R/Z-chassis Alloy Rear Upright Differences

[JarrettL]

How's it going, guys? First post here, but I've used this site countless times as a source of great information on this chassis.

I've recently purchased an ENR34 25GT Four coupe and am awaiting transport for it to show up in person. As I wait, I've begun to assemble quite a few parts, including suspension bits. I'm wanting to change the rear knuckles to an alloy type that will accept the larger GTR-sized rear hubs to match the Z33 diff change. I'll preface the information below by saying that I've used Nissan EPC Data and Amayama's pages to determine as much backwards compatibility as I can.

I purchased a pair of alloy rear knuckles from a '96 Infiniti Q45 (G50). It shares the part number with the Z32. In looking at photos, I can't find a difference between these and the R32 parts, or even the R33/R34 parts. I've read that the width of the rear lower shock mount is 40mm at the metal sleeve on the older ones vs. 50mm of the R33/R34 variants. Honestly, the R33/R34 rear lower shock mounts don't really seem any wider from the pictures. 

Can anyone lay out what the differences might be between the multiple allow knuckles? I'm guessing a HICAS vs. non-HICAS knuckle are going to have different numbers despite the various bushings or joints that are different being removable.

In summary, what will prevent me from taking these Q45/Z32 rear alloy uprights and using them on my ENR34 with R34 GTR-style coilover bottoms? Thanks for the help! I'll upload pictures in a little while of the uprights I have, if that helps.

 

[robbo_rb180]

the ball joint taper is different. There is no need to change the knuckle to run the gtr hubs, I'v run run them on all my s chassis' with no issues.
I've got a set here and will get some pictures & measurements to show the difference

[JarrettL]

That's the first I've heard of the ball joint taper being different. And I'd like to pose a follow-up question, as the part numbers would seem to indicate a different story. On aluminum knuckles, all seem to use the same Nissan part number (40173-33P00), and that adapter/spacer/bush fits perfectly into the aluminum knuckle.

Here are the compatible chassis for that taper from Amayama https://www.amayama.com/en/part/nissan/4017333p00

Here is that taper bushing fitting into the knuckle that I have (which doesn't really prove anything about the inside taper size or pitch, I'll admit) 

 

 

And here are a few more to show the appearance and some dimensions of the Q45 rear upright.

 

 

 

Shock Mounting Boss

 

 

 

Bearing Bore Large Dimension

 

 

 

Bearing Bore Smaller Dimension (Inner)

 

Edited October 6, 2020 by JarrettL

[JarrettL]

Talked to a US retailer that had new OEM R34 GTT/GTR knuckles on hand and his caliper measurement (through plastic packaging) comes out to the same as the knuckles I have. So I guess I'm going to assume SuperPro rear lower shock mounts for an R34 GTT/GTR will fit these fine and allow me to run R34 coilovers all around.

[OldMateDavey]

Hey Jarrett, how'd you go with these? I'm in in the middle of doing this swap to my ER34 using R34GTR/GTT knuckles too. 

That ball joint spacer bush, is not in the knuckles I have, is that a standard part?

Edit: Found the part I need. It's: https://frsport.com/nissan-40173-33p00-genuine-oem-lower-ball-joint-tapered-seat-nissan-z32-300zx-89-93?gclid=CjwKCAiAp4KCBhB6EiwAxRxbpOACc7Axqake_emVHYEYGj0CFEixIjF5ZrN6P683va9rFDvts4IRsxoCr0UQAvD_BwE

Cheers 👍

Edited March 4, 2021 by OldMateDavey

[OldMateDavey]

Further to this, the R34GTR/GTT lower shock mount bush crush tube length is definitely 50mm.

[JarrettL]

Sorry Dave, I didn't have alerts turned on!

Glad you found the tapered seat. And yes, it's a standard part across multiple generations. Even the V36 Skyline (G35 sedan here in the US) I pulled a rear differential from used these at the rear knuckles. If it ain't broke, don't fix it, I suppose.

And thanks for the pictures of the crush sleeve dimensions. I imagine the thickness of the aluminum surrounding that bushing on yours and mine are the same and that they each take the same bushings. I purchased some BNR34 SuperPros, but just haven't gotten around to installing them yet.

[OldMateDavey]

58 minutes ago, JarrettL said:

Sorry Dave, I didn't have alerts turned on!

Glad you found the tapered seat. And yes, it's a standard part across multiple generations. Even the V36 Skyline (G35 sedan here in the US) I pulled a rear differential from used these at the rear knuckles. If it ain't broke, don't fix it, I suppose.

And thanks for the pictures of the crush sleeve dimensions. I imagine the thickness of the aluminum surrounding that bushing on yours and mine are the same and that they each take the same bushings. I purchased some BNR34 SuperPros, but just haven't gotten around to installing them yet.

Hey Jarrett, 

All good mate, ended up ordering them new through Kudos Motorsports here in Aus for $25ea.

The lower shock mount bush OD on these R34 knuckles are larger than Z32/R32 GTR, see below comparison photo between my R34 knuckle and Z32/R32 complete replacement spherical bearing bush from GKTech. I incorrectly ordered this spherical replacement as I originally thought that these were all the same. I've since decided to not press the old bush out in this instance and re-use it. 

I would do a quick double check on your Super Pro bushes compared to your knuckle/knuckle bushes (if you still have them). Let us know what you find.

[JarrettL]

Well, it seems you are correct. My SuperPros have an OD of just over 54mm. The bushing also measured 29mm wide, whereas the boss pictured above is 32mm, but I imagine there's not much to be gleaned from that.

Maybe it's time to look for some R34 GTT/GTR rear knuckles.

Cheers for the input so far!

[OldMateDavey]

Not a problem mate.

I doubt there would be much to be gained from this particular bushing, compared to Z32/R32 GTR in regard to geometry.  So, searching specifically for these R34 knuckles may be a waste of time when you already have a good pair. Push in a set of SuperPro Z32/R32 bushes and be done with it 👌.