Gas octane

pafbsoftball · Jul 1, 2008

Tankereng said:
I've heard that lower octane = lower mileage. I haven't tested this myself. Perhaps on the next tank. Just filled up this morning...

Since premium around here is 93 octane, I started doing a 50/50 mix of 89 and 93 octane gas. Although this is by no means scientific, I got 2mpg better with the 50/50 mix than the full 93 octane. There could be a couple of reasons for this. I could be subconciously driving differently and the daytime tempeatures have reached the summer norm. But reguardless, I have noticed at least if not better milage with a lower octane fuel. I normaly was getting around 38 - 39 mpg on my weekly travel to work. Now it is in the 39 - 40 range. I've only done this for two tanks of fuel.

RobsTV · Jul 2, 2008

I hate to keep bringing up the E10 connection, but it keeps falling into the mix.

E10 is an octane booster, and is used as such by oil companies.
I have seen pumps at a station where only mid-grade and premium were labeled Ethanol added, with the regular pump 87 not having ethanol added. If all they are doing is taking cheap gas and using different amounts of ethanol to increase the octane for resale as premium, then that might be why performance when using 93 octane is actually worse than when using lower octane.

In my '93 ST1100 I have a choice, as it only calls for 87 octane. I definetly get worse gas mileage when I run 93 octane in it. I do run 93 octane in my car (Mark VIII) and van ('70 BBBuick 455 powered), so would use 93 if it even ran the same as 87 in the bike. But it is worse with 93.

OldBlue · Jul 2, 2008

My :tc1:

When I picked up my '07, the dealer had filled it, but with 87 octane. I did notice some pinging, but didn't realize until later that they had put in 87 octane. On my first fill-up, I put in 92 (my choices here are 87, 89, 92, 94, or racing fuel), and noticed an improvement in performance.

For the following fill-up, I put in 87 again, recorded the mileage on the highway, did it again with 92, and noticed 3 to 4 mpg improvement with the 92 octane fuel. Here in Northern Ohio, there is a $.10 difference in the price between regular & mid-grade, and another $.10 between mid-grade and premium. Let's not talk about the price of the racing fuel, which is unnecessary in the ST

.

IF my ST was completely empty, you're talking a increase of $1.54 between regular and premium for a tank of fuel. I'm guessing my annual mileage between 8k and 10k per year, so for me, it's a no-brainer (which I've been accused of

). I'll use the 92. I haven't spent the time to do the math, but I'm ok with the difference in the price. Remember, YMMV!!

sroddy7855 · Jul 4, 2008

mitch96 said:
What I don't get is the FJR and the ST have close to the same compression ratio and the ST needs premium..........

Hummmmmmmmmmm

mitch

It's not just compression I've seen bikes with 12:1 compression that run on 89. Valve and ignition timing are big factors,also the size and shape of the compression chamber and piston top,plug angle etc. To many varibles to second guess the engineers. If you run the low octane long enough it will cost you(or next owner) more than you will save. As someone else said Honda has nothing to gain by recommending 93,there's probaly a few folks that didn't buy for that reason alone.

racer1735 · Jul 5, 2008

So here's another spin on the question. I've moved to othe Texas Panhandle, which is considered to be at 'some' elevation. As such, VERY few stations have 91 octane. It's 86, 88 and 90. Which leads me to believe that at elevation, octane requirements are lower, but I have no proof for that thought, other than it is the norm up here. Both the ST and my car supposedly take 91. Anyone with an answer?

Blue STreak · Jul 5, 2008

You're correct, Racer:

http://en.wikipedia.org/wiki/Octane_rating#Regional_variations

"The reason for this is that in higher-altitude areas, a typical combustion engine draws in less air per cycle due to the reduced density of the atmosphere. This directly translates to reduced absolute compression in the cylinder, therefore deterring knock. It is safe to fill up a car with a carburetor that normally takes 87 AKI fuel at sea level with 85 AKI fuel in the mountains, but at sea level the fuel may cause damage to the engine. A disadvantage to this strategy is that most turbocharged vehicles are unable to produce full power, even when using the "premium" 91 AKI fuel."

racer1735 · Jul 6, 2008

Thanks, Bob! I was using excess gas driving around town trying to find the one station that carries 91. Guess 90 is the way to go.

willie2323 · Jul 8, 2008

Never a problem with my 05 running 87 octane with either pinging, mileage or power but then I am 155lbs soakiin wet and short shift all the time. I commute 55 miles daily here in phoenix with both my 1100 and 1300.

Bill

darren10000 · Feb 22, 2015

This is an old thread but here in the UK the normal Gas is Unleaded 95 and the Super is 98 or 99. I always run my Bikes on 99 and they love it

kevhatch · Feb 25, 2015

darren10000 said:
This is an old thread but here in the UK the normal Gas is Unleaded 95 and the Super is 98 or 99. I always run my Bikes on 99 and they love it

95 for me every time. I don't think there is any benefit in using Super except to lighten the load on your wallet! Not sure what the price of fuel is like in the UK these days ( I escaped

) but here in France I pay 1.326 € (97p)/ L for 95 - 1.369 € (?1) / L for 98. Mounts up if you do some miles.

Superzuki · Feb 25, 2015

darren10000 said:
This is an old thread but here in the UK the normal Gas is Unleaded 95 and the Super is 98 or 99. I always run my Bikes on 99 and they love it

Your octane is measured differently. It's all about the same.

darren10000 · Mar 4, 2015

kevhatch said:
95 for me every time. I don't think there is any benefit in using Super except to lighten the load on your wallet! Not sure what the price of fuel is like in the UK these days ( I escaped ) but here in France I pay 1.326 € (97p)/ L for 95 - 1.369 € (?1) / L for 98. Mounts up if you do some miles.

It's currently ?1.07 litre of 95 and ?1.11 for the Super 99, it did peak at ?1.48 a couple of years ago which worked out at $10.75 per Gallon for our US friends, so never moan about Gas prices in the US. Diesel is even more expensive, LPG is the way to go as it's not taxed only 60p a litre but I don't fancy strapping a 15kg Propane bottle on my rack

CDNolddude · Sep 19, 2017

Rather than starting a new thread, I thought I would just add to this one. Always use premium here which is 91 octane. 94 is rare here but available. Just got back from 8 day 4500klms trip and mostly used 94 at petro Canada stations in Canada and 93 premium in the north east. States because they didn't have 91. Did not really notice a performance boost but the engine did run smoother than it ever has. Big difference when cruising at 4300-4500 rpm, making it more enjoyable

Oldbikefixr · Sep 19, 2017

roginoz said:
My '93 1100 was happy with regular, which I believe was specified by Honda.

I have used 86 octane numerous times in my 1991. No problems. Recently higher octanes have been unavailable locally...I'm assuming it's a post hurricane recovery problem.

CDNolddude · Sep 20, 2017

Mine is an ST1300 which calls for premium. Doesn't the ST1100 call for regular?

DeanR · Sep 20, 2017

CDNolddude said:
Mine is an ST1300 which calls for premium. Doesn't the ST1100 call for regular?

yep..

Jjonahjamison · Sep 22, 2017

CDNolddude said:
Rather than starting a new thread, I thought I would just add to this one. Always use premium here which is 91 octane. 94 is rare here but available. Just got back from 8 day 4500klms trip and mostly used 94 at petro Canada stations in Canada and 93 premium in the north east. States because they didn't have 91. Did not really notice a performance boost but the engine did run smoother than it ever has. Big difference when cruising at 4300-4500 rpm, making it more enjoyable

FYI, PetroCan's 94 is achieved using an ethanol blend to increase octane, so if you are looking to avoid ethanol, avoid PetroCan.

CDNolddude · Sep 22, 2017

Too much work trying to avoid ethanol. Canadian tire is one of the only ones that say their 91 is ethanol free out here

cdnemsguy · Sep 22, 2017

I have run premium, I mostly run regular. I do not see any difference in anything as these bikes are not high compression race bikes with wild cams. The other thing is that you can pay for premium, but the first hose full and a half are whatever the guy filling before you used. The guy behind you will get the residual hose and a half from your fill. A rip off IMO the way they can dispense from one hose all the flavors of fuel. Also, do you feel that many motorist are burning the high octane higher priced fuel? If not, that high priced fuel will sit in the gas stations tanks for awhile I would think. I am and will still burn regular.

Gerhard · Sep 22, 2017

CDNolddude said:
Too much work trying to avoid ethanol.

Shell premium is no ethanol, lawnmower, snowblower, generator and bike get that most of the time.

Gerhard

Gas octane

Bob Meyer