Andrew

Lets look at it mathematically.
take the gear ratio and multiply it by the final drive.
so 944N/A with 5th gear of .73 times the final drive: .73 x 3.89 = 2.839
2.839:1 is the # of revolutions of the engine to every ONE rev of the wheel.
Same for the 924S, 5th of .83 times the final drive: .83 x 3.89 = 3.228

Now using these two numbers we find out how many revs the the wheel turns at redline. so lets use 6400 as our redline for both cars. redline divided by 'engine:wheel' ratio equals wheel revs per minute (WRM):

944N/A =6400/2.839 = 2254.3 WRM
924S =6400/3.228 = 1982.6 WRM

now this is going to be alot but bare with me. I just measured my extra tire and it is 79 inches around so I'll use that as a base. there are 60240 inces in a mile (5020ft*12in) we take these numbers and we'll calculate the max distance traveled at redline per min. then MPH at redline first 944N/A:
2254.3*79 = 178089.7 Inches per min.
178089.7/60240 = 2.956miles per min
2.956*60 min. = 177.36mph
177.36 mph @ 6400 rpm

Same process for the 924S will equal
156 mph @ 6400rpm

Now, ask your self do you think the either car has the power to get there? next which do you want if you had the power (ie supercharger) either way you slice it the factory cars both have the same top speed rated for each other. though one may get there a pinch faster, they both will get there. just take your pick. Remeber though the 924S tanny will be harder to find. It would be alot easier to go buy the 5th gears and swap them i bet.

Whoa! Did i just do all that?
Good Luck
-Andrew

MAS

The 924S tranny has a 5th gear that is more evenly spaced, and closer to the the other gear ratios. The (regular) 944 5th gear is more like a cruising economy gear... in fact it is (just like the 2nd gen RX7s).

-MAS

Steve Lavigne

I had a '87 944 a couple of years ago. The car was basically stock. I spent some time with it at SIR and PIR. The car had acceptable power UNTIL fifth gear. At this point the tall fifth gear would cause it to fall out of the powerband and on its face somewhere around 120 mph. I ran it to probably 50 rpm of the fuel cut in fourth due to this. I suppose chips would allow it to rev a little further, possibly putting it in the meat of the powerband.

'86 951 -- doesn't fall on its face at 120mph
-Steve

Steve Lavigne

I made some changes to that file I uploaded earlier. The file now has the 944, 924s, 944s2, 951, 951 with euro R&P, and 968 gearboxes. All you have to do is plug in your tire specs or tire diameter and max engine rpm. From this it will tell you max speed, rpm range, and speed range for each gear. You can click the tabs at the bottom to look at these values for each gearbox.

Gosh what a surprise, I like the 968 box.

944gearingv2.xls

'86 951
-Steve

Danno

Just a quick reminder that the 924S tranny is the same one in the '88+ 944NA cars.

Also the 944 Turbo, 944S, and 944S2 are fitted with an 083-series transmission, while the 944 and 924S are fitted with an 016-series transmission. And the 968 uses a completely different 01E tranny.

None of the R&P sets will interchange across different series of tranmissions. So you can only swap R&P 016 families (951/944S/S2), or between 944/924S. Nothing but a 968 R&P will fit in a 968 gearbox and vice-versa.

But I agree, Gangha's gear box takes a HUGE jump from 4th to 5th. Probably due to gas-mileage concerns at the time. However, he's never likely to see more than the top of 4th (115mph) at a racetrack anyway, so the top-gear issue is really an issue of comfort at freeway speeds (do you have to shift or not to acceralate).