Octane

[MikeFossl]

I'm on my second tank of "mid" grade fuel, 89 octane in Canada.  I didn't notice any difference.  

According to the Haynes manual, the US model has a lower compression.

Is everyone else using premium fuel?

Thanks,
Mike

[Tony Smith]

I'm on my second tank of "mid" grade fuel, 89 octane in Canada.  I didn't notice any difference.  

According to the Haynes manual, the US model has a lower compression.

Is everyone else using premium fuel?

If I may I'd like to partially hijack your thread, I'm interested in what fuels are actually in use around the world.


In my corner of Australia you have the choice of:-

"Standard ULP" = 92 Octane
"E10" (10% ethanol) = 94 Octane
"Hi-Octane" = 94~96 octane depending on brand
"Premium" = 98 Octane (not available in all brands"
"Opal" =  91 Octane. Modified  Avgas with a Green dye - sold in some communities where petrol sniffing is endemic - the lower volatility of Opal makes it useless for sniffing.


Avgas 100 Octane "Low Lead" aka IATA 100LL. A misnomer as although a "low lead' fuel by aviation standards, it still has more than twice as much TEL in it than the old leaded "super" ever had.


I'd be interested what fuels are generally available elsewhere.


For the record my R65 runs 1979/80 pistons in iron bores with heavily modified heads that fortunately have more or less post 1981 combustion chamber volume - I am therefore running slightly less compression than a stock post 1981, but more than a 1979/80.

My R65 loves Avgas, and feels quite "snappy" with it but as it is expensive and illegal to run in a road going vehicle, it is a rare treat.

It runs just fine on 92 Octane. Every once in a while I treat it to a tank of PULP, generally because all the other pumps are in use and the extra $2.50 for a tank full doesn't worry me.

Can't say I notice too much difference in performance on PULP, but i imagine that it is there.

Following two very, very annoying and expensive outcomes following the use of ethanol blends in motorcycles I will not use E10 under any circumstances.

I use "valve saver" lead replacement additive, more out of hope than anything else. I try to keep 20 lt of Avgas on hand and throw a litre or so in every few tankfuls, hopefully one or the other will stave off valve seat recession.  

[Barry]

In the UK our standard unleaded with 5% ethanol is 95 Octane (Ron).  This is very marginal with the high compression engines with one fill being fine then another will ping a little.  Can't imagine using anything of a lower octane.

Super unleaded in the UK is 98 Ron.


Mike,

Because the US and Canada use a different octane rating system (Ron + Mon/2) your 89 would be approx. equivalent to 94 Ron.  That might well ping on a high compression engine.

I think most of the rest of the world uses a Ron octane rating.

[Burt]

Tony,

AVGAS was due to be retired in 2014 and one of the reasons our Air Force finally withdrew the DHC Caribou from service.  The fuel (and quality) was becoming more and more unreliable throughout Oz.  We used 100LL but in days gone by used higher octane ratings.  

As for the general aviation running all their reciprocating engines on AVGAS, they have now moved over to normal motor vehicle fuel (the cheapest option).  However you have to calculate the octane rating (?) to work out which grade you require for the various engines.  I was told the formula once but have since forgotten it.  

In days gone by the Air Force had a policy of not re-using fuel once an aircraft was defueled for maintenance purposes and stored prior to disposal.  Apparently the trick was to mix no more than 50% AVGAS in your car fuel tank.  How that happened I do not know.    

So all the commercial aircraft running gas turbine engines use AVTUR which is essentially aviation kerosene.  

Also, I am told, that due to the higher burning temperature and chemical additives of AVTUR it was not a good solution for cheap fuel in a kerosene heater in winter if you wanted the heater to survive.  Not to mention the toxic stink.  

Slightly off topic so grab all the AVGAS you can.  Don't know how long it lasts in storage but it is a good cleaning agent.  

Dave.

[montmil]

A recent posting from Bob Fleischer on AirList discussing avgas in motorcycles suggested adding no more than one (1) cup of aircraft fuel to your cycle's tank. Bob also mentioned that avgas, properly stored in a sealed container, will remain 'fresh' for five years. Unsure if he has this info on his website. Suggests small airports and helpful line boys as avgas sources.

[Warbucks]

I used to work at Williamtown RAAF Base many years ago. The Dassault Mirage III was using aviation kerosene at the time and all of the staff living on the base were using it to fuel kerosene heaters. We used a kerosene heater at home and ran it on household kerosene. It would need to be cleaned every week due to the element being clogged with black soot. The heaters at the base did not need cleaning. The element would turn white, but I don't recall them having a "toxic stink". The heater at home was heaps worse.

I assume that at the RAAF base they were not concerned about replacing the heaters because they are Government funded and therefore tax exempt. One thing I found out while I was there is that each year the Air Force is allocated a huge sum of money so that it can operate. However, if that that allocated money is not used, that military base will have it's annual funding cut.

Surplus fuel and ammunition that is left over at the end of the financial year is therefore disposed of out on the bombing range. This ensures that the base will be allocated the same funding for the next financial year.

As for my R65 and also my car; Premium 98 octane is all that I use. Every 6 months I'll add a bottle of Wynn's Spitfire Fuel System Cleaner to the tank. I haven't had any problems with that.

http://www.wynns.net/

[Luca]

I use premium 93 (ron+mon)/2

I know the engine will run on lower grade gas, but I'm pretty sure premium grade fuel has stabilizer added to it in its additive package.  I don't winterize my bike and I've never had any trouble in the spring with stale gas or water in the fuel.  I've also heard rumors that it doesn't contain the full 10% ethanol.

[montmil]

Reading here and on several other Airhead sites and forums about our Northern USA brethren prepping their bikes for a long winter's nap. Here in Tejas, the good news is that there are very few non-rideable days during our rather brief season that passes for winter. The bad news is, well, there's really no bad news.

I've always run regular-grade in the R65s. The R100S gets the higher octane fuel as does the Triumph 900. Shell premium seems to be popular with the street tracker rowdy crowd. I may try a splash of avgas in my lawn equipment just to see how that goes as their is less yard work done during the cooler weather. El Niño may have something to contribute this year.

[mrclubike]

I run the highest octane I can get at the pump
I think I would have pinging if I didn't

[Motu]

In New Zealand we have regular at 91, premium at 95 and also 98 at some stations. I use 91 in my R65, never used anything else.  Only one fuel company has an E10 premium, have never gone anywhere near that.   Turn of the century I had a Falcon that would only stop pinging on 98, but could mix it with 95 for just one tank.  Close to a race track near me you can buy race fuel at the pump, but only in a container, not in a vehicle.  When I worked in the city I would often detour through that town on the way home and pick up 10 litres...my DT230 at the time used to love it.

[Bob_Roller]

I need to use  ' premium ' grade fuel, 91 octane in the hot weather, or the R65's and oilhead detonate on heavy throttle use .
During the cool weather, ' regular ' 87 octane works fine .
This explains the different rating systems used for octane rating .

https://en.wikipedia.org/wiki/Octane_rating

[k_enn]

I use premium 93 (ron+mon)/2

I know the engine will run on lower grade gas, but I'm pretty sure premium grade fuel has stabilizer added to it in its additive package.  I don't winterize my bike and I've never had any trouble in the spring with stale gas or water in the fuel.  I've also heard rumors that it doesn't contain the full 10% ethanol.

I am sort-of with Luca.  I use the 93 (ron+mon/2) in both of my bikes.  Around here, you cannot get gas that does not contain ethanol, I have heard from several sources that the 93 does not contain as much ethanol.  Ethanol is not your friend on these old bikes.

I depart when it comes to winterizing.  For many years, I did not winterize it.  Then, a few years ago, a couple of seasons after ethanol became required, I had the tank rust out due to condensation.  The ethanol attracts water, which will settle out to the bottom of the tank and corrode it.  Now, I either drain the tank or treat it for storage (dry-gas, or seafoam).  

k_enn

[Bob_Roller]

Auto fuel for on road vehicles, contains 10% ethanol in the US, there is no difference regarding different grades of fuel .
It's added at the refinery before it goes into the distribution pipelines .

[JBwell]

Bob Roller I am somewhat confused.  Do all grades of pump gas contain 10% ethanol?  I am in Iowa, we have 3 choices at the pump.  Unleaded with 10% ethanol, and two other grades that are higher octane but supposedly do not contain any ethanol.  Do the two other grades contain a lower percentage?  

[montmil]

I have seen gas stations in southern Oklahoma that sell No-Ethanol gasoline. Could be that Iowa has a similar situation. As a major producer of corn being raised as a fuel additive, and thereby removing the product from our Nation's food chain, some states may be playing back-room games to their citizens benefit. Just my humble opinion