Printable Version of Topic
Click here to view this topic in its original format
914World.com _ 914World Garage _ Let's talk high performance CVs/Axles
Posted by: vintage914racer Sep 21 2020, 12:37 PM
I became the member of the failed CV joint club when the inner joint on my 914-6 vintage racer exploded entering turn-one at Road America. Just to spice things up, the tranny I was running has a welded diff, so the failure sent me into a spin....fortunately I avoided contact damage.
My winter project is to upgrade to a guard LSD and find beefier CVs that can handle the power my car is putting out.
I know there are options out there that consist of taking other Porsche CVs and adapting for use. I'm hoping to find an off the shelf option, as my available time to tinker in the garage is limited these days. I see Tarett sells high performance half shafts and I know Renegade does or did at one time.
Is there anything else out there that I should know about?
Posted by: brant Sep 21 2020, 12:42 PM
lots out there.
you can upgrade to 944 joints fairly easily (thread in the classics)
that will increase the size to 100mm
and the later hubs (911) can bump you to 108mm
is your chassis braced on the rear swing arm mounts?
these cars without tube bracing on the pivot point... will flex the entire frame and swing arm out due to modern tires.
flexing or stretching that CV joint in a corner when you are putting power down... is how I have blown all of my joints.
and adding the brace bars into the swing arm mount solved my problem 15 years ago... zero blown CV's since that time.
of course really big torque.. a V8 may just be too much for the small joints.. but I don't know how much torque your putting out.
Posted by: ClayPerrine Sep 21 2020, 01:04 PM
is your chassis braced on the rear swing arm mounts?
these cars without tube bracing on the pivot point... will flex the entire frame and swing arm out due to modern tires.
Brant,
Do you have a link to the braces? I would like to add a set to Igor (the 4.0L car).
Clay
Posted by: brant Sep 21 2020, 01:09 PM
is your chassis braced on the rear swing arm mounts?
these cars without tube bracing on the pivot point... will flex the entire frame and swing arm out due to modern tires.
Brant,
Do you have a link to the braces? I would like to add a set to Igor (the 4.0L car).
Clay
I don't.. sorry
I bet CFR sells something similar off the rack
I have 2 cars with swing arm braces... but my race shop added them in house and not a pre-fab part.
brant
Posted by: vintage914racer Sep 21 2020, 01:40 PM
lots out there.
you can upgrade to 944 joints fairly easily (thread in the classics)
that will increase the size to 100mm
and the later hubs (911) can bump you to 108mm
is your chassis braced on the rear swing arm mounts?
these cars without tube bracing on the pivot point... will flex the entire frame and swing arm out due to modern tires.
flexing or stretching that CV joint in a corner when you are putting power down... is how I have blown all of my joints.
and adding the brace bars into the swing arm mount solved my problem 15 years ago... zero blown CV's since that time.
of course really big torque.. a V8 may just be too much for the small joints.. but I don't know how much torque your putting out.
My car is indeed braced. I have a tangerine kit that was installed a few years ago. It was reinforced again last year when I had a suspected soon ear replaced.
Posted by: Mark Henry Sep 22 2020, 09:11 AM
My 901/914 trans I have the 108mm CV's, hubs, stubs, and input shafts (early 70's 911) and use Sway Away axles part # 2420.
I used later G50 108mm CV's, cheaper, easier to find, but they don't have the gasket groove. I carefully cleaned the mating surfaces and used a sealant.
Posted by: 914forme Sep 22 2020, 06:34 PM
Nice Mark - good call on the G50 parts over the 930 parts.
Posted by: Mark Henry Sep 22 2020, 06:53 PM
Nice Mark - good call on the G50 parts over the 930 parts.
The turbo CV's are quite a bit wider, I don't know if that would cause an issue. The G50 CV's are the same spline but are IIRC only 1-3mm wider. They work perfectly.
Money shot, you can't really see anything but the bright red Sway-Away axles look pretty.
Posted by: sixnotfour Sep 24 2020, 09:27 PM
The fact you had a welded diff, that alone will lessen the load..as it 100% bind every
slight angle from str. and even str with varing road surfaces...
hence the differential..
Posted by: mb911 Sep 25 2020, 05:48 AM
What about the bolt on cv/axle kit from tarret? Seems like a simple solution
Posted by: vintage914racer Dec 18 2020, 10:00 AM
What about the bolt on cv/axle kit from tarret? Seems like a simple solution
Good question. I’m curious about this as well. From what I can tell they, and pelican, re-sell the renegade high performance kit. The options mentioned above are all good options, but a ready to go solution from tarett, without having to source new flanges, stub axles, etc, is pretty appealing.
Posted by: Gary Dec 18 2020, 11:51 AM
I'm running a 108mm setup also:
* 1970 - 1973 sportomatic trans flanges. Part number 901-332-209-15. I believe 901-332-209-22 works too. These are coarse - splined and IIRC about 3/8 longer than the manual transmission flanges, making up part of the difference in length between 914 and 911 axles.
* 1969 - 1975 911 CV / axle; P/N - 911-332-033-08; 108mm 4 bolt CVs.
* early 911 stub axle / wheel hub - sorry I don't have the exact years handy.
Saw this combination described on the old listserv many years back posted by someone who raced. Has been working fine with my 3.2 for a few years now.
Posted by: 914Sixer Dec 18 2020, 05:02 PM
Using 911SC hubs, stubs and 915 coarse spline transmission flange. They are 100 mm 6 bolts. Using 944 CV's with sway away full floating axles. Plenty of axle choices over in the Classic Section.
Powered by Invision Power Board (http://www.invisionboard.com)
© Invision Power Services (http://www.invisionpower.com)