PBR Calipers and large rotors...

[Mikelly]

I just put new pads and rotors on the Vette this afternoon and these PBR calipers that come on the Vette are the same caliper that comes on the Mustang Cobra... It seems to me that this caliper setup could be adapted for use on the Zcar...

 

The rotors on the Vette are massive. 13 inch up front and 12 inch in the back vented... AND the E-brake assembly runs on the inside of the rear rotor... Slick design. I had $300 SHIPPED in a new set of AC Delco rotors and performance Friction Carbon Metalic pads.

 

Mike

[260DET]

The earlier model American cars which used PBR calipers on the back had the handbrake work the rotor pads, same as the main brake. My 260 rear disc brake setup uses similar PBR calipers to those. Last pads I got were Bendix Ultimates (Axxis in the US?) at around au$90, under us$70.

 

IMHO PBR make a good, lightweight, mass produced caliper and the pads are usually cheap. Or cheaper anyway.

[Moridin]

The PBR's work well on the Cobra for around town, but as soon as you start to get on them repeatedly, they start to fade pretty bad (The Cobra is 3600lbs without me in it though). I think Ross's setup utilizes PBR's slimline caliper to fit a 13" rotor in 16" wheel.

[Mikelly]

Moridin, I think the problem with the cobra setup is the pad, not the caliper... The Vette is 3200# and I could get the stock pads to fade after about 15 hard 80-0 stops. We used some Hawk performance pads on our 95 Mustang GT (Cobra R brake kit on the front from http://www.discbrakesRus.com) and it was a night and day difference. The brakes don't fade now at all. I got that tip on Corral.net about 16 months ago, so you guys might want to try that with your mom's cobra...

 

Mike

[Modern Motorsports Ltd]

First off Happy New Years!!!

 

Thanks for the PBR plug guys:)

 

Your own longtime hybridz member/contributor has a front PBR Xtreme setup and will very shortly have an Xtreme rear PBR setup as well, very close to production (260DET, you don't list an email, drop me a line if you can, we're likely similar).

 

PBR has many calipers as we know, my Xtreme combo will clear 16" wheels handily with it's 13" 2 pc rotors, and we're just now looking to see if it will clear 15's by any chance. We never thought it would but appears my geometry even has a shot at that If our standard Xtreme doesn't clear we'll be doing a slightly smaller setup that will clear 15's handily and still provide a large OD (ie. very close to 13"!!) rotor to offer the leverage and appropriate mass (ie. not boat anchor, OEM 13" PBR rotors are some 19-20 lbs!! not rotating on my Z!) for the Z car braking needs. It'll include our usual detailed design/engineering effort already completed.

 

I'll reply at greater length later, I've got to attend to some familial duties with relatives in the meantime on this fine New Years Day!

 

Zya till later,

[240hoke]

Hey guys,

 

My friend has just finished his C5 brake upgrade on his 240z. the rest of the car isnt quite finshed so it isnt on the road yet but its almost done. i know that hte 13" brake setup would not clear 16" panasports and he had to go with 17's. I am using his old C4 brake upgrade on my car with aluminum hubs up front, i am very happy with this setup and may be more practicle for the Z. Overall shaved more than 20lbs off the front. I posted some pictures of both the C5 and C4 swap in the public gallery heres a teaser;

 

[Moridin]

Thanks for the tip Mike. I also know the Cobra is probably close to 400 lbs heavier than your wife's GT, and another 800lbs heavier than my Z.

 

There was a big debate on corner-carvers.com with a bunch of info on PBR, Brembo, Porsche, AP Racing, and many more calipers and how well they performed for people at the track.

 

We need to get a list going of brake mods done to Z's - and other cars, because so many systems have been adapted to the Z cars - and see how they perform.

 

Here's a piece about the C5 braking system: http://forums.corner-carvers.com/showthread.php?s=&threadid=13299

For all the calipers I know, the food chain for what is better goes somewhat like this: PBR > Wilwood > Brembo > Stoptech > Alcon > AP Racing

Here's the link with some of the info that I got on Corner-carvers: http://corner-carvers.com/forums/showthread.php?threadid=11646&highlight=Brakes+Wilwood

I may be we off with that statement, but I just trying to recall what I've read here and there. Then again, we are talking about tracking a car when it comes to those brakes, otherwise the list would change for street use (because it isn't just about all out stopping power and fade resistance).

 

Sorry to hijack your thread Mike, but I had these links hanging around and have been looking for a place to post them

[wrenchtech]

I'm new so bear with me please.

 

If you go to the trouble of doing a big brake upgrade why not go to a 5 lug hub. If there is such a thing? Thanks

 

Matt

[Moridin]

There definitely is such a thing. Ross' website actually has them on there if you look closely. Most brake upgrades offer a 4 lug or 5 lug rotor hat, especially with two piece rotors. Biggest benefit, by far, is the wheel choice. It's much easier to get a 5 lug wheel than it is a 4 lug. Another may be strength (force is spread out over 5 studs, instead of 4), but I'm not sure how important that is unless you're running some major power. Then again, ARP studs are very, very strong from what I hear. Maybe someone (Ross?) can chime in here.

[Modern Motorsports Ltd]

I myself haven't bought wheels in a few years now so can't really say what has the best wheel choice. Off hand I'd comment for used-OEM style choices their's more favourable 5lug options but for aftermarket I'm not sure if their is a difference or not, depends as well on wheel styles you like. Some styles are much more availble in certain bolt patterns. I know both the 4 lug and 5 lug setups are popular with both having wheels available. Either way one has to check out offsets. A number of my customers have run newstyle (ie. Cobra R knockoffs) 5lug wheels on the front 5 lug hubs WITHOUT additional spacers (some state spacers are required no matter what when going 5lug, they're not).

 

For overall strength, we're quite fortunate as our Datsun OEM parts at the spindle (and many other places) are VERY strong. Now apples to apples with same studs a 4x4.5 bolt pattern is stronger than a 4x100, and thus a 5x4.5 is a step stronger yet. (and 5x5.0 stronger...) Now thankfully we haven't seen (I'm not aware of) failures with various hybridz experiments using these bolt patterns and all have stood up fine to date.

 

If I had the same wheel choices in any wheel pattern and the budget to go 5lug (it is an additional cost over 4lug) I would go 5lug as I have on my own ride. Being an anal engineer extra strength is always appreciated ARP studs are a fine piece of work and I love the tapered/unthreaded snout on the end for initial wheel mounting.

 

I don't have them on my webshop but I've offered used and prepped 5lug hubs for some time of which I typically include them with my Xtreme setups as my customers typically want a soup to nuts package in one box that allows their full install.

 

Just prior to Xmas I sent out a full front/rear brake (Xtremevented/rear solid), adj. bias valve/ Illumina set/coilover set/ Z to Honda adaptors/ swaybar setup to a customer who had planned a single day install for everything with a couple friends helping. Only post shipment response I got from him was " went great, nice stuff ". That's the nature of the packages I ship, cover all requirements and are engineered to your setup.

It was with that all inclusive intent that I invested my R&D into creating the PBR setups amongst others that I have.

 

I hope that helps & didn't babble too much.

 

PS Moridin, I read your links with interest and after some lengthy reading only found the PBR 11" Stang GT setup faulted, with no surprise as it was packaged as an economical setup on their still notably 'not light' setup. THeir are MANY different one piece rotors available for 13" PBR setups, some truly suck and some are very good. Friends have raced and cracked the undesirables in the first few laps, others have raced on the top end stuff and loved them. I only use my HD Nascar balanced/stress relieved heavy duty pieces. I don't skip quality steps in any way, one way to do these things IMO. In the one thread the one racer was still using 12 lb 2 piece rotors happily with his PBR 13x1.1" setup on a brake intensive course(v. similar weight rotors to my own) with his led sled stang (no offense, I can enjoy those cars as much as many others, just differentiating because comparing an 11" PBR setup to my own is not apples to apples at all, they're very different calipers actually let alone rotors and vehicles of application).

[Guest Your Car is Slow]

Switching to a MUCH larger front brake system saved 20lbs????

 

was it all in the rotor? I cant imagine the larger calipers saved that much weight??

[240hoke]

hey,

 

yeah over 20 lbs. mainly due to the aluminum hubs which weigh 4.5 lbs a piece. The aluminum calipers are also very light I dont know the weight off hand i'd have to look through my notes, but they are ALOT lighter then the 4 pot toyota calipers!

[Mikelly]

Absolutely... The calipers are MUCH MUCH lighter when not loaded with pads... However, regain some with the addition of the larger pad material, which is good, because THAT is one of the reasons to GO to bigger brakes in the first place.

 

I've got both the outlaw 4000 caliper and the Wilwood Superlight and both are extremely light weight caliper setups...

 

mike

[Moridin]

I have the Dynalites for my Civic and they are very lightweight. Compared to the bigger EX calipers, there must have been an 8 lb. difference. Amazing.

 

Ross: I thought the rotor in question was a stock C5 piece and not a GT. Maybe I need to read it again. I'm more worried about the PBRs and there fade resistance on the track. I'm going to to want to open track my Z, and I'm not sure the PBRs will keep going when I'm continually hauling the car down from 100+ MPH on the main straight at Laguna. Maybe I need to look into the Porsche 996TT calipers with ceramic rotors, but I'd rather do an Alcon or AP Racing setup on a rotor that will fit under 16" wheel. I am interested in the PBR setup you have, but am wondering if they've been track proven. I know the 13" rotors are a huge help, because of the added mass.

 

Mike, are you going to open track the Vette at all? I want to know how that thing does under a little obuse.

[Mikelly]

I'll be trackin' the Vette. I have an extra set of wheels and will be buying some dot Kumho V700s to abuse the car with, and I've just gotten the russel speed bleeders and braded lines for the brake system. I'll likely upgrade to a two piece rotor for the front if I can source the parts.

 

Mike

[Modern Motorsports Ltd]

Ross: I thought the rotor in question was a stock C5 piece and not a GT. Maybe I need to read it again. I'm more worried about the PBRs and there fade resistance on the track. I'm going to to want to open track my Z, and I'm not sure the PBRs will keep going when I'm continually hauling the car down from 100+ MPH on the main straight at Laguna. ..... I am interested in the PBR setup you have, but am wondering if they've been track proven. I know the 13" rotors are a huge help, because of the added mass. ....

 

Moridin, perhaps someone commented on their C5 setup, but that's a different PBR model (pin drive I call 'em, like LS1's, LS1's are heavy, not sure on C5 models...and yes LS1's are aluminum but I'd never put 'em on my car). The caliper alone does not create fade as you know. It's the entire engineered package and it's designed balance (too much to type now/out of town on webmail for a few days) that will lead to fade or not. Rotor design, not JUST OD, but ID/all rotor specs lead to it's mass in a 2 piece system....and the location of that mass and ability for air to flow etc.

 

PBR's have been track proven for years on heavier cars using http://www.baer.com PBR setps. With my system in competition it would come down to the correct pad depending on the top speed and differential you have to scrub. I look at this individually on more unique systems. ie. the setup I did for a high speed (150mph+) fullout road course racing Z I bumped the rotor mass up as a result of my calculations and the pads were matched HT10's. I could do the rotor's 11lbs or 20........I won't go into it much more detailed online as the great effort I put in this area is the result of a lot of work both on my own and with different model cars I sponsor and am just buds with and I don't share some hard earned procedures so easily. I can't recall how many hours went into the spreadsheet alone for some of the thermal work as one aspect. The rotor has to accept the heat created such that the rotor temp does not exceed the pad temperature limits. With my PBR setup it's not just rotor mass as I"ve engineered them into a lightweight 2 piece rotor, not the 20 lb door stoppers the OEM like domestic pieces are (but that 20 is required for those heavier cars, nothing wrong their). 13" gives you a far greater swept area at a greater radius to name just a couple benefits. The greater area has more exposure/cools easier etc. The greater diameter increases your brake force lever and subsequent braking force available which has the great byproduct of improved modulation as well. I'm not a whiz track driver and the modulation gain is incredible, much easier to drive near braking limits comfortably. It would be a tougher feat to fit the commonly wider/taller AP or Brembo calipers with 13" rotors under a 16" wheel. That's why most setups with similar sized calipers are the just over 12" diam. rotors. The newer supercars have larger and larger OD rotors while they maintain their mass with designed allowances for appropriate heatsink/thermal cycling to meet their pads etc. C5's as I recall came out with sub 13" rotors and some tracking them promptly cracked some rotors during sessions which was alarming (I want to say their rear rotors but don't recall, doesn't matter, just babbling I guess!)

 

My own and 1 tuff Z's PBR setups tracked great with all we could throw at them with no fade running stock KVR carbon fiber street pads. Others in use with feedback being breif and very positive, "installed and works great, thanks". One other customer's wife thanked me at an event, I was quite surprised and then she relayed the car saving stop they had to do on a weekend getaway they were on, car was fine but they had sore necks for a day or two, written up here I believe:

 

http://www.hybridz.org/phpBB2/viewtopic.php?t=29771

 

 

Not all like typing as much as some of us do so feedback details aren't always that verbose. KVR doesn't reccomend these pads in general for track use as they are a street designed pad so not designed for the higher temps. But I know my limits reasonably and thus can drive my Z to the track and keep my VERY friendly rotor wearing carbon fiber weave KVR pads in and enjoy their linear increase in friction as I heat my rotors beyond my typical street temps. Not many can enjoy a 'no sacrifice' street setup and take it to track events on same pads with no sacrifice (ie. lapping days/I'm not a competition driver by any means, but my V8 280ZX hustles just fine with 300rwhp).

 

I have NO qualms they'd suit your needs, only tuning required would be stepping up in pad types if you're getting into higher heat levels, a very easy and common thing for racers to do which I can easily coordinate with you. Nothing wrong with the brembo calipers, I have a lot of respect and admiration for their products. But knowing what goes into a properly balanced system I'd rather save you both the time and $ and see you enjoy the Xtreme setup front and rear which would meet all your needs without question. I didn't casually name it 'Xtreme' , as an engineer I'm a little cautious (understatement!) in making claims so those I do are very well backed up. My own PBR setup I've had on for some 4 yrs now with daily driving and road course events in WA, California (Thunderhill) autox and at present my rotors show less than some 25 or 30 thou wear.

 

Hope that helps.

[Moridin]

Dang Ross, you're a very dedicated vendor and engineer. I guess I should have been a little more detailed in my response and not just mention rotor mass (I've been doing more and more research in the brake design department). I really do appreciate the detailed response. It will really help when it comes time to make my brake decision. I just need to make sure I don't get into that ego thing (Look, I got 6 piston AP Racing brakes on my car although saying 13" rotors is fun too). You will definitely be getting a call from me in a few months (if I have the money), about braking and suspension systems for my car.

[260DET]

On brake fade, PBR's are usually a more open design as compared with your average four spot. So, all other things being equal, the PBR's should run cooler along with the pads and brake fluid.

[Modern Motorsports Ltd]

On brake fade, PBR's are usually a more open design as compared with your average four spot. So, all other things being equal, the PBR's should run cooler along with the pads and brake fluid.

 

Richard very cool, I've NEVER considered that caliper advantage, and a very fine point that just explains itself to me. Pin drive PBR's are somewhat more enclosed than the types I use. The models I use are very open, with the front face/outboard pad exposed to a lot of air on front edge/rear and underside let alone part of it's backing plate as well.(see photo, two circles are backing plate)....and the unexposed portion is tight to the aluminum outer caliper 'flange' that is a great heat sink to transfer heat. Backside/business side of caliper with the pistons is very open between the pistons and on the underside. Here's one install to see how expoed the outboard pad is and the low profile that allows it to clear wheels as well as my maximum inboard location to also aid wheel clearance and bring the assembly closer to inboard ducting should track junkies want to go that route.

 

Here's '1 tuff Z's Xtreme front and old OEM setup pictured.

[260DET]

Well Ross, I ain't pissing in your pocket, as far as I know, re PBR calipers. I have four spot Nissan calipers on the front with appropriate rotors and pin type PBR's on the back. I can get the fronts very nice and hot to the point where the pad material starts to pick up on the rotors.

 

But this doesn't happen with the (correctly biased) rears, they seem to run nice and cool without any ducting, etc and the same compound pads as the fronts. I might add that the fronts are 28mm ventilated while the rears are IIRC 12mm solids.