Boxster Brakes

[SteveF_911]

After a few laps of Queensland Raceway on Saturday I was suffering severe brake fade.

I think I read somewhere that it could be possible to fit boxster brakes to an early 911.

Has anyone ever done this upgrade.

John, (FISHCOP) will back me up that the brakes feel rather second hand after a few laps.

The other option could be Volvo 4 spots on the front, which I have seen done on early cars.

[Victor]

Hi Steve, greetings from sunny Melbourne. With a fat budget, you can do anything (Big Red's, Volvo, Brembo etc.) Out of interest, what sort of nick is your 29 year old braking system in? There is a guy down here who runs a similar car to yours (VERY competitively) on standard brakes and R comp rubber.

[SteveF_911]

The car is in good condition, was a 912. Now 911ish.

I am running SC brakes on the front and stds on the rear. I run Yokahama A008RS tyres. I find that at QR there ar 4 realy hard brake applications. 180kph + down to about 70kph for the corner. After 3 laps with new pads and fluid, the brake get realy spongy.

The engine is a 2.0 with S pistons, S heads and E cams. About 155 hp. I run very similar times to 3.2s with road tyres.

I am currently running equal 2nd in the Queensland Club Championship, equal with Wayne Hennig.

[jtkkz]

Yes
My cousin has boxster front brakes on his 72 911.

My friend has boxster brakes front and rear of his 73 911.

It can be done, but heard it is expensive.

[masraum]

I believe there is a kit for Boxster to SC or Carrera brakes, but just changing to Boxster calipers won't do much to solve your fade problem. Fade occurs when the pads and fluid get too hot. Pads and fluid get too hot when the rotor isn't absorbing enough heat or dissipating enough heat.

What sort of pads are you running, high temp race pads or street pads? Do you have cooling on your brakes?

I would think in good shape a 66 chassis with SC brakes should be ok, but with sticky rubber it probably needs a high heat type pad and cooling.

I'm no expert though, so this is just my .02.

Just looked through the thread again, you don't specifically say "boxster calipers", so some of what I say isn't necessarily valid. Fitting a more or less complete boxster brake system, I would think would improve things.

[confused]

You can put Boxster brakes on a early car with 3.5" caliper spacing. There is a kit available, really its just 2 machined aluminum blocks that bolt to the stock location. I think the kit was $750US and the calipers new from the Porsche dealer were about $660. So it can be pricey.

If you are using A calipers and rotors (SC brakes) on a pre 74 car then maybe just drilled rotors and racing pads, higher temp fluid. Boxster brakes work better on cars with over 200HP.

[SteveF_911]

Thanks,

I have done the maths in $AU looks like it would cost around the $4000 mark to do the boxster upgrade. Which would look realy cool on an early car.

I think I will go down the path of changing pads to something better than the std Porsche pads and change the fluid to ATE or SRF.

Many thanks
Cool looking brakes will have to wait

[marcesq]

Steve:

I did monoblocks on the front, Carrera rotors and calipers on the rear with Hawk SPs and everything works great. Fronts lock up before the rears. No need for an apportioning valve, however you will need a master cylinder at least as big as a SC or late S.

Take a look: http://www.pelicanparts.com/motorcity/marcesq1/BrakeUpgrade.html

[dimps8]

Steve,

If your vehicle was a 912 in a previous life(god have mercy on your soul), are you still running the solid rotors on the front? Why not try later 911 vented front rotors and space out the original calipers.

Also is your master cylinder single 17mm? Upgrade to a 19mm Ate for a couple of hundred.

[SteveF_911]

No Damon,

I have SC A calipers and vented rotors.

Still have the solid rears, but they see to hold up ok at the momment.

Problem is a 2.0 S has a bit more poke than the old 4 cyl 912.

All the early cars that run sub 1:35 at Queensland Raceway are having big problems with brakes.

Problem is they designed the track for V8 Super Cars. Real boring if you have any less than 600hp, but real hard on brakes. Three realy heay applications each lap.

[Fishcop]

"All the early cars that run sub 1:35 at Queensland Raceway are having big problems with brakes."

Just as well I'm running 1:45.....

[SteveF_911]

You will be there soon John...

First time out I did a 1:49, I needed a packed lunch and a water bottle to get down the back straight.

Bill had no brakes after 3 Laps and ended up in the gravel.

This was a week after he lost a oil cooler hose and empties 10 ltr of Penrite over the Mt Cotton Hill Climb Track and shut it for 4 hours.

He even had to go out an buy 10 bags of cement and clean up the mess.

[kellzey]

I think you need 16" wheels for the Boxster monoblocks, but I may be mistaken.

Regards,

[AES]

If interested in brake upgrades read this

Lots of very good info. Bill V. posts here frequently

[ChrisBennet]

The '84-89 Carrera brakes are a bolt on upgrade for SC brakes. They are usually pretty cheap too. They take the same pad but have a thicker rotor - more thermal mass. Are you ducting air into the eye of the front rotors now?
-Chris

[JmuRiz]

Kellzey: you are correct, you need 16" wheels to fit over the boxster monoblocks. I have them on my 914...using Carerra rotors and struts. They ROCK. Never thought that I'd have a 914 that has brakes that are only limited by the rubber on the road Makes me want to get some wider front tires just to get the max out of them.

Nathan

[marcesq]

Originally posted by JmuRiz
Kellzey: you are correct, you need 16" wheels to fit over the boxster monoblocks. Nathan

Not true . . . I have a set of 7x15 cookie cutter (23.3 et) track wheels that fit just fine. Not much room to spare . . . 930 calipers don't have much room to spare either.

[Bill Verburg]

you need 16" wheels to fit over the boxster monoblocks

Marcesq Is correct(he has them on his car!!) The monoblocks on Carrera rotors fit fine w/ 15" wheels. That is a stage 3 upgrade as listed in the page AES cited.

Also note that matching oem Carrera rear rotors and calipers should be used w/o a p/v.

You can get by w/ a 19mm m/c but it is at the extreme lower end of acceptable. 21.5mm or 23mm are recommended for best feel. Though 23mm is a bit on the large size for those calipers.

[JmuRiz]

I stand corrected (was just going on info given to me, not personal experience), thanks for the info guys!

Where does one get a 21.5 MC from? I have a 19mm and I'd agree it's on the low end...then again I only have 914 rears.

Nathan

[kellzey]

There has been some debate as to whether there is really a 21.5mm Master Cylinder. To my knowledge, no one has been able to confirm with a part number and description, and actually MC (at least according to all the threads on this forum) that the 21.5mm MC exists.

From what I understand that the 23mm MC comes from a Mercedes. The 21.5mm MC also is a Mercedes, but the ones that were obtained had the same part number on the casting. The thought was maybe that the came from the same casting, just bored differently?

Do you have any insight into this dilemma?

Regards,