Fuel Recommendation; Fuel Filler Cap - Porsche 928 1980 Owner's Manual

Fuel filler cap

The fuel filler cap is located under the flap in
the rear quarter panel behind the right rear
wheel.
When putting the cap back on the fuel filler
neck, be sure cap is securely seated. Twist
cap counter-clockwise, until it stops with an
audible click.
We recommend you turn off the engine
when filling the fuel tank.
56
Fuel tank capacity
Fuel tank capacity is listed under "Filling
Capacities".

Fuel Recommendation

Your Porsche is equipped with a catalytic
converter and must use UNLEADED FUEL
ONLY. Minimum octane rating is 91 RON
(87 CLC rating on U.S. fuel pumps).
The use of UNLEADED FUEL ONLY is criti-
cally important to the life of the catalytic con-
verter. Deposits from leaded gasolines will
ruin the converter and make it ineffective as
an emission control device.
Cars with a catalytic converter
smaller fuel tank opening, and gas station
pumps have smaller nozzles. This will pre-
vent accidental pumping of leaded fuel into
cars with a catalytic converter.
Unleaded fuels may not be available outside
the continental U.S. and Canada. Therefore,
we recommend you do not take your car to
areas or countries where unleaded fuel may
not be available.
Porsche recommends not to use any fuel
additives.
Octane ratings
Octane rating indicates a gasoline's ability
to resist detonation. Therefore, bying the
correct octane gas is important to prevent
engine damage.
Regular fuels have an octane rating ranging
from 91 to 95 RON (Research Octane Num-
ber), which corresponds to 87 to 91 CLC
(U.S. Cost of Living Council octane rating).
The 91 RON octane rating which you will find
on a label on the right side of the engine
compartment of your car is based on the re-
search method. The CLC octane rating usu-
ally displayed on U.S. gasoline pumps is
calculated as research octane number plus
motor octane number, divided by 2, that is:
RON + MON
have a The CLC octane rating is usually 4 points
lower than the RON rating:
91 RON equals
95 RON equals
Never carry additional fuel in portable
containers in your car. Such containers,
full or partially empty, may leak, cause an
explosion, or result in fire in case of a
collision.
2
87 CLC
91 CLC