The gear ratio on my 87 is 2.20. In the 87 Euro models and starting in 89 for the US automatic the gear ratio was 2.54.

How many rpms are you folks with 2.54 turning when you run at 80MPH? I guess the size of tires may make a small difference too.

The reason I ask is at 80 with my 2.20 rear end it really an awesome ride for cruising. I have to set the cruise to keep it near the speed limit . I guess I give up a few tenths 0 - 60 also?

 

Jerry,
Click on this <a href="http://www.928trackcars.com" target="_blank">http://www.928trackcars.com</a> and scroll to the bottom.
HTH
Andy K

 

Nice link, thanks. Looks like the answer to my question is an additional 500 rpms at 80.

 

I couldn't get the lower one to work for me. If I use the road speed calc, plug in gear ratios, 25.5" for tire diameter, and 3000 rpm, this is what I got.

GT 2.73 ratio = 83mph
2.54 ratio = 90mph
2.20 ratio = 103mph

Illustrates pretty well why the aceleration of the GT is so strong above 100 compared to a 2.20 geared car.

 

My actual rpms are 3000 at about 80mph with a 2.20 - something seems amiss. I was calculating the 2.54 at 3500 rpms at 80?

 

err, guys... Don't quote me, but I think the transmissions have different gearing, too. <img border="0" title="" alt="[Wink]" src="wink.gif" />