Can a G50 transmission be put in an SC?

[jwakil]

I really like my SC except for one thing, the sorry 915 transmission. It really sucks having to slow shift and all the other tricks necessary to be able to get into 2nd properly. (Yes, I know about all the little improvements you can try to make but I believe mine is as good as it's going to get). Can one replace a 915 with G50 easily or are there major other mods necessary? I haven't done a lot of research into this, hoping someone can save me some time.

[Trackrash]

With enough money it is doable.

[john walker's workshop]

G50s wear out too ya know. too much effort for too little gain. fix the 915.

[trak ratt]

Lots of money unless you can do most yourself. Works well with rear coil overs since you have to cut the torsion bar tub to install. This means you r T-bars don't fit. Trans mount is dif too but not a big deal. I also think it takes a dif shifter, shift rod, coupler etc. too. Lots of other little things. A well built, fresh 915 should last a long time if you don't "speed shift" that much.

[porschenut]

don't forget the hydraulic clutch too. Big mods here, lots of money even if you can do it yourself.

Far easier is to sell the SC and buy a G50 Carrera.

[vash]

not to mention the entire hydraulic fluid issue..it would be daunting.

probably cheaper to buy a G50 car.

[vash]

porchenut..i call that a tie..well, you win by a hair!!

[Matt Monson]

Figure $1500-2000 in parts not counting the cost of a G50 gearbox. And G50 gearboxes have gone way up in price ever since Factory Five spec'd them as the gearbox for their GTM kit car. It's probably a $5000 conversion with free labor. $6000-7000 if you've got to pay for it.

[AlfonsoR]

Jwakil, have you driven a 915 that has an upgraded shifter? There are folks like Wevo and Seine that sell shifters and/or components for shifters, that will make a big improvement. Some of these can be pricey, but still a lot less money than doing the conversion.

Also, what lube are you using? Peter Zimmerman, one of the 915 masters, recommends Kendall Three Star dino oil, now it's called NS-MP, and it's sold on Amazon. IF your lube is due for a change or isn't the right viscosity, it definitely won't help matters. Some people swear that having the right lubricant, not just the right weight, makes all the difference in the world in terms of shift quality.

Seine also has a procedure on their website for blueprinting your shifter. You might want to try that first. Change your oil to Swepco or Kendall NS-MP too. I would do the NS-MP since that's what Peter Z recommends, and he's had a lot of experience and success with it. Then come back and tell us what you think.

If that doesn't do it, then upgrade your shifter, and if that doesn't do it, then as others said, sell your SC and get a G50 Carrera.

Your 915 shifter probably just needs some TLC. The 915 is a good transmission when everything is in proper working condition.

[Packy]

Patrick Motorsports sells a short bell housing G50 so you dont have to cut the torsion bar tube, for what its worth. The only real reason to go to a G50 is to handle more power/torque, otherwise give you 915 some TLC and deal with the first gear.

[Scott R]

My rebuilt 915 displays none of the "classic" 915 issues since the rebuild. I can shift to first rolling, 1st to second is like shifting any other car. If the box is rebuilt/repaired correctly it works like a dream.

[crashmy911]

Just drop your car off at a good shop and let them fix it. My 915 is fine in my car. At the track I have no problem with it. Also unless you are speed shifting it I have no idea why you are having so much problems with it. Do some searches you can make it shift pretty good.

[tcar]

Originally Posted by Scott R

I can shift to first rolling,

Scott, Storz in Denver told me that if I want it to shift well, not to shift into first while the car is rolling. FWIW.

I don't now.

My 915 shifts great.

[nineball]

i just installed a factory short shift and new bushings in my 915 and i had to re-learn how to shift. that's how dramatic of a change it was for me.

[NY65912]

For a street driven / mild modified car, no reason to go G50, the 915 is fine.

Not worth doing.

I am going G50 only because of a 3.8 putting out 415 hp /300 ft pounds of torque.

I really wanted to build up my 915 but I don't think it will work.

[Evan Fullerton]

While I agree with all the above, I just broke the second gear retaining teeth off a mag case 8/31 915 box with a stock 3.0L and while it was apart getting the updated main shaft it also got 5 new syncros, 4 new dog teeth, and a new 2nd gear. I have had a Wevo shifter for a while and it is a slight improvement over stock as far as shift feel and a major reduction in throw, in a street car I would just stick with a stock shifter with new bushings as the effort on the Wevo unit is rather high for relaxed driving. With brand new internals (they weren't bad before as the trans was gone through 5k miles previous to this) I would term the shift quality as merely adequate. I am sure that it will improve some more when I put in the Wevo engine and trans mounts but it will never compete with a G50 as far as quality and speed of shift. Even after spending ~$5k on my 915 I still plan on upgrading to a G50 in the future as you will never ever be able to reliably slam shift with the 915. If you have no interest in speed shifting, the 915 is probably all you need but I race and I see significant benefits to going to a G50 even at a $6-8k price tag and plan to do so in the future.

My $0.02

[jwakil]

I have Swepco, and there is nothing wrong with my transmission based on what I have read from many other postings. The problem is I DO want to be able to speed shift and I know this transmission wasn't designed for it. As I understand, even if its perfect, you still have to do the pause or double clutch crap. That's what sucks. I was so used to just flipping first to second like butter on my 300Z TT. I guess I want similar from a 27 year old car, which probably isn't fair (although my Z was nearly 20 so I don't think its too unfair). Anyways, there is no way I'm going to spend that kind of money on a conversion, so I'll live with it.

[petevb]

Originally Posted by Evan Fullerton

...(The 915) will never compete with a G50 as far as quality and speed of shift.

I'd suggest some 915s can match G50s in shift speed, and certainly the best ones can be faster than the average G50 5 speed.
I had three 915s. Two were slow (one still quite slow after a good rebuild) and one was much faster and smoother. Never figured out exactly why- all had wevo shifters, two had internal wevo gateshifts. In my experience I'd agree the average 915 is inferior to the average G50, and the best 915 is inferior the the best G50, but the good 915s work mush better than most image.

Unfortunately I also believe pushing the shift speed up does cause the synchros in the 915 to wear out faster, etc, and that plus power handling was a major reason I moved to the G50.

The 6 speed G 50 shifts much faster than the 5 due to improved syncho design, btw, which it the main reason I went with a 6 over a 5.

[winders]

Originally Posted by jwakil

I was so used to just flipping first to second like butter on my 300Z TT. I guess I want similar from a 27 year old car, which probably isn't fair (although my Z was nearly 20 so I don't think its too unfair).

You can just shift from 1st to 2nd just like butter. It's just a slightly slower shift and the butter is a little thicker.

Scott

[woywitka]

For what it is worth I test drove a number of 911 SCs and 3.2s with 915s. I was not impressed with the shift performance in any of them really, but all the cars had a commonality, they all had the original non rebuilt boxes. All cars had 200,000+kms

I nearly increased by budget to buy a G50 car until...

The car I ended up buying had beautiful shifting. I actually bought it mostly because of the lack of rust and the quality of the shifting. Guess what, the 915 has been rebuilt. It never doesn't go into gear, I can select first at like 40km/hr if I want to, and other than occasional 5th to 4th downshift bit of resistance the gears engage like butter. Rebuild and clutch was in 1995 and the car has done 50,000kms since, shift action is lovely. 1978 Targa.