Real world running costs were as low as 43p per mile for a Porsche 928 S4 in the UK in 2005

A couple of our mail list participants posted their running costs data which makes useful reading for anyone considering a 928 and interested in cost of ownership.

According to What Car? its less than a new top of the range Mondeo. No further questions.

Andys running costs for a 1987 Porsche 928 S4

I've kept figures in a similar way to Graham - 3.5 years and 80,000 miles (!) - this was in a 87 S4 auto - bought with 82K on the clock and sold with 162K on the clock. All servicing work was done by myself - including most major work, although there are a couple of invoices in there from an OPC and from 2 other garages for bits. All major work (cambelts (x2), water pump, torque tube, bearings, discs etc and lots of minor work, pipes, seals, boots, leads, etc etc ) was done on the car in this time - the worst part was around 110 - 120 K miles when lots of bits came to the end of their natural life spans.

My cost worked out at 17p / mile for petrol and 26p for spares, tax, insurance etc - total cost of 43p/mile. This is lower than Graham's because I have done most of the work and also due to more miles per work done I would imagine - his end comment about the cost of running is true - two people at work ran Jags - an XK8 and an XJ8 and they were paying between 68p and 85p / mile to run their cars over similar mileage. In both cases the pain at the end when selling was a lot more scary!!

My additional comment is that if you use these cars daily they seem to suffer a lot less niggly issues than if they are used weekends only etc. Of course it is a big help if you do even the basic work yourself.


Grahams running costs for a 1991 Porsche 928 S4

I posted this to the list at the end of 2004. It might help:

"I have been monitoring the running costs of my 928. My experience over the 3 years and 18,500 miles I've owned the car may be of interest. Its not scientific and its not necessarily representative but it may be reasonably typical.

The car is a 91 S4 automatic. It is a daily runner, insured fully comp on a standard policy with two named drivers and no restrictions (but I come into the "Old Git" category which helps). All servicing work (including flex plate!) carried out according to schedule by local specialist. I've had no major problems over the 3 years. I guess cheaper cars might have had higher costs early on to get everything working, but this would be offset by lower depreciation.

The only guesses are (unfortunately) the two biggest items:

  • Petrol price - I've assumed an average of 75p per litre over the three years. (I've actually used 4,185 litres giving almost exactly 20mpg).
  • Depreciation - as my car was at the top end of the price range when I bought it with more or less everything working I've assumed £4k.

"Other" items includes cambelt change, new front disks and various odds and sods.

Petrol                 £3,138 = £1,046 pa or 0.17 per mile
Insurance            £1,043 = £468 pa or 0.08 per mile
Service & MoT     £1,849 = £616 pa or  0.10 pm
Tyres                  £397  = £132 pa or 0.02 pm
Road Tax            £485  = £162 pa or 0.03 pm
Other                  £913  = £304 pa or 0.05 pm
Depreciation        £4,000 = £1,333 pa or 0.22 pm

Total Cost £12,184 (ouch!!) = £4,061 pa or 67p per mile (59p per mile if you exclude insurance).

According to What Car? that's less than a new top of the range Mondeo or mid-range C-class Merc (and about the same as a Passat V6). I know which I prefer!!" Good Luck Graham