SEW QUIK

I am contemplating the purchase of a 84 Euro 930 that had a 915 5 speed gearbox put in. Other mods were also done (1 bar boost spring, Andial fuel enrichment). I know the G50 conversion for 930's works well, my concern is whether the 915 box is strong enough to handle the power of a modified 3.3 motor on a long-term basis. I am not planning furher huge mods, maybe an intercooler, powerflow, etc. as I plan to drive the car daily. Any advice would be appreciated.

thanks,

SEW QUIK
87 Carrera coupe

Dean

I can't speak about how long it will last. I put a 75 930 in my SC with a 915 trans. I have had it about 1 year and 6k miles. I never dump the clutch but I do drive hard. I did see a video of a guy who dumped the clutch at 6k rpm in a turboed Carrera with a 915. He did it 3 times. I couldn'd believe that it could take the abuse. I figure if you don't drive like that it should last a long time. But what the hell do I know.
Dean

Christian K

Wasn't the reason for Porsche to not put the 5 sp. 915 in the turbo that it wasn't able to handle the torque?

/c

mic

I have a 915 being loaded by a 400hp 930. It is great - after i had it professionally rebuild 2 years ago. The previous owners turned it to swiss cheese.
The mechanics that it say it should last long as i dont drag with it (drop clutch at start). Considering the cost of rebuild over going to a G50, it was worth it.

FYI: I also have a G50/50 behind a stock 930. I like the gearing of the 915 better and the 915 even shifts quicker than the G50/50. However, if i drop the final gearing of the G50/50 to euro spec it should also be awesome. (1st and 2nd gears are too high for my liking).

Also, I have driven a few 930 w/ 4spds. I prefer the 915 with the gearing that i have.

garrickl

I purchased a 1978 930 with a fully rebuilt 86 915 5 speed that was installed by the PO that had approx 17,000 on it by the time of purchase. I added a K27\7006, Kokeln intercooler, euro exhaust and a free flow borla muffler. After 2000 miles the transmission started sounding like there were marbles rolling around inside, so noisy that I would keep the clutch depressed when idling. Car was not tracked and I never popped the clutch or even match raced anyone on the street. I have heard from other owners that have had similar problems, cracked 2nd gear, melted 5th gear .... that the box is simply not strong enough once you start mods on the engine. I have heard from others with basically stock 930 engines that have had no problems and there are quite a few racers out there also running 915 boxes without major problems. The weakness of the box is with the brake band synchros and the bearing retainer plate. There are after market billet and steel bearing retainer plates that can be installed and you can adapt 930 dog and synchros during a rebuild. The box could also benefit by having a pressure bar installed and squirting oil over the gears and R&P with an external oil cooler. I weighed all my options of reinstalling the factory 4 speed, rebuilding and beefing up the 86 915 ... I decided to sell both and go with a shortened G50 because it is a better shifting stronger box.