Suspension upgrade, vented disc brakes, Porsche wheels +more

[Bill K.]

This has been 4 years in the making and it's great to have it all come together in a looong weekend. Started stripping down Friday evening and drove to work on Monday

* 17 x 7.5 x 55 ET Porsche Cayenne wheels; 195-40 front (edit: mistake of 195-45 corrected); 205-50 rear
* 911M front calipers (48mm) with 944 vented rotors (20.4 x 282 mm)
* 20AE Golf rear calipers (38 mm) with 944 vented rotors (20.4 x 290 mm)
* Brake bias valve removed for 1.60:1 brake bias with stock 19mm 412 master cylinder (same as 911)
* Delrin bushings front and rear
* Adjustable front camber and caster
* Lowered front with BMW 318i springs and Koni adjustable struts
* Super Beetle strut bearings and strut brace
* Mazda front spring plate bearings
* Rebuilt steering box
* Modified NOS centerline and ball joints
* Re-sealed fuel tank















Notes:
* Fuel tank is full in before shot and empty in after shot.
* Not aligned yet - front subframe is shifted to right a bit.

Driving observations:
* Much firmer front end
* Steering response quicker and less force required
* Shimmy is gone
* Some squeaks and rubs to debug
* More brake bleeding needed

[Bill K.]

Rear disk brakes and delrin control arm bushings

[Bill K.]

Front end upgrades, struts, and wheels

[Lars S]

Nill,
once again impressed of your work! You always do things the way one should do - no shortcuts.

Many thanks for sharing, cant see enough of images like that...


/Lars S

[raygreenwood]

I hope some of my rantings over the years have helped you. Except the wheels and rear discs (yet)...you have used almost every upgrade I have ranted about. The delrin bushings make a huge difference. You photos of filling the steering box with superlube...look just like mine did. Very nice work. Ray

[Chris V]

Everything looks really sharp...but the rear caliper brackets, looks as though they could benefit from a gusset or two...maybe some grade 10.9 hardware.

I don't remember if I ever mentioned it, but unless I'm mistaken you live just up the street from an ex-gf of mine - I think I saw you on a member's map dealio.

[plumcrazee]

nice work dude well impressed

nice wheels as well think they suit these cars

[Bill K.]

Thanks guys. It was a fun project. Thanks for your input and inspiration.

Got the e-brake hooked up tonight. Replaced cable, extended the 412 sheath, made adapters, and used standard ebrake handle adapters with set-screws.



Found the source of the rubbing - the press fit I used to assemble the front 412 bearing insert to the 944 hubs did not hold causing the hub to slide on the bearing insert. Good thing the caliper was there to hold the rotor or the wheel could have came OFF The fix was to pin the 944 hub to the 412 bearing insert.



The strut bearing doesn't look right. Shouldn't the flange of the cap be preloaded onto the rubber ring of the strut bearing. There is a big gap now. I didn't account for the movement of the strut bearing under the load of the car. Should I shorten the spacer under the strut bearing to eliminate this gap? What effect would this gap have on handling? I measured the distance between the top of the thread on the strut rod to the inside surface of the trunk lid using Play Doh while jumping on the bumper and found there to be a 5/8" gap, so I could safely lower the car 3/8" to eliminate this gap and provide preload on the strut bearing. Please advise



P.S. Cool upgrade Doc

[raygreenwood]

Hang loose. I have spec for that gap. The top cone should not rest all the way on the delrin glide ring. But you do have too much gap. If the top cone rests on the delrin ring....it means there is no room for the bushing to flex. The upper cone will then quickly crack the delrin ring.
When the upper cone rests tightly on the delrin ring its usually a sign that the rubber bushing needs replacment.
You want some gao...just not so much that the rubber bushing can overflex. Ray

[Bill K.]

Thanks Ray, but note that these strut bushings don't have the delrin ring. The top ring is rubber, but I imagine the principle is the same.

What are the dynamics of the bushing? Wheel hits bump, bushing flexes up (and can cause top of strut to smash trunk if too close). Wheel rebounds, cap limits travel down. So, with big gap, the rebound is "mushy"?

[raygreenwood]

You are spot on in every comment. I have a apare hood with dents in it to prove it .

yes, the ring is a bumper of sorts to allow flexing of the rubber donut underneath during rebound. I have never seen a rubber one. It could stop teh cracking issue of the delrin on rebound...but that only happens when teh main rubber donut is worn out or when the struts are shot and rebound is uncontrolled. Too much gap allows to much rebound and the bearing cone may not stay in contact with the donut. Too much and it can gget mushy as you note. To little is not really a problem...except that there is a little side loading of the top metal cone and strut when you go through sweeping turns . Not much...but some. Ray

[Bill K.]

Thanks for the confirmation. The bearing was obtained from CIP. It's a '74-79 super beetle part. There is an unusual dynamic in the car at <50mph where the front end bobs up/down and I suspect this gap as a contributor.

Walter - what does your setup look like at the strut mount? Does your car bob at lower speeds? See here for Wally's project that I copied.

[raygreenwood]

What strut inserts did you use? The excessive gap can very well be part of it. The harmonic rhythem of the strut damper might be slower or faster at arresting motion than the rubber bushing. They canstart an assymetrical movement between them where the bushing is moving ahead of or behind teh up and down movement of the strut cartridge and spring.

Also..if the strut cartridges used were stock....this is a symptom of worn or improperly valved rebound damping. If they are far too tight of valving far the car...a sharp up and down harmonic in one particular range of speed is simptomatic of arresting up or down motion too quikly....and the enertia transfers to flexible parts like teh bushing. Again...you are correct that decreasing that gap can alleviate a lot of that. Ray

[vwbill]

It would be a cool experiment to mount a camera with lights in the hatch compartment and watch the strut mount and movement! Bill,jr.

[ubercrap]

Fantastic job!