'84 swapped with 944s engine
04-19-2021, 02:13 PM
#1
5th Gear
Thread Starter
Join Date: Oct 2020
Posts: 5
Likes: 0
Received 0 Likes
on
0 Posts
'84 swapped with 944s engine
So I'm currently putting in a 944S engine into my '84 944. Got a good deal on the engine and installment. I am concerned about my '84 transmission.. with the 16v engine and HP gains, I know the Rings and Pinions are weaker than the 944S. I do like autocrossing but I'm afraid my current trans will give out with this engine. Are the transmissions that much different I know the gears are shorter in the S. I guess I have to baby it for awhile until I come across a turbo trans.
04-19-2021, 02:24 PM
#2
Race Car
I think you will be fine with a standard NA transmission. The ratios for the S trans are like the Turbo but the ring and pinion I believe is the same or close to it. So should be fine but the only issue I would see is the S motor likes to rev so the ratios are better matched with a different trans. I wouldn't be worried about killing your transmission, most modded NA (cam, headers, tune) can get close to the same flywheel horsepower as the stock S. The S only benefits really from the 16v head which flows more and the higher rev limit.
I personally feel they changed the trans just to better match the engines rev limit more than for power but I could be wrong.
I personally feel they changed the trans just to better match the engines rev limit more than for power but I could be wrong.
Last edited by CyCloNe!; 04-19-2021 at 02:26 PM.
04-20-2021, 11:29 AM
#5
As a 944S owner i would love to swap in an 8v transmission. I won't since i don't want to give up the lsd i have.
The final drive ratios are the same so i would assume it has the same ring and pinion and then the same gear ratios of the turbo.
I am of the opinion that Porsche did this for cost reasons more than anything else. The S and turbo have a 5th gear that is better for top speed and the 8v get a fuel economy 5th gear. Since top speed stats were more important in the 80s than they are now for marketing purposes the S would need that top speed. Acceleration of the 3 944s were nicely spaced on paper but the 16v would drive accelerate better with the shorter gearing. Porsche did something similar on the current cayman gt4. They used a transmission that they admit was not optimized for the car, in this case they said they would have had to make a new trans case to fit the gears but that would be too expensive. The engine wants to breath but you can only hit redline in 1st for legal non highway speeds. For myself i prefer 5th as a low rpm low NVH cruise.
The final drive ratios are the same so i would assume it has the same ring and pinion and then the same gear ratios of the turbo.
I am of the opinion that Porsche did this for cost reasons more than anything else. The S and turbo have a 5th gear that is better for top speed and the 8v get a fuel economy 5th gear. Since top speed stats were more important in the 80s than they are now for marketing purposes the S would need that top speed. Acceleration of the 3 944s were nicely spaced on paper but the 16v would drive accelerate better with the shorter gearing. Porsche did something similar on the current cayman gt4. They used a transmission that they admit was not optimized for the car, in this case they said they would have had to make a new trans case to fit the gears but that would be too expensive. The engine wants to breath but you can only hit redline in 1st for legal non highway speeds. For myself i prefer 5th as a low rpm low NVH cruise.
04-20-2021, 01:13 PM
#6
The S trans is based on the turbo case, which is nice, but the gears were not hardened like they were in the Turbo. Power output wise i wouldn't be afraid of breaking the NA transaxle with the S motor. Enjoy the 16v action, my S was a marked improvement over my 924S in speed, especially when wound up. Down low i couldn't really tell, but still a worthwhile swap IMO.