Steve Weiner-Rennsport Systems

Reg:

If a can of brake fluid has been sitting around for more than 30 days, throw it away. Overall, its cheap stuff,....

OK,...about brakes;

1) Big Reds (993 TT) brakes have been discontinued since the tooling wore out and Brembo has replaced them with the GTP package. It uses the same size (lighter front) rotors with similar calipers and pad sizing. These require 17" wheels. Equivalent braking power to Big Reds only with much improved pedal feel and modulation.

2) GTP-L's use a full floating front rotor package and a smaller front caliper to clear the 16" Fuchs. These are about 3-4 lbs lighter (per wheel) than GTP's. Stopping power is slightly less than Big Reds.

Given that you are doing track events, I cannot recommend the 964 brake or Boxster brake kits in good faith since both will fail on the track. The rotor sizes in both cases are simply too small for the caliper/pad package.

I'd recommend either a 930 brake kit or GTP-L's. Overall costs are very similar.

afinepoint

Steve,

Thanks for the information, the education and your time. I have a long memory for such things especially the latter.

Do the duct systems work with a front air dam? I am trying to figure out where the scoops would go.

Brembos are in my future. Boosting HP to catch up is somewhere behind that. Getting my skills honed is job No. 1.

Reg

Steve Weiner-Rennsport Systems

Hi Reg:

My pleasure, sir.

The brake cooling kits can be installed either with the provided A-arm scoops or ducted to the front airdam for greater effectiveness.

Skill honing is ALWAYS Job #1,.....

afinepoint

Sorry Steve they are.

I will change them with the rotors.

Reg

Noel

Steve,

I too was on your website looking and had a couple questions that I thought I would ask here to also benefit others:
1) The diameter of the rotors is stated, but how wide are the GTP L and the GTP rotors front and rear?
2) Since I do track my car about 4-5 times a year the cost of rotors and pads is a consideration as part of the upfront costs. Simple stated, I don't what to buy the kit that upfront is cheap but ends up costing me more in the long run over the next five years. Which kit (930, GTP or GTP-L) in your opinion is most economical in terms of continued maintenance?
3) Do you have any customers with the 17” Lindsey Fuchs Wheels using GTPs? I really like the look of Fuchs on my car and would consider having 17” Fuchs made to accommodate the larger brakes.

Many thanks,

Noel

Steve Weiner-Rennsport Systems

Hi Noel:

1) The GTP rotors are 322x32mm on the front & 322x28mm on the rear; same as 993 TT.

2) IMHO, the GTP rotors/pads cost less in the long run due to much lower brake operating temperatures and thats really the big payoff here. This whole exercise is all about reducing and containing brake temperatures.

3) The Lindsey Fuch wheels use the same centers as 911 Fuchs so they need some 1/4" spacers to fit. You'll gain caliper clearance if you have Mike use 944 Turbo Fuchs wheels.

Peter Zimmermann

Whoa, whoa, whoa!!! Your rotors were only a quarter inch thick??? On an '84 Targa??? You've got to be kidding! Their wear limit is 22.0mm (.866 inch) front and rear. What are you doing on the track with those brakes? Of course Steve W. and the others are correct with their advice regarding fluids, upgrading, etc., but .25 inch? That's barely wide enough to cover the internal vents. It also forces the caliper pistons to work radically extended, even with new pads. Most important, there is so little rotor material left that they can't absorb or dissipate heat.

Steve, sorry to jump in like this but you must not have seen Reg's post about his rotor thicknesses.

Reg, your Haynes manual listed the wear limits for non-vented '69-71 rotors.

Best to all, Pete

Noel

Many thanks Steve. How wide are the rotors on the GTP light setup?

afinepoint

Sorry Pete,

Thanks. I did a copy and paste with the wrong numbers. Staying up too late. I couldn't figure out your response until I reread my post. .25 inches? Indeed!

The real numbers are Front: 22.3 mm. Rear 22.8 mm.

I hope you didn't hurt yourself when you passed out.

Reg

Noel

I had assumed that those measurements were incorrect. Adding almost 2mm wider rotors by simply replacing yours with new OEM ones will increase your heat sink capacity a small bit.

Peter Zimmermann

Reg: WHEW!!! Put some new fluid and quality pads in there and go have fun! Also, I can't remember reading about how old your brake hoses are...
Pete

afinepoint

I think the hoses are original. I don't have a good history of the car. I go by mechanic's observations, present appearances and performance. So far it has done well.

A neighbor with an 83 SC offered braided hoses but so far I have been hesitant. One article I read said no to braided because you can't inspect for degradation. Others seem to like them.

I bled them the other day. I intend to order the air ducts, blocking plates and tool metioned by Steve for pressurizing the reservior so I can bleed them without help.

Reg

Peter Zimmermann

Reg: Replace those hoses immediately! They're only good for 10 years/100K miles, whichever comes FIRST. They break down internally, and they're dated so you can verify how old they are. That will also take care of some of your brake problem - get factory original, Porsche replacement hoses. Many aftermarket, braided hoses are not DOT approved...
Pete

r911

There is an old Pano article noting that the non-DOT braid covered hoses blew apart at the coupler...

Get the rubber hoses as above. The people that favor them are - generally - blinded by bling, and not thinking about what real function and performance means.

Steve Weiner-Rennsport Systems

Hi Noel:

The front GTP-L rotors are 32mm thick and the rears are 28mm thick.