BMW S1000RR Forum banner
1 - 20 of 22 Posts

Registered
Joined
27 Posts
Discussion Starter · #1 ·
I am going to try my best to run ethanol free on my other bikes. I have a station 10 minutes away that has 91 ethanol free and even 97 for twice the price. Would you guys run 91 ethanol free or 93 ethanol?
 

Registered
Joined
2,550 Posts
I am going to try my best to run ethanol free on my other bikes. I have a station 10 minutes away that has 91 ethanol free and even 97 for twice the price. Would you guys run 91 ethanol free or 93 ethanol?
I'd run the ethanol free. If you're running a high-boost motor in something, the 93/ethanol (or 97 if you really need it and can spend the $$) would probably be a better choice.
 

Registered
Joined
2,550 Posts
Why non-ethanol? I try to run as much ethanol as allowed in my car to get the best knock protection.
Your car shouldn't care what the chemical itself is to prevent knocking, so 91 octane pure gasoline should be better than a 91 octane mix of gas and ethanol for the reasons listed below.

Ethanol attacks seals, plastics, and other things in the fuel system. Also, while it DOES have some knock protection when mixed with gas, it also decreases the energy per gallon, meaning you'll get less power and mileage, sometimes drastically. I got some gas in Montana once years ago that dropped me over 5mpg! If you have a car with VERY high boost, alcohol helps, the more the better, but then, it's a specially built and tuned motor specifically for that fuel. So, for a stock engine, gas without it is better.
 

Registered
Joined
34 Posts
Your car shouldn't care what the chemical itself is to prevent knocking, so 91 octane pure gasoline should be better than a 91 octane mix of gas and ethanol for the reasons listed below.

Ethanol attacks seals, plastics, and other things in the fuel system. Also, while it DOES have some knock protection when mixed with gas, it also decreases the energy per gallon, meaning you'll get less power and mileage, sometimes drastically. I got some gas in Montana once years ago that dropped me over 5mpg! If you have a car with VERY high boost, alcohol helps, the more the better, but then, it's a specially built and tuned motor specifically for that fuel. So, for a stock engine, gas without it is better.
I think ethanol gets a bad name, there are a lot of studies out there showing ethanol is not as bad as people make it seem. In addition, ethanol has way more knock protection than regular fuel. When you see tuners dial in for an E30 or higher mix, the power difference is staggering.

For a vehicle tuned on 91, anything higher than 91 or with more knock protection than 91 is a waste. For vehicles that can adjust to higher octane and benefit from additional anti-knock, the added ethonal is worth it if you are trying to maximize performace. I live in CA and our 91 retards most performance vehicle performance because they are built around high quility, higher octane fuel.
 

Registered
Joined
2,550 Posts
I think ethanol gets a bad name, there are a lot of studies out there showing ethanol is not as bad as people make it seem. In addition, ethanol has way more knock protection than regular fuel. When you see tuners dial in for an E30 or higher mix, the power difference is staggering.

For a vehicle tuned on 91, anything higher than 91 or with more knock protection than 91 is a waste. For vehicles that can adjust to higher octane and benefit from additional anti-knock, the added ethonal is worth it if you are trying to maximize performace. I live in CA and our 91 retards most performance vehicle performance because they are built around high quility, higher octane fuel.
Ethanol got a bad name for a good reason. Granted, we were forced to come up with better gasket, o-ring, and plastics materials, and we did over the years, so it's LESS of a problem than it was. But the fact remains that ethanol is hygroscopic and it actively pulls moisture from the air and into your fuel.

I agree, as I mentioned, when you have a RACE engine specifically tuned for high-ethanol or pure ethanol fuel, you can make LOTS of power because of it's inherent knock resistance, meaning that even with the low btu/gallon of the higher-ethanol fuels vs gasoline, you can pack a lot more of it in the cylinder. You run into icing/freezing problems actually, but that's another discussion.

I also agree, in part, about the 91 octane comment. People think that running race gas in an OEM motor makes more power. Wrong, and it usually produces LESS, as generally the higher you go in octane, the less btu/gal the fuel has. As we agree, ONLY if you have a tuned engine will high-ethanol and pure-ethanol fuels and race gas be a benefit, in all other cases it's a waste of money and can actually damage your engine if the viscosity is high enough to make the engine run lean. Many people burned pistons back in the carburetor days because they tried to use the same jet sizes they did before trying to run, say, high-octane avgas (thicker) and it created a very lean condition. It's less of an issue with modern FI (because of the pressure), but it can still rear it's ugly head.

Well, I agree that CA is run by the tyrants such that it "retards" everything... 馃ぃ
 

Registered
Joined
34 Posts
Ethanol got a bad name for a good reason. Granted, we were forced to come up with better gasket, o-ring, and plastics materials, and we did over the years, so it's LESS of a problem than it was. But the fact remains that ethanol is hygroscopic and it actively pulls moisture from the air and into your fuel.

I agree, as I mentioned, when you have a RACE engine specifically tuned for high-ethanol or pure ethanol fuel, you can make LOTS of power because of it's inherent knock resistance, meaning that even with the low btu/gallon of the higher-ethanol fuels vs gasoline, you can pack a lot more of it in the cylinder. You run into icing/freezing problems actually, but that's another discussion.

I also agree, in part, about the 91 octane comment. People think that running race gas in an OEM motor makes more power. Wrong, and it usually produces LESS, as generally the higher you go in octane, the less btu/gal the fuel has. As we agree, ONLY if you have a tuned engine will high-ethanol and pure-ethanol fuels and race gas be a benefit, in all other cases it's a waste of money and can actually damage your engine if the viscosity is high enough to make the engine run lean. Many people burned pistons back in the carburetor days because they tried to use the same jet sizes they did before trying to run, say, high-octane avgas (thicker) and it created a very lean condition. It's less of an issue with modern FI (because of the pressure), but it can still rear it's ugly head.

Well, I agree that CA is run by the tyrants such that it "retards" everything... 馃ぃ
Lol, if it wasn't for the money and my wife's family, I wouldn't need to worry about CA gas and the other thousand CA problems.
 

Registered
Joined
929 Posts
I'm not a big fan of ethanol beginning with its politics and economics. But given that, I would take the 2 extra octane if a bit of performance is important since all modern engines deal with ethanol quite well. The dragstrip folks even use E85 for that extra octane and power, assuming they get a tune with the right fuel maps.

BTW, gasoline has about 35% greater energy density than alcohol, so mileage suffers a bit even with E10.
 

Registered
Joined
2,550 Posts
I'm not a big fan of ethanol beginning with its politics and economics. But given that, I would take the 2 extra octane if a bit of performance is important since all modern engines deal with ethanol quite well. The dragstrip folks even use E85 for that extra octane and power, assuming they get a tune with the right fuel maps.

BTW, gasoline has about 35% greater energy density than alcohol, so mileage suffers a bit even with E10.
Yup to all of the above. Using a food crop as a fuel makes no effing sense, like subsidizing electric cars doesn't, but I digress on that one... I got a nasty surprise somewhere in ID back in 2013 when I realized that I was getting mileage in the low 30's instead of high 30's low 40's after calculating it. I was seriously stressing because I didn't know if I could make my next fuel stop...in the middle of nowhere. Luckily I kept the speed down to just below posted (TOTALLY new experience for me! LOL) and found a gas stop that wasn't on my map that was shortly after my last one so I topped off. The bike felt a little sluggish even after that, but didn't sputter or anything like it was bad fuel, it just felt weak and the mileage sucked. After running that tank dry and filling it with actual gasoline instead of the ethanol-watered down version, everything was good again. I think that "gas" station was running a very high concentration of ethanol in it's gas. That's the only reason I could think of for the drastic performance and mileage drop. So, yeah, I'll avoid ethanol every time I can. Unless you can specifically tune for that with a boosted engine (N/A engines can't use the benefit) you're just losing power.
 

Registered
Joined
196 Posts
What cars knock? This isn't 1977.
If you want to see the damage of ethanol, take apart a 2003 cbr600rr barn find carburetor
 

Registered
Joined
27 Posts
Discussion Starter · #11 ·
Good discussion. I will stick to the 93 for the RR and 91 ethanol free for the KTM with the plastic tank. I add stabilizer for the winter but still don鈥檛 like leaving gas just sitting for to long.
 

Registered
Joined
34 Posts
What cars knock? This isn't 1977.
If you want to see the damage of ethanol, take apart a 2003 cbr600rr barn find carburetor
Modern cars have knock sensors for a reason. Crappy CA91 pulls enough timing to significantly impact performance. It also doesn't help that CA91 has additional additives that are probably not good for performance.
 

Registered
Joined
2,550 Posts
Good discussion. I will stick to the 93 for the RR and 91 ethanol free for the KTM with the plastic tank. I add stabilizer for the winter but still don鈥檛 like leaving gas just sitting for to long.
I'd use the ethanol free on the 'RR as well. It'll get fractionally better mpg and power, and you'll not have to deal with any possible corrosion issues, however minor. The 'RR certainly doesn't need ethanol as there's no benefit and a possible negative.

As for the KTM, I've not heard of tank issues with them when using ethanol/gas fuels. Unlike my friends aprilia Tuono where the tank swelled up and he needed a new one under warranty. I've heard of issues with other bikes too, but so far I've read of no issues with the modern KTM's.
 

Registered
Joined
27 Posts
Discussion Starter · #14 ·
I wish they had a 93 ethanol free but they only have 91 and 97 for crazy money. Super is closer too. The KTM is a 690 which a few guys have had tanks warp and leak.
 

Registered
Joined
935 Posts
I think ethanol gets a bad name, there are a lot of studies out there showing ethanol is not as bad as people make it seem. In addition, ethanol has way more knock protection than regular fuel. When you see tuners dial in for an E30 or higher mix, the power difference is staggering.

For a vehicle tuned on 91, anything higher than 91 or with more knock protection than 91 is a waste. For vehicles that can adjust to higher octane and benefit from additional anti-knock, the added ethonal is worth it if you are trying to maximize performace. I live in CA and our 91 retards most performance vehicle performance because they are built around high quility, higher octane fuel.
Not bad? I had to sign an waiver paper when buying the bike about ethanol. Even my Honda power washer has warning on gas tank about ethanol!
 

Registered
Joined
2,550 Posts
I wish they had a 93 ethanol free but they only have 91 and 97 for crazy money. Super is closer too. The KTM is a 690 which a few guys have had tanks warp and leak.
Interesting, what year? My buddy has a 690, so far he hasn't said anything about an issue.
 

Registered
Joined
27 Posts
Discussion Starter · #17 ·
2014 Duke 690. No issue with mine. I just got it. While researching potential issues, I found a few posts about gas tank deformation. Possibly due to over filling and heat or ethanol.
 

Premium Member
Joined
4,519 Posts
Gasoline tanks made of PA6 nylon swell when exposed to gasoline containing ethanol.

Of what is the KTM tanks made?
 

Registered
Joined
81 Posts
Pretty damn sure these motors are tuned for 91 octane. Many states don't have anything over 91 octane. Any octane over the recommended octane is a wasted.

Consult your owner's manual if you don't have heavy modifications.
 

Registered
Joined
34 Posts
Not bad? I had to sign an waiver paper when buying the bike about ethanol. Even my Honda power washer has warning on gas tank about ethanol!
You had to sign a waiver for a K67? In CA, you have no choice but to use ethanol, what if you moved to a state with only ethanol?
 
1 - 20 of 22 Posts
Top