brake upgrade 911

jason.k911 · 11-10-2007, 02:54 AM

ive heard there is a brake upgrade for 80's 911 using boxster callipers ,has anyone done this mod and is it worth the time and money,thanks

Mr.Puff · 11-10-2007, 03:17 AM

I've also heard you can use 930 calipers

. Just minor modifications.

jester911 · jester911's Garage

First question is what sort of driving are you doing that you need upgraded brakes? Not trying to be wise here. Many times the stock brakes are more than sufficient. Is this for track use or street? If you do a search you will come up with tons of info.

There are also upgrade kits available right here with our host.

tonythetarga · 11-10-2007, 04:55 AM

Do you have an SC or a Carrera? If you have an SC you could upgrade to Carrera calipers and rotors for the front and use the stock rears. There are many threads on this topic as well as the boxster caliper upgrade. Search and yee shall find and you will learn that Bill Verburg has addressed the issue many times and believes that the Carrera upgrade for the SC is a better, less expensive upgrade than the boxster upgrade.
If you have a Carrera, then the best, but expensive upgrade is the 930 brake system. (and usable with 15' wheels)

hcoles · 11-10-2007, 05:36 AM

+1 for letting us know why you want to upgrade - the only reason to upgrade IMHO is because the brakes are overheating - Bill Verburg has a lot of info and experience....

jason.k911 · 11-10-2007, 09:02 AM

want to do track days

hcoles · 11-10-2007, 09:48 AM

I suggest putting in good fluid and new good pads and give it a try and see what happens... that what most if not all of us have done to start with...

Bill Verburg · Bill Verburg's Garage

Quote:

Originally Posted by jason.k911

want to do track days

It's all a matter of cost vs benefit

at the cheap end
lighten the car
cool the rotors and calipers w/ ducts
use fresh high temp brake fluid
use track appropriate pads
minimize brake use

at the expensive end
full 930 bbk
full Brembo bbk

Carrera or Boxster will be somewhere in the middle, benefit is closer to the cheap end but in some cases thats all you need, Carrera fronts only is the most bang for the buck

Dave Nordhoff · 11-10-2007, 11:11 AM

Jason,
I have an 80 SC with stock zimmerman rotors, PF97 pads and 993 diverter plates. I track my car alot and it has plenty of stopping power. I have spent alot of $ on making it faster and safe. I suggest you R and R your brakes and upgrade your pads and hit the track.
My 2 cents,
Dave

Christien · Christien's Garage

My first year of track driving I was also considering upgrading my brakes - my (non-boosted) brakes seemed woefully inadequate for slowing the car after a long straight, preparing for a tight turn, and I was boiling my brake fluid at almost every event, and that's even with S front calipers. Then as I started driving better and braking less I found the brakes are more than adequate, and I rarely if ever boil the fluid, so no need at all for an upgrade, unless I do an engine transplant.

jason.k911 · 11-11-2007, 03:10 AM

thanks will try new fluid and possibly being a bit less agressive with my braking

Mr.Puff · 11-11-2007, 03:27 AM

=\ As a side note, how hard is it to change my brake lines out for some steel ones?

Mr.Puff · 11-11-2007, 03:28 AM

Woops... wrong thread... I'll leave it though =).

Jim Smolka · 11-11-2007, 04:57 AM

On the 82 SC w/ 3.6 that sees a bunch of DE's, and has a brake kit made by a friend. A really great improvement. One of the best things is the pad life. A stock caliper with race pads can wear really fast (~3 track weekends). The big brakes pads have gone 2 years with out any significant wear and no fade during hard braking

Mothy · Mothy's Garage

I have upgraded my 83SC about 4 months ago to Boxter Calipers and Carrera Rotors at the front and Carrera Calipers with Carrera Rotors at the rear.

I track the car and was finding the old original setup was overheating on warm track days.

The cost was not high - my rotors all needed replacing anyway and Carrera is not much different to standard SC. The rear Carrera calipers were easy to source 2nd hand and inexpensive. The Boxter calipers I picked up on ebay second hand and again in good condition from someone who was upgrading to Brembo's. They came with the adapters.

My last track day I had no problems at all and they feel very good - firm pedal all day and no sudden lockups. Happy to bury the foot with confidence.

One word of warning - if you have an SC then make sure you upgrade the rear brakes to Carrera if you go with the front Boxter. If you don't you will have way too much balance towards the front and will lock them up too easily. Its nothing to do with the Pad area - the Carrera and SC have the same - its about the size of the piston in the caliper. The Carrera ones have bigger pistons which balance well with the Boxter calipers. I know this because I did the Boxter brakes on the front first then did a track day - and locked up the fronts all day.

Bill Verburgs site has some great info on the brake options available. I found the way I went (which was one of his options) was the best bang for buck given the availability of second hand parts.

Tim

hcoles · 11-11-2007, 07:20 AM

it has been mentioned that "easy" braking can contribute to more overheating compared to sharply applied "hard" braking... and lots of people say the over heating problem is reduced as driving skill improves... I'm still on the learning curve..

cowboyrolo · 11-11-2007, 08:44 AM

Will the boxter calipers fit the 3" spacing on the early long hoods?
How about the carrera calipers on the back?

JG911 · 11-15-2007, 04:26 AM

Iv been looking into the brake conversion for some time,and i also heard that you can use Boxster front calipers but have to be mono block whats that mean ?
Which calpers would just bolt straight on ? or more suited to my '84 carrera ?

hcoles · 11-15-2007, 07:14 AM

mono block = the caliper body stays fixed to the strut and pistons on both sides. Sliding caliper design has the piston(s) on one side. This saves space, maybe weight and $$$.

Bill Verburg · Bill Verburg's Garage

all Porsche calipers form day1 till, MY99 996 and Boxster used calipers that bolted up. There was a left side, a right side and often a middle piece and sometimes other parts. The single exception was the aluminum S caliper.
here is a 930 caliper disassembled into it's component parts

Here a 964 caliper split into it's 2 halves

A monoblock caliper is simple cast in one piece
S monoblock

996 Monoblock Big Red on let vs 993 2 piece Big Red on right. Notice the seam on the 993 caliper?

They are all fixed mount calipers which have opposing pistons, in this design the caliper is solidly mounted to the suspension, neither half moves, as opposed to the other caliper design which is called floating.

In a floating caliper there are only pistons on one side of the caliper. One side is fixed and the other floats or moves in a kind of hammer and anvil motion.