JHowell37

Of course I look at the back side of the rotor and the ball joint. But you know what's more important to check for evidence of rubbing than the steel body of the ball joint? The dust boot on the ball joint which sits ever so slightly closer to the rotor is actually the first thing that would make contact with the rotor and probably tear the boot or leave it heavily marked.
I'm not using S4 rotors, I'm using 993 rotors. I'm not '85/'86 spindles, I'm using the early spindles from '80 or '81.

Landseer

I upgraded using the entire S4 suspension.
Its a fairly involved job that will require many more parts than you've listed. More parts still, if retaining antilock is an objective. (am still working on that)

Alternately, adapter route has worked for racers and road.

So has using earliest spindles, though there is much talk about close tolerances, lower ball joint carrier to rotor.

Worth depends on your use-plans for the car.

Will you be running at GingerMan road course, near you?

Are you outrunning (well-maintained) S brakes now ?

The car has been advertised for a while. Are you keeping it?

KenRudd

“Even with wider DOT track tires I can lock the brakes. Nothing more is needed.”

I have seen variations of that point elsewhere on this forum. It’s based on the premise that what determines adequate braking is the ability to lock the wheels ( or almost lock them, if you have ABS). This seems to make sense on the surface.


However, the purpose of brakes is not just to create maximum amount of friction/force at the rotors. If that was the case, SmartCar brakes and enough boost could do that ( assuming the materials did not fail). Or carbide spiked pads driving into the rotors, to take it to the silly extreme

The purpose of brakes is to quickly convert kinetic energy into thermal energy AND dissipate that heat quickly. Larger, more massive rotors will absorb more heat and dissipate it more quickly ( at the obvious trade off of more unsprung weight). Larger pads are then required to take advantage of the greater swept area. Multiple pistons are more efficient at evenly distributing the force on that bigger pad than one large piston.

My understanding of the physics may not be perfect, but I think I hit the majority of the factors.

More importantly, I have driven the same car on the same track with the same tires and same brake fluid but different brakes: ~4 sessions on S3 w/street pads, ~6 session GTS w/street pads. And I can tell you categorically that the GTS setup had significantly better braking and less fade. At least 1 or 2 markers deeper after every straight and much better modulation after the system got hot. And before that, I had hundreds of laps in my S4 at the same track with similar tires, and I can tell you the S3 also fell short on braking to the S4 by enough of a margin that it surprised me in a bad way until I dialed it back.

BTW: I do NOT typically run street pads at the track. That I just what I had at the time for testing and set up.

I am leery of the Torque vs HP, Mobile1 vs. Amsoil, etc. arguments and hate to dive into that type of pool and I don’t feel I am enough of an expert to support my conclusions better than what I have laid out, but my confidence is high enough that I stand behind it with my wallet ( the GTS upgrade was not cheap or very easy) and my ***, every time I get out on the track.

123quattro

Ken pretty much covered it...

KenRudd

Arrgh..I had to drop everything and run out and inspect my rotor/ball joint!!!!!

My dust shield seems to be between my ball joint and my rotor..

KenRudd

BTW: I considered doing the full S4 suspension upgrade and would have done so if the Perfex mfg kit had not worked out for me. It is likely the best solution, but as has been pointed out also most complex and costly.

xschop

I never understood the reasoning behind changing the entire front suspension just to get on a better caliper. There are many calipers out there that will mount with an adapter.

tv

Yup that's all been well covered ...................... ..... so let's keep it off the thread and just go with the idea that some people want bigger brakes for the hell of it and post how that might happen w/o mickey-mousing the set-up into some home grown hack-job. Greg below says it was a simple swap.








Greg in Aus did with his Ferrari F50 brake upgrade
https://rennlist.com/forums/4510827-post14.html
https://rennlist.com/forums/5259311-post50.html

from thread -- https://rennlist.com/forums/928-foru...f-a-928-a.html



some info on newer stuff;
https://rennlist.com/forums/928-foru...g-yellows.html


By now some company must be making an aftermarket Carbon Ceramic kit for 911 variants that might fit our cars. Is there some definite thread that explains just how to do one of these upgrades, like a waynes garage deal with pics?

JHowell37

What about the circumcised vs uncircumcised debate? Think that's comparable to those you've mentioned?

KenRudd

Mark Anderson

I will toss in some of my own experience with brake upgrades on my racer.
When I simply went from a 13" rotor to a 14" the difference was huge. I'm sure having 12" sticky slick tires allowed me to utilize that advantage and this was using the F50 caliper which essentially an S4 made to fit a 14" rotor. You can even use S4 pads with a slight mod. The added diameter gives you leverage as well as a bigger heat sink. It did bring about the need for better cooling with the added heat generated.

James Bailey

And mention how fast you were going at Fontana It was awsome

Mark Anderson

170 into turn 1

Hilton

LOL.. the day that Normy got banned was a classic in the history of RList.

GlenL

I simplify as I don't want to spend a lot of time typing. Dissipating heat is good, too. Sure. I'm not fading the brakes and am working them very hard. You don't mention that having happened and give subjective evaluations.

Me neither.