I have a 1973 914/6 conversion with 2.4 L engine(being rebuilt now), and I am running the Alloy "S" brake calipers up front. I am looking to upgrade the front brakes. Boxster calipers are cheaper than the Big reds and a bit smaller as I would like to run a 17" wheel or smaller.

Anyone have the boxster calipers installed? Which rotors did you use? Adapters?

I have an old set of Bremtek calipers that I might use if I can find some seal kits for them still.

New to these forums, but love all the stuff on this site...especially all the racing pics

Hey Torque Junkie,

For my $$, you can't beat WILWOOD brakes! On my V8 conversion 914, I'm running 12.19" x 1.25" vented Wilwood rotors ($42 on summit)
(http://www.summitracing.com/parts/WIL-160-2895/ (left) &
http://www.summitracing.com/parts/WIL-160-2894/ (right)
and the 4-piston Dynalite Calipers (http://www.summitracing.com/parts/WIL-120-6804/) $125.

All you have to do is find the right aluminum rotor-hat to fit your application, drill them to you bolt pattern and make a very simple caliper mounting bracket.

Don't be scared! When I mount the rotors, I use a dial indicator to get them centered within 0.005" and tighten them up.

The bracket is also TOO simple..check out my pics and see.
BTW: I did ALL this fabrication myself in my garage with only a drill press and a wire-feed welder.

With the extra Chevy engine weight + driver, my rig weighs 2800 lbs and after a hard session on the Streets of Willow Springs, the front rotor only reach 420 deg. F., while the rears run at 300 deg. F.

Enjoy,
Terry

Depending how extreme your car is, and your use for it, the S caliper setup may be just fine. Regardless, you will not want to go any bigger in front without doing something in back as well.

You are most likely adding significant unsprung weight with any brake upgrade, so that also needs to be taken into consideration.

I don't need a setup as wild as Terry's since I have much less grip and aero and weight, but I may go to a Boxster setup when I add flares and go somewhat wider on tires. Right now I have a 911SC "A" caliper setup which is the same as your "S" calipers except steel vs. aluminum. It works very well on my narrow-bodied car.

Hey Campbellcj,

You have a good point that you don't NEED as much braking as I have (if there is such a thing as TOO MUCH braking), but my real message is how much Bang-for-the-Buck you get with these Wilwood products. Pricing is so good because the brakes are used by several stock car classes all over America and thus high volume production and price competition.

BTW: The calipers are aluminum and lighter than the originals, while the rotors are mostly air, mounted to aluminum hats. I haven't weighed old vs new, but would guess I'm weight neutral after the upgrade.

Regardless, Enjoy your car & good luck with your competition.
Terry

Thanks for the input. The willwood set-up looks nice. I will take a look and see what I can find. I believe for now the alloy S calipers are enough, but might want to upgrade and the engine will have a bit more power this time around. and looking to add wider tires as well.

So does the rotor hat have the bearings in it, or does it slide over a hub of some sort?

"Upgrade" in regard to 914 brakes is bandied about quite a bit, here's my take on it.

Real upgrades actually consist of increasing the heat sink and/or cooling capicity of the brakes. Another is increasing the mechanical advantage of the rotor vs the wheel/tire.

The former is straight forward by adding a vented and/ or thicker rotor.
The latter is a bit tougher. You need a larger diameter rotor, a caliper with more clamping force/pad area, bigger wheels, a larger master cylinder.
Both of these add weight.....and the worst kinds, unsprung and maybe rotational weight.

If you track your car and have you've turned your 914 into a 2500 lb sled some of the above is a good plan.

The original poster needs none of this, IMO. The S caliper set up is light/vented/ and designed to stop a 300-400lb heavier car repeatedly. The soft pedal ever allows better modulation of the brakes. If you're tracking it the most I would do would be to add some racing pads.....but those suck for the street.
Big wheels have a similar weight problem.

I use the S set up also. Works for me.

Hi camaroz1985,

The rotor hats slide on the wheel studs.

In my case, I have adapter-spacers that bolt onto the Porsche 5-bolt pattern, retaining the rotor& hat with 5 studs sticking out in a Mustang pattern. Thus, I can set up the rotor position with a dial indicator, tighten the adapter and have the freedom to remove the wheels without disturbing the setup.

I could easily see 914s using Porsche-Porsche pattern spacers to do the same thing.

Best,
Terry

quick question about you brake setup. what hubs and hats are you running? my 73 911t hubs are roughly 6.55" and all the rotor hats in the 8.00x7.0 rotor bolt patern are to small in the inner dia.
so i was just wondering what hubs you were running?

I think you just need to buy the proper pads
I doubt you need anything more than an S caliper
they are good for 250-300hp on the track

what pad are you running?

how much does your car weigh?

Hi Rick:
I'm running the same 911 hubs as in the photo of the Yellow 914. For rotor hats
I'm using Wilwood P/N 171-3758 in front and P/N 170-0764 in the rear. Per the Wilwood Drwg, the ID of these hats is 6.82". I drilled the 911 pattern holes in the hats on my drill press allowing a loose fit. Then I sandwiched the hats between the 911 hubs and my wheel adapters, snugged the nut a bit and then centered the hat/rotor assy with a dial inidcator (Harbor Freight has been selling them for $7).

I hope this helps,
Terry

Go watch an HSR 2 Litre Challenge event. If you're in the West, watch Frank Best. East? Bill Lewis Jr. Let us know if you can drive faster than either of them (if "yes", you're lying). Check out their calipers. Report back.

For a good (did not say cheap) street/AX pad, go get factory/dealer '76 Turbo pads. '76-'78 Turbo used the good ol' 911S aluminum caliper and they were heavy cars. This is 30+ year technology tho...

I have had no issues on the street with Porterfield R4S in my 300HP 5000-lb daily driver (slotted disks) or Joy's 250HP 3000-lb DD on Hawk HPS.

S calipers and good pads is a setup that is hard to beat. Porsche could have put anything on the first Turbos (and wound up with 917/RSR calipers when they uprated to 3,3 liters) but they didn't see the need...

And good, fresh fluid.

I am going to keep my Alloy S calipers for now and reseal them and see why they are locked up. Will look into more modern pads. Had perf. Friction Z rated pads in there and they worked fine 10 years ago...cant believe it has been that long without my 914....

A good addition to S calipers is a set of Stainless steel pistons. The stock steel ones corrode over time.
Pelican carries Stromski's or buy them direct. Not cheep but very worthwhile.

http://www.stomskiracing.com/

and I've had good luck with the Pagid 4S street pads on street teeners.
I'm a big fan of cool carbon on race teeners

a lot of what you read on the internet regarding pads and porsches are really for heavier cars. the KFP (cool carbon's new name) work really well on cars below 2500lbs

it depends on tire adhesion and weight
but the S calipers can be really really effective when everything is dialed in.
Make sure your tires (10years old) are upgraded too.

I have stainless pistons in them. Car sat out and was fine until I brought it in. I did apply the brakes to stop as we pulled it in, but now fronts are frozen. Hope to get up to my warehouse and get them apart this week. I was digging through all my brake parts and I have 18 sets of NOS brake pads for the alloy S calipers. The good ones that they cannot make any more...wink. I have enough pads to last me for a while.

It is amazing how much a person can forget in 10 years of racing and working on other vehicles. I sure miss the 914. I am determined to have it up and running by the end of the year.

I would guess that the caliper seals are toast after sitting for the 10 years. They also act to retract the pistons. All the rubber stuff is in the rebuild kit, IIRC.

I think you will find that the modern carbon pads are MUCH MUCH better than the old DS11's and asbestos based pads.

I still have a set of the "good old ones" and the difference in back to back driving is significant

brant

just to add to this, I have 993 rear calipers on the front of both my race and Targa cars, stock carrera rears on the back. I really like the brake feel - feels like my 993 street car, and can out-brake anyone on the track. No fade, no heat problems, nothing. Use Hawk Blue for racing, straight Porsche/Mintex for street.

Rotors are stock from the 5 lug Carrera set up I took them off of. (yes, my wheel wells could use some cleaning up)

OK, i just looked at this picture and realized I also have completely different suspension and spindles, so this isn't applicable for most.

The 993 rear calipers will ALMOST fit onto 3.5" stock spindles - that's what Huey has. You have to wallow out the caliper holes a couple mm to the inside, but they fit perfect on the rotor. I've run them on Huey for street, AX, and Targa Newfoundland for 4 years, and on Papa Smurf for at least 6 years.

Bob,

What size master cylinder are you using with your setup?

Andys

23 mm.

Huey should be back at the shop next week or so to fix the oil leak, and I'll take new pictures of the brakes and set up there.

I'm running Boxster calipers front and rear. Very happy with the setup. No squeaks or squeals and great breaking!! Up front i'm running 3.5" struts with standard 911 ventilated disks. In the rear early ventilated 911 disks. Adapters front and rear are from Richard Johnson. I'm also running a 911 emergency brake. I'm also running a 19mm master cylinder. Seems fine to me, but I have never tried a bigger one.

Building my track car now. I am using 951 front calipers and SC/Carerra rears with a 911 e-brake setup. I'll let you know how it goes after the first event in late July.

seams to me that with the relitive inexpence and availibility of wilwood parts, stock porsche parts would not be the way to go. way to hard to come by any way way way over priced.
is there any advantage to running porsche parts?

I'd like to do some vintage racing later this season. Although the 951/SC brake setup may be frowned upon by the organization, a fellow teener was allowed to compete. A new Wilwood setup would not be allowed.

I know vintage racing out here requires the brakes to be from the year of the car and also something that was available from the factory.

so an S caliper (per a factory gt) would work
a 951 caliper would not

everybody's different obviously.

Brant, I know what you are saying about the originality factor. The way it was put to my friend was "Please take care of that as soon as you can". I believe he was bumped up a class or two. He was also running an FI 3.2 in his GT-look teener!! Car count may have also come into play.

The club out here used to allow cars like that (3.2) to run as exhibition
when car counts came up, they decided to no longer allow exhibition cars this year. They had never issued log books to exhibition cars. This year there are a lot of angry people who have been racing for years with the club that are suddenly not. I was on the eligibility team, representing porsches for about 6 months. It was not fun fighting. I quit.

I agree with JP that the original poster doesn't need to go crazy for a street application.

When I wanted to upgrade the brakes on The Beast I asked Matt Lowrance what to do.

He said run Carrera calipers both front and rear. We are running 10 and 11 inch slicks on the car so needed some extra umph.

I've driven the car at three different track days and it worked perfectly. Never faded even a little.

I got the calipers from Rich Bontempi.

If I were to go the next step it would be with the Wilwood setup. But remember to change the master cylinder as 19mm one won't work. Been there, done that.

Carrera calipers are the heaviest calipers ever made for the front of a 911. Weighing in at 9lbs. 6oz each (without pads)

S-Calipers have the same pad and piston size and weigh 5lbs. 4oz.

The Carrera rotors (which are not needed on a lightweight 914) also weigh an additional 4lbs. each.

All tolled, the Carrera system will add almost 35lbs. of unsprung/semi-sprung weight to your car.

Also, PP is "still" listing SS pistons at $240.00. They are now available at 1/2 that price. Almost "all S-Calipers pistons are bad due to the nickle plating for dis-similar metal fusion issues.

You're right, Eric, but I had no luck with 914 rear calipers/rotors with S fronts.....the rears were not carring their load.
Had to go to an M set up in back.

And this is why 914.6 rear calipers use 'M' size pads and bigger pistons...
For a dedicated track car with no E-brake requirement, M's in the back pretty much duplicates the factory (street, non-GT) /6 setup. Should work really well.

Probably saved a little weight with that set-up... 2 ounces each to be precise (over a 914-4 caliper).

However... unless you took the spacers out, you added a vented rotor so, that would add an additional 4lbs. (approx. 2lbs. each). Good move regardless because I don't think 914 rear calipers are a good match for 48mm pistons or that larger pad. They're basically not a good match for anything but a 914 front caliper. The BMW (quazi) "upgrade" does the same thing. A Suby guy in the garage did this and had the same results. Again, 48mm pistons and a pad that is almost identical to the A-Caliper (Carrera) and S-Caliper size.

One way to do it (as eluded to above) would be to use 911 rear calipers for the best brake bias with the 38mm pistons and larger pads. Take out the spacers and use early 914-4 front fasteners (M7 stuff is virtually unavailable). Then use the lighter 914-6 rotors. This would shave 1lb. 12oz. off the weight of a standard 914-6 set-up. More if you consider the savings from no cables and not handbrake.

This is "way" cost effective (when flown in the face of the costly 914-6 caliper). I put a few sets together from time to time and threw them in the classifieds but... nobody seems to understand the application.

The pro autocross guys can weigh in here but, I don't think you'd need a vented rotor back there for autocrossing. I guess it depends on how close the run groups are or, how many runs per. Not sure. That said, I would contend that autocrossing is probably harder on the brakes than road courses where fairly long stretches might allow for better cooling all around.

It came dow to time, money, & effort.I knew the Ms would do the trick and allowed me to adjust the bias to just where I wanted it......about 3/4-1 turn from full open after some foolin' around. The extra weight was not a bonus and I'm sure there is something lighter that would do the trick but I'm happy. Prior to that I had taken about 1.5 lbs off each swing arm. I was net looser.

Then I moved on to the next challenge. Bought some 16 X 10 wheels that weigh 11 lbs ea... we were back on path.

OK..there are lots of brake "upgrades" that can be done. I feel that the "big reds" are overkill for a 914. What I used on my six conversion is this. I built it for DE's and maybe future club racing, but most of the miles will be street miles.

Front: C2 calipers, Carrera slotted rotors that were "frozen", Hawk street pads for the street and Hawk "blue" pads for the track. The front brakes are cooled with a cooling kit and block off plates.

Rear: C2 Turbo calipers, Carrera slotted rotors that were "frozen", Hawk street pads/"blue" track pads.

19mm master cyl. and Tilton proportioning valve.

Some may agree/disagree with this setup, but it has worked great at the three DE's I've been to with no fade and great stopping power. Using 15" wheels with this set up.....

Fronts:

Click to view attachment

Rears:

Click to view attachment

Well I finally got my brakes off and rebuilt. Alloy S up front with Ferrodo old skool pads(have 12 sets NOS) so figured can burn them up. Rears are the M 911 calipers with the thicker rotors. This worked out fine. Thought that by sitting they would be ruined, but had the stainless pistons in the s calipers and the rears cleaning up fine too. Will see how it holds up with the new power plant. 2.4 with 2.2S pistons and Solex cams with Webers.