Unleaded or lead replacement fuel?

[repenttokyo]

um no one in north america can buy leaded fuel at the pump outside of anairport.

[repenttokyo]

I never use anything less than Octane 99 on my car.... which is widely available here in the UK....

I havent had the chance to use our new Octane 102 as its only available in a few select stations at the moment...


remember, your octane ratings are different than ours.

[repenttokyo]

yeah I know yours is lower.. I couldn't imagine it!


Like Dave said - no, it's not lower. It's just measured differently.


The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing these results with those for mixtures of isooctane and n-heptane.

There is another type of octane rating, called Motor Octane Number (MON) or the aviation lean octane rating, which is a better measure of how the fuel behaves when under load. MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, a higher engine speed, and variable ignition timing to further stress the fuel's knock resistance. Depending on the composition of the fuel, the MON of a modern gasoline will be about 8 to 10 points lower than the RON. Normally fuel specifications require both a minimum RON and a minimum MON.

In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and even deliver 98 (RON) or 100 (RON).

[525iZA]

So the guy I bought my '92 525i from swears that the car can only run on LRP, but I filled up with unleaded 93 and the car runs fine.

What do you guys use?

[pgrindstaff]

I always fill with mid 89 or premium 91/93. I have not tried leaded 87 in my car nor do I intend to.

[Jon K]

um no one in north america can buy leaded fuel at the pump outside of anairport.

Sure they can :) C16 @ the track :) BAM!

[whiskychaser]

So the guy I bought my '92 525i from swears that the car can only run on LRP, but I filled up with unleaded 93 and the car runs fine.

What do you guys use?
My owners manual (stamped by a garage in Cresta, ZA) states:
Super (premium) petrol containing lead to DIN 51600 standard, minimum octane 93 (research method).
I never even looked until you asked the question:) I use bog standard unleaded and have no problems. LRP hasnt been around for years here

[glen-sj]

BMW recommends unleaded premium and I'm using unleaded premium for my 92 525ia here in Calif.

[Spice Boy]

I never use anything less than Octane 99 on my car.... which is widely available here in the UK....

I havent had the chance to use our new Octane 102 as its only available in a few select stations at the moment...

[Spice Boy]

yeah I know yours is lower.. I couldn't imagine it!

[whiskychaser]

I never use anything less than Octane 99 on my car.... which is widely available here in the UK....

I havent had the chance to use our new Octane 102 as its only available in a few select stations at the moment...
You might find this article of interest. Especially the bit about no engine needing more than 98:D
http://www.petrolprices.com/about-fuel.html

[Dave M]

yeah I know yours is lower.. I couldn't imagine it!

Lower rating, not actual value.

[Ken35i]

We have 92, 95 and 98RON here in Aus. I use 98...well I did and I will when the car's up and running. :p
Also have, I think it is, 100RON but it''s hard to find. It has ethenol in it.

Oh btw...really confusing finding who posted first in this thread.:(