What Octane to run?

[CanberraR3]

I just find mine runs no better on what we call Premium here - generally 98 RON. I use "regular unleaded", which is 91 RON, which I think is equivalent to your 87. I am fortunate that almost everywhere around where I live and regularly ride I can get fuel with no alcohol in it. Have said before that on 91 RON there is less engine noise, the bike starts easier and feels like it runs better. I'm saving around $3 a tank, which I used to put in a jar every time I filled up and bought a leather jacket with it.

 

[BillB]

As for the gasohol (typically E10 nowadays in the US), the difference in mpg that most people will see is on the order of a few percent. The calorific value of the fuel on a gravimetric basis is very close to normal gasoline (E0). The actual weight per gallon for the E10 is slightly higher than the E0. So it turns out that the real differences are small, and most likely attributable to driving habits, and wishful perceptions..

Agreed as far as 'true' E10 goes. However gasoline does not come mixed in the pipeline with the ethanol, that is delivered separately and then mixed by the tank truck driver by a weight to gallon formula which some of them aren't too good at. Least ways that is how it was explained to me.

When I was specializing on wrenching on the high end German stuff, Benz and BMW we had an ethanol content analyzer. First thing that we would do for weird drivability issues was test the fuel load. It wasn't uncommon to find the content as high as 30-37% on the ones that were really acting up. 15-23% was pretty usual.

I buy the 93 octane premium gasoline that they sell near the lake for boaters. Its got the full complement of additives (anti foaming, detergent, etc), and its blended so that the AKI is at 93. The chances of having a fuel problem with this stuff is somewhere between 0 and epsilon..

That marina fuel *is* some good stuff alright, and it don't have any corn squeezin's in it

BillB

 

[Power-Tripp]

When I was specializing on wrenching on the high end German stuff, Benz and BMW we had an ethanol content analyzer. First thing that we would do for weird drivability issues was test the fuel load. It wasn't uncommon to find the content as high as 30-37% on the ones that were really acting up. 15-23% was pretty usual.

I see similar results locally. Drivers mix ethanol in a portion of the tanker, and may add it first or last. 30-32% ethanol is not uncommon, 15-20% is normal. If ethanol sits in a tank it separates relatively quickly.

Since there seems to be a LOT of confusion as to fuel differences around the western world, I have put this list together with the help of a lot of others.

RON= Research Octane Number (Chemical test) - European/UK/AUS/NZ pump octane number
MON= Motor Octane Number (heated research motor test)
PON= Pump Octane Number (AKI/anti-knock index - R+M/2) - US pump octane number


Europe/UK:
98 Octane____________95 Octane_______________Shell V-Power (typical analysis)
98.3 RON_____________95 RON__________________99.7 RON
86.9 MON____________85.5 MON________________87.9 MON
92.6 PON_____________90.25 PON_______________93.8 PON

AU/NZ:
Actual test data or info from suppliers is scarce to nonexistent, but this data comes from several suppliers.
Premium___________Regular
95 RON____________91 RON
85 MON___________82 MON
90.5 PON__________86.5 PON

US:
Premium 93 ___________________________________________Premium 91
(actual results from 25 stations)___________________________(Actual test results)
98.5 RON________________________________________________96.3 RON
87.9 MON________________________________________________87.9 MON
93.2 PON________________________________________________92.1 PON

Regular 87 (absolute minimum US standard)
91 RON
83 MON
87 PON


While this is not an absolute, and some locations may be higher or lower, I hope this helps clear up the BS.

 

[Molinoman]

Since my manual for the R3T says 87, that's what I put in it. I haven't had the bike all that long but under various conditions, hills, flats, normal speed and "mov'in on out there speed the bike runs steady. I'll stay with 87.

 

[TURBO200R4]

ok that explains it.
you can run 87 and the pdp additive.

 

[El Toro Rosso]

Agreed as far as 'true' E10 goes. However gasoline does not come mixed in the pipeline with the ethanol, that is delivered separately and then mixed by the tank truck driver by a weight to gallon formula which some of them aren't too good at. Least ways that is how it was explained to me.

True. Even more wasteful, they truck the ethanol to the mixing point too. There are very few ethanol compatible pipelines to transport ethanol in the US.

When I was specializing on wrenching on the high end German stuff, Benz and BMW we had an ethanol content analyzer. First thing that we would do for weird drivability issues was test the fuel load. It wasn't uncommon to find the content as high as 30-37% on the ones that were really acting up. 15-23% was pretty usual.

I am a bit surprised with these numbers. The pumps are clearly labeled as "Up to 10% Ethanol" and many vehicles are clearly labeled not to exceed E10. Now that you've brought this point up, I'm going to buy samples at a few local stations and test them myself.

One benefit of running alcohols is that the enthalpy of vaporization is much larger than it is for gasoline, and so the evaporative cooling that takes place tends to improve volumetric efficiency. E10 doesn't have a large enough ethanol component to make much difference, but you guys are talking E30+.

Just thinking out loud here, I wonder if you've got some idiot owners who have bought a tank of E85 because it was so cheap, and then since it gave really lousy mpg figures, they switched back to regular gas. If that happened, you could expect to see some E30+ in gas tanks of misbehaving vehicles.

In some parts of the US, I've read that they have pumps that blend at the actual pump, like Sunoco used to do. So you can buy E10, E20, E85, at the same pump, blended from two onsight tanks. I've never seen this set up in person. If you had that sort of system, I would expect the residual fuel in the pumps and pipes from an E85 fill up to give higher than expected ethanol content in the next customer's order for E10 or E20.

 

[El Toro Rosso]

The factory spec is at the crank. You will loose a bit by the time you get to measure it at the back wheel.

That's a good point, but that would imply 10% loss in the drive train, and that seems high for a shaft drive.

 

[hossman]

Thanks for the replies. I'm going to run the 87 octane the book suggests. No sense wasting money for no performance gains.

 

[MarvinM]

For purposes of my annual bonus, I'd prefer you all to buy V-Power in large quantities...but it really doesn't help the bike, and typically decreases fuel economy on a low compression engine. Across most brands of fuel, the additives are the same across their range, except the octane booster. NEVER buy "unbranded" gasoline for any vehicle (generally seen at large grocery store or department store parking lots). There is typically little or none of the additives (detergents) and they're pretty helpful.

MarvinM

 

[BillB]

I am a bit surprised with these numbers. The pumps are clearly labeled as "Up to 10% Ethanol" .

"I'm from the government and I'm here to help..........."

BillB