold more water than conventional
gasoline, phase separation is less likely to occur with
oxygenates present.
For any gasoline, simple precautions to prevent phase
separation from occuring should be taken. First of all, gasoline
should not be stored for long periods of time, especially during
seasonal changes which usually have large temperature changes
associated with them. (For both oxygenated and conventional
gasolines, gumming can also occur which is detrimental to any
engine.) If it is unavoidable to store gasoline for a long
period of time, one should be sure that the tank if full to
prevent condensation of water from the air, and the addition of a
fuel stabilizer should be considered. Lastly, care should be
taken not to allow water into the fuel sytem while filling fuel
tanks or operating the engine – in the form of rain or a spash,
for example.
Good! Essentially, the same precautions you take with Methanol should be taken with Ethanol containing gasoline.
In a Rotax Max - you want the lowest octane rating and most ethanol you can get. The compression is so low and the ignition is timed so far back that it’s almost impossible to get detonation, and there is a “chemical supercharging” effect with alcohol. I ran 87 E10 for a full year without any failures.
Definitely would like to hear more about this. Don’t get me wrong, I understand you can make more power with alcohol, if the circumstances are right.
But I’m having trouble understanding how those circumstances would occur with an FR125
How much tonque and horesepower are we talkin’ here Gary?
Depends on which octane and what you are using now. We have a dyno from a Mustang 500 hp car on 93 pump fuel. We added Mach 116 and got 91 hp and 72 lbs of torque. I would guess a couple of hp on the smaller kart motor. Torque is what you would want the most increase in, so you could pass. The shipping charges are crazy. HazMat fee of 33.00 on a 5 gallon jug. Plus it weighs almost 60 lbs. What most of our customers are doing is chip in buy the first 5-gallon jug. Run it …Then they place an order over $3000.00 where you would get free shipping on a single octane,
A couple things to think about here is that most kart engines don’t run a high enough compression ratio to get a benefit from race gas. I remember back in Yamaha our engines actually ran better on 93 pump gas at the club than they did on 110 race gas. I believe engines like an X30 do need 110 to run well but I don’t know specifically which engines prefer 110 vs 93.
Another thing is most series have a spec fuel to run. Our club has a specific gas station they get fuel to test from, and the traveling series all have a spec gas, usually either Sunoco or VP. If you wanted to get more sales in karting (which isn’t nearly as much per person, we’ll go through maybe 5 gallons in a typical weekend) you would have to go through the race organizers to promote your gas, not the racers here. We really don’t have a say in which fuel we run at a track.
So I am going to wave my admin flag a little bit, because although the thread topic is about different types of pump fuel for karts, we try to stay away from hype posts/trying to get people to buy stuff. (IE: ‘Our stuff is great. Order now.’
Not a huge deal in this case, just something to bring up.
I use 93 octane pump gas and Phillips66 Injex in my Leopard - no problems to report so far. I take the header off once in a while and shine a light on the piston through the spark plug hole to check the mixture, but it’s pretty forgiving fuel. I remember using 87 octane Gulf pump gasoline in my Rotax Max and gaining a few hundredths per straightaway over the legal MS98L, but the jetting is a little harder with the ethanol in that fuel and the possibility of detonation - it always felt “soggy” because it had to be enriched.
Coming back to this from a while back, but I just realised North America measures pump gas octane different to everywhere else in the world. Europe uses RON (research octane number) on the Pump. North America uses the average of RON and MON (motor octane number) which is typically 8-11 points lower.
So if its reads 93 on the pump its probably about 98 RON which is more then acceptable for every TAG motor out there. We used to run that stuff most of the time in Formula A with almost free timing and head volumes. My only caveat would be try and use a popular gas station so there is quick turn over of the fuel in their tanks. You want to avoid stale fuel.
You didn’t have to run that fancy Atol control fuel? Lucky you ha.
Again, my main concern is that we’re only looking at the octane number… it’s important to take the composition into consideration too. It’s less of an issue in UK\Ireland where the temp swings are not bad, but in the US they ethanol content can vary a lot.
When everyone found out Atol was the same as pump fuel it all sort of fell apart. But we did run the Atol fuel at Super 1, yes.
What are thinking, like composition of the fuel to run at low temperatures, and/or detergents etc. They are different from brand to brand but almost certainly won’t be present in a race fuel right.