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  View original topic: Porsche 930 CV conversion axle length? Page: 1, 2, 3 ... 16, 17, 18  Next
syncrodoka Wed Jun 02, 2010 7:32 pm

I bought the kit prebuilt for my van but figured I wanted to do it myself this time for the truck. I went out and bought all the parts to convert the rear axles over to the 930 cv's. The guys that I got all of the stuff from told me that I have to install the tranny drive flange and the rear stub axles to determine the axle length. Is it a simple method of measuring flange to flange at rest and at full compression and droop and subtracting a little to get the axle length needed. I really want to avoid taking a axle off the van and stripping it down to get the length needed. I bought all the stuff from avery's- http://store.averysaircooled.com/merchant2/merchan...de=Offroad

blakeck2 Wed Jun 02, 2010 7:41 pm

I believe Gowesty sells a kit, maybe ask them for the length

onwardtothestars Wed Jun 02, 2010 9:04 pm

the measurements for the 16" axles is in the 16" trailing arm thread. One of the empi axles is very close in length, and I figured using one of those greasing plates as a spacer would make up the difference otherwise it's to sway-a-way for their axles

ALIKA T3 Wed Jun 02, 2010 9:19 pm

I don't know why the axle lenght would change if the 930 flanges and stub axles are the same total depth.If not measure the difference :wink:

r39o Wed Jun 02, 2010 9:19 pm

syncrodoka wrote: I bought the kit prebuilt for my van

I really want to avoid taking a axle off the van and stripping it down to get the length needed.
I think you got your answer.

What about the company that you bought the kit from?

The below site has some axle lengths.

Just which one you need is the question.

As an aside, do you really need the 25 degree swing of the 930 CV?

http://www.blindchickenracing.com/How_to/CVJoints_Axles/axles_and_cvs.htm

syncrodoka Wed Jun 02, 2010 9:31 pm

The guy that I got the last 930 CV axle assembly had put them together and they were plug and play, no putting things together. I would like to avoid undoing work that has already been done and installed to get a measurement, but I can if needed. I can poke around google and may get the answer but I thought checking with people familiar with this conversion first would be best.

onwardtothestars Wed Jun 02, 2010 9:44 pm

SyncroGhia wrote: onwardtothestars wrote: ....

Anyway, on the 16" trailing arms subject - What length axles are people using with their longer arms and 930 CV's ?

Not sure what length others are using but the stock Syncro 16 rear driveshaft length end to end is 525mm. I took the time to measure the stock ones on my 16 when I replaced the rear CV joints last time.

I've moved the rear shocker mounting up by 85mm (allowing the rear arm to drop that much lower) and the stock syncro 16 rear CV joints (they're just Audi CV joints for your info) are about 3mm away from going into bind.

MG

syncrodoka Wed Jun 02, 2010 9:50 pm

Thanks for digging that up for me. The stock syncro 16 axle length won't work due to the additional thickness of the 930 CV's I am told. I'm still digging around hopefully someone can point me in the right direction before I tear apart a perfectly good axle assembly. :?

onwardtothestars Wed Jun 02, 2010 9:59 pm

if that's the truth the next choices available without being custom made are
19.25" (empi and swayaway)
20.25" (empi and swayaway)

a little shorter then the 16" units @ 20.6692913"

I'd guess they are off the shelf parts others are selling, my guess, 20.25"

SyncroGhia Thu Jun 03, 2010 5:07 am

syncrodoka wrote: Thanks for digging that up for me. The stock syncro 16 axle length won't work due to the additional thickness of the 930 CV's I am told. I'm still digging around hopefully someone can point me in the right direction before I tear apart a perfectly good axle assembly. :?

Could you measure the thickness of the 930 CV joints? and I'll measure a Syncro 16 (Audi) CV joint here and report back.

Mike

syncrodoka Thu Jun 03, 2010 6:14 am

40.36mm. Thanks

onwardtothestars Thu Jun 03, 2010 7:07 am

syncrodoka - I think you shared this site with me before, it's got all the measurements....
http://www.blindchickenracing.com/How_to/CVJoints_Axles/cv_joints_101.htm

edit- but not the audi ones

ALIKA T3 Thu Jun 03, 2010 4:20 pm

The Audi CV joints and others 108mm should be 32mm thick.
Porsche ones are thicker,like said,40mm-ish,depending on the factory....

I don't know why the axle length would change mounting thicker CV joints like the 930's,the end clip will still be at the place.(If the stub axles and flanges respect the same depth dimensions as the Typ25)

Measure to be sure,but you should find the same length as an original axle.that's my theory.

Syncroincity Thu Jun 03, 2010 6:29 pm

ALIKA T3 wrote: The Audi CV joints and others 108mm should be 32mm thick.
Porsche ones are thicker,like said,40mm-ish,depending on the factory....

I don't know why the axle length would change mounting thicker CV joints like the 930's,the end clip will still be at the place.(If the stub axles and flanges respect the same depth dimensions as the Typ25)

Measure to be sure,but you should find the same length as an original axle.that's my theory.

Right... your distance flange-to-flange is not going to change, just how much of the splined portion of the axle is engaged with the CV splines. The tips of the axle will be relatively in the same position. I just ordered the EMPI axle length closest to stock 14" syncro for my setup, but I haven't tried it out yet... so I may be talking out my a** :lol: We'll see.

The question I really want answered is what we need for the front axles; is there an off-the-shelf axle that works with 930 inners and Syncro 16" outers? Different splines on either end, correct?




syncrodoka Thu Jun 03, 2010 7:04 pm

The stock 14" rear axle is 542 mm. The syncro 16 with their thicker CV's and more articulation are 528 mm. I gotta assume that the axle is going to be even shorter for the 930 CVs. Remember that a pair of 930 CVs are 5/8" thicker than a pair of stock 14" CVs. That height difference has to go somewhere.

syncrodoka Thu Jun 03, 2010 7:18 pm

Dug this up from the syncro 16 trailing arm thread-
Quote: I have been going through this same dilemma with my 16" DoKa. I switched to the 930 joints and did not go to shorter axles. The 930 joints are about 1/4" thicker than the factory 16" joints. That meant about a 1/2" total per side.

Syncroincity Fri Jun 04, 2010 12:20 am

:? Hmm, OK, I guess I'm asking the same question as you now. :oops:

http://www.dansperformanceparts.com/buggy/susp/buggysusp%20IRS.htm

I'm pretty sure I got the 20.25" axles... next one down is 19.25", then 18.75".

syncrodoka Fri Jun 04, 2010 12:41 am

I found some Sway-A-Way measuring instructions online- http://www.swayaway.net/joomla/images/InstallInstructions/AxleLengthMeasurementInstructions.pdf

Syncroincity Fri Jun 04, 2010 10:15 pm

Correction... I got the 21.375" axles; 543mm :? I would probably need the next smaller one available; 20.25", at 514mm; 29mm shorter.

SO, 5/8" = 15.8mm is the 930 CV thickness differential, x2 per axle, for 31mm and the difference between the available axle sizes is 29mm. I would call 20-1/4" axles the correct ones, since the next available size is 19-1/4 or 489mm, which would leave us 23mm too short.

Any thoughts?

syncrodoka Fri Jun 04, 2010 10:55 pm

I don't know about your tranny flanges/stub axles, but I was looking at mine and they are taller than stock and I will definately have to install them to determine the axle length. The Sway-A-Way instructions are the way that I am going to get a axle length, but they say to check both sides as well. Unfortunately it means ripping out the tranny drive flange seals and installing new ones. Pulling everything out to install the hardware temporarily then switching back to stock then reinstalling everything once the axles arrive sounds like a waste of at least 4 seals. Having the truck non-operational for a time is no fun either. :cry:



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