w00tPORSCHE

I thought I would share a great article on the 915 gearbox that featured in my favorite magazine, Total 911 issue number 78. The pictures, quality of articles and authors featured in this magazine are always brilliant. Philip Raby their editor in chief is a stud.

Here are some excerpts from the article titled "box of delights".

For years, a myth has been perpetuated that Porsche's 915 gearbox isn't very good. However like many things in Porsche folklore, the truth is very different.

Check the classifieds and you'll see that prices of the 3.2 carreras are usually higher for post-87 cars and these adverts invariably include the magic words "G 50 gear box".

The 915 gearbox was derived from the 916 unit which had been built for competition in the 908 racer.The 915 made its first appearance on a 911 in '72 with the 2.4 liter engine which had 8% more torque than the previous 2.2. The 915 is a fine competition gearbox; light fast and accessible. Just look at it's racing record - all the 911's successes from the seventies and eighties.


Attached though Porsche was to the design of the 915 gearbox, it's torque capacity was ultimately to prove finite despite continuous upgrades. But as each new 911 iteration was introduced, torque increased between 5 to 10 %... finally the 915's capacity to transmit was reached. Rather than invest in tooling for a new gearbox casing for a larger capacity 915, Porsche turned instead to a cheaper solution represented by the Borg Warner synchromesh which was already sued in the Audi gearboxes fitted to the 924 and 944 models. So Schmid's light, competition oriented design was reluctantly abandoned.

The 915 was a classic product of a company devoted to competition and owners were expected to know how to use the clutch correctly. But the problem was drivers did not always use it correctly with the result that the gearbox was eventually prone to baulking with which it is associated today and the lower ratios become more difficult to engage.

John Sadler an unshamed purist for whom the 915 is an integral part of the Porsche experience accepts that Porsche had to switch to the G50 as both the torque and weight of the 911 had increased. But for him the G50 was somewhat of a variance with the principle of the 911.


The classic 911 enthusiast who finds an exceptional 915 car, could get himself a 911 that is closer to traditional Porsche values and for real aficionados will offer more satisfaction than a 911 with the G50 transmission.

Article written by Kieron Fennelly and Philip Raby.

Quadcammer

I don't necessarily believe that poor clutch work alone is the source for the baulking from 1-2 and 2-3

Caferacer

Total 911 was my downfall. Just saying.

Ed Hughes

What a unique concept! The 915 actually being viewed as a good gearbox? Whodathunkit?





Bravo to them for priniting that viewpoint. Maybe we'll get a couple of less threads: "WTB 87-89 G50 Carrera"? I've often used the race record reference as well. Much of Porsche's reputation was forged during the 915 years.

Turn3 Autosport

I am with Ed, and not that many others..... A properly set up and functioning 915 is an excellent gearbox. Fitting with the spirit and feel of the <89 911. I prefer them to the G50. Simple clutch arrangement, far cheaper to rebuild than a G50 and with the right bits are excellent.

We are working with an early mag one right now, and it will be wonderful when we hand the keys back.

Cheers

450knotOffice

I have driven a couple of 915 transmissions that have been EXPERTLY rebuilt, and I now know that these 915's, when in perfect working order, are absolute GEMS to use. They are smooth and easy to use, with NONE of the balkiness of most of the 915's I've used. This confirms in my mind that these transmissions, if rebuilt expertly, really ARE as good as some old timers claim.

salukijac

"915 gearbox: Can you handle the truth?: Yes I can, can you?

Ok, I’ll bite… (Just some argumentative writing).

This argument is getting old. 915 transmission owners are going to say their transmission is as capable as the G50. And they have a good argument.

No one is saying 915 is a bad transmission, but you cannot refute G50 is an update to the 915. Period!

So when someone is looking to buy an 80s 911 and they’ve targeted an 87-89 911, 3.2 L, G-50, and if they have done their research, they have a good reason for their approach.

Sorry Amar but I’m going to use your reference as backing material for my point.
Per w00t's referenced article…”But as each new 911 iteration was introduced, torque increased between 5 to 10 %... finally the 915's capacity to transmit was reached.”

In addition per w00t's reference…”John Sadler an unashamed purist for whom the 915 is an integral part of the Porsche experience accepts that Porsche had to switch to the G50 as both the torque and weight of the 911 had increased.”

So there…915 transmission is a fine transaxle…the G50 is an update to handle increased torque and weight.

BTW, I almost bought an 85 911, prior to buying my 87. I wish I had pulled the trigger as it was one of the nicest 911s I have ever seen…8 months later I ended up with a G-50 911.

Fire away!

w00tPORSCHE

Hey peace here guys. This is not something I wanted to post to upset the G50 Carrera owners. I am sure they are fantastic and highly desirable in the marketplace. I just did not want someone else to make the same "mistake" as you Salukijac or I (but for Ed hughes) almost made which is walk away from a pristine 911 just because it is not a '87 to '89 model year. So hopefully when someone searches for threads on a 915 gearbox, this shows up. That's all. Imo there is just too much negativity associated with the 915 and I wanted to dispel some of the fear for a potential new buyer. And yes Ed I thought about your posts when the racing reference was made. Thanks to Rennlist most of this article was familiar territory for me. I guess I can't call myself an air-cooled newbie anymore.

salukijac

I didn't make a mistake when I passed on the 85. I passed on it because Boeing laid off 700 engineers the Friday before I looked at the 85, which was on Saturday. As a Boeing employee at the time, I didn't think was the prudent thing to do. That put a delay on my quest for a 911. 8 months later I found an 87 that suited my taste...but that 85 was sweet.

Again, I'm not arguing for the G-50 because I own one...just noting the facts. I agree that no one should overlook a 915.

w00tPORSCHE

Point is well taken. But you have to agree that there are many who are misinformed out there.

Ed Hughes

That is really the point. Most that come on here saying they want 87-89 are only saying that because they think the 915 is inferior, because they read it on the internet, i'll say it again, if it was all about improvements, we should all have deposits down on 991's right now, as ALL of our 911's have been eclipsed.

ivangene

my little 915 whooped them yesterday

I gave a ride to one of the senior driving instructors thru the autoX...upon exiting the course with a huge smile he said...man...I see the appeal to this car, its really unique and amazing the way it just comes around and GOES!...a very diferent car..wow...I love it - I have not been in an older 911 for quite a few years, they are really great cars, I have forgotten.

a few comments regarding my handling of it and the obvious love I have, the smoothness and ability to anticipate and allow the car to be where it needs to be....

yea I felt pretty damn good - and I will drive it to work tomorrow....I do believe I chose the right car....I would not go to a G50 mainly because of the clutch set up being not what I want..........so who cares, they are all great.....drive what you like just dont doubt the 915 as being anything other than GREAT !

450knotOffice

(Delete my entire post. I got my facts wrong Re: the gearing differences. It seems the G50 box has a 2% taller first gear ratio at the wheels than the US 915 in my '84 Carrera, BUT it has a 3% LOWER second gear at the wheels than my 915. Third gear in both boxes is almost identical at the wheels, with the 915 being about .7% lower. So, first gear launches in the 915 are stronger, but the G50 has a better accelerating second gear.)

ivangene

I wanna drive a 901

Steve Weiner-Rennsport Systems

Well said, Mister Hughes.

A properly built 915 is simply a delight to use provided all the shift linkage bits are in perfect condition. Adding a Wevo shifter offers a precision that the OEM version never had and its well worth the $$$.

Problem is, there aren't many really good 915's out there for people to sample and thats the root of prevailing opinions about these things.

For a 915 owner (or any prospective ones), finding someone to correctly rebuild these is well worth the hassle it might be as that will provide years of pleasure with these often overlooked models.