How can I put 911S brakes on my 67 911 normal?

[larry47us]

Tom:

So, just to clear my mind on this issue, on my 73E, the only thing that I would gain by going to S brakes would be the lighter caliper? The rotors would be essentially the same, and the braking surface of the pads would be the same?

The only difference would be the lighter weight of the calipers, and then possibly the greater heat dissipation of heavier pads and thicker rotors? So, in effect, other than the panache of having S brakes, if I'm not racing, there would be no advantage to my moving my E up to S calipers?

larry

[ttweed]

Guys,
I'm not sure about whether there is a difference in rotor thickness between the heavier M and light alloy S rotors on the 1969-73 brakes.

All the vented 911 front rotors were the same thickness and diameter until the 3.2 Carrera came out. That is why they are so cheap, there are many aftermarket manufacturers who jumped in because there are a lot of cars using them. Try to get a set of rear rotors for a SWB "S" car and you are screwed, though- from the factory only because they were unique to only '67-68! $300 each.

[nick-moss]

All of you guys are missing the point that Shawn's car is a SWB. The only difference on the 67S/68S over the base model was the vented rotor and wider caliper with 3" spacing.

[larry47us]

All the vented 911 front rotors were the same thickness and diameter until the 3.2 Carrera came out.

So if that's the case then, on LWB cars, there is no advantage to S brakes except for the weight difference and the panache of being able to say you have S brakes?

If that's true, I will cross it off my list of future considerations.

larry

[ttweed]

So, just to clear my mind on this issue, on my 73E, the only thing that I would gain by going to S brakes would be the lighter caliper? The rotors would be essentially the same, and the braking surface of the pads would be the same?

Yes, that is correct, Larry. You have to remember, however, that the weight saved by the lighter alloy calipers is all unsprung weight. That is worth much more in handling than the net difference in weight, which is why the factory did it. I doubt you would be able to notice the difference in normal street driving however. It is much less than the difference between, say, alloy wheels and steel wheels, since the wheels are not only unsprung weight, they are rotating, which the caliper does not do. There is a difference then in rotational inertial as well as unsprung weight.

Here's the killer, though. The alloy calipers can flex on their mounts more than the steel ones in heavy usage, so some racers end up going with the SC "A" iron calipers instead because of uneven pad wear! I did. I changed out my "S" calipers on my '73E to "A" calipers, and then to 930 calipers when I upgraded HP in the car. Talk about heavy- you should pick up a 930 rotor sometime and compare it to an early S rotor!

TT

[ttweed]

All of you guys are missing the point that Shawn's car is a SWB. The only difference on the 67S/68S over the base model was the vented rotor and wider caliper with 3" spacing.

Not "all you guys"- I didn't miss that, please re-read my posts in the thread. That is exactly why I chimed in on this.

[larry47us]

Tom:

I appreciate your chiming in on this, and giving me the nuances that I was missing on this "breaking" issue. You have added immensely to my knowledge on this subject. Seriously!!

thanks

larry

[gruen911]

Since we are considering all aspects of the early S alloy brakes and their benefits and liabilties, it may also be worth considering that a little more weight in the front by going with non-alloy M calipers may not be such a bad thing since we are talking about a very tail happy creature in the early 911, and that extra weight is at the wheels and low to the ground. What are we talking about weight wise anyway, 5 lbs.? The design geniuses in the factory were so desperate to create extra weight in the front of the SWBs that they came up with the bright idea of inserting lead weights into the SWB front bumperettes to get better weight distribution!

[nick-moss]

Tom

Sorry. I started writing my reply but didn't finish it for some time. You had replied in the meantime!

[Shuie]

Did we ever find out if Shawn was asking about installing the 3.5" alloy S calipers like are on his '70T or if he asking about the earlier 67-68 3" S brakes? I re-read the thread and I’m still thinking he was asking about the 3.5" calipers. Shawn?

So to go from SWB standard brakes to 67-68 S spec brakes will require a vented rotor and the wider 3" ear steel caliper specific to the early S.

Just for my own edification, what would be necessary to convert a SWB car with standard brakes over to the later 3.5" alloy S calipers?

TIA