Just found some interresting facts in a vintage french magazine.

Test was made in January 1970 by a french magazine

Porsche 914/4 1.7 80 HP DIN at 4900 (85 HP SAE at 5000)

Test was made at Montlhery ring ( near Paris) by a cold day (6 °C / 42.8 F )
Driver alone

Targa ON / lights OFF max speed 167.4 kmh (104 mph)
Targa ON / lights ON max speed 164.9 kmh (102.5 mph)
Targa OFF / lights OFF max speed 163.8 kmh (101.8 mph)
Targa OFF / lights ON max speed 161.5 kmh (100.4 mph)

Conclusion:

At theese speeds, with this temperature and the targa OFF you better wear a thick coat and gloves ...

What was the speed with the:

TARGA OFF / LIGHTS ON AND TIRES FLAT.

Tires seemed OK on the picture ...

How do jackstands affect top speed?

Johannes,

Merci,

Very interesting information. Anybody out there able to translate this data into drag coefficients ?

Michel

Johannes,

Can you scan and upload the article ?

Michel

Cool, I got some genious co-workers maybe next week.

But that's logical about the results.

I must be making mad power and a bit more aero stuff. I can accelerate pretty good even from 100 MPH.

Seems to hit the aero wall about 117 - 120 range.

I notice differences in head temps with top off windows down too. Maybe I need "air tabs"

Its 10 pages of very small printed text ... Its also larger than my scanner ... and all in french ... I am afraid I won't upload that ...

Old thread.