General musings on 4-piston brake upgrades

I've been a little lax in working on this because my rims are another 2 weeks from getting off a boat. Thanks to all for the links to rotors. I think I've finally settled on some off the shelf Wilwood rotors 279.4 x 20.6 in the front and 273.1 x 20.6 in the rear. I just did a quick design of the rotor top hats I will be making a few nights ago. The custom hat lets me keep my hub-centric mounting too.



Another huge bonus it they turned out to be really light (1.55lb for the top hat)...right around 9.5lb each for the fronts combination and 9lb in the rear. Hell, that’s over 5lb less per wheel than the brick like Galant rotors I have on the front now. I have acres of room around the caliper so the next task is connecting the dots between the caliper mounts and wherever I decide to mount on the hubs.



I just took another cut at the top hat design...they're now about 0.45lb lighter with almost no difference in stiffness. I love computers when they behave and do what I tell them :-) You can see most of the difference in the outside profile but there are a few more subtle changes too. The billet blanks are getting ordered tomorrow and I'll probably cut some top hats in the evening early next week.





Edited 2 time(s). Last edit at 04/25/2007 08:55PM by Tim Taylor.

Knocked out OP1 this evening...



Hopefully I'll be able to get the fixture and the flip side done tomorrow.

yo,
good work with the Catia.

I would suggest that
your hats may be a bit thick,
- the rotor should be able to flex some
mainly,
i would not trust rotors threaded into aluminum. nuts and bolts.

if machining cool stuff is your job, I may be able to come up with some bit for my car. are the rates reasonable?
do you trust outside code?

---

"I put the hurt on dirt" - adam crane
http://CraneRallyCrew.com
corolla gt-s "Patches"
Op: S.S.

acrane Wrote:
-------------------------------------------------------
> yo,
> good work with the Catia.

I can't afford Catia...just lowly old Solidworks. They look the same though since Dassault bought them out in '97 and they merged the interface.


>
> I would suggest that
> your hats may be a bit thick,
> - the rotor should be able to flex some
> mainly,
> i would not trust rotors threaded into aluminum.
> nuts and bolts.

They're still to thick because the picture above is OP1 and they get cut smaller on the flip operation. I also haven't put in the helicoils yet. I'll admit it's not ideal but I doubt there will be any problems with them as long as I safety wire the bolts. I debated making the rotors floating for at least a week and then finally gave up when I couldn't do it without custom rotors or a lot more work. However unnatural this mounting method is, it seems to work in a lot of applications. I can always cut them again with t-slots for floating mounting if it doesn't. The billet blanks were only $32 each.

>
> if machining cool stuff is your job, I may be able
> to come up with some bit for my car. are the rates
> reasonable?

I'm a design engineer and I specialize in prototypes and high dollar low volume parts (machined and sheet metal). Mostly I design and make boring things that people actually need. All depends on what you consider reasonable I have Bay Area overhead :-( I'm more than happy to look at your parts though. PM me and I'll give you my e-mail so you can send some prints or files.


> do you trust outside code?

Hell no. Sorry, unless it's a really intricate by the time I proof someone else's code I could have programmed it myself and have it optimized for my machine. Just not worth it from my perspective.

>
>
>
> "I put the hurt on dirt"
> ex. madmann28
> adam crane
> bellingham wa
> corolla gts
> bs. from VRI @ WWU

I didn't feel like doing real work today so I stopped early and finished off the rotor hats.











Edited 1 time(s). Last edit at 05/01/2007 08:57PM by Tim Taylor.

Holy cow. I just found this thread.

Beautiful machining, Tim.

I am using the same calipers on the Mazda3 now. Nice thing about radial mounts...if you ever want to put big honkin' tarmac wheels on, you just get bigger rotors and space out the calipers.

Attached are some photos of the 3 stuff we made up. Not nearly as pretty as your cnc hats, but functional.

Lurch

---

Lurch
Eric Burmeister
The west coast...of Michigan

here they are installed.

---

Lurch
Eric Burmeister
The west coast...of Michigan

Are those custom rotors Eric?

---

Grant Hughes

Edit...duh...I thought you were asking about the hats, Grant. No, the rotors were off the shelf Wilwood parts. /edit

Yeah. If you get me an accurate drawring Pop can turn 'em out in a day. Turns out Wilwood had off the shelf rotors that fit perfectly, we just had to make hats and our own radial bracket to fit Protege uprights. Fastened together with ARP Camaro wheel studs...same as I use in the hubs, just shortened.

We were using RX7 stoppers, but needed to move the wheels inboard to reduce hub-level offset (sorta like scrub radius, but measured at the hub level) to get rid of some crazy TORK STERE! Those pretty lil' Wilwoods with internal bridges are much lower profile to the outside and work great.

---

Lurch
Eric Burmeister
The west coast...of Michigan



Edited 1 time(s). Last edit at 05/03/2007 01:12PM by Lurch.

Hey Tim!

Any chance you can write an IGES (I GUESS) file of the calipers you have there and pass it along? I have been revising my master file of my rally car as needed and would like to get the calipers in there.

Very nice work.

---

Lurch
Eric Burmeister
The west coast...of Michigan



Edited 1 time(s). Last edit at 05/03/2007 01:46PM by Lurch.

Lurch Wrote:
-------------------------------------------------------
> here they are installed.
>
> Lurch
> Eric Burmeister
> Greatlakesknowitallatlarge
> Dee-troit
> Still work at Ford...for now...check back
> tomorrow.

come on Lurchie, diameter, thickness, mounting PCD, PN wtf I need to ask for!!!???

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

john vanlandingham Wrote:
> come on Lurchie, diameter, thickness, mounting
> PCD, PN wtf I need to ask for!!!???

Rotors:
11" x .810's P/N 160-5840 on this web page: http://www.wilwood.com/Products/002-Rotors/005-ULSV/index.asp

All dims are on there. Before I was buying custom 8-bolt frisbies from Coleman, but these are cheaper.

Only downfall I've found with the Dynapro is the fact that ONLY Wilwood makes pads for them. At least that I've found, but I haven't done a ton of searching yet.

I would safetywire the pad retention clips for gravel use...they sure are nice and quick...but perhaps too easy when rocks and sticks are present.

---

Lurch
Eric Burmeister
The west coast...of Michigan

Lurch Wrote:
-------------------------------------------------------
> Hey Tim!
>
> Any chance you can write an IGES (I GUESS) file of
> the calipers you have there and pass it along? I
> have been revising my master file of my rally car
> as needed and would like to get the calipers in
> there.
>
> Very nice work.
>
>
>
> Lurch
> Eric Burmeister
> Greatlakesknowitallatlarge
> Dee-troit
> Still work at Ford...for now...check back
> tomorrow.
>
>
>
> Edited 1 times. Last edit at May 3, 2007 by
> Lurch.

Not a problem. Just let me know what format and where to send it.

Tim

A generic IGES file should work. Export faces as trimmed surfaces if it gives you the option.

It is going into Alias AutoStudio.

Thanks!

If just sending a caliper, it should be emailable. You can zip it if you want and send to sirlurch atsign gmail period com.

Didja get this from Wilwood or just model it up yourself?
(edit...nm...just read you didityerself...cool)

Eric

---

Lurch
Eric Burmeister
The west coast...of Michigan



Edited 1 time(s). Last edit at 05/03/2007 03:51PM by Lurch.

Lurch Wrote:
-------------------------------------------------------
> A generic IGES file should work. Export faces as
> trimmed surfaces if it gives you the option.
>
> It is going into Alias AutoStudio.

Bastard, one seat of Alias is worth more than my machining center :-) I usually have better luck with parasolids for generic files. I can't remember if Alias uses the parasolid kernel as a core...last time I played with it was 8 or 9 years ago. But IGES it is for now.

>
> Thanks!
>
> If just sending a caliper, it should be emailable.
> You can zip it if you want and send to sirlurch
> atsign gmail period com.
>
> Didja get this from Wilwood or just model it up
> yourself?
> (edit...nm...just read you didityerself...cool)
>
> Eric
>
> Lurch
> Eric Burmeister
> Greatlakesknowitallatlarge
> Dee-troit
> Still work at Ford...for now...check back
> tomorrow.
>
>
>
> Edited 1 times. Last edit at May 3, 2007 by
> Lurch.


My rotor hats are for the same wilwood rotor you're using. In the rear of the car I was planning on PN 160-5839...same rotor but 10.75" OD instead of 11". Do you have the same rotor on all 4 corners? I'll send you the model I have but it's for a 1" thick rotor ( I originally planned on custom rotors but have become more pragmatic as this project drags on). I should have my new calipers in a few days and then I'll rev the model.

Tim