VT928

I was looking at the owners manual that came with my 1980 Euro S and it has a Zero to 100 km of 6.6 seconds. That got me to wondering how much of that time was due to the traction limitation of the almost thirty year old tire technology of Pirelli P7's. I currently run 285/40 17 Kumho SPT tires on the rear and they are a quantum improvement over the P7's. My car dynos ar 269 to 273 rwhp and on a G-Tech did a 5.8 with me being careful with the 1/2 shift and some wheel hop on the start.

I was wondering if the big of an improvement is being seen by others?

Paul Mammorella

1980 Euro S Red/Bkl Lea

Jim bailey - 928 International

The Porsche numbers were conservative , contemporary magazine tests (some of which are real ) often had better numbers. Real drag strip numbers benefit from the much better preparation of the track...

pcar928fan

That is a good question. I would say if you kept the tires the same size and put newer better tires on the car it might help. I would say w/ the tires you are running you are probably slower though as they will be MUCH heavier than stock and that is the equivalent of taking HP right out of the car... Probably 20 more...

VT928

James,

The dyno runs were made with the tires that are on the car, so if horepower is down it does not show in the numbers. The 5.8 second runs timed on the G Tech were considerabally faster then the Porsche numbers. My thoughts are that the ability to put significantly more horsepower to the ground than the origional P7's more makes up for any lost hp. When I first bought the car it had P7's on it and they broke loose very easily. I can launch the car much harder now and the 1/2 shift does not spin the tires nearly as aggressively as it did with the stock P7's. The only change to the engine is the exhaust, I took of the rusted three muffler Euro system and reolaced it with a single True X Magna Flo muffler in mounted where the cat goes in a US model and 2.225 inch pipes back to the rear corner. That change really woke uop the engine it revs like a motorcycle and it is suoer easy to hit the limiter at 6300 RPM. I actually think I could get a quicker 0 to 60 time but do not want to abuse 28 year old car.

Jim Bailey is most likely right the Porsche numbers are conservative but is still is quicker by a significant margin.

Paul Mammorella

1980 Euro S Red/Blk Lea

pcar928fan

Paul,

All I am saying is that with stock weight size (but stickier) tires on you would have made more HP and even faster 0-X runs...

Ask anyone who has dynoed their car and then went to bigger (and in virtually ALL cases) heavier wheels... They see a decline in HP/Tq numbers...always.