RON vs. Octane (US vs. Europe) Differences explained? - Rennlist - Porsche Discussion Forums

Go Back  Rennlist - Porsche Discussion Forums > Air/Oil Cooled Technical Discussion Areas > 993 Forum
Reload this Page >

RON vs. Octane (US vs. Europe) Differences explained?

Notices

RON vs. Octane (US vs. Europe) Differences explained?

Reply

Old 05-08-2006, 02:08 PM
  #1  
ceboyd
Addict
Lifetime Rennlist
Member
Thread Starter
 
ceboyd's Avatar
 
Join Date: Jan 2004
Location: Mount Prospect, IL
Posts: 4,495
Question RON vs. Octane (US vs. Europe) Differences explained?

Can someone tell me if this is correct:

These are different octane blends, rated with the same method, the US method.

EU ratings are 95/98, which are equivalent to US ratings of 91/93.

So, EU 95 octane = US 91 octane and EU 98 octane = US 93 octane.


Top performance with EU 98 octane = 93 US octane.
Small loss in performance with EU 95 octane = 91 US octane.


So on a 993, it needs minimum 91 US octane.
ceboyd is offline  
Reply With Quote
Old 05-08-2006, 02:29 PM
  #2  
przt
User
 
przt's Avatar
 
Join Date: Apr 2006
Location: Lithuania, Europe
Posts: 29
Default

RON Reaserch Octane Number. (Used in Europe and elswhere in gas stations)
MON Motor Octane Number.
AKI Anti-Knock Index. This is the number that is posted on the gas station in the USA as "Octane". It is derived as (RON + MON)/2
przt is offline  
Reply With Quote
Old 05-08-2006, 02:51 PM
  #3  
brucec59
Addict
Rennlist Member
 
brucec59's Avatar
 
Join Date: Nov 2004
Location: San Francisco
Posts: 1,796
Default

Seems the highest octane I can find anywhere in NorCal is 91 (with the exception of the 100 octane stuff). Is 93 available commercially? What about octane booster additives? Or should I just forgetaboutit and keep driving?

Thanks.
brucec59 is offline  
Reply With Quote
Old 05-08-2006, 03:52 PM
  #4  
STLPCA
Addict & Guru
Rennlist Member

 
STLPCA's Avatar
 
Join Date: May 2001
Location: St. Louis
Posts: 3,885
Default

Chris - you are correct. Using 91 AKI gas should result in a slightly retarded ignition w/a resulting loss of power on a stock NA 993.

As you know, the "octane number" is a measure of a fuel's anti-knock (or pre-ignition) characteristics.

There are different accepted standards used to measure the anti-knocking characteristics of gas. The octane number you see at US pumps is the average of two such octane numbers; the Research Octane Number (RON) and the Motor Octane Number (MON). This average number is sometimes referred to as the Anti Knock Index ("AKI") or the US Cost of Living Council method ("CLC"). The RON and MON numbers are determined by American Society for Testing and Materials ("ASTM") laboratory tests. Thus, US octane numbers are described as, e.g., 93 AKI or 93 CLC. The equivalent RON number in other countries would be 98.

The RON method determines low speed and low load knock characteristics while the MON method tests high speed, high load, high temperature conditions such as exist during periods of high speed power accelerations, hill climbing, or any period of high power output. The MON method results in a higher octane number & is the more relevant value for racing.

Maybe more than you asked, but ... .
STLPCA is offline  
Reply With Quote
Old 05-08-2006, 03:59 PM
  #5  
ceboyd
Addict
Lifetime Rennlist
Member
Thread Starter
 
ceboyd's Avatar
 
Join Date: Jan 2004
Location: Mount Prospect, IL
Posts: 4,495
Default

o.k. thank you very muchfor explaining.

I know out west it seems more diffucult to get 93 octane at the local station but here in the midwest almost every gas station carryies 93 octane (only the cheapie gas stations carry 92 instead of 93) and some even carry 94 octane (like Sunoco for example)
ceboyd is offline  
Reply With Quote
Old 05-09-2006, 03:18 AM
  #6  
nonzerosum
User
 
nonzerosum's Avatar
 
Join Date: Nov 2003
Location: Canada
Posts: 26
Default

In Alberta, Canada - even though we are the oil capital of Canada, all of our fuel >91 octane has ethanol, which I have read may be a problem for our cars.

I've also read that you can consider the fuel's octane rating to be 1 higher for every thousand feet of altitude above sea level. I am only a lowly doctor. Any engineers out there to enlighten me?
nonzerosum is offline  
Reply With Quote
Old 05-09-2006, 03:23 AM
  #7  
ceboyd
Addict
Lifetime Rennlist
Member
Thread Starter
 
ceboyd's Avatar
 
Join Date: Jan 2004
Location: Mount Prospect, IL
Posts: 4,495
Default

so wait? The 10% ethanol in our 93 octane (been there for years) is bad for our cars????????
ceboyd is offline  
Reply With Quote
Old 05-09-2006, 03:28 AM
  #8  
nonzerosum
User
 
nonzerosum's Avatar
 
Join Date: Nov 2003
Location: Canada
Posts: 26
Default

Something about ethanol being hygroscopic and drying out seals. Like I said, any engineers out there to help shed light on this?
nonzerosum is offline  
Reply With Quote
Old 05-09-2006, 03:51 AM
  #9  
nonzerosum
User
 
nonzerosum's Avatar
 
Join Date: Nov 2003
Location: Canada
Posts: 26
Default

hmm, just did a search. Try Steve W. of Rennsport Systems' posts about potential problems with ethanol and rubber seals. It may not really be an issue until our cars really age. But I'm still not clear if the 91 octane sold here (about 2.5k feet above sea level) can be considered about 92.5 octane on the coast.
nonzerosum is offline  
Reply With Quote

Thread Tools
Search this Thread
Quick Reply: RON vs. Octane (US vs. Europe) Differences explained?


Contact Us Advertising Cookie Policy Privacy Statement Terms of Service

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: