Newest and best transmission for exchange

[moab911]

What is the best and newest transmission to use in my 79' 911 SC.It has a 3.0 engine.

[jluetjen]

What's wrong with the one it's got????

[moab911]

Gee, thanks for the help!

[blue82coupe]

You can install a G50 . They were first introduced in 1987. Patrick Motorsports makes a kit . Dan

[moab911]

Dan- Thanks for your help.

[john walker's workshop]

the G50 is kind of high geared. you may not care for it with a 3.0.

[Oh Haha]

Mr. Walker,
You've got my interest now.
What briefly is the gearing difference between the two.
I feel the first gear of the 915 is too short.
Thanks,
Wayne

[blue82coupe]

Have to agree with John. It's also about 100lbs heavier... you just don't need it with a 3.0. The clutch is hydraulicly operated , so it requires all of its plumbing.Dan

[john walker's workshop]

915 final drive is 3.87
915 1st is 3.18
2nd is 1.83
3rd is 1.26
4th is 0.96
5th is 0.76
(out of the early carrera manual) SC and earlier transmissions may differ a bit.

G50 final drive is 3.44
G50/00 1st is 3.50 (and G50/01)
2nd is 2.059 (and G50/01)
3rd is 1.409 (and G50/01)
4th is 1.074 (G50/01 is 1.125)
5th is 0.861 (G50/01 is 0.889)

1989 G50/00 5th is 0.868 (1989 G50/01 5th is 0.892)

[Oh Haha]

Alrighty then!
Thanks John.

[john walker's workshop]

i do have a complete '87 G50 setup with trans, pedals, plumbing, master and slave available. the trans was in my car and it shifted fine. the rest is from a '88 i parted out.

[Jack Olsen]

moab911, it would be more helpful of your question included more information about what it is you're looking for that your current transaxle doesn't address. Your aluminum 915 is a pretty strong and durable transaxle. John Walker could rebuild it with a few updates that would make it better than new.

Swapping in a G50 is a very big deal. Budget at least 4K (I've heard people spending as much as 7K on the swap).

[emcon5]

So,

What's wrong with the one it's got????

Tom

[john walker's workshop]

i agree, there's nothing wrong with the one you have, other than it may need work.

[PorscheGuy79]

While we are on the subject, what upgrades to the transimission itself would you suggest you do while rebuilding that would help it perform better. (for someone on a limited budget)

[jluetjen]

moab911; I wasn't trying to be funny -- just get some further definition around the word "Best". In spite of it's issues, the 915 is very much the "Best" transaxle for your car given it's torque, the transaxle's weight, the cost, gear ratios and such.

* By many accounts the 901/911 shift nicer and have the dog-leg first, but they weren't built to handle a 3.0's torque.

* A G50's shifting feel is supposedly better then a 915's (I've never driven one), but it weigh more, costs significantly more and doesn't start out with the best gearing for a 3.0.

* A Hewland sequential box would be a really cool update (or possibly one of the current 911 transaxles), but the complexity and costs of doing the conversion would be daunting.

So what is your complaint or what aspect are you trying to improve upon for your 915?

* Shifter travel? There are a number of short-shift kits.
* Shifter feel? See the above short-shift kits. Possibly redoing the syncros and or shifter bushings might help too.
* Gear ratios? Regear it with a shorter set or a set tailored to your driving.
* Tire spin or car balance? Get a Limited Slip or torque biasing diff.
* Service life? Get a transaxle cooler.

Basically a 915 is a pretty well engineered box and there are a lot of "add-on's" available that can allow it to survive as a full-race box. Compared to the transmission support available for most cars (even the popular RX7's and Mieta's), the Porsche 'boxes have just about everything.

[moab911]

jluetjen- Thanks for the reply. I have to pull the transmission to have it repaired and thought that if there was a better one to replace it with I would do that rather than rebuild the one that is in the car. If,as most of you do, recommend the 915 then that is what I will stay with. Thanks Bruce

[Bill Verburg]

Here is a comparison of some of the available gearing
***ooops to bad the picture poster is nfg***

[RickM]

Bill,

You have a ton of previously posted pics/charts. Perhaps you can show them here via a link. [ img ]Your pics address here[ /img ] (No spaces between the brackets and commands)


For the record to retrieve the full address of an image right click on the image, select properties, hilight the entire Address line, right click on it and copy. Then you can easily paste it between the [img] commands.

[Bill Verburg]

I know how to do it, I just won't anymore, my time is very limited these days, search is not being used enough any way