The ultimate brake upgrade page.

[kent olsen]

So we all have options, here's mine.

I've had my 72 for over 20 years. I'm a racing nut. When I found out about track days I was hooked. My employer back in the 70's raced Corvettes so I helped him for about 8 years. Then back in the late 90's when I moved to Oregon I found this car and was delighted with it's performance. As I got better on the track I went back to the old days and started with weight reduction (power/weight).

The car and me, became quicker. With stock "M" brakes(and racing pads), I was pushing that envelope. You need good brakes when braking from 130 mph. Which brings out the question, 'How big brakes do you need on a street car?' An then there is the issue of 'Sprung and Un-Sprung weight'.

One day while at Sebring (I lived in Florida for awhile) coming down to I think turn 5, a slow 2nd gear turn after a fairly long straight, I started getting brake fade.

Ok so talking to some friends, who raced Porsches, I decided that bigger brakes MIGHT require, bigger wheels, or bigger tires, and then probably fender flares. I like the original look so flares where out.

Anyway my solution was to get 'drilled and slotted' rotors and SC calipers on the front. The SC caliper is about 20% more area than the "M".

I have had this combination for about 10 years with no fade or cracking of the disc I had heard about. My wheels/tires are 15x7 and 205x50. I run a hard street pad.

My engine has gone up from a 200hp 2.7L to a 245hp twin-plug 3.0L. Anyway that's my story on brakes on an early car.

[Bill Verburg]

through '77 930 used the same rotors as all other 911s and used the same hubs
from '78 through '80 1/2 the same 911 hubs were used but w/ the bigger 304x32mm floating rotors

'78-80
911 hub, 32x304 rotor, floating hardware








from '80 1/2 the separate 21mm spacer used on older 911 was incomporated into a new extended bub and 1 piece 304x32mm rotor, there push the wheel out too far for use on a regular 911

[Bill Verburg]

Originally Posted by kent olsen

So we all have options, here's mine.

I've had my 72 for over 20 years. I'm a racing nut. When I found out about track days I was hooked. My employer back in the 70's raced Corvettes so I helped him for about 8 years. Then back in the late 90's when I moved to Oregon I found this car and was delighted with it's performance. As I got better on the track I went back to the old days and started with weight reduction (power/weight).

The car and me, became quicker. With stock "M" brakes(and racing pads), I was pushing that envelope. You need good brakes when braking from 130 mph. Which brings out the question, 'How big brakes do you need on a street car?' An then there is the issue of 'Sprung and Un-Sprung weight'.

One day while at Sebring (I lived in Florida for awhile) coming down to I think turn 5, a slow 2nd gear turn after a fairly long straight, I started getting brake fade.

Ok so talking to some friends, who raced Porsches, I decided that bigger brakes MIGHT require, bigger wheels, or bigger tires, and then probably fender flares. I like the original look so flares where out.

Anyway my solution was to get 'drilled and slotted' rotors and SC calipers on the front. The SC caliper is about 20% more area than the "M".

I have had this combination for about 10 years with no fade or cracking of the disc I had heard about. My wheels/tires are 15x7 and 205x50. I run a hard street pad.

My engine has gone up from a 200hp 2.7L to a 245hp twin-plug 3.0L. Anyway that's my story on brakes on an early car.

opinion has nothing to do w/ it, it's all about the kinetic energy that the brakes are expected to transform into heat ad for how long and for w/ how much recuperation time will be provided.

The more KE the more often and for the longer duration w/ less recuperation the bigger the the cooling or heat absorption needs are going to be,

lighter, slower, more recuperation time, better cooling scheme more heat resistant components the less brake you need,

not to mention the better the driver the less the brakes will be abused

and each story will be different

discounting driver and mods here's a comparison of brake stress levels for various cars

[porschke911]

Then I should be able to just bolt on 78-80 930 front rotors? Why doesn't anyone do this?

[Flojo]

Originally Posted by porschke911

Then I should be able to just bolt on 78-80 930 front rotors? Why doesn't anyone do this?

because you need a caliper that needs a slot to accept 32/304 rotor.
this and the floating-rotor style is $$$$.
plus, in this case, you also need to adapt the rear calipers and master cylinder with extra money.

so most try to find a "cheaper" way.

correct me if I'm wrong.

[911tracker85]

great info.

from '80 1/2 the separate 21mm spacer used on older 911 was incomporated into a new extended hub and 1 piece 304x32mm rotor, there push the wheel out too far for use on a regular 911

and I had been thinking about this issue. with the SC struts/hubs/brakes the PO had 3 piece BBS wheels on the car. I have suspected the offset on them helped set the tires out to where they needed to be with the turbo front fenders.

I appear to have the older/sc hub and standard length studs. so was considering replacing the studs with something a bit longer so I could use spacers if necessary.

still not sure I'll be using the BBS wheels. and I want the car to be able to accept my 17" kinesis wheels I ran on my 85 911 and my 16" fuchs from the 951.

and I may be wanting to be able to have too many options....

and I do not want to go the floating rotor path, too much $$ and hear they are a bit noisy and rattle.

will read again but not sure I can pick my solution out of this info.

[Bill Verburg]

Originally Posted by 911tracker85

great info.



and I had been thinking about this issue. with the SC struts/hubs/brakes the PO had 3 piece BBS wheels on the car. I have suspected the offset on them helped set the tires out to where they needed to be with the turbo front fenders.

I appear to have the older/sc hub and standard length studs. so was considering replacing the studs with something a bit longer so I could use spacers if necessary.

still not sure I'll be using the BBS wheels. and I want the car to be able to accept my 17" kinesis wheels I ran on my 85 911 and my 16" fuchs from the 951.

and I may be wanting to be able to have too many options....

and I do not want to go the floating rotor path, too much $$ and hear they are a bit noisy and rattle.

will read again but not sure I can pick my solution out of this info.

It sounds like the p/o did it right, when spacers are used to push the wheel out increasing the already large 911 scrub radius even more, this will have multiple ill effects of the dynamics of the car. A stock 911 w/ ET23.3 7s has a s/r of 52.4mm, add a 21mm spacer and that becomes 73.4mm. What a wider wheel w/ the correct ET does is minimize and sometimes reduce s/r.. For a point of reference most if not all modern cars have a s/r from 0 to -15, clustering just on the neg side of 0, They need 0 to neg for ABS to functioning correctly but the point is the small magnitude used.

[911tracker85]

I understand. but doesn't the hub / spacer solution for the early 930s do this? what is the SR for the 930 configuration?

[Bill Verburg]

Originally Posted by 911tracker85

I understand. but doesn't the hub / spacer solution for the early 930s do this? what is the SR for the 930 configuration?

73.4mm

[911tracker85]

^^^
LOL...
after posting got to thinking about this and came to that conclusion.

so my PO put on different offset wheels to compensate for the SC hub. as far as I can figure that is no different that adding spacers if the wheel offset does not get the wheel out where it needs to be.

my 17" kinesis wheel offsets were made for the 85 carerra. I am running them on the 86 951 at the moment, surprised they worked both front and rear. so expect to need maybe a 20mm spacer for either the kinesis or fuchs them - TBD.

was just taking pics of the BBS wheels for someone who is interested in buying. had meant to measure the backspace on the fronts but forgot. may remember next time I am there.

your posts always make me THINK.

Happy new year to all.....

[Bill Verburg]

Originally Posted by 911tracker85

^^^
LOL...
after posting got to thinking about this and came to that conclusion.

so my PO put on different offset wheels to compensate for the SC hub. as far as I can figure that is no different that adding spacers if the wheel offset does not get the wheel out where it needs to be.

my 17" kinesis wheel offsets were made for the 85 carerra. I am running them on the 86 951 at the moment, surprised they worked both front and rear. so expect to need maybe a 20mm spacer for either the kinesis or fuchs them - TBD.

was just taking pics of the BBS wheels for someone who is interested in buying. had meant to measure the backspace on the fronts but forgot. may remember next time I am there.

your posts always make me THINK.

Happy new year to all.....

You may want to read through this, there are probably other similar threads to peruse as well
how to make a widebody steer like a narrowbody

[911tracker85]

thanks Bill, will do.

[porschke911]

Originally Posted by Flojo

because you need a caliper that needs a slot to accept 32/304 rotor.
this and the floating-rotor style is $$$$.
plus, in this case, you also need to adapt the rear calipers and master cylinder with extra money.

so most try to find a "cheaper" way.

correct me if I'm wrong.

Thanks. I already have the proper calipers so that isn't an issue. Found 4000 reasons why no one uses the floating rotors. Plus they are so noisy. Steve at rennsport is currently making me some hats for 304/32 rotors. Can hardly wait.

[911tracker85]

Steve at rennsport is currently making me some hats for 304/32 rotors.

Steve will be supplying my rotors too.....

[coomo]

Just received a Boxster adaptor kit, via One of our Pelican colleagues.I have a full set of Calipers all media cleaned & ceramic coated.Then yesterday, via one of my UK guys, these lovely alloy original 911S rebuilt front calipers with Titanium pistons no less, were offered to me at a price I couldnt turn down.The dilema I now find myself in, is as to what to use on the rear.Use the Boxster calipers, find a pair of Carreras or something else.Like to hear your views on this Bill Verburg, if your around.

[Bill Verburg]

Originally Posted by coomo

Just received a Boxster adaptor kit, via One of our Pelican colleagues.I have a full set of Calipers all media cleaned & ceramic coated.Then yesterday, via one of my UK guys, these lovely alloy original 911S rebuilt front calipers with Titanium pistons no less, were offered to me at a price I couldnt turn down.The dilema I now find myself in, is as to what to use on the rear.Use the Boxster calipers, find a pair of Carreras or something else.Like to hear your views on this Bill Verburg, if your around.

W/ S fronts you want M rears and a 19 - 21mm m/c

[coomo]

Originally Posted by Bill Verburg

W/ S fronts you want M rears and a 19 - 21mm m/c

Thankyou for the prompt response Sir! Re the "M" calipers anything year specific, and I presume standard SC rotors are fine.Do I have any lightweight alloy options?

[darrin]

coomo -- wouldn't running wider Carrera rotors help with cooling/etc.? Here's a thread on challenges/options running Carrera rotors with S calipers 3.2 Carrera Rotors with S Calipers??

[coomo]

Originally Posted by darrin

coomo -- wouldn't running wider Carrera rotors help with cooling/etc.? Here's a thread on challenges/options running Carrera rotors with S calipers 3.2 Carrera Rotors with S Calipers??

Thanks for that.However, after many hours reading threads on the subject im convinced that Porsche did a pretty good job.The standard brake set ups are fine for a street car.I was only changing to Boxsters, for cosmetic/weight reasons really.Any weight saved is largely used up by larger rotors anyway!
The "theme" with this build is lightness.Thats my main priority,obviously not compromising performance,

[Bill Verburg]

Originally Posted by coomo

Thankyou for the prompt response Sir! Re the "M" calipers anything year specific, and I presume standard SC rotors are fine.Do I have any lightweight alloy options?

All the rear M's are the same from '69 - 83, all are steel, all use the same rotor and no alloy options that I know of.