930 brake upgrade, first generation
 

I dont want to go nutso but I have the worst brakes ever offered on a 930. '77 930's had I believe the NA S brakes. Is there a generally excepted upgrade for these? Can I put the fronts on the rear? If so what would be a good match on the front? I don't want to spend fortune on Big Reds but since mine are so pathetic I shouldn't need to go that far for a big improvement. Open my eyes guys!

930 second generation brakes are usual "update"....they also accept 15-inch wheels if you want them. I have vague memory that you need floating rotors in front.

I run 17" Ruf wheels and thats not going to change so bigger is fine. If I can run the front calipers on the rear I will have a bigger budget for the front. '78 and on 930 brakes don't excite me too much as I've drivin them and although better they don't get my juices flowing to spend the dough. Not sure about the floating fronts, hmmm

930 78- brakes are perfectly fine. They are actually upgraded 917 brakes. Unfortunately they are quite pricey, even used. If that won't do you can do same setup as on our project-car:

Big Reds (with adapters) and 964T rotors in front, OEM 930 in rear (need some caliper modification).

It will give you all stopping power you need. Besides, Big Red calipers aren't so expensive compared to 930 brakes...

floating 930 rotors are mucho $$$...

Can I ask what the $ is to go to Big reds up fron only? Ballpark of course

I'm doing the 930 upgrade on my Carrera now. You don't have to have the 930 floating rotors in front. Places like VCI and Rennsport have aftermarket non - floating rotors for these calipers. I'm going with the floating factory rotors however as they are about the same price as aftermarket.
If I didn't want to run 15" wheels, I'd do the big reds as it's about the same cost and you get a bigger rotor.

You can check out VCI's site and it should give you some ideas on the cost of big reds. I'm guessing $1300 - $1500 for the front but don't know for sure.
http://www.vehiclecraft.com/index.html

Sounds like $1650 for the front from VCI. Hmmm

Anyone have thoughts on my using my current fronts in the rear? What rotor would be required, am I on crack?

The fronts have 3.5" between the ears the backs have 3.0". Front to rear is not too good of an option due to inability to bolt them on.

No good as you will need custom rotors that have correct thickness and "hats" for handbrake pads...

930 are "tried and true"... we still don't know how brake-distribution looks like when mixing 930 rear calipers with Big Reds up front but guy who sold them to Mattias lives of building race-prepped cars and insists that it works perfectly.

That's what I've got--Big Reds up front, stock in rear. Works great.

Fair enough, but do I not have inferior rears to '78 and up 930's? Does it matter that much?

Sorry, dunno. Checked Bruce Anderson's book, and although he discusses the differences between the '78-'89 and the '75, '76 and '77 brake set-ups (page 219), he doesn't give any hints as to the matchability of the Big Red fronts with the pre-'78 rears.

If you're starting with a '77 930, then you can upgrade to 78+ 930 brakes with little hassle. I suggest you avoid the floating rotor setup for parts availability and cost reasons.

You can use stock 930 calipers up front with a small spacer (10mm IIRC) and stock 930 calipers in the rear after the mouting holes have been 'moved'.

The special VCI setups are for narrow-body cars, and are necessary in order to clear the inadequate fenders. This would be an unnecessary expense for you. However, you can get pre-modidied rears from VCI or Steve Weiner (what the heck is his shop called again?)

Check out http://vintagebus.com/howto/brakes/rear/index.html

and

http://vintagebus.com/howto/brakes/front/index.html

Private mail sent....

Pelican Parts sells big Reds I think

Well,

I am thinking keep my stock rears and go to Big Reds up front. If I find there is a problem then I will move to the rears. I am a bit worried that my rears wont be doing anything though. Does anyone have big reds on the front of a '75-'77 S ? Cause I believe we have the same rears.

Setting the fit issues aside for a moment, what are you trying to accomplish with bigger brakes? It sounds like you're really trying to sell yourself on Big Reds. Why?

First off, are your current brakes inadequate? Are you currently experiencing fade?

From what I've seen, the people who need brake upgrades are the ones who start their post "I was at Lime Rock/Sears/Thunderhill/Laguna/Road Atlanta and after [n]n[/i] laps going into turn y my brakes began to fade and I had to pit for an hour for them to cool off.

Your brakes will tell you when you need to upgrade. If you have to ask, you're not there yet.

The people who start off with "Will Big Reds/GT2/Boxter/Ferrari/Honda brakes fit my car?" seem to be more interested in the bling-factor. Budget-bling would be to paint the calipers and get drilled rotors.

Your brakes - even the piddly 930 Turbo Carrera brakes - are better than 90% of the production cars out there. Your braking upgrade path should actually be something like:

• remove backing plates
• better pads
• better tires
• brake cooling
• bigger brakes

Thom,

Definitely don't care about the bling factor. As far as why I want to upgrade:

I cannot lock up my tires now. Maybe this is indicative of another problem? It would seem to me that if I can't lock them up they just don't have enough clamping force and/or pad area for the application.

They do not pull, shudder, or act weird in any other way just not very powerful. OK, maybe they can lock up but it has never happened and I have done a few track events where I remember thinking I was cramming my foot into the firewall. I know what you are saying about fade and I have never experienced this yet, just reliable sucky all the time. Pad wear seems to be even.

One time a year ago I lost the peddle to the floor, it only happened once then went back to normal. This was driving on the street not track. Shortly thereafter I pulled the engine so I just havn't gotten to the brakes yet.

Is what I am experiencing normal? Thanks.

Listen to Thom, please!!

If you do anything his setup '78-89 930 f/r is the one you want. The big reds are overkill unless you have a heavy car that is raced hard and long.

You do not want to move any front caliper to the rear unless you want bias problems. Similarly do not do only one end of the car.

You do not need floating rotors(though they are nice for race use!). Use the one piece '80-89 930 f/r rotors, as long as you have a turbo flared car.

Some of the '75-77 930s already have the correct 3.5" mounts on their trailing arms in addition to the 3" mounts used by the existing calipers, look!

You should also plan on using the '78-89 930 m/c. Though not strictly necessary it is a very worthile upgrade w/ 930 calipers

Thanks guys! I will do the MC, fluid, pads, etc.. before I move on. The calipers were rebuilt about 4 years ago. It sounds like you guys have it down. Thanks.

Actually, the floating rotor is not expensive, I paid £60 ($100) per for 78-80 floating rotors. The "floating disk bell set" or disk clamps on the other hand are insanely so. Expect to pay $1000 for these. Here are aftermarked items from Ninemeister

My Porsche dealer adviced me to upgrade to 81- 930 brakes, as these are not floating, and have the bell and rotor integrated. Seems that 78-80 had the floating brakes, and 81- was non floating. I'm not familiar with the 77 design.

lendaddy
I agree with widebody. Do an upgrade. My 80 brakes had terrible fade on the track, and they were wobbling my stearing wheel like crazy. Scared me, and I just had to coast into the pit.

Changed the rotors, kept the old (and corroded bell set), new Red Stuff pads, and new ATE Super Blue fluid. They are now very much improved. Wish I changed the lines at the same time. Still have a tendency to sprongy feeling. Well, its gonna cost me an extra quart of Super Blue.

When discussing brake lines, some people advice against steel spun lines, and say to go for OE rubber lines. Reason: Steel spun lines has teflon liner that can burst after as they grow older Shure, they are used by racing teams, but they change brake lines frequently.
Any opinions on this out there.

I know it sounds a little stupid maybe, but shouldn't I be able to lock up the brakes? I mean isn't that the measure of the systems power? Not that you want to but you should be able to right? After that it's a matter of modulation and feel I would assume. Hmmm, am I alone in this area? Can you guys lock them up?

You should always be able to lock the brakes if you press hard enough. Frankly, i think Big Reds in front are good solution as price is roughly the same compared to 930 brakes.

Asseem,
That's a good deal. I wasn't aware of an aftermarket floating rotor. I bought my last set for around $250. Discount parts places have them for over $300 and the local dealer probably wants over $400. I had VCI supplied Coleman before this set and I don't think they wore that great.
-Chris

Reeves Porsche and Sunset sell parts for cost +15%. Factory floating rotors cost just under $270 each from these places. Last week I bought a pair and paid $575 which included shipping.

$100 for factory floating rotors would be a steal.

lendaddy,

Granted, this is not specific to turbos but rather a little anecdotal evidence to support Thom's recommendations. Last year I bought my '86 Carrera. Brakes seemed okay but not stellar. I could lock 'em up but barely. Over the winter I rebuilt the calipers, replaced the rotors with stock components due to wear and cracks, replaced the pads with budget street pads and added steel braided lines. Filled the whole thing up with ATE Super Blue. Braking performance is amazing. I am scared to use my brakes now for fear I'll be rear-ended everytime I do. I never knew a car could stop so fast and so smoothly! And this is just a stock Carrera system. After a simple rebuild I would bet your turbo brakes will knock your socks off.

Now that sounds great. I look forward to my results now! I wonder what your "weak link" was or if it was a culmination.?.

I think it was a combination of worn pads and spongy lines. I couldn't find any evidence in my records that the lines had ever been replaced in 92K miles. Anyway, I am very pleased with the results. I have a high, hard pedal now and when I stomp on it she stops hard. Others here with high-zoot braking systems may not be as impressed but I sure enjoy the heck out of the results. I hope you enjoy the same success.

I agree with the above that stopping power shouldn't be a problem with stock brakes. For street use, stock brakes are more than adequate. If the problem is stopping, I'd guess the system is suspect.
Heat is the only reason I am upgrading to 930's, not stopping power.

You might profit from reading this

They are OE rotors from Berlyn Services in the UK
930.351.047.00 TURBO FL DISC 80 £64.68

If you search here on Pelican , partno: H-352-045-01, you will find they are only $148, and you don't have to pay atlantic shipping. Dont know if these ar OE or after marked items

lendaddy: good luck on your upgrade, i hope you will be satisfied with your "new" brakes

Unfortunately, that's the price for the rear rotor, which isn't exclusive to the 78-79 models. The fronts are the tough (and expensive) part. I don't think Pelican's site even lists them.

Yep, the fronts are the problem for narrow cars. Pelican can't get the early floating front rotors. I paid 575 for the front floaters. With hats, the pair of front rotors alone will be $1000.

Yes Jack, you're right. I misread the pricelist.
But still, the Berlyn price is nice isn't it, and it is genuine Porsche parts for 930 front 78-80 brakes. Are the prices much higher in the US?

If they are, Don, you should check out Berlyn, even thou you have to have them shiped across the pond.
They are nice people, but their web isn't exactly high tech :D

From the prices I am seeing the Big Red kit is looking down right reasonable @ $1795 for the front(from Pelican) which includes the 322x32mm floating Brembo crossdrilled rotors, the only downside is the extra weight of the 322s and the cost. The sweet spot is still the 993 caliper and the 993 304x32 front rotor, 2 piece floating for track, 1 piece for street.

I wouldn't bother w/ the rear kit. A better option is to use 964T rear calipers and stock 930 309x28mm rotors. The calipers are easily modified to fit on SC/Carrera trailing arms w/ 3" mounts.

Don't forget that a 930 m/c is mandatory w/ this setup.
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