Auto Racing: 1984 Porsche 944, manual gearbox, differential gear

Question
the Porsche is an auto car and it seems to rev too high at 80 to 90 kms the tach reads 3000 to 2800 rpms and at 110 to 120 the tach read 4000 to 3800 rpms is this the right rpm for these speeds?

Answer
I presume by 'auto car' you mean that it is fitted with an automaatic gearbox.

Since I'm in the US I had to convert KMS to MPH .  That gives me 75MPH+ at 4000 RPM. Yes I think that's a little high - - -but just a little.  It could be that the car is fitted with a lower than standard differential gear which would explain it.  If the car is fitted with a manual gearbox, the 4000 RPM at 75 MPH would be expected in fourth gear, but not fifth.  In fifth gear it should be running about 3500 at the 75MPH (120 KPH)

Enjoy your day !

Dan Liddy
Sarasota, Florida