Announcement

Collapse
No announcement yet.

Cayenne Calipers on UFO Hub Carriers

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Cayenne Calipers on UFO Hub Carriers

    6-piston calipers on UFO struts

    Originally I was thinking of installing the HP2 brakes from the B5S4 I am parting out on to my UrS6 by using the UFO brake style hub carriers. Then I got a deal for a full set of Cayenne calipers that was too good to pass up.
    The UFO brake hub carriers were originally fitted to the Audi V8, 200 & early UrS4. I got the idea for using these hub carriers together with the 6-piston Brembo calipers from trolling various Audi-themed forums. A post by amd is the best on motorgeek showed that the B5S4 rotors & calipers could be adapted to the UFO brake style hub carrier. http://www.motorgeek.com/viewtopic.php?f=17&t=29978
    I read on RS246.com that the 6-piston Cayenne/ Touareg front brake caliper would bolt up directly to the B5S4 hub carriers. Then I found popdemonic’s post on S2 forum where he adapted the 6-piston Brembo caliper to a ROW S6 with HP2 style front brakes. (Rest of World, I am North America based) So I figured that there was a possibility that the 6-piston Brembo caliper would bolt right up to the UFO hub carrier.
    To begin with I used the 18z 6-piston calipers that are on Cayenne/Touareg vehicles with 350mm diameter front rotors vs. the 17z 6-piston calipers that use 330mm front rotors. The rear calipers are the same for vehicles with either the 18z or 17z front brakes, save for the color of the paint. Please advise me if this is incorrect. Adapting the 6-piston caliper to the “normal” G60 brake style front hub carrier is a simpler matter of machining a proper brake caliper mount and I found there are other benefits to using the UFO front hubs.
    The goal was to use as many bolt-on parts with minimal machining work. There were compromises that were necessary but I feel worthwhile for simplicities sake. Starting with the UFO hub carriers I followed popdemonic's thread on the S2forum. http://www.s2forum.com/forum/showthread.php?t=46223
    I think the UFO hub carrier & HP2 hub carrier dimensions are nearly identical but without Hp2 parts to compare with, it is only speculation on my part. The part #s are different between the two hub carriers.
    Just as popdemonic discovered, using the HP2 hub carriers & the 6-piston Brembo caliper, the rotor runs closer to the caliper at the trailing edge than at the leading edge. He removed material from the outer rotor dimension, turning the A8/S8 360X34mm diameter rotor down to 350mm. He also used the 17z brake pad set as they are not as "deep" as the 18z brake pad set. By machining away the outer rotor diameter, the rotor surface swept area that the brake pads contact is diminished. Something I am trying to avoid, hence the A6 347X30mm rotor. There is a weight difference of 3kg between the 360X34 &347X30 rotors. Also, cutting the larger rotor down to size changes the balance of the rotor as this is where material is machined away when balanced during manufacture. With the 347mm rotor there is about 2mm clearance between the trailing edge of the caliper & brake rotor without grinding on the caliper. With this setup & the 18z brake pads the rotor & caliper are not concentric with one another & the brake pads overhang at the outer trailing edge a few mm. I would rather grind brake pad material away in this area than cut down rotors & grind on the calipers. The inner edge of the rotor has enough material for the 18z pad to completely contact the rotor fully & has a slight amount of overhang. The 17z pads would have this same issue of overhanging the outer edge of the rotor & would not completely cover the rotor swept area. It is a concern that the rotor is not as thick as the caliper was designed for but I can shim the pad to make up the difference. At this moment custom rotors with alloy hats are out of my price range.
    The mounting bolt holes for the original UFO calipers were 12X1.5 thread size. This size was increased to 14X1.5 thread size. The reason for this is because this is the size fastener that holds the HP2 caliper to the hub carrier as fitted on a B5S4. Remember, my original intention was to fit HP2 calipers from the B5S4 to UFO hub carriers. The UFO hub outer diameter was turned down from 143.1 to 131mm. The spacer used is 14.3mm in thickness, welded to the hub carrier & shaped to better support the caliper. Not as fiddly when changing rotors with it welded on. The original heat shield to protect the ball joint & ABS sensor from rotor heat is retained. The rotor inner surface is approximately 10mm from the hub carrier.
    A mounting bolt kit from JH Motorsport that was designed to fit the 6-piston Brembo caliper to a B5S4 chassis was purchased.
    http://jhmotorsports.com/shop/catalo...ton-p-467.html . It turned out I only needed the 14/16mm spacer sleeves that came with the kit. The nuts would contact the rotor if this hardware were used in this application & make changing rotors a hassle. The caliper-to-hub carrier mounting bolts are 14x1.5x50mm in length. They were sourced from our extra bolt & hardware bucket. They are Grade 8.8 so there may be room for improvement there.
    There was an “Hmmm…” moment when I happened to place a UFO style hub next to a B4 hub I had setting around. It appeared that the hub offset between the two were nearly identical. Further investigation led me to compare the UrS4/6 hub, the S2 front hub & the UFO front hub. As measured the UFO hub has 3.2mm more offset than the G60 hub. The UFO hubs & S2 hubs have nearly the same offset with the s2 hub having 1.2mm more offset. According to KATE, the rear hubs on cars equipped with UFO front brakes have the same part #s as the UrS4/6 with G60 hubs. This hub is used both front & rear for cars with G60 brakes. The ROW S6 & S6+ with HP2 brakes use the same front hub as the G60 brake equipped cars.
    The brake caliper cleared (barely) without spacers the Sportline 18” RS6 factory wheel as now fitted on my car. They would not fit under a set of 17” B5A4 wheels without spacers. Currently these parts are not installed as I am investigating altering the steering arm length & position along with possible changes in Ackerman angles. A coil-over setup is also being considered. When the conversion is done I will post up the difference in weight between the g60 & Cayenne/UFO components.
    A Thank You goes out to all the other Gearheads that post up their projects as it all begins with observation & imagination.
    Chris
    Attached Files
    Last edited by A1QSHIP; 24 April 2014, 13:37. Reason: clarification
    "Nulla tenaci invia est via"
Working...
X