The ultimate brake upgrade page.

[Flojo]

T‘is what I got. Guess these are rears...?

[anil999]

I was also looking at using the 964 calipers and 28mm discs on the front of my 1988 3.2.

Spotted a post on Rennlist from 9xx Parts in Finland regarding their 964 front brake caliper adapters for the 78-89 911 models, but unsure if they went into production:

https://rennlist.com/forums/911-forum/986509-964-brake-calipers-to-911-a.html


I've sent them mail but received no answer. Shame as it seemed like a good option.

Is anyone else manufacturing similar adapters?

[Bill Verburg]

Originally Posted by Flojo

Hello Bill, help, I don't understand.

There are 3 n/a 964 brake setups shown here. The first one is the 4/4 and the next one is 4/2. The bias from the 4/2 is better @1.5.08 than the 4/4 @1.7

[Bill Verburg]

Originally Posted by Flojo

T‘is what I got. Guess these are rears...?

I can't tell from pics(pure WAG they look like rear), you have to measure the pistons, you can get a rough idea from the rubber seals but to be sure you remove the seals and measure actual piston diameter. 36/40 is a front and 28/30 is a rear

[Flojo]

Thank you Bill, measured... they are obviously rears... so search for fronts goes on. Oh well...

Originally Posted by anil999

Spotted a post on Rennlist from 9xx Parts in Finland regarding their 964 front brake caliper adapters for the 78-89 911 models, but unsure if they went into production:

https://rennlist.com/forums/911-forum/986509-964-brake-calipers-to-911-a.html

saw this as well, but doesn't it spoil the offset?!
The changed angle obviously enhances the purpose of more diameter discs but it wont fit under a 16 Fuchs anymore?

[Bill Verburg]

Originally Posted by Flojo

Thank you Bill, measured... they are obviously rears... so search for fronts goes on. Oh well...



saw this as well, but doesn't it spoil the offset?!
The changed angle obviously enhances the purpose of more diameter discs but it wont fit under a 16 Fuchs anymore?

Done right 964 calipers on 930 rotors fit in 16s

Here's a set I ran years ago
front, not easy to do as the calipers will need to be converted to axial mount




rear, easy w/ some car. plug existing mounts and re-drill to fit the rotors



You could do the same w/ 993 calipers, they would also fit 16 and the fronts would be even easier to do, if you can get 964t rear they are easier than 993 rear

still 930 on 930 is the best way to go

[911pcars]

Originally Posted by anil999

I was also looking at using the 964 calipers and 28mm discs on the front of my 1988 3.2.

Spotted a post on Rennlist from 9xx Parts in Finland regarding their 964 front brake caliper adapters for the 78-89 911 models, but unsure if they went into production:

https://rennlist.com/forums/911-forum/986509-964-brake-calipers-to-911-a.html


I've sent them mail but received no answer. Shame as it seemed like a good option.

Is anyone else manufacturing similar adapters?

I asked too. Crickets. But still interested.

[Flojo]

Hello, what 28mm Discs to get?
I can only source the 24s for a plug and play mount to the SC hub (Sebro 275197 or Zimmermann 45662Z).

And what hard line do I get to adapt the 964 caliper?
re-bend the SC line? get the 964 line and re-bend?

Thanks

[Aircooled4evr]

Originally Posted by jph83

My 83sc, ex GT2 disks and calipers........
380 x 32 fronts
322 x 28 rears
custom pedal box with 2x 0.625" m/c for adjustable bias




Braking is err.... ample!

wow !! This setup looks amazing!

But I do have one question for the whole brake upgrade thread:
what's the largest "kit" possible in a 15 "rim?

[Ian Comerford]

Originally Posted by Flojo

Thank you Bill, measured... they are obviously rears... so search for fronts goes on. Oh well...



saw this as well, but doesn't it spoil the offset?!
The changed angle obviously enhances the purpose of more diameter discs but it wont fit under a 16 Fuchs anymore?

Flojo,
I’ve just sent you a pm about a set for sale

Ian

[Bill Verburg]

Originally Posted by Flojo

Hello, what 28mm Discs to get?
I can only source the 24s for a plug and play mount to the SC hub (Sebro 275197 or Zimmermann 45662Z).

And what hard line do I get to adapt the 964 caliper?
re-bend the SC line? get the 964 line and re-bend?

Thanks

The only way to get 28mm rotors on a pre 964 911 w/o modifying the hubs is to have some custom flat hats made and purchase the rotors from Brembo, AP, or Willwood.

The hat is just a flat aluminum disk drilled to mate the hubs to the rotors
simplest is a non floating configuration
backside

front side


There are several ways to do floating
here''s a simple floating setup for a 993, for a 911 the hat would be flat



28mm rotors come is various diameters and mounting configurations
here's a typical one from Brembo 28x320



Once you have the rotors then the caliper needs to be adapted to fit the strut and rotor

a stock 964 front is axial mount, it's unlikely that the stock caliper mounts will space the caliper wrt the rotor properly, so the caliper needs to be converted to radial mount and use an adaptor


modified 964 front w/ adapter


this is a lot of work, btw a 930 32x304 works fine w/ the 964 front and is easier to source.

then you have to do the back.

There are radial mounts calipers that can be used, the Boxster is popular and does increase brake torque a bit but it uses the small 24mm C3.2 rotors an will exacerbate the heating issues experienced w/ 911s, So the best alternative is 993 fonts on 930 rotors which still need matching rears

[Bill Verburg]

Originally Posted by Aircooled4evr

wow !! This setup looks amazing!

But I do have one question for the whole brake upgrade thread:
what's the largest "kit" possible in a 15 "rim?

full 930

[Aircooled4evr]

Originally Posted by Bill Verburg

full 930

So, the most expensive setop ..... sigh
I'm actually wondering, if I could make copies from scratch (you know, sand casting and machining)...

regards, Mads

[Bill Verburg]

Originally Posted by Aircooled4evr

So, the most expensive setop ..... sigh
I'm actually wondering, if I could make copies from scratch (you know, sand casting and machining)...

regards, Mads

Hayden B. at Wevo did just that, great brakes that were just not economically competitive

Honestly there is no inexpensive way to get much improved brakes on a 911, The 930 setup is among the best, w/ least compromise and least expensive

[kent olsen]

Bill your probably right but?

A racing application vs a street/track application I believe is different, hence my opinion.

My 72 911 has the weight down to 2210lbs so with my 3.0L that puts out 245hp at the crank I have just 9.0x1 power to weight.

For me on the track it's still a momentum car. Not enough power to really go fast so I don't need too much brakes, which again is weight. Hence my solution was to leave the "M" brakes in the rear and I just got some SC calipers for the front. The SC's bolted right in and increased my brake size by about 20%. I also have drilled and slotted disc's.


A few tracks that I remember I was able to get to about 130 on the straights and the brakes worked fine.

[Bill Verburg]

Originally Posted by kent olsen

Bill your probably right but?

A racing application vs a street/track application I believe is different, hence my opinion.

My 72 911 has the weight down to 2210lbs so with my 3.0L that puts out 245hp at the crank I have just 9.0x1 power to weight.

For me on the track it's still a momentum car. Not enough power to really go fast so I don't need too much brakes, which again is weight. Hence my solution was to leave the "M" brakes in the rear and I just got some SC calipers for the front. The SC's bolted right in and increased my brake size by about 20%. I also have drilled and slotted disc's.


A few tracks that I remember I was able to get to about 130 on the straights and the brakes worked fine.

How stressed the brakes are depends on hp/torque, all up weight, track and technique. I've now way of assessing the the last 2 but here's a comparison of stock vehicles



The brakes get into trouble at many tracks when the stress level gets to ~34+/- depending on technique, track and idiosyncrasies of setup. You can lower the stress level w/ weight loss, better technique, better pads, better fluid, better cooling etc.

It would be rare for any of this to apply to street use, those driving the Stelvio or similar would be included in that exception.

For a single stop the tires used are the limiting factor, for multiple stops from speed as at the track, heat, particularly in front is the limiting factor

[kent olsen]

That's a very interesting chart Bill.

I've never seen the braking addressed as a stress level on paper. Years ago I was at a track day at Sebring running stock brakes, just racing pads. I was experiencing brake fade going into the hairpin, #7. Now there was some stress there on both me and the brakes.

A little later I moved back to Oregon and put the SC calipers on the front and drilled and slotted disc's on all four corners. I could reach 130 on the back straight at Portland and had no issues.

[Flojo]

Thank you Bill.

what about this? below, the connecting line:

And what hard line do I get to adapt the 964 caliper?
re-bend the SC line? get the 964 line and re-bend?

regarding the 964 caliper, I recently spoke to a friend that converted it to fit the Carrera strut and running the 24-Carrera disc.
No issues.

with new pads and the anti-vabration pads being kind of a spacer the perfectly grip the 24 disc without worrying about reaching the spec of a "wear-limit" compared to a 28 disc.

So I'll do it.

Overall, its not THE! brake upgrate getting an award for, but it solves three issues for me:
a) I can keep my historic licence according to German law(*)
b) I get to upgrade from 20 to 24 disc
c) I get a lighter caliper than the Carrera one

(the one rule for historic tuning is, any modification must be within a 10 year maximum range. so since I have a 79 SC a 89 caliper is just about in the range's limit)

[RWebb]

Bill, I'm just curious how the Brake Stress Index is calculated?

also, the Brake page link in your sig. is dead

[Bill Verburg]

Originally Posted by Flojo

Thank you Bill.

what about this? below, the connecting line:



regarding the 964 caliper, I recently spoke to a friend that converted it to fit the Carrera strut and running the 24-Carrera disc.
No issues.

with new pads and the anti-vabration pads being kind of a spacer the perfectly grip the 24 disc without worrying about reaching the spec of a "wear-limit" compared to a 28 disc.

So I'll do it.

Overall, its not THE! brake upgrate getting an award for, but it solves three issues for me:
a) I can keep my historic licence according to German law(*)
b) I get to upgrade from 20 to 24 disc
c) I get a lighter caliper than the Carrera one

(the one rule for historic tuning is, any modification must be within a 10 year maximum range. so since I have a 79 SC a 89 caliper is just about in the range's limit)

Do what you want but it's a mistake to put 964 front on 24mm rotors for multiple reasons, but you obviously think you know better and I would caution no else to emulate that move