Extra 16bhp from Fuel
Rennlist Member
Joined: Jun 2001
Posts: 3,881
Likes: 164
From: California Boardwalk, Skanderborg Denmark
The owners manual for a 964 is confusing in that it states that one must use at least 95 RON or 90 AKI= HR+M/2 octane, then goes on to contradict itself by stating that the knock control system allows operation with a R+M/2 fuel = 87 octane for "temporary use".
The owners manual for a 993 clearly states that it is optimized for 93 octane R+M/2, and that fuels as low as 90 R+M/2 could be used.
The Supplement to the Drivers Manual 911 Carrera RS states: "The engine is designed to provide optimum performance and fuel consumptin if unleaded premium fuel of 98 RON/88 MON is used. If unleaded premium fuels with octane numbers of at least 95 RON/ 85 MON are used, the engines's knock control system automatically adapts the ignition timing."
So, deciphering this I would think that:
The normal 964 is optimized for 90 R+M/2 fuel and would probably not benefit from any increase in octane above that and can run on as low as 87 octane R+M/2 fuel.
The 993 and Euro RS will run on 90 R+M/2 but will make more power up to 93 octane fuel.
The owners manual for a 993 clearly states that it is optimized for 93 octane R+M/2, and that fuels as low as 90 R+M/2 could be used.
The Supplement to the Drivers Manual 911 Carrera RS states: "The engine is designed to provide optimum performance and fuel consumptin if unleaded premium fuel of 98 RON/88 MON is used. If unleaded premium fuels with octane numbers of at least 95 RON/ 85 MON are used, the engines's knock control system automatically adapts the ignition timing."
So, deciphering this I would think that:
The normal 964 is optimized for 90 R+M/2 fuel and would probably not benefit from any increase in octane above that and can run on as low as 87 octane R+M/2 fuel.
The 993 and Euro RS will run on 90 R+M/2 but will make more power up to 93 octane fuel.
Rennlist Member
Joined: Jun 2001
Posts: 3,881
Likes: 164
From: California Boardwalk, Skanderborg Denmark
Correct, increasing octane above the optimization point will make no more power, using lower octane will probably lower power though.
In general the knock sensor system will tolerate a R+M/2 octane number of 3 less than the optimum for the engine.
In general the knock sensor system will tolerate a R+M/2 octane number of 3 less than the optimum for the engine.
Three Wheelin'
Joined: Jan 2005
Posts: 1,328
Likes: 2
From: Rossendale, UK
I know this isn't very scientific but i run my Turbo in the UK on Optimax 98 RON despite Porsche saying it can run on Unleaded 95 RON. This is as on the one occasion i did this it was so sluggish that i thought the fuel pump was broke.
I have used V-Racing (V-Power) fuel from Shell which is standard premium fuel in some Eastern Bloc countries rated at 100 RON. Without any actual tests done the car did feel more responsive under acceleration but consumption was effected compared to normal Optimax use.
I have used V-Racing (V-Power) fuel from Shell which is standard premium fuel in some Eastern Bloc countries rated at 100 RON. Without any actual tests done the car did feel more responsive under acceleration but consumption was effected compared to normal Optimax use.
