morghen

if the 931 is the US version and not making more HP/TQ than stock, you should be fine with the 944 NA box...i had lots of fun with it(brutal acceleration and sudden traction loss in third gear :P) before the 931 engine crunched the diff on an uphill full throttle

1bar, euro model, intercooled

Po924S

Its been port and polished? Whatever that means to you speed people's... pretty sure it's US because of the bumpes, etc.


If I end up picking it up I will surely post pictures!

Richgreenster

I love how the 931 Looks. This was the first Porsche I had and that got me hooked.
The motors are very reliable. It was the turbo that would go out at about 70K miles. If you let the motor cool down after hard driving, the turbos life can be extended beyond that.

I think that the value of the 931 will go up but will never see super high values. If you like how they look and want to own a very unique fun to drive car then go for it..

morghen

If you open a 931 engine you will notice that it is ported and polished from the factory. The 931 engines were hand finished and hand built!

Last year i replaced the headgasket and took the head to a performance shop. They said that there are marks that the head was hand finished and hand assembled as well as polished, however the port matching was not that good. I also looked and the ports look nicely polished and are very smooth to touch.

FRporscheman

the fact that the '81 has that audi 5-speed transmission is exciting not because of how (un)awesome the audi 5-speed aka 944 transmission is, but because of the implication that you can use any 944 transmission, like 951, G44 from 968, etc. And 944 trannies are cheap and abundant.

Can I start a tangent? Is it possible to adapt or convert an earlier 931 or plain 924 to use a 944 transmission? If I got a 924, I'd plan on going '86 944 rear suspension, if that matters.

morghen

it is possible, you can use the 944 TT and a clutch disk from some audis or fords...or cut&weld a coupler and use the 924 TT.

The 944 gearbox is the same as the 924 gearbox..the late 944 ones are taller geared and for the simple 924 it would mean the car would accelerate slower...for the 931 the S2 or 951 gearboxes are just perfect for street use.

I'm using a 944 TT and a 944 S2 gearbox with my red 924 turbo, and the snailshell system on the blue one. i love them both and i can never decide which one i like more.

Po924S

Well why you guys dream about a 924 with 944 suspension (924S?)... or whatever it was, it seems all she needs is a new input shaft.

Here is a text he sent me "I launched hard and the torque broke the cast iron case at the bearing on the bottom shaft that comes from the ring and piñon. I got a new case with new bearings it did no damage to internal parts..."

V2Rocket

931 with 944S2 box..yum

Arominus

The 931 still has the steel rear suspension, swapping in the later 944 parts gets you the lighter aluminum suspension.

TurboAngel

In Europe the 931 retained the G31 until the end of production. It was many years ago now but I remember having to replace the fuel tank to fit the Audi gearbox. This might only be the case on Euro S2 versions though? That was a big "Gotcha" at the time as I had already replaced the torque-tube, linkage, and complete rear torsion bar subframe...

Funny, now I'm using the complete G31 set up in a 951 project lol.

Po924S

I'm much too "blah" about transmissions, etc... so to any savvy transmission people out there does this sound fixable? Or sthe time and just buy a new transmission.




Arominus - I see.

V2Rocket

Is it really any lighter? Those cast trailing arms are HUGE, I think the steel ones are hollow...not to mention probably stronger...

J1NX3D

the G31 uses a lot less space than an audi box. I remember my 932 being very expensive to fill. It sure felt like a larger fuel tank than my 944!

will post a photo of the underside of my 932 when im home from work.

very keen to hear about how your 951 goes with a G31 _b

FRporscheman

Po924S, I would definitely get a used transmission. I don't know what 931 transmission go for, though. Just the time it would take to open that messed up tranny and fix it (assuming you know what you're doing, and you actually fix it correctly), it's going to take too long and not worth it. Let alone the difficulty and the risk of F'ing up. If you can find a transmission for a few hundred or less, I'd do that. Plus you'd have a spare that you can fix in your free time.

If an original-type tranny (like a G31 if that's what it has) is too expensive, look into the cost/effort of converting it to use a 944 tranny. I know 944 trannies can be found for less than $200.

Spencer, the aluminum ones are indeed lighter, IIRC it's like 10lbs lighter each, but that's just the arms. Since the hubs, bearings, brackets, etc are all also different, the net weight difference might be less, but I think the aluminum setup would still result in less net weight. I wouldn't do the conversion for the weight advantage, though. I'd do it so I'd have the much better bearing design (I've had a bad experience with the early WBs).

TurboAngel and J1NX3D, how big is the 931 fuel tank? I like large tanks (i.e. large range) so it would be hard for me to sacrifice that in order to fit the audi style gearbox. If one did want to fit the audi gearbox, does the tank really need to be changed? Can't you just pound the metal tank in?

Morghen, so the 944 TT is a bolt-in for the 924 (using a special clutch)? Nice!

TurboAngel

The tank may not be an issue on earlier 924/31 models with the dogleg box. The 81-82 932 (rhd) version got a larger tank taken from the 937 (CGT). Thats a good enough reason not to attempt a pounding in approach. I would guess it has a similar capacity to the later plastic 944 type.