Any Vintage Racers here? 911S Alloy caliper question.

[Martin Baker]

I am getting my car closer to running some Vintage Races with a more authentic organization next summer, most recently installing a set of early S calipers in place of a set of 951S Brembo 4 piston rear brakes on the front of my 914-6GT replica. Any suggestions on pads for this type caliper? Was running the Porterfield R4 pads, currently have padgid orange compound which came with the calipers. Seem to be quite difficult to bleed succesfully, your thoughts? Already have stainless pistons installed from a prior owner. Good/Bad? Car seems to alternate from pulling one way then the other under heavy braking. Did not do this with the Brembos...not at any speed. I miss them already! Using ATE Super Blue. Any comments about racing with these brakes, I mean real, wheel to wheel racing, not AX, or street racing, are welcome. I can see backing up my braking points a few feet already! Thank you, and hope to see you at the track.

Martin

[pcpaternie]

Hi Martin,

I've had no issues running the S calipers with Porterfield R4 pads on my 1968 911 (knock on wood) with stainless brake lines. Pad life has been very good running at tracks like Willow Springs, which admittedly is not a heavy braking track, but also Fontana, Buttonwillow and Coronado. Car weighs about 2100 lbs with fuel plus another 220 for its cheeseburger eating driver.

Patrick

[CamBiscuit]

I like Hawk Blue's on my car.

MUCH better than the previous Ferodo DS2500's

[JohnT]

Martin,

I think you might be mixing your braking "metaphors" and perhaps being confused by the symptoms. I run Pagid orange pads with ventilated steel discs, stock 1967 steel calipers, and ATE DOT 4 fluid. These pads take at least one lap of hard work to begin to come in. The symptoms of cold Pagids are lack of braking and "darty" handling. Often my brakes take a pace lap and a race lap to begin to really work.

So question #1 is, are you getting them hot enough? Pagids really want to be hot. I mean I have removed my piston dust shields because they would catch fire at the end of a race and "blued" rear rotor hats are not unusual.

I can say that amongst the early ('65-69) 911s in CSRG and SOVREN I think there are no aluminum calipers. I haven't tried them, but I was fondling a set at a swap meet when the guy who built my car told me to "put them down."

I'm considering trying pads and rotors from Centric when my current supply of Pagids is exhausted. Not because I'm dissatisfied with the performance, but because of the price. Since the dollar imploded stuff priced in Euros is damned expensive. Here's a blurb on their new Brake fluid. Centric Parts.

This company has quietly established itself as a major player worldwide in brakes and has developed some excellent competition pieces for more modern cars. Their stuff might be worth a look.

Whatever you do, you are not going to reproduce Brembo, multi-pot braking performance with a set of 45 year old single pot calipers with small (miniscule!) pads.

johnt

[TRE Cup]

S alloy calipers flex a lot under heavy braking. Doubt it? Take your wheels off, have some one repeatedly pressure the pedal and watch them move. A good alternative is either the cast iron A caliper or the Carrera 3.2 caliper (with corresponding thicker discs) . You can find these used on Pelican fairly cheap. Then Centric offers these in rebuilts, which makes a heck of a deal for something that is ready to use.
Porterfield R4 has always done me right on the track.

FWIW- the owner of Centric has raced a Porsche 993 TT, as well as other competitive cars for many years. They are no cheap fly by night operation

[Flieger]

Other than than a little bit longer pedal stroke, what is wrong with caliper flex?

[Chuck Miller]

Other than than a little bit longer pedal stroke, what is wrong with caliper flex?

It's not very confidence inspiring Max...... and harder to modulate on the very ragged edge of deeeep braking.

I switched from my stock alloys to SC's years ago........ much better feel braking my well over 2400 lb. car......

Just one less thing to think about and drive around……


BTW- I run PAGID 'black' (blue box) performance street pads.......

Cheers

[JohnT]

Other than than a little bit longer pedal stroke, what is wrong with caliper flex?

Max,

The flexing is usually inconsistent. Left and right fronts may flex different amounts. Hence the directional instability........ scientific for they can scare the $hit out of you

johnt

[John Straub]

I use the Portfield pads on my GT with aluminum calipers, I'm sure I get some flex with them. It reminds me of something a friend of mine, Alan Johnson tells a story about Milt Minter. Alan asked Milt when he knew when to break for a corner.

Milt said, "I'm on the gas until my foot starts to dance...and then dances over to the brake pedal." So I guess it's just how hard you drive.

Anyway, I'm happy with the Portfield pads, flex or no. The GT weighs about 2150.

Maybe I'm not driving as hard as some, buts that's OK.

John

[JohnT]

John.

As I understand it, the fastest guys use the brakes less and therefore have fewer brake issues.

...............My foot starts dancin' early and hard..............

johnt