Porsche 915 trans

[Mike Dozier]

OK

I'm getting conflicting info.
Kennedy Engineering (Bert?) told me flipping the ring and
pinion was easy. But Steve at German Transaxle said no.
Can anyone shed light?

MikeD

[Chuck]

Easy with a press. Inverting is different.

[Kalun D]

""I'm getting conflicting info.
Kennedy Engineering (Bert?) told me flipping the ring and
pinion was easy. But Steve at German Transaxle said no.
Can anyone shed light?""

depends on what you define as easy. Just from memory, I had one apart about 3 years ago. You have to pull the side cover and split the case. Then pull the main shaft out of the front case. Put the diff in backwards and re-assemble. You will have to check your gear mesh and back lash on the ring-and-pinion. If you have to change shims you will need a press. I believe there is also an issue with the speedo electronic pickup, you have to change the location because it picks up off the diff.

[Gary Gibbs]

There "may" be issues of oil control (drainback, etc.). I am not sure at all. Maybe some of the G50 experts can chime in here.

[andys]

Might I suggest talking with Jeff Field at Transaxle Engineering for the straight scoop. He pretty much specializes in 915's, and he's been doing it for a very long time. Don't let the site's dune buggy bias mislead you. http://www.transaxleengr.com/index.html

Andy

[Mike Dozier]

Thanks Andy...I will.

I guess I'm a bit curious why more GT40s aren't running
the 915 if all it takes is to flip the R&P.
Appears to me the 915 is stronger with better ratios
than the Audi 016. Maybe it's just because CAV and RF
support the Audi rather than the 915.

I've seen 915s sell on E-bay for less than $ 1,000 and
it's looking like modifying an 016 (either higher top gear
or new ring and pinion) will cost $ 1,000 or more
(inc labor) just to get ratios equal to the 915.
And that doesn't address the strength difference.

Of course if your car is already set up for the Audi
(adapter, shifter, drive shafts, etc) then the cost to convert to another trans is high. But for those just
starting out, I'm thinking the 915 may be the better choice.
Of course a G50 would be even better...but they are
lot's more money than the 915.

I know a few guys on the Forum are running a 915...
any complaints?

MikeD

[Lynn]

I do know that guys who use the G50 over the 915, do it in large part because the G50 uses a hydraulic clutch. I know a guy who converted his 915 to hydraulic because he had a lot more options in terms of gears AND R&Ps. These options are also much more affordable as well. You can find new ring and pinions for G50s, but as one knowledgable fellow put it, "they cost absolutely stupid money." Gear sets don't cost as much as the R&P, but they ain't cheap either. I could put G50/50 gearsets in my G50, but it was much more cost effective to buy a G50/50. Only took 3 years to find one though [img]/ubbthreads/images/graemlins/wink.gif[/img]

To my knowledge, the only issues with inverting a G50 is getting the fluid level right so it oils well. It does take a bit more gear oil, but the cost is a nit. The other issue is that once you get the proper oil level, the input shaft and, of course, the seal is under the oil level. If you have a bad seal, your going to have a bad leak. So, you put a new seal in it to begin with. The speedo pick up is also under the oil level. Everyone has said that the oil does not interfere with the magnetic fields and this makes sense. But, if there are ferrous particles they can build up on the pickup and this WILL interfere with its operation. Of course, if you have that much ferrous metal in your oil, you probably have bigger problems. An inverted G50 does lower the engine, but is that a bad thing? I think it is a good thing; my GT-40 oil pan is flush with the bottom of the car. I don't know what the issues with inverting a 915 are; possibly the flow back issue that Mike mentioned. At worst, this would require drilling ports between the sections I would think.