The official memo from Porsche states 944 1982-85 must use 98 (97) ron only and cannot be adjusted so super unleaded is preferable or if not available use L R P With any Porsche, lead is not the issue its the octane rating As a point of interest the only water cooled Porsche that will not run on regular unleaded is 944 1982-85 (source; Porsche tec. bulletin 25/05/99) regards Bert Gear - 20th June, 2000
I have done some research and in all of the 944S2 related material I have,
the same answer is given in that you can safely run your car on unleaded fuel.
Indeed, I bought my S2 a year ago and have only ever used unleaded. Below is
an extract from the Dec 99 edition of 911 & Porsche World magazine, in which
the whole issue of unleaded fuel, was examined:
"The UK's familiar star rating for petrol was introduced in 1967. Initially
four grades were available: 2* 90 octane 3* 94 octane 4* 97 octane 5* 100 octane
The higher the octane rating (and thus the number of stars), the greater was
the fuel's ability to resist knock (pinking). Significantly 5* petrol disappeared
as long ago as 1977 - to the undisguised horror of many owners of high-compression
sports cars - as the environmental lobby began to raise the first concerns about
the level of lead in the atmosphere. Two and three star were discontinued in
1989, leaving 4* as the only leaded fuel. Unleaded was first introduced to the
UK in 1985 by the way.
Today then the following types of petrol are sold in the UK: 4* LRP (leaded
replacement petrol) 95-97 octane Premium unleaded 95 octane Super unleaded 98
octane You will often see the octane rating shown as RON, which stands for Research
Octane Number. Unfortunately this isn't standard throughout the world. In some
EU countries you may find what is known as Regular Unleaded (or it's local language
equivalent) with an octane rating as low as 91-RON, and you might even see 98-RON
unleaded branded as Premium!"
The following is an extract from the first page of my 1989 S2 owner manual:
Fuel Octane Rating Cars with catalytic converters: Only unleaded premium fuel
DIN 51607, minimum 95 RON / 85 MON Cars without catalytic converters: Unleaded
premium fuel to DIN 51607 or leaded premium fuel to DIN 51600, minimum 95 RON
/ 85 MON
So I would say that it is quite safe to use ordinary Premium Unleaded in your
S2 as this meets the minimum RON specified by Porsche. I would also add that
if you take the car abroad, because of the confusion over octane ratings do
as I do and always use the higher RON, which will do no harm and ensures that
you do use the minimum specified. If you would like any further confirmation
of this I suggest that you either contact your nearest Official Porsche Center
or speak to Bert Gear the 944 register tech advisor on 01271 866818 - Martyn
C - 20th June, 2000
My 1989 S2 normally runs on standard 95 Ron unleaded, however recently I had to fill it with 98 Ron Super unleaded (the garage was out of standard). I was expecting the car to run a little better and it did seem to have more ooomph (though this could be imagined), but I was very surprised to find the MPG consumption was much better. For example, I usually fill up just before the 'red zone' putting in 14 gallons (63 litres) having done about 400 miles. However with the tank full of Super I managed to get to 450 miles before having to fill up by the same amount. This equates to over 10% better consumption!!! When you take into account that Super Unleaded is only 5% more expensive (90p per litre as opposed to 85p per litre in Northampton) then this is definately the more sensible option. I have since filled up twice more with Super and got the same mileage, followed by one tank of standard whereby it dropped down to the 400 mark again. 90% of my mileage is at motorway speeds travelling back and forth to work. The manual states that 95 Ron is the preferred fuel grade, but I was just wondering if anyone knows of any long term problems or implications of using this higher grade (but ultimately cheaper) option? Cheers, Paul S - 29th June, 2000