jphughan

Interesting info. Please update on the DS1.11 after getting them bedded, because I've been reading that they're quieter than PFC 08, and having run the latter before on the street only before and after track days for scraping purposes, I knew I wouldn't want to run them full-time even if noise were the only downside, so I definitely wouldn't want something noisier. I've already got a brand new set waiting to be installed, so hopefully this improves.

For Loctite, I thought you only needed 1-2 drops per stud for it to be effective? I've already got another bottle of blue (and the PMNA studs have red pre-applied anyway), but I'm surprised that what Tarett includes isn't enough for 4 caliper studs. Or were you trying to use it for the bracket studs as well?

electron mike

Another data point on the DS1.11s.. I have them paired with AP rotors and they are loud as hell on the street. Even after bedding and two days at COTA they are very loud. Great on track, and bite cold on the street, but screechy.

Mech33

Mine haven't been loud at all on the street really (surprisingly). They have a bit of a muffled grinding noise when stopping, but no screeching.

electron mike

I guess I'm just unlucky. I have grinding, screeching, and squeeling. I'm trying to drown out the brakes with the exhaust, but it's going to take more than just headers.

jphughan

Interesting to see such different impressions. Mech33, are you on AP rotors as well? I'm planning to install those whenever I next swap pads. Did one of you maybe install brand new rotors at the same time as the DS1.11 and another didn't? Did either of you add any sort of anti-squeal plates/grease? Just trying to figure out what might account for such a significant difference here.

myBailey07

AP Rotor Awareness Issue.

I wanted to just make folks aware of a potential item when mounting the AP Rotors and re-using the oem set screws.

I ran into a problem as I mounted a new set of Forgeline GA1R Track Wheels. The new wheels immediately started having horrible vibrations. I took them off and remounted a few times only to have the issue continue.

Here is what I found and what I did to remediate:

The AP rotors I received did not come with new set screws for the rotors. These are the two screws that go in the front of the rotor. My shop just re-used the oem screws. I was also told that folks are being told to just re-use the oem screws.

Here’s a pic of the rotor mounted with the oem screws re-used.



The problem is that the hole in the rotor is v-shaped, while the oem set screw has a flat top. As a result it does not fit properly into the hole on the rotor, it will barely grab the thread, work itself loose, and most importantly, they protrude and do not sit flush. On the oem rotors it is not a problem as the hole is recessed in a way that matches the oem screws.

You do not notice this protrusion on the oem wheels as they have material removed on the back of the wheel that will fit over the protruding screws. Some aftermarket wheels, like the forgelines I got, have a completely flat mounting surface . As a result, these wheels will not be able to mount completely flush and flat against the rotor, causing them to vibrate and/or wobble. It is not visually obvious, unless you look closely. But a wheel not mounted flush can be a a safety hazard, especially on track at a high speed/forces.

I simply replaced the oem set screws with a different screw that is v-shaped and fits into the hole properly. I used M6-1.0X14mm.

Here you can see the oem screws (Flat) vs. the replacement screw (V-shaped).



On the next pic you can see the new screws installed. They grab the thread properly and no longer protrude, allowing the wheel to be mounted flush and torqued properly. This caused the wheel vibrations to go away. On this picture you can also see that the holes are v-shaped and if you look closely you can see that the flat oem set screws barelt touched the outside rim of the hole with very little surface touching.



Anyway, this has been communicated to the vendor where I got the rotors from and they were very helpful. We also communicated to Essex to either supply different set screws or change the recess hole on their rotors.

Either way, probably not a good idea to re-use the oem ones.

Later.

Happy hunting.

jphughan

^ Interesting! The rotors I ordered from Clark at Apex recently came with replacement screws. I was wondering why they were necessary, but now I know and will make sure that the shop that will be doing this swap along with some other stuff is well aware.

myBailey07

Can you check what type of screws they sent you? Clark and I talked a bit and we suspect it might be just a set of replacement oem screws, in which case, the problem will persist. If they sent different screws it will be good. I just received a set of rears and they did not come with any screws.

electron mike

All new rotors and pads for me, no anti squeal. The noise is mainly as the car is almost completely stopped.

I had the same problem and had to have Essex send me more screws as I only had enough for one axle:

jphughan

They're black but shaped like the top screw in your earlier post. I ordered a pair of front rotors on 4/19/16 and in ONE of the rotor boxes was a bag with all 4 screws and a note saying, "These two screws are for use with the Porsche GT4. Use these to fasten the disc assembly to the hub in place of the original screws." I have since gotten a second bag to have two screws with each rotor to minimize the chances of this being done incorrectly.

myBailey07

Good news, that means they fixed it!, or that I am just plain wrong and that my shop just messed up and never installed them - it's always possible

jphughan

Ok, in that case I'm wondering (hoping) that maybe this will go away as the rotors get some use on them. The PFC 08s had the worst squeal toward the end of a stop too, but it was bad when it happened. I felt bad for any pedestrians waiting at the intersection.

Nice! Doesn't explain why the rear rotors that it sounds like you just ordered didn't come with them though, unless maybe the rear doesn't require the different screws? Maybe the OE setup is different or maybe AP uses a different hat design back there, or maybe they've since switched ALL of their hats to a new design?

ExMB

Not trying to be an asshat here but I addressed this issue with Jeff at Essex (AP) as well as Clark at Apex after fitting the original set as a test case. Originally I was told to reuse the Lenshead screws that came with the OEM steel rotors (999-015-025-09) only to find out that the correct ones were the ones for a 987.2 steel rotor (900-269-047-01) or the GT4 OEM PCCBs chamfered ones (900-269-047-03)

I was reassured and sent 1 screw per rotor by AP and after talking to Clark I was assured that he would cover the issue and supply 2 screws per rotor. The screws sent to me by AP were a bit longer than necessary. I bought the correct length screws through my dealer. The OEM screws had blue loctite applied whereas the AP supplied ones were bare.

jphughan

Wow, blue Loctite on a Philips head screw? How easy will that be to remove when the time comes to replace the friction ring without stripping the screw head? I was actually surprised to discover that the rotors are secured with just two screws, so Loctite makes sense to me in that sense, but even though these screws are easily replaceable, I'd rather not have to deal with drilling out stripped screws to replace a friction ring.

myBailey07

I only checked one box, maybe they are all in the other one like your's - I'll check later today.

Edit: I checked and yes, they were all four in the second box. I only opened the first box, expecting two screws to come with every rotor. So, my rears are all good.