Originally Posted by Peter Zimmermann

Douglas: Very unusual (hard to shift cold), are you sure that you have a high-quality synthetic oil in it?

Originally Posted by rllevin

....have been in a well maintained, low mileage '88 with a G-50 and, call me crazy, but I really prefer the 915. Lots more character, not hard to drive if you know what you're doing and you know you're in a real 911. I guess I didn't like the light pedal of the hydraulic clutch release and the lack of feedback from the modern synchros.

Originally Posted by douglas bray

As you start your search for the perfect car and you find a G50 tranny don't be scared off by it if it is cold out. My rebuild now has 9,000 miles on it and it is very stiff when it is cold. after about 15 minutes or so it warms up and is a delight to drive. It tells you that you found the gear and then that you have it in. I have a weekends only cab that is very easy to jump into and go. The tranny just takes a little love.

Originally Posted by Tyson Schmidt

The weight difference between a G50 and a late model aluminum 915 is 25#. That's with similar clutch and flywheels set-ups. The stock G-50 clutch and flywheel are what add on the extra weight between a stock G50 car and a stock 915 car.

Originally Posted by 911-32

FWIW, the difference G50 vs 915 is 45lbs, but that includes everything flywheel forwards. The bare trannies are about 27lbs. You can fairly easily save 20lbs on the G50 by going for a lightweight aluminium pressure plate, a spring centred clutch and L/W flywheel. Now you are only 25lbs difference and you get the benefit of an engine that revs much quicker between gears and has less reciprocating mass for better acceleration. That's not to say you can't save some weight on a 915 as well, but you get the idea.
Richard

Originally Posted by jwerion

I have weighed the late 80's G50 and the aluminum 915 and there is 20.5 lbs difference stock trans to stock trans. I figured by the time I beef up a 915 and add a cooler I would only have about a 10 lb savings, not worth sacrificing the reliability of the G50 in my opinion. My G50 is bullet proof with out a cooler and I have been very happy with the decision. There is another 10 lbs savings if you use an older mag case 915 but that would not hold up to a 3.8 RSR motor from what I hear.

Originally Posted by Peter Zimmermann

Let's look at this a little closer. The weight of a filled 915 RoW version 915/67 with cooler is approximately 60 kg (132 lbs). The cooler weighs almost nothing (I can testify to this because I've cleaned a number of them), so let's call the USA 915/68 at 130 lbs. The weight of a filled RoW G 50 version 950/00 is 66 kg (146 lbs), which is virtually identical to the USA version 950/01. So we have a weight difference between the two transmissions of 16 pounds.

The 915 flywheel weighs 12 lbs, and so does the G 50 flywheel, so that's even.

The stock 915 clutch weighs 18 lbs, the G 50 clutch weighs 29 lbs. So, in total, the G 50 package is approximately 27 lbs heavier, which was offset (in 1986) by an increase in rear torsion bar size from 24.1mm to 25mm. Something else comes into play here that contributes to the 915 car "feeling quicker" to some drivers. Back in the day of Hemi-Cudas, 427 Vettes, etc., the ticket to really quick quarter mile times was having a "short", 4.11 rear end (final drive) ratio, or an even shorter 4.56 ratio. Of course, the big compromise with a short ratio was having to run at much higher revs at freeway speeds. Cars with a taller, aka longer, 3.00, or 3.30 rear end (ring & pinion ratio) just wouldn't come out of the hole as quick, and the race was usually over in 2nd gear. In 1974, 911s were fitted with a 7:31 ring & pinion, which is a final drive ratio of 4.43 (remember, the bigger the number the shorter the ratio). Later SCs and early Carreras w/915s had an 8:31 (3.88) final drive ratio, BUT, G 50s are fitted with a 9:31 (3.44) final drive ratio. Yes, the factory fitted all new, "shorter" ratios to 1st-5th to try and make up for it, but, while striving for better mileage and reliability, couldn't overcome that "longer" ring and pinion, which can make, combined with the extra pounds, a G 50 car feel more sluggish than a 915 car. A lightweight clutch will help the G 50 car, but on a road course there should be very little difference between the two because the rpm drop between second and third, between third and fourth, and between fourth and fifth, is very similar when comparing a 915 to a G 50. Yes, the 915, in some situations, will "feel" quicker, but can it generate quicker lap times on a road racing course? I doubt it.