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?

[Martin Baker]

Martin,

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.

johnt

Little update, ran the first time with the 911S Alloy calipers and the Pagid Orange Pads @ Laguna (HMSA Club event). Not bad. Gained some confidence in them, and had a great event. I did notice everything mentioned by all the Racers who commented. Little darty when cold, need to be really hot etc. I ran on Hoosier Bias ply Street TD tires. Allot of fun and met some great people, and saw some old friends. Car went great, now trying to decide which event to run next! There are allot to choose from.


Martin

[Martin Baker]

First, thanks for all the info/wisdom. I bought the 911S alloy calipers to satisfy the group I want to race with, as the 914-6 GT cars raced with these calipers back in the day. Trust me, I hate seeing those Brembos layong on the work bench, and am well aware of what these brakes can do. As I got more track time in the car I was amazed at how late I could brake and still make the corner! I have two 914-6 cars, a real one and a SONAUTO replica built off a 4 cylinder chassis. My real one which has been a race car for a long time has Wilwood Superlites on the front and Bremteks on the rear. I know it ran with VRG on the East coast. My SONAUTO now has the S fronts and widened 4 cylinder on the rear. I want to run with HMSA, and I was told the Brembos had to go. I am interested in authenticity and willingly bought the S calipers when a set happened my way. Didn't like the price but I want to have the right parts to make the Tech guys happy. Just wanted to get some feedback from folks who have raced with S calipers, I have heard all about the flexing thing, but if they flexed in 1970, then I guess I will experience what the guys experienced then, which is what its all about, I'll read all of this info and go from there. I have only tested them so far on a couple of very spritied street runs, on street tires to get a feel for them. Not quite ready to do a test day with yet, as I still have some suspension parts to swap out. Again thanks to all you Racers!

Martin

[Chuck Miller]

Martin,

Even though I'm a big advocate of storing alloy S brakes in a box, the other side of this is that you're absolutely right, the alloy brakes were raced successfully for over four decades. My late friend, Topper Chassie, successfully raced his orange 914-6 from new (I believe it was one of the original Bozzani 'celebrity cars') for over the next 30 years with it's alloy brakes. In it's biggest 2.7 engine configuration he would get down to a 1.30 flat at Willow....... all with alloys, and never a complaint about brakes.

Cheers

[JKW]

Martin: Since it was restored in '92, I've used either the slightly wider 908 and the S alu brake calipers in front on my 914/6 racer. I haven't noted a problem at any of the west coast tracks I've raced (Laguna, Sears, Thunderhill and in SoCal) with either type of caliper. I do run the correct 2 liter motor, so try to keep my speed up in corners. Maybe the "problem" is associated with cars with bigger engines (i.e., "point and squirt" cars versus "momentum" cars?). Try them out and see what you think. It's not hard to experiment. Cheers! Jon