Thoughts and experience with the Light Duty PBR Calipers

[Mike Kopstain]

Since this has proven to be a controversial issue among those around here I thought I would vocalize my findings after a couple months experience. To clarify, the upgrade in question is the light duty PBR Caliper upgrade utilizing the 10.9" rotors.

To start it seemed many were concerned with the braking capabilities of the smaller rotor. This proved not to be a concern as the larger surface area of the pads and the aluminum calipers are significantly better at dissapating heat than the smaller 601 pads and the cast iron calipers. Fade was minimal and only present after many repeated hard stops and though it was present, it was not a dangerous amount though it was noticable. As an added note we change out the phenolic pistons with steel pistons to further aid in heat dissapation. The calipers you would get from a parts yard or an auto parts store will have phenolic pistons.

Pedal feel is good and still quite firm.

I took the time today to weigh the different setups (One side caliper, rotor, two pads, and bracket) and here is what I got in order from lightest to heaviest:

(89' - 91') 23.02lbs
(PBR light duty Upgrade) 25.00lbs
(94' - 95') 29.06lbs
(96' Upgrade) 32.10lbs
(Cobra Upgrade) 37.03lbs

A savings of 7.20lbs is per wheel is realized from using the PBR Upgrade instead of the 96' Upgrade.

A breakdown on the rotors shows a savings of 2.2lbs rotational mass per wheel when using the PBR Upgrade of the the 96' Upgrade and a 4.1lb savings from the 13" Cobra setup. This is important as not only are you spinning less weight, but you are spinning it closer to the center of the hub which introduces further gains.

The people using this setup so far have been very pleased, one of which switched to this setup from the 96' brake upgrade and prefers it.

More information and pictures of the kit can be found here.

I'm interested in hearing any additional comments.

 

[Dr. Tweak]

They look awesome. Do you need the '94-'95 spindles? And how much are the pads?

 

[Mike Kopstain]

By popular demand we will be offering an 11.6" version of this kit starting Febuary first.

Pricing will be $499 and the kit will fit under the slicers.

Those upgrading from our current PBR kit will only have to pay $139.00 for the upgrade.

 

[Dave Kegel]

Just to add another option, my Wilwood rotor, caliper and two pads weigh about 15 lbs.

Dave

I took the time today to weigh the different setups (One side caliper, rotor, two pads, and bracket) and here is what I got in order from lightest to heaviest:

(89' - 91') 23.02lbs
(PBR light duty Upgrade) 25.00lbs
(94' - 95') 29.06lbs
(96' Upgrade) 32.10lbs
(Cobra Upgrade) 37.03lbs

A savings of 7.20lbs is per wheel is realized from using the PBR Upgrade instead of the 96' Upgrade.

A breakdown on the rotors shows a savings of 2.2lbs rotational mass per wheel when using the PBR Upgrade of the the 96' Upgrade and a 4.1lb savings from the 13" Cobra setup. This is important as not only are you spinning less weight, but you are spinning it closer to the center of the hub which introduces further gains.

The people using this setup so far have been very pleased, one of which switched to this setup from the 96' brake upgrade and prefers it.

More information and pictures of the kit can be found here.

I'm interested in hearing any additional comments.

 

[MI-SHOFEAR]

How much does the 96+ upgrade cost?
New Calipers, Brackets, Pads, and Rotors???

Thanks,
Jeff

 

[Shoaz]

I have no doubt that these light PBR calipers are great on the street or even probably for general autocross use. Personally I'd steer clear of them for road course track use, though.

So if you have no intention of ever taking the car to the track these are a nice option.

 

[Hack]

I have no doubt that these light PBR calipers are great on the street or even probably for general autocross use. Personally I'd steer clear of them for road course track use, though.

So if you have no intention of ever taking the car to the track these are a nice option.

Should be an excellent option for drag racing as well.

 

[Slo-Sho]

How much does the 96+ upgrade cost?
New Calipers, Brackets, Pads, and Rotors???

Thanks,
Jeff

You can use your 1994 SHO calipers. The PFC AutoZone pads cost me $55. The rotors were $19.99 ea. The brackets you can get from a U-Pull-It yard. You want the ones from a 96+ continental/SHO. Make sure they have the 'FN74 ' stamped on them.

 

[Mike Kopstain]

I have no doubt that these light PBR calipers are great on the street or even probably for general autocross use. Personally I'd steer clear of them for road course track use, though.

So if you have no intention of ever taking the car to the track these are a nice option.

Experimenting with different pad types we've been able to put the kit through it's paces with minimal fade under road course conditions. This comes a long way from when we first started testing and were bending the caliper after each session. For the serious track car, however, we suggest people look at the offerings from TCE/ Wilwood or our Stage III brake upgrade utilizing the HD PBR calipers.

Using the 11.6" rotors allows for an even larger swept area and lighter caliper while still benefiting from the pad choices we have researched to work best with this kit.

Just to add another option, my Wilwood rotor, caliper and two pads weigh about 15 lbs.

Dave, this is beyond the skope of some consumer's budgets, though it is the best as far as something that will fit under the slicers. Our intent is not to replace this kit; rather we want to offer something cheaper that will still offer a significant gain for those that don't have the cash to shell out for the Wilwoods.

We're toying with a 12.4" rotor also which has been playing nicely with the rest of the kit however rotating mass is a concern as the rotor is 30mm thick.

 

[.SHOoff.]

By popular demand we will be offering an 11.6" version of this kit starting Febuary first.

Pricing will be $499 and the kit will fit under the slicers.

Those upgrading from our current PBR kit will only have to pay $139.00 for the upgrade.

What about people who want to upgrade that already have the current 96-upgrade?
Could we get it for the price minus the rotors?

 

[wood_e]

Mikey,

Why not modify cobra calipers to fit on 11.6" rotors? It has been discussed here before. I believe the caliper bolt holes have to be drilled 3/4ths of an inch upwards.

 

[Shoaz]

Experimenting with different pad types we've been able to put the kit through it's paces with minimal fade under road course conditions. This comes a long way from when we first started testing and were bending the caliper after each session. For the serious track car, however, we suggest people look at the offerings from TCE/ Wilwood or our Stage III brake upgrade utilizing the HD PBR calipers..

There's a reason PBR makes a heavier caliper.

I've seen too many pictures of these bent and heard too many near-catastrophic stories of the associated loss of control under heavy use with track cars that I think it is a serious safety issue. IMHO I still strongly suggest that anybody wishing to regularly open track or road race their car use the HD PBR or Wilwood calipers. Even the stock iron calipers would be better IMHO, since they won't exhibit the bending tendency that these do when they get hot.

If you don't plan to use your car this way then I think these are very fine calipers. They'll offer better modulation (since there are two pistons instead of one), lower cost, and a nice weight reduction as has been mentioned. For those looking for a nice street/autox upgrade that looks good and works nicely I think these should be considered.

I don't often speak up on stuff like this, and I do want to support the fine folks that put together kits like this for the SHO community, but I think this one is a potentially serious safety issue under certain conditions and awareness is a good thing. When the limitations are understood all is well.

 

[gdsqdcr]

What about people who want to upgrade that already have the current 96-upgrade?
Could we get it for the price minus the rotors?

Mikey,

I would second this comment.

I dont track my 94, but I do play with it from time to time in the twisties ... these would hold well to that?

Anthony

 

[Mike Kopstain]

I've seen too many pictures of these bent and heard too many near-catastrophic stories of the associated loss of control under heavy use with track cars that I think it is a serious safety issue. IMHO I still strongly suggest that anybody wishing to regularly open track or road race their car use the HD PBR or Wilwood calipers. Even the stock iron calipers would be better IMHO, since they won't exhibit the bending tendency that these do when they get hot.

I can appreciate the concern but that is why we have testing. We have been able to eliminate the problem with the caliper bending altogether in testing simply by changing to a different pad with a higher coefficient of friction than what we were initially using. Agreed that this kit is not ideal for a full time tracked car, but this is not it's intended purpose anyhow.

Friction coefficient seems to play a large roll in heat and thus caliper integrity. FWIW, the HD calipers also suffer from the same bending problem the light duties do. Neither of the calipers stop grabbing if they bend but they are obviously not up to the task of track use in this scenario. One of our test cars drove from California to Illinois with the caliper bent up.

I don't often speak up on stuff like this, and I do want to support the fine folks that put together kits like this for the SHO community, but I think this one is a potentially serious safety issue under certain conditions and awareness is a good thing. When the limitations are understood all is well.

I do appreciate the concern. My intent is not to discredit you; only to state that we've recognized the problem, experienced it ourselves multiple times, and worked towards a fix for it.

 

[Mike Kopstain]

Mikey,

I would second this comment.

I dont track my 94, but I do play with it from time to time in the twisties ... these would hold well to that?

Anthony

Anthony, the kit shares no components with the 96' brake upgrade other than the rotor. Pads, calipers, caliper brackets, etc are all different. The cost to upgrade would be the cost of the kit minus $60.00 to cover the rotors.

 

[K-Dawg]

Friction coefficient seems to play a large roll in heat and thus caliper integrity.

I'm not sure what you mean by this. Could you elaborate?

Also, could you give some more details on the 12.4" x 30mm rotor? What caliper are you planning to use with it?

 

[jelloslug]

Humm... Now I am very torn am what to do. I have a full '96 upgrade for my '90 in hand waiting to be installed. On the other hand I could sell it and get most of the cash to pay for the PBR setup and save a few critical unsprung pounds...

 

[DHMag]

Mikey,

Why not modify cobra calipers to fit on 11.6" rotors? It has been discussed here before. I believe the caliper bolt holes have to be drilled 3/4ths of an inch upwards.

close, but not quite. the hole needs to be relocated .7" from its original location. any more than a .1" deviation and the caliper bracket will rub on the wheel. this is what i did and total cost was $350.

as soon as i get around to replacing the wheel bearings, ill be running the Cobra setup again.

 

[Shoaz]

I can appreciate the concern but that is why we have testing. We have been able to eliminate the problem with the caliper bending altogether in testing simply by changing to a different pad with a higher coefficient of friction than what we were initially using. Agreed that this kit is not ideal for a full time tracked car, but this is not it's intended purpose anyhow.

And that's fine as long as a number of things stay true: the car is driven just as it was driven in your testing and on the same tracks, same weight, same pads, same hp, etc., etc. Driving style has a lot to do with it and people change pads, drive on different tracks, attach superchargers, etc.

It's just an issue of which people should be aware.

I do appreciate the concern. My intent is not to discredit you; only to state that we've recognized the problem, experienced it ourselves multiple times, and worked towards a fix for it.

As you mentioned, even the HD PBR calipers have been bent under extreme conditions. My concern comes from the fact that many of the folks that show up to the conventions and drive the track days are neither engineers nor experienced race drivers, nor should they need to be. Inexperienced road course drivers with fast, heavy cars (i.e., a lot of the crowd that shows up at the conventions) are the most susceptible to brake related issues. My personal feeling is that they should be aware of things that may contribute to safety issues and non-HD aluminum calipers on a fast, heavy car like an SHO are one of them.

Your efforts to work toward improving the situation and minimizing risk are appreciated. I think you've been pretty straightforward and up-front on the issues and I think what you're selling is a fine kit for the majority of SHO owners out there. I just don't want to see something tragic happen to someone as a result of a misapplication.

 

[Dave Kegel]

For those of you that want to use the 11.6" rotor, keep in mind the swept area of the pads. It's my understanding that the '96 and up SHO pads offer a larger swept area than the PBR pads do. Larger swept area means stronger braking. I would bet that given the same brand of pads, you'll probably get better braking with the Gen3 calipers. The downside is that they are heavier, and the inside pad will tend to "potato chip" under track use due to the single piston caliper. YMMV.

Dave