What grade gas?
12-17-2013, 12:39 PM
#42
Banned
Join Date: Sep 2013
Location: NYC
Posts: 663
Likes: 0
Received 0 Likes
on
0 Posts
Heres an article I wrote about a year ago for DS regarding octane measurements. It will either clear some stuff up, or confuse you even more.
A little help for those of you outside North America, who get 91, 95, and 98 octane from your pumps.
Octane is rated in multiple ways, RON, MON, AKI. Lets explain them.
RON - Research Octane Number. RON is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing the results with those for mixtures of iso-octane (RON & MON 100 by definition) and n-heptane (RON & MON 0 by definition). This is how they measure gas in most of the world. You'll normally find 91, 95 and 98 octane.
MON - Motor Octane Number. MON is also known as aviation lean octane. MON is a better measure of how the fuel behaves when under load, as it is determined at 900 rpm engine speed, instead of the 600 rpm for RON. MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, 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, however there is no direct link between RON and MON. Normally, fuel specifications require both a minimum RON and a minimum MON.
In the US, we add both RON and MON together and divide by 2 (RON+MON/2)to get our pump octane (87, 89, 91, 93, etc). This is the octane rating that the DiabloSport tunes are based on. Its also known as the AKI, or Anti Knock Index. Because of the 8-10 point difference between RON and MON, the octane rating in the US and Canada is 4-5 points lower then the rest of the world, for the exact same fuel.
RdON- Observed Road Octane Number. Derived from testing gasolines in real world multi-cylinder engines, normally at wide open throttle. It was developed in the 1920s and is still reliable today. The original testing was done in cars on the road but as technology developed the testing was moved to chassis dynamometers with environmental controls to improve consistency. Its rarely used in the automotive world, and most people don't even know it exists.
I hope this clears up the confusion for those of you not in the US/Canada. Use the 91 tune if you use 95 RON octane fuel. Use the 93 tune if you use 98 RON octane fuel.
A little help for those of you outside North America, who get 91, 95, and 98 octane from your pumps.
Octane is rated in multiple ways, RON, MON, AKI. Lets explain them.
RON - Research Octane Number. RON is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing the results with those for mixtures of iso-octane (RON & MON 100 by definition) and n-heptane (RON & MON 0 by definition). This is how they measure gas in most of the world. You'll normally find 91, 95 and 98 octane.
MON - Motor Octane Number. MON is also known as aviation lean octane. MON is a better measure of how the fuel behaves when under load, as it is determined at 900 rpm engine speed, instead of the 600 rpm for RON. MON testing uses a similar test engine to that used in RON testing, but with a preheated fuel mixture, 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, however there is no direct link between RON and MON. Normally, fuel specifications require both a minimum RON and a minimum MON.
In the US, we add both RON and MON together and divide by 2 (RON+MON/2)to get our pump octane (87, 89, 91, 93, etc). This is the octane rating that the DiabloSport tunes are based on. Its also known as the AKI, or Anti Knock Index. Because of the 8-10 point difference between RON and MON, the octane rating in the US and Canada is 4-5 points lower then the rest of the world, for the exact same fuel.
RdON- Observed Road Octane Number. Derived from testing gasolines in real world multi-cylinder engines, normally at wide open throttle. It was developed in the 1920s and is still reliable today. The original testing was done in cars on the road but as technology developed the testing was moved to chassis dynamometers with environmental controls to improve consistency. Its rarely used in the automotive world, and most people don't even know it exists.
I hope this clears up the confusion for those of you not in the US/Canada. Use the 91 tune if you use 95 RON octane fuel. Use the 93 tune if you use 98 RON octane fuel.
Thread
Thread Starter
Forum
Replies
Last Post
kreativecid
Q5/SQ5 MKI (8R) Discussion
16
10-04-2021 12:30 PM
Monsoonenough
S4 (B8 Platform) Discussion
3
10-03-2015 02:59 PM
Ray_QT
Q5/SQ5 MKI (8R) Discussion
21
10-02-2015 01:50 AM
