Link-X

Hi Everyone,

I'd like to collect opinions on which of these 5-speed trannys is better. Specifically, if I were considering deciding between two conversion 930s how much more/less should I pay to get the G50 over the 915 transmission? A thousand thanks in advance for your help!

t.p.

The 915 would be much cheaper because it's an easier install - it pretty much bolts on and you don't have to convert to a hydraulic clutch. I couldn't tell you how much cheaper it would be to install a 915, but I would figure $2-3k cheaper to do. The G50's require extensive modification to the body of the car, and then you gotta install the clutch master and slave cylinders. PITA.

But I wouldn't do either. Many w/ experience have said that the 915 isn't strong enough for a turbo motor. That's why they weren't used on the 930s.

What I would suggest is changing the gear ratios on your existing tranny and maybe the ring & pinion too. This reportedly helps a ton w/ acceleration. You'll give up some top end, but honestly, how often are you on the autobahn?

Steve Weiner-Rennsport Systems

Hi Todd:

There is a world of difference in shift quality & strength between the 915 and G-50, especially as would be used in a 930. If I was contemplating increasing the power in a 930, I would not use the 915.

You will pay in the vicinity of $8-9K to overhaul a G-50, regear it, and install this in a 930, complete with hydraulic clutch setup.

Link-X

Thanks t.p.

More specifically what I'm looking for is how much more should I pay for a G50-equipped 911 turbo over a 915-equipped 911 turbo? Assuming that other than the tranny the cars are identical.

Gracias.

930chas

You don't want to do the 915. It is not meant to cope with the power of the turbo motor. If it had been, they would have installed it instead of the 4 speed. Also, I don't know what mods you have, but that 4 speed gets better with the more power you car makes.

930chas

Sorry, I didn't mean to post the same thing everyone else said, my computer just had a REALLY delayed response. Anyhow the 89 911 turbos definitely command a premium over the earlier years. I'd say the price difference would probably be about $5000-$7000 depending on all the mitigating factors.

t.p.

if not already apparent, the 915 was not available on any 930's.

pig4bill

The original poster said "conversion 930" which is an oxymoron in my book. Apparently he means a 911 that was converted into a Turbo? If so, the comments re:915 above apply. Does that also mean the G50 is from a standard Carrera and is not a G50-50 as what came in the 930? Then maybe the answer to which trans is "neither".

SEW QUIK

I interpret conversion 930 as a 930 that has been converted to either a 915 or a G50 5 speed, not a normally aspirated car that has been converted to a turbo. In this case, the above comments on durability and ability to handle power certainly apply.

garrickl

Whatever, my 1978 930 came with a rebuilt 1986 915 5 speed installed by the PO. It had 17K on it and after 2K more I took it out because the internals did not sound good, synchros were shot and I was worried that it would soon break. It now has a shortened G50 in it. I would stay away from using 915 transmissions in 930's. IMHO they can't handle the power and torque of the turbo motor.

Link-X

Thanks for the insightful replies. My machines is a '79 chassis with '89 Speedster bodywork and a '89 3.3L turbo motor. The seller claimed that the car ahd a G50, but after a driveshaft came out and chewed up some junk I discoverd that it was a 915.

I'm trying to figure out how much he took me for...

Link-X

....specifically the seller claimed (in writing) that it was a 5-speed G50 from a '89 911 turbo.

garrickl

The 1989 Turbo came with a G50/50 transmission which is stronger and heavier than a standard G50. If the seller represented in writting that the 915 was a G50 he misrepresented a material fact and you have an action against him for fraud. The costs of suing him will be expensive but so is the G50.

pig4bill

Sorry to hear about you getting ripped off. It's a shame, because if you'd had a chance to drive a real G50 before, you would have known the car didn't have one. The difference between them is extremely obvious from the feel.

I don't know what a conversion to a standard G50 is worth, but on a Turbo it's about 10 grand or so. Partly because the car itself needs some changes for it to fit.

mic

Sorry to hear about being ripped off.
You can tell the difference without looking at the transmission - the shift pattern is different.

Just to let everyone know:

The reverse gear is completely opposite between them.

On the 915 it is below 5th gear. On the G50 it is to the left and down from 1st as follows:

915 shift pattern:
1 3 5
| | |
|--|--|
| | |
2 3 R

G50 shift pattern:
1 4 5
| | |
|--|--|--|
| | |
R 2 3

BTW: I have both a 915 and G50. I have over 400hp behind the 915 and with the gearing and clutch setup it is fine (just dont drop the clutch). Note that it had to be rebuilt after 130kmiles on it. But I can shift much quicker with the 915 and the gearing is actually much better for acceleration than the G50. The G50 is like shifting a truck compared to the 915. We will see how it really compares after I get the G50 juiced with over 500hp (a project in process with a couple years to go).