Wives tale broken?

[1977930]

 

I found this quite interesting, 

 

 

 

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.

[MaxzmusSC]

" 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."

So what is the correct way to use them and be able to shift quickly?

[tazzieman]

I suspect the Florida wives had a say in it.

 

Good comments here http://forums.rennlist.com/rennforums/911-forum/660010-915-gearbox-can-you-handle-the-truth.htmland I would agree , it has to be set up properly , a 911 should be respected like a stradivarius.

[Uncle]

While I do find great pleasure and reward in getting the shift right with a 915 and find it's quirkiness endearing to the 911 I don't think I would stretch to saying its a great gearbox. It's just not. Good? Yeah ok I'll give it good just because I like the fact is makes me drive the car correctly. If you don't pay attention to what you are doing and instead of driving you are operating it will get grumpy with you. 

 

My gearbox is well set up with new bushes everywhere,fresh oil,new mounts and a Wevo shifter. Basically everything I could do to make it the best set up possible. Is it nice to drive? Yep. Is it easy to drive? If you understand a 915 yep. Can you get it into first at anything other than a snails pace? Nope. Do I quietly enjoy the fact getting to know how to use a 915 is like a right of passage only other guys who have or had them understand? Yep.

[clutch-monkey]

it's a decent gearbox but the G50 is no doubt the better piece of equipment. i do think a lot of the bad feedback from 915's is from 30 year old units with shagged bushings and linkages driven by people who don't know how to use older gearboxes; once set up properly they're pretty decent.

for me if trying to buy between a G50 car and a 915 car the difference in condition will matter far more than which gearbox it has*.

 

 

*unless going turbo!

[_Tony]

Have never driven a G50 car.. maybe for the better as id probably want one but im finding i have a much better understanding and appreciation of the 915's nuances now. I really dont mind the gearbox.. 

[Airhead]

That headline had me thinking something entirely different.

[cyberpunky]

when I raced go karts, I raced with a lower spec J motor which was great as it taught me to be very clean with my racing lines and to be smooth so as not to wash off momentum, so I understand reward for doing things right, and it was great beating guys in the higher S motored karts because they lacked the basics in skills and would wash off speed and try and use power to compensate, however for me I would have gladly moved to an S motored kart if I had the funds once I had mastered the J spec kart.

 

Many of the great Porsche racing drivers say there favourite racing cars were easy to drive fast and a pleasure to drive, and not the brutal hard to master pigs, that although a rush to drive were far more demanding. Derek Bell still owns a 944 and has nothing but praise for them.

 

The latest Porsche Cayman S/Boxster S are getting insane reviews, to the point where some are saying why bother even buying a new 911 when they have got these cars sooo right. Personally I would love to own a lot of new Porsche cars and a lot of old ones like a 73/74 RS, a GT2, GT3, Carrera GT, 918 or even the latest Cayman S.It is hard to understand why it is a wives tale that these boxes are not sought after like the cars with the G50's, as to me it just makes sense to want better, all else being equal and the old advice of buying that later more advanced versions of any particular line still makes sense, as it not saying the earlier cars were rubbish, just that Porsche did their job and made better. Unless you are a masochist or a romantic then for me a G50 is the way to go but if anyone wants to give me a 911 with a 915 box I'll be very happy to accept

peace

Cyberpunky

[MaxzmusSC]

I take it from ppls responses you need to shift slowly with these things.

[Uncle]

Not so much slowly just correctly. Out of gear>Slight pause>Next gear. You need to mover your hand smoothly but firmly. 

 

Incar from one of my runs at the SM1000 last year. 

 

http://www.youtube.com/watch?v=JtmdncKC5tA&feature=c4-overview&list=UU7rJoENVnOs_F95tt5bbY9w

[Cal]

Derek Bell still owns a 944 and has nothing but praise for them.

 

Not wanting to be a dick, but I don't think he does. He does own a 924 GTS though. I saw it a few years back.

[tazzieman]

0-100 in 4 secs + time taken to change gears 

[Harvs11]

Down-shift to 2nd, accelerate a bit to move into a gap in traffic. quick shift to 3rd and bang! I've got a new photo for the collection. And a lighter wallet

915 boxes can be expensive, even when they are working perfectly.

[pocketscience]

Not wanting to be a dick, but I don't think he does. He does own a 924 GTS though. I saw it a few years back.

Correct - it's a 924 GTS that he was given by Porsche. Awesome car. Nearly as awesome as the 924 GTR he raced.

[Doish13]

Down-shift to 2nd, accelerate a bit to move into a gap in traffic. quick shift to 3rd and bang! I've got a new photo for the collection. And a lighter wallet :(915 boxes can be expensive, even when they are working perfectly.

Ok that's your second reference today - did you get caught?

[Simonk]

Not so much slowly just correctly. Out of gear>Slight pause>Next gear. You need to mover your hand smoothly but firmly. 

 

Incar from one of my runs at the SM1000 last year. 

 

http://www.youtube.com/watch?v=JtmdncKC5tA&feature=c4-overview&list=UU7rJoENVnOs_F95tt5bbY9w

That's shifts better than my G50!!!

[Harvs11]

Ok that's your second reference today - did you get caught?

maybe...

[Doish13]

With the election looming its a good time to write to your local Polli.... As long as your record otherwise is clean. It's worked before for people I know.

[_Tony]

Out of gear>Slight pause>Next gear

 

I never noticed if i do this or not, i.e. the slight pause. Made a conscious attempt at it this morning and the transitions were smoother. Thanks for posting this. As you also mention, smooth but firm i find to be important.. a very deliberate shift to the gear helps

[SteamWolf]

Slow shifting helps but as Uncle said, a slight delay between going for the next gear is the trick.  Double clutching and match revving works even better, especially on downshifts or skipping gears (which I do often and comfortably with my 915).

 

It is frustrating trying to get between say 2nd and 3rd in a big hurry and having the gearbox shout at me for doing it. Does remind me to chill a bit when driving in a spirited fashion.

[Harvs11]

With the election looming its a good time to write to your local Polli.... As long as your record otherwise is clean. It's worked before for people I know.

 

Good advice D.  If they responded it would be the first useful thing they've done.

 

Maybe someone besides me should write that letter.   People in glass houses.....

 

getting a bit OT here.

[clutch-monkey]

Slow shifting helps but as Uncle said, a slight delay between going for the next gear is the trick.  Double clutching and match revving works even better, especially on downshifts or skipping gears (which I do often and comfortably with my 915).

 

It is frustrating trying to get between say 2nd and 3rd in a big hurry and having the gearbox shout at me for doing it. Does remind me to chill a bit when driving in a spirited fashion.

i've never really had trouble upshifting as fast as i want, it's just the downshifts need the proper attention i find.

plus the upshift into 5th as it clicks through the gate is just great

[Russ]

is the speed of change issue with a 915 beating the syncros? or is it something else?

[tazzieman]

In Paul Frere's book he says Porsche were happy with the reliability & durability of the 915 (It was the base for a racing box) , but aware of its higher shifting forces than the (admittedly heavier) BorgWarner G50. That , plus the expense of adding an oil pump/cooler to cope with the 3.2s torque , caused the shift (pun intended) to the G50.

In the 80s stop-start traffic was becoming the norm for a lot of 911s bought by city boys  , thus you can imagine the complaints to Porsche (no mention of weak wrists or wive's grumbles ) . The damage wrought by uneducated forced 1-2 shifts in the stress of the daily commute would have contributed to the bad press and a move to an idiot proof mechanism.

 

Over time , as we know there was a move from the concept of a pure driver's car (with mandatory warning in the owner's manual) to more user friendly standard models . They even decommissioned the cool ventilation system! Marketing genius. 

[Harvs11]

The damage wrought by uneducated forced 1-2 shifts in the stress of the daily commute would have contributed to the bad press and a move to an idiot proof mechanism.

 

 

Nothing is idiot proof. There's always a bigger idiot to find new ways to ruin something.  We've got a slightly different phrase in the engineering office, can't print it here though.