Cutting late dual spring plates down to single?

Steve Arndt · Post by **Steve Arndt** » Thu Jan 21, 2016 7:13 am

Turbo 4 piston 951 calipers are also a direct bolt on to the early 944 rear setup, no adapter needed. I have that setup sitting on the shelf (since 1999 doh...)

Ol'fogasaurus · Post by **Ol'fogasaurus** » Thu Jan 21, 2016 7:18 am

The 7075-T6 is much stronger than 6061-T6. We used the 7076-T6 for primary structure and the 6000 series of material for areas where its ability to handle corrosion is much better.

Since I never worked with "cut and paste" like you guys are doing here I wonder if a re-temper would be judicious in this case. You can get those thing glowing red hot on the road course so maybe they are OK as it assuming you used the right material to rejoin the halves.

Just a thinking out loud.

Bruce.m · Post by **Bruce.m** » Thu Jan 21, 2016 7:47 am

My hubs pictured above are steel. Aluminium would be lighter but may need to be fatter in places to maintain the strength. That maths is beyond my knowledge. My steel hubs replicate the boxster steel front hubs although the boxster version is pared back to the minimum (backed up by full CAD failure analysis). My steel hubs are lighter than I expected as a large part of the original disc has been removed. The new disc is supported by M5 screws during assembly but in use, the wheel studs take the load, exactly as per OEM use on the boxster.

Post by **Piledriver** » Fri Jan 22, 2016 1:55 am

Steve Arndt wrote:http://www.racersedge-inc.com/racersedg ... &id=9.3.18
http://www.racersedge-inc.com/racersedg ... &id=9.3.17

Precision inner and outer 944 torsion bar delrin bushings. I would just go this route. Racers edge also has some trick inner trailing arm pivot spherical bushings for alloy arms. can those be fitted to steel arms?

I also meant to follow up with knobby vs smooth on the inner bushings. They are smooth as shown, not knobby like VW torsion.

These are Delrin, for T1 made by SACO.
Might be easily moddable for 944, curious what the dimensions of the outer 944 one are.
Given the wee price delta vs the 944 bits I think I'd try, Note: Each part# is a pair of inners and outers in a variety of sizes.
http://www.pacificcustoms.com/mm5/merch ... ange_high=

Theres a bunch of different sizes so something would likely either fit or be made to.
They have the inner bushing setup in delrin as well.

Looks like I'm just going to have to do T1 single plates unless I just take a grinder to the duals in place.
Backyard is under water so it will probably be another week anyway.

Anyone have a set of clean LATE T1 IRS single spring plates for sale?

At least it drives good. Looks funny with the rear "jacked up" tho.

So, if I cut off the inner trailing arm mounts ~flush, and weld an oversize flat plate on the torsion and the mount, 2 bolts above/2 below with floating nutplates on the front (and slotted holes) , it gives me adjustable camber, right?
Late T3s lack frame horns, so nothings in the way.

What am I missing? Seems like the 944 guys would have done this forever.

Bruce.m · Post by **Bruce.m** » Fri Jan 22, 2016 5:21 am

Why mess with the inner pivot? The 944 camber adjuster does the job (+/- 1 degree adjustment at least) and can be fitted to single Spring plates with some hand filing.

Bruce.m · Post by **Bruce.m** » Fri Jan 22, 2016 5:29 am

Here it is (shiny one), you can see the sway bar stud on the other side (there is a version that is missing that, although you could easy cut it off).

Post by **Piledriver** » Fri Jan 22, 2016 10:42 am

That was ~the plan, but I don't have enough tire clearance at that location, unless I seriously thin the nut and shorten the bolt.
...and the ride height/camber adjustment are the same adjustment.

I had an idea how to mod the Porsche arm so the adjustment was on the bottom of the arm, but I really don't need an "easy" height adjustment as I have no plans to seriously AX or such..

Plus, I'd like to be able to drop it 2" and set camber back to stock range.

I was eyeing the weld in rear torsion adjusters, the T3 rear torsion unbolts...
Probably excessive to my needs.

Bruce.m · Post by **Bruce.m** » Fri Jan 22, 2016 12:03 pm

Ah, gotcha on the bolt clearance.
Fwiw - the camber bolt only effects the ride height by a small amount as a byproduct. On the 944 Spring plate there is yet another offset bolt to adjust the ride height.

Bruce.m · Post by **Bruce.m** » Fri Jan 22, 2016 1:06 pm

Come to think of it. It would be fairly easy to recreate the 944 bolt as a stepped washer with flats and offset drilled. Very easy with a lathe but also possible without. Then you could use a countersunk bolt (head to 'outside') and a nyloc on the inside. The section of the washer that would fit inside the Spring plate should be 18mm diameter (as per the 944 part). Make sense?

Ol'fogasaurus · Post by **Ol'fogasaurus** » Fri Jan 22, 2016 7:47 pm

There are 4 CSK angles for flush fasteners and the same for CSK washers, yes, they are available but may be hard to find. The ones I played with that I thought were 90 degree turned out to be 82 degree so be careful. The 82 degree CSKs are deeper so if you want to stay shallow you may have to do some searching for the 100 or 120 degree heads. The higher the degree number is the larger diameter the head will be. Also check for the torque value will be before failure as you are dealing a thin head.

Again, a lot of homework to be done.

Lee

Update I just checked and they show 60 and 110 degree washers and bolts and were not hard to find. I think the biggest problem will be unit price and minimum unit availability.

https://www.bing.com/images/search?q=co ... &FORM=IGRE

https://www.bing.com/images/search?q=co ... &FORM=IGRE

Lee

Post by **Piledriver** » Fri Jan 22, 2016 11:41 pm

Bruce.m wrote:Come to think of it. It would be fairly easy to recreate the 944 bolt as a stepped washer with flats and offset drilled. Very easy with a lathe but also possible without. Then you could use a countersunk bolt (head to 'outside') and a nyloc on the inside. The section of the washer that would fit inside the Spring plate should be 18mm diameter (as per the 944 part). Make sense?

Gotcha, that was sorta the plan, with an additional weld on bit for setting the ride height on the adjustable part putting a jack screw on the bottom, and using countersunk bolts for clamping.

I just need to find another set, had some ordered but they apparently previously went home with somebody, so I got my money back at least. All that's on Ebay now are the turbo/S2 ones for the aluminum trailing arms, shorter and different bolt pattern, and more money. Sadly those arms are far too wide unless I narrowed my torsion and moved the inner pivot further in. (again, easily doable with no frame horns)

My tire guy put 45 PSI in the back tires, despite asking what pressure I wanted, actually rides almost stockish with 30, and much quieter.
I need to put a tape around those 50s and see what dia they really are, the car was already dropped a little, and they have the back end sitting (seemingly) higher than stock. They are supposedly 25.5" bit I am now dubious..

Didn't have a chance to work on my front hubs this week, they were apparently OG VW issue 914 rotors, I knew I saved them for some reason. Maybe I'll run into work this one night this weekend.

Considering something more like your disc setup to go on them, as I really don't need 1.25" vented rotors up front, although with the steel hats and Wilwood 8x7s its probably a few lbs lighter.
Recall the ID of those rotors? I imagine Porsche has a std ID size to center on.

CB sells rear 914 rotors (or something very close) for their kit with the CrMo T3 style hubs in 5x130, might be cheaper and far more available than 914/6 rotors out back.

Maybe the Cayenne/Toureg rotors will work up front, those are ~cheapish.

I'm going up to my sons place calipers in hand to measure some single spring plates, if they used the same thickness as the duals I'll just cut the outer off what I have unless anyone really wants them.

Bruce.m · Post by **Bruce.m** » Sat Jan 23, 2016 12:04 am

Front rotor?
I had the hub turned down to 154mm to allow for the radius (nominally 157mm) and give a little clearance.

Rear rotors have a larger ID (944 part). By that I mean compared to the 98mm bore in the diagram above. I considered using the matching rear boxster rotor on the 944 hub but none of the 944 handbrake parts work with the smaller 2.7 boxster rotor.

Post by **Piledriver** » Sat Jan 23, 2016 12:43 am

Thanks for the drawing!
Does Brembo have those online?

I'll probably make them to center on the hub within a few thou if I go that route, I'd do it just to make sure the hold down screws//holes aren't a critical dimension part, far easier to nail the hub dia in the lathe.
No runout is good runout.

The current 914 rear rotors centered shockingly well on the new 3" studs shoulders, but that was only a happy accident. Had to turn the hub OD down a bit as the hats are smaller ID than the T3 factory hubs.

I previously had (machined to dia) 3 TIG braze silicon bronze lumps for centering the 914 rotors, but the Wilwood hats are smaller (3.060 nominal 3.055 on the hub) so they had to go.

I have some 996TT rear calipers and rotors (radial mount, black, but usually red in the aftermarket)

Those might balance well with the 1.25"/31,75mm 4 pot Wilwood Superlights out back with the the Big Reds up front. (not for the Squareback of course, for the 914 under the twists from same car)

...Just realized i can probably sell the Brembos and just buy a new set of Wilwood forged superlights for the front. The 996 discs do take the 911 parking brake setup I have tho...

Bruce.m · Post by **Bruce.m** » Sat Jan 23, 2016 1:09 am

The brembo online catalogue has a few of those drawings but it's just a random mix. Oddly, they also have the VW bug disc too

Helpful for knocking up machining instructions for turning them into hubs for those who don't have access to the necessary kit.

Post by **Piledriver** » Sat Jan 23, 2016 1:13 am

I'm thinking I'll need to TIG braze some steel rings on for the 71.3mm Porsche wheel hubcentric bit up front.
Fortunately it sticks really well to iron.
It's not load bearing so it should work fine, and shouldn't distort things.

There's at least plenty of material to center the hats or maybe rotors.

The following link has a metric buttload of various rotor dimensions from VAG and Mercedes rides.
http://www.vaglinks.com/Pics/Brake_Info ... _C5_A6.pdf

The offsets may be too shallow for most of our uses, but you never know.

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