Caliper Weights

[jeffball610]

I'm looking to upgrade the front brakes on my dime with something pretty substantial. (I've already converted to 5 lug hubs front and rear) I was first going to use the Toyota 4 piston caliper, but have been looking at Z32 calipers lately. I know the Toyota units were pretty heavy. What kind of weight are we looking at here? I know the Z32 came in both aluminum and iron versions. Of course I'd want the lighter aluminum pieces, but is there really a weight savings there either? Can we make a list of caliper, rotor and spindle weights to make a better informed decision on unsprung weight penalties vs braking performance?

[thisismatt]

I had some Toyota 4 piston SW12+8. I ended up selling them, and shipped them in a priority mail flat rate box. I believe I weighed the box just for kicks because it was so heavy for the size and I knew it was going to be surprising when a postal employee picked it up. If I remember correctly it was around 22-24lbs for both.

[okayfine]

Can we make a list of caliper, rotor and spindle weights to make a better informed decision on unsprung weight penalties vs braking performance?

I don't think you can really draw anything from that unless you include a brake test. And even then it would only really be valid if you swapped each brake setup onto the same car.

[RWD_NissanMan]

Well, I use the aluminum Z32 ones and they are very light as compared to the cast iron units. I'd have to weigh one for you I guess if you are compiling a list. There is apparently a disadvantage to the aluminum over cast though - some people have claimed that it is the capacity to absorb and dissipate heat. This sort of makes sense if you are just using the car for a street application and depending on the pads you are using - you might want to retain some heat in the calipers/pads if you are not heavy on the breaks all the time such as you might be on a tight road racing course. Personally, I have used the EBC Red Stuffs in the aluminum Z32 calipers on an SR powered 510 for 2 Targa Newfoundland events as well as a number of track days and am nothing but pleased with the combo for that type of work.

[510rob]

Can we make a list of caliper, rotor and spindle weights to make a better informed decision on unsprung weight penalties vs braking performance?

I don't think you can really draw anything from that unless you include a brake test. And even then it would only really be valid if you swapped each brake setup onto the same car.

Rene Descartes would be proud of you

[okayfine]

Rene Descartes would be proud of you

I don't know about that. Just thinking you could get all the weight info by sitting in Napa's warehouse with a scale, but it won't tell you squat about changes in braking performance.

[jeffball610]

By braking performance, I was more thinking of static performance like pad area and piston area. Things you could measure completely objectively. Even if you did a side by side comparison of calipers on the same car, on the same day, on the same tires, you can have a wide range of variables.

Vehicle weight, rotor weight, rotor hat material, caliper material, brake pad, air temperature etc. All of these can cause there to be too many variables. I keep seeing "big brake" tests in performance magazines where they show that big brake kits actually reduce braking performance over stock components. Most big brake kits are designed for racing where heat is needed to be built into the friction material to gain an advantage. Or they are designed to dissipate heat better for repeatable hard stops, not single stops like most tests conduct. Also, they typically account for the car having wider stickier tires to give the car a larger contact patch to use the bigger brakes.

I know there are a lot of holes in my request, but I think it's just as valuable as the "Suspension Setup" topic. If you have any info that can help other enthusiasts make an informed decision, it would be much appreciated. If the info is just to say that weighing a caliper and components is not a good basis for choosing a brake/rotor package, then that is also helpful.

What are some measurable variables we can record to help us choose a braking package?

[okayfine]

By braking performance, I was more thinking of static performance like pad area and piston area. Things you could measure completely objectively.

I understand. I just don't see the strict value of those measurements without the knowledge necessary to interpret the objective data presented into something relating to braking performance. All else being equal (and I admit it rarely is, but bare with me), more pistons at the caliper will give less pressure at each piston when compared with fewer pistons. Less pressure is less performance. I'm not saying that all four/six/eight piston calipers are junk, but the objective number of pistons doesn't automatically equate to more or less braking performance.

Even if you did a side by side comparison of calipers on the same car, on the same day, on the same tires, you can have a wide range of variables.

True. However, would you agree that the variables would be much reduced compared to even the second-best scenario of each owner listing their components and reporting a braking performance stat (that was, hence, unverifyable)?

If the info is just to say that weighing a caliper and components is not a good basis for choosing a brake/rotor package, then that is also helpful.

Less unsprung weight is better for handing performance. It has only a small effect on braking performance.

What are some measurable variables we can record to help us choose a braking package?

Variables should be dictated by the expected driving style. You can easily have too-big of a brake system, and if you don't drive the car within the range dictated by your chosen components, you might be surprised at the lack of performance of your system.

I know I was.

I had 11" front rotors, Wilwood Dynalite calipers up front, and stuffed with Porterfield's street pad. Impressive specs, compared to stock. I'd wager a stock-brake 510 would out brake me on that first 50mph of decelleration, and the 280ZX stuff I was upgrading would probably peform better overall given my driving habits. From a strict braking-performance standpoint, I should have kept the 280ZX rotors and calipers, despite the OE calipers being boat anchors compared to the Wilwood numbers.

[jeffball610]

Thanks for the update on the 280ZX stuff. I keep hearing that they are a great upgrade for daily drivers. Although my car will be street driven 90% of the time, I really am looking for more braking power when I get a chance to hit the track. I'll also be running a 300+hp engine and need something to help haul all of that down.

However, I think I've past the point of no return. I have already "upgraded" to 5 lug hubs front and rear (rears are a permanent upgrade) so I'll need something that won't likely bolt directly on like 280ZX stuff. I'm not set on Z32 calipers, but thought I'd try to get some info on what others thought and if the weight gain (or loss if the aluminum units are light enough) was worth any handling or single braking short comings.

[bertvorgon]

Just as a reference point then..

On my car, 280ZX rotors, with Brakeman calipers on the front, and BMW 2002 front calipers on the rear, with 200sx rotors, will with stand a 30 minute road race, on a track know for being VERY hard on brakes. And that was slowing from the fastest at 125 MPH, to multiple stabs over the entire track. Pads are obviously selected for that type of event. I also have very good cooling ducts, to the inner rotor, which makes a tremendous difference. With my street pads in, I have more than enough brake, for any circumstance encountered, and work well enough when "cold".

Personally, from experience, go as light as possible, BUT...make sure it is as STIFF as possible. I used to use the JFZ/WILWOOD caliper, in their original permutation (of this size), and found them just a bit too flexY. The new Brakeman calipers are way better. I think having the best unsprung weight as possible, from a pure handling point, is not to be discounted.

again, my car zips to speed pretty fast, and thats with 250 RWHP.

As RWD said, I have more of a problem keeping some heat IN, for most of my driving, and only in the true road race situation, did I have a problem, before I put the air cooling ducts on. The gang at Specialty all use brake water sprayers also, which work VERY well. I have mine ready to go on, but our lack of track days now has kept me from following through. I run as SOFT a pad as possible on the street. Don't out trick your self by putting on "race Pads" on the street...been there, done that. You want something that is nice and lineal, with some good bite COLD, just in case Gramma runs the red light in her Buick. My street pads still let me do many stops from 100 MPH, with no sign of fading.

Our cars are light, and if you have discs on the back, other than extreme cases, you should have spectacular braking for the most part. Run good fliud, change it often, and make sure your bias is good, not too much to the rear. If you have bias adjustment, make sure you do some tests in a safe enviroment, settin ght ebias to both extremes. That way you will know HOW the car will react. It will change of course, a fuel load changes, and pads heat up. Plus, make sure you try your car out on safe corner, to make sure, that as one wheel gets light, it does not have a penchant to suddenly lock up, specially on the rear.

Just some thoughts.

[heirfaus]

Rene Descartes would be proud of you

I don't know about that.

Oh Rob...

[heirfaus]

Less unsprung weight is better for handing performance. It has only a small effect on braking performance.

This factor alone is worth knowing.

[Eric P]

Keith, do the Brakemans fit under 13" wheels?

I have some 911S calipers, aluminum, that I plan to fit at some point (Defdes gave me the idea and pics). BUT, note that some Porsche guys actually switch to the steel calipers because the claim is that the alum. ones flex too much. I dunno but it lines up a little with what Keith said...

E

[bertvorgon]

The Brakeman/Wilwood Dynalites fit in my PANASPORT 13" wheels. Those are thin wheels, but I do have good clearance to the rim. Byron put my Wilwoods on the BRONZE car, so we know they fit with the American Racing style 13" wheels also. When I up graded to the Brakeman calipers, I stayed with that size so that I could use my smaller 13' wheels for gearing purposes. That caliper is WAY better than the Wilwoods were, in terms of flex, but even they still flex a bit. That being said, it is hardly noticable in terms of pedal feel. It just has been a whine of mine for years. In some ways I overcame that feel when I actually stopped running race pads on the street, and just went for a grippy pad. Now, when I just snub the brakes for traffic or a light, the car actually feels like the pads are doing something...COLD. Pad choice ultimately make how the car feels a very important choice. In the real world of cruising, and high performance street driving, race compound pads have no place. Pads material has come a long way since I started, I'm likely a generation behind on what works now also.

On a good handling car, good brakes are very important, as they can be used in some types of corners, to set the car up. Trailing brake going in to the apex point works very well in my car, getting the rear to come around just a hair, and then I can rely on my rear toe-in to keep the car from oversteering. You want your brake pad to have a lineal temperature rise, so you get no surprises. Byron has tried a new pad on the front of his, so he may chime in. He still has drums on the back though.

I can beleive the aluminium flex thing for sure, you cannot beilve how steel feels. Just as an example, on my car, we wanted to determine where the flex was really coming from. We disconnected the front calipers, so just the rear was working. The brake pedal was like stepping on a brick of steel. Hooked up the front, kinda mushy feel. We put a dial indicator on the caliper, and you could see it open up, as the bridging is not very good on those original Wilwoods. The Brakeman, and others like it, have gone to a forged housing, and better bridge bolts, so flex is less.

They are easier to bleed also. So, I would say that anyone running larger wheels, has a much better choice of nice light, and stiff calipers to choose from. And, for most of us, our cars are not pure race cars, so any track days, time attacks, Solo, etc, you will have more than enough brakes. Ask your self, when was the last time I hauled my car down from 120 to 130 miles an hour, repeatedly, and had brake fade? For most 510's, getting to a real 120+ miles an hour is a bit of a work out, or, on your last Canyon Cruise, how often did you have to hammer the brakes to get the car hauled down? REPEATEDLY?!

Make your choice!

[datsun510]

Todd Kaneko's orange rotary 510 had Wilwood discs in front and rear for years and when they decided to run the Timeatek races they ran into brake fade with the car no matter how many times they bled the brakes. Mario at TSR convinced him to upgrade to his Brembo kits for the front and rear. They took the car out to Laguna Seca and ran 2.5 seconds per lap faster and had no fade for the whole day of racing. Not cheap but his car was hitting 140 mph+ at Laguna so he was really pushing the brakes.

Seth