is the G50 that much better?
08-20-2002, 05:21 PM
#16
Guys:
Like so many of these posts, we tend to lose the intent of the original post.
I was answering the question, .." Is the G50 trans *that* much better that I should hold out for it, instead of the earlier 915..."
...to which I posted my reply. I still stand by the facts that the G50 is only superior if the appropriate mods are made, because it otherwise has an achilles heel of becoming a problem. Not "if"... but"when"....
No question that a modded or sorted-out G50, operating more smoothly than a 915, would be more desirable. I was simply pointing out that each has positive and negatives...so, I would say , yeah, it may be better...but *much* better? I still say no.
As to fluid changes, I guess compared to "none" for the 915, the G50 is at a disadvantage here too, even if the change interval is infrequent.
--Wil Ferch
Like so many of these posts, we tend to lose the intent of the original post.
I was answering the question, .." Is the G50 trans *that* much better that I should hold out for it, instead of the earlier 915..."
...to which I posted my reply. I still stand by the facts that the G50 is only superior if the appropriate mods are made, because it otherwise has an achilles heel of becoming a problem. Not "if"... but"when"....
No question that a modded or sorted-out G50, operating more smoothly than a 915, would be more desirable. I was simply pointing out that each has positive and negatives...so, I would say , yeah, it may be better...but *much* better? I still say no.
As to fluid changes, I guess compared to "none" for the 915, the G50 is at a disadvantage here too, even if the change interval is infrequent.
--Wil Ferch
08-21-2002, 04:03 PM
#17
Instructor
I wasn't challenging your statements Wil. I am honestly curious regarding the fluid change issue. It's something I have not heard before and would like to know why fluid changes are more frequent for a G50.
08-22-2002, 11:56 AM
#21
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I like the 915 better. I have driven cars with the G50 and, personally, I thought it felt too much like a Honda. It did not feel like a 911, thats just my opinion/preferance. I ended up buying a low mileage 86 that shifts wonderfully and 'feels' like a 911 should, with a bit of effort needed. It is after all a sports car.
08-22-2002, 12:11 PM
#22
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I've thought about that issue of 915 folks upgrading to a G50. Not sure whether it can be done, but I don't see why not. I have a friend with a '77 Targa, who just did a 3.2 conversion with no problem - I know that's the reverse of this question. But I believe the 3.2 engines got 10 more HP in order to handle the much heavier G50. You'd have to get a new flywheel, complete clutch kit, guide tube and then run a master-slave hydraulic line. So it's quite a job. I think it would be better to just buy an '87 or later car.
08-22-2002, 01:05 PM
#23
Instructor
Changing to a standard G50 is a big job. It's not just a trans. swap. You have to modify or change out the rear suspension torsion bar tubes to accommodate the different case/shape and added heft of the G50. If you remove the 915 torsion bar tubes and replace with G50 tubes (instead of modifying 915 stuff- I don't even know if this has been attempted), you must also replace the spring plates and torsion bars to accommodate the different number of splines within the G50 tubes. Looks like if you go with a shortened bellhousing G50/50 like the unit from the 89 930, you don't need to do the torsion bar tubes. You also must plumb the hydraulics for the clutch system and change the pedal cluster in order to accept the clutch master cylinder, which resides in the pedal cluster on the G50 cars. Gotta change the shifter assembly. Gotta change the clutch disc, pressure plate, flywheel...... can't use ANY of your 915 stuff here! I think the trans. mount dimensions are the same, so at least that's one less hassle to deal with!!!
Patrick Motorsports is the first shop that comes to mind regarding G50 conversions.
<a href="http://www.patrickmotorsports.com/g50.html" target="_blank">Patrick G50 Conversion Page</a>
Check it out. This job ain't cheap- especially if somebody else (a shop) is doing your labor!!!!! I think money would be better spent on a 915 rebuild by one who is fluent in 915 boxes. JMO. Plus, I believe I recall Roland Kunz saying the 915 is stronger trans. especially when a fluid cooler is added.
I think the added 10 hp was a change in how HP was rated.
Patrick Motorsports is the first shop that comes to mind regarding G50 conversions.
<a href="http://www.patrickmotorsports.com/g50.html" target="_blank">Patrick G50 Conversion Page</a>
Check it out. This job ain't cheap- especially if somebody else (a shop) is doing your labor!!!!! I think money would be better spent on a 915 rebuild by one who is fluent in 915 boxes. JMO. Plus, I believe I recall Roland Kunz saying the 915 is stronger trans. especially when a fluid cooler is added.
I think the added 10 hp was a change in how HP was rated.
08-23-2002, 11:47 AM
#24
Guys:
No "axes grinding"....
I wasn't clear...the 915 uses a cable...the G50 uses hydraulic actuation. It's "that" fluid change I'm talking about...the hydrauilics for clutch actuation. I thought my statement about 915 requiring "none ( implying cable)..was clear enough. Apparantly not...sorry.
--Wil <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />
No "axes grinding"....
I wasn't clear...the 915 uses a cable...the G50 uses hydraulic actuation. It's "that" fluid change I'm talking about...the hydrauilics for clutch actuation. I thought my statement about 915 requiring "none ( implying cable)..was clear enough. Apparantly not...sorry.
--Wil <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />
08-23-2002, 04:16 PM
#25
Instructor
Ohhhhhhhh! That fluid! Yes, most definitely another thing to consider about the G50- bleed clutch when you do the brakes. Forgot about that aspect. Good point Wil!
08-24-2002, 02:18 AM
#26
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[quote] Carrera51 I'm with Wil and John. 915s are great.
Of course, I am biased towards the 915 since my Carrera has one. Once you learn the quirks, and know how to shift them properly, they hold up well.
<hr></blockquote>
So what is shifting them properly? I've had a 915 for 2 years and don't do anything special. 2nd has always seemed a little hesitant, but after a linkage adjustment it is much better. I had my first DE day this summer and didn't do anything fancy, just shifted a little harder (less hesistation) and I was generally very impressed with how well it shifted under harder driving. I was a bit deliberate though as I didn't want to miss a shift.
Do you 915 drivers hesitate between gears? Is going into 2nd worse than the other gears (up or down)? What do you do differently on the track?
Of course, I am biased towards the 915 since my Carrera has one. Once you learn the quirks, and know how to shift them properly, they hold up well.
<hr></blockquote>
So what is shifting them properly? I've had a 915 for 2 years and don't do anything special. 2nd has always seemed a little hesitant, but after a linkage adjustment it is much better. I had my first DE day this summer and didn't do anything fancy, just shifted a little harder (less hesistation) and I was generally very impressed with how well it shifted under harder driving. I was a bit deliberate though as I didn't want to miss a shift.
Do you 915 drivers hesitate between gears? Is going into 2nd worse than the other gears (up or down)? What do you do differently on the track?
08-24-2002, 12:42 PM
#27
Instructor
these discussions of 915 vs g50 very rarely bring up the subject of weight. if i'm wrong i'm sure someone will correct me but it's my understanding the g50 is about 100lbs heavier and since weight is the enemy...
08-24-2002, 01:17 PM
#28
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Wil, yes of course there are different maintainence issues with the 915 vs. G50... for instance, not having to adjust & replace cables could be considered advantagous to some owners.
Weight is one critical metric of a component, but the overall performance of a drivetrain & chassis as a system is ultimately the determinant of cost-benefit. Throw in the ergonomic & operational modes for a complete analysis.
I believe the overall weight differential between the '86 & '87 Carreras is less than 100 lbs, & there are numerous distinctions in the year-to-year "build list" that may comprise that. It is suprisingly difficult to make apples-to-apples weight comparisions for that reason. The fact that these trans. are so difficult to interchange makes the direct comparison practically moot (to me anyway). Another complication... is the G50 support subsystem weight further forward in the chassis?, higher or lower in the body? etc...
When in standard mechanical condition, operated as appropriate for their distinct "personalities", how much of a difference in performance & usage is there between the alternative models? The G50 is simply a later solution, one driven by numerous factors, the main ones having to do w/ the on-going transition to higher torque powerplants (the change in synchros from Porsche design to BW) and supplier issues. I like my '87, I like all the 66-86 911s I've driven too.
Weight is one critical metric of a component, but the overall performance of a drivetrain & chassis as a system is ultimately the determinant of cost-benefit. Throw in the ergonomic & operational modes for a complete analysis.
I believe the overall weight differential between the '86 & '87 Carreras is less than 100 lbs, & there are numerous distinctions in the year-to-year "build list" that may comprise that. It is suprisingly difficult to make apples-to-apples weight comparisions for that reason. The fact that these trans. are so difficult to interchange makes the direct comparison practically moot (to me anyway). Another complication... is the G50 support subsystem weight further forward in the chassis?, higher or lower in the body? etc...
When in standard mechanical condition, operated as appropriate for their distinct "personalities", how much of a difference in performance & usage is there between the alternative models? The G50 is simply a later solution, one driven by numerous factors, the main ones having to do w/ the on-going transition to higher torque powerplants (the change in synchros from Porsche design to BW) and supplier issues. I like my '87, I like all the 66-86 911s I've driven too.
08-25-2002, 06:19 PM
#29
Just finished changing all the bushings and adjusting my 915 shift linkage.
The shifting improvement is very noticeable - more precise, sure shifts. Still no speed shifter like an Americam muscle car but not "balky".
I have the feeling that most 915 cars have gradually developed enough "slop" in the shift mechanism to exacerbate the "sensitivities" inherent in the transmission and have fed the bad reputation.
In my '86 (less than 90K miles), the shift coupler bushing bores were obviously "ovalized", with the other bushings not visually defective but definitely worn.
I haven't driven a G50, and it probably is still better, but $50 and 4-5 hrs work seems to address a lot of the negatives with the 915 that make folks think they need the G50.
The shifting improvement is very noticeable - more precise, sure shifts. Still no speed shifter like an Americam muscle car but not "balky".
I have the feeling that most 915 cars have gradually developed enough "slop" in the shift mechanism to exacerbate the "sensitivities" inherent in the transmission and have fed the bad reputation.
In my '86 (less than 90K miles), the shift coupler bushing bores were obviously "ovalized", with the other bushings not visually defective but definitely worn.
I haven't driven a G50, and it probably is still better, but $50 and 4-5 hrs work seems to address a lot of the negatives with the 915 that make folks think they need the G50.
