Octane levels
06-04-2009, 06:11 PM
#2
4th Gear Member
Join Date: Mar 2009
Location: NJ
Posts: 1,110
http://www.carmemories.com/cgi-bin/v...erience_id=232
My guess is Premium and that would be 93-94 Octane at most US gas stations
My guess is Premium and that would be 93-94 Octane at most US gas stations
06-04-2009, 10:51 PM
#3
6th Gear Member
Join Date: Apr 2007
Location: California
Posts: 10,468
Which 302? Chances are it'll run on crap low octane fuel. The engines of that day in most cases were modest compression and had poor cylinder filling, so detonation isn't really an issue, provided it's tuned right.
06-04-2009, 11:03 PM
#4
3rd Gear Member
Join Date: Aug 2007
Location: New Jersey
Posts: 588
in my original 1968 manual my 289 needs 93 octane...and that was regular back in the day...so basically you need something around that. ive found that when i run my 289 on 87 it doesnt run as strongly as with higher octane
06-05-2009, 12:55 AM
#5
6th Gear Member
Join Date: Apr 2007
Location: California
Posts: 10,468
You're not going to feel the car running worse on lower octane fuel unless it either detonates, or if it's EFI and the computer is pulling timing. Fuel quality matters a lot more. Depending on where you get fuel, the higher octane usually has better additive packages, so it tends to be cleaner. Higher octane fuel will make your car run slower though(but the difference between 87 and 93 may only be noticed at the track), higher octane fuel has more resistance to ignition and burns slower.
In extreme cases too much octane can actually destroy an engine. Running 115 in a 9:1 engine for example can result in the fuel not igniting properly and not burning completely, and you can get liquid fuel up in the ring lands and unseat the rings, which results in flutter and fubars the rings and cylinder walls. Plus it acts as a solvent and washes oil off the cylinder walls.
In extreme cases too much octane can actually destroy an engine. Running 115 in a 9:1 engine for example can result in the fuel not igniting properly and not burning completely, and you can get liquid fuel up in the ring lands and unseat the rings, which results in flutter and fubars the rings and cylinder walls. Plus it acts as a solvent and washes oil off the cylinder walls.
06-06-2009, 09:51 PM
#10
2nd Gear Member
Join Date: Oct 2008
Location: CO
Posts: 224
In the "old days" when these cars were built gasoline was rated at Research Octane Number (RON), not Motor Octane number (MON) which is much lower.
Now the Octane rating at the pump is an average of the two (RON+MON)/2, and is known as Pump Octane Number (PON).
This should be on a sticker on the gas pump at your local station.
IIRC, PON relates to about 3 points off RON, but a quick google search on the above terms will get you the actual percentages.
http://en.wikipedia.org/wiki/Octane_rating
Now the Octane rating at the pump is an average of the two (RON+MON)/2, and is known as Pump Octane Number (PON).
This should be on a sticker on the gas pump at your local station.
IIRC, PON relates to about 3 points off RON, but a quick google search on the above terms will get you the actual percentages.
http://en.wikipedia.org/wiki/Octane_rating
Below seems to be a decent article comparing the numbers:
http://www.btinternet.com/~madmole/R...RONMONPON.html