915 to G50 conversion on '85 911 - What's needed guide‏

[-Levi-]

Originally Posted by GH85Carrera

Like most major modifications, it just does not make economic sense.

Sell the current car and get a G-50 car. You will be much better off. Just my opinion, it is your money and time. Do what you want.

that's the hard part. with the heavy modifications I have made to my sc
-cage, stripped to a massive level, reinforcements, oil cooler modifications, engine swap, seat modifications......so on...so forth I really cant break even or come ahead doing a new car. :/

[safe]

Originally Posted by faverymi

Long shot but.

Would a 996 transmission work for this conversion.?

My 3.8/ 915. Will eventually need some thing. I'm following this thread closely

If it is a GT2/3 or a turbo it will bolt on to the engine. The normal 996 gearbox has a completely different bolt pattern.

[safe]

Originally Posted by -Levi-

any more additional information ever come from this thread?

Like what?
I'm 95% done with my conversion, 3.6+g50 into a 69.

[ALEX P]

Originally Posted by -Levi-

any more additional information ever come from this thread?

What more info were you after? There is a fairly comprehensive kit of parts that outlines the costs involved - Sadly it was just too much $$$ for me so I have just limped on with my tired 915 since and have been concentrating on fixing the bodywork instead.

There's a thread on here that I really like and am mulling over as a good 'cost' option to a better gearbox that the 915. I know everyone who has a nice 915 says when they're good they're really good BUT they do have their limitations and you cannot abuse/rush them without causing damage and they are very expensive on parts.

Subaru Impreza gearboxes on the other hand are modern, cheap-ish and two a penny........

Subaru transmission in place of a 915

[930cabman]

Our '87 930 has a G50 transplant by a prior owner, no idea how much, how many headaches, ... but it rocks for sure.

I like it much better than the 915 in our '75 911S

[cnielsen]

G50 is an amazing upgrade! Worth 8-10K? Shoot, probably not but I was mating mine with a monster turbo motor so I didn't have a choice. I have never looked back! I did not cut the torsion tube but I did shorten the bell housing via California Motor Sports.

[-Levi-]

My biggest questions-
1 has anyone figured out why some cars need the body cut and others don't?
2 what is the cost in today's terms?
3 with a 3.6 swap- can a 915 be built up to Handel the power long term (on a track) or is the g50 the ticket

I called Patrick motorsports to see what they would charge (they carry all parts and transmissions) to drop off the car and have them do the swap and provide all parts. Respectfully they were $19,000-21,000 in and out. I can do the work myself- I more wanted a base shop price. Any ideas

[safe]

Originally Posted by -Levi-

My biggest questions-
1 has anyone figured out why some cars need the body cut and others don't?
2 what is the cost in today's terms?
3 with a 3.6 swap- can a 915 be built up to Handel the power long term (on a track) or is the g50 the ticket

I called Patrick motorsports to see what they would charge (they carry all parts and transmissions) to drop off the car and have them do the swap and provide all parts. Respectfully they were $19,000-21,000 in and out. I can do the work myself- I more wanted a base shop price. Any ideas

1. With a shortened g50 you could just push back the engine a few mm if there is a clearance problem. But depending on car you may have to enlarge the back seat hump, I had to in my 69 even for a 915.

2. depends on you skills, luck with finding parts etc, but I think you can do it for 6-7000.

3. Probably but that ain't cheap either, but a lot easier.

[otto in norway]

The SBH G50 will fit any G-model, but you may have to cut a little out of the torsion tube shell. Especially when installing into a non-tubo body. As I have come to understand, the turbo bodies have a little extra spacing from the tunnel to the rear motor mounts. This measurement varies a little bit from mode to model within the G model range.
I put a G50-00 SBH (-shortened 28mm) into mine (911SC), and had to cut out some materials from the tube shell, (Gained about 10mm), and move the entire engine/tranny assembly rearward by about 15mm. (I Just bent the cross member for the engine mount slightly)

Be prepared for a noisier transmission though. Especially if you, like me, have the SBH together with a lightweight clutch package. Vibrations from the engine flywheel becomes very audible in the G50, especially at low revs.
Also, as others have mentioned, it's pricey.

Otherwise, it is a nice upgrade.

If I had a stock 3.6 NA engine, I wouldn't want to install the G50. It is cheaper to strengthen and service the 915. Many people regularly use 915 on track with a 3.6 engine. But if you go with a turbo, or go near 300 and above horsepower, you may want to think about putting in the G50 for long therm dependability.

I put in the G50 so I can really "abuse" the car. I would find it annoying not to be able to dump the clutch once in a while. And the shifter improvments alone is pretty nice. No more tricky shifts.

[Sboxin]

Originally Posted by -Levi-

My biggest questions-
1 has anyone figured out why some cars need the body cut and others don't?
2 what is the cost in today's terms?
3 with a 3.6 swap- can a 915 be built up to Handel the power long term (on a track) or is the g50 the ticket

I called Patrick motorsports to see what they would charge (they carry all parts and transmissions) to drop off the car and have them do the swap and provide all parts. Respectfully they were $19,000-21,000 in and out. I can do the work myself- I more wanted a base shop price. Any ideas

Levi,
We are using a race built 915 with our 3.8L engine. We have considered swapping out for a G50 but the cost just doesn't justify the swap.

CMS in Lake Havasu, AZ did a rebuild and upgrade to the race built 915 that came with the race car and 3.2L engine. https://californiamotorsports.net/

We broke a pinon tooth in the 3 year old box after installing the 3.8L and that's why we took it to CMS.
They replaced the R/P, 3rd gear set, syncros, sliders, misc, bell housing, LSD clutches, side plate upgraded to Turbo w/Turbo bearing - - all for $8K
We also use a trans cooler for racing - simple pump and coil arrangement - but this is a race car and lives most of its life at 5-7K RPM

They are very helpful if you call and talk with them - lots of Porsche transmission experience.
We are very satisfied with their work.

This is Sean (the CMS owner's son) and behind him on the bench is a real 935 transmission . . .

Regards,

[aston@ultrasw.c]

Originally Posted by -Levi-

My biggest questions-
1 has anyone figured out why some cars need the body cut and others don't?

I think because it's a close fit and there are many ways to skin a cat.

We all have different preferences, skills and equipment.

For example I did not like the idea of bending the engine cross member but others are happy with that. I did not mind shaving the torsion tube, but later came to find it was not such a great decision.

[patz]

Rebuild the 915 and use WEVO upgrades. Works fine. The G50 while nice is overkill.

[Tremelune]

Sounds like it'd be cheaper to cut out the seats and install a Cayman drivetrain...

If I could spend $10k and magically have a G50 in my '84 coupe, I would. Hell, I think that's the market difference anyway.

[cnielsen]

I think everyone assumes you need to cut the torsion bar tube or remove it all together and install coil-overs.

This is not the case! Mine is done on an SC chassis. I did not cut the torsion tube. I did do the short bell housing conversion by CMS. And, with a very careful installation, it will move the engine backwards in the car by almost 3/4". I don't think there's any way around this without cutting the torsion tube. However, you can easily modify (not bend) the motor mount bar so the motor will bolt right in. It does not change the handling of the car. The axles and everything else still work just fine.

$10K would be on the cheap side. 20K is the high side. Low teens is probably realistic for a DIY.

[winders]

Who wants to move the engine further back in the car? Why bother with the conversion if you are going to take this negative step to do so??

[cnielsen]

In my case, I didn't have a choice. I had to convert to a G50 and I wasn't going to cut my torsion tube.

[Matt Monson]

Originally Posted by safe

2. depends on you skills, luck with finding parts etc, but I think you can do it for 6-7000.

Need a pet leprechaun to do it for that price.

[winders]

Originally Posted by cnielsen

In my case, I didn't have a choice. I had to convert to a G50 and I wasn't going to cut my torsion tube.

You didn't HAVE to do anything.......

[cnielsen]

591hp said I HAD to do something. The 915 would have been a ticking time bomb

[safe]

Originally Posted by Matt Monson

Need a pet leprechaun to do it for that price.

I got the G50 here on pelican for 3500 and I don't think I have paid more than 1500-2000 for the rest of the parts.

It's not a short bellhousing, I cut the torsion tube instead because I have coilovers.
The engine looks to be in the original position, if I choose to in the future I could shorten it and move the engine forward.

Found an RS flywheel second hand, but unused. Got a free slave cylinder, free clutch plate (well not free, I've probably done something in the past to get them). Bought guide tube and bearing new.
The shifter I made from a 944 one, if ut turns out as good as I think I'll post something about it.
Clutching generic copper fuel line. Master cylinder, found used, made a linkage in the foot well, that I need to redesign in the future.

So depends on luck and skills....