930 brake upgrade, first generation

lendaddy · 06-05-2003, 06:37 AM

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!

beepbeep · 06-05-2003, 06:47 AM

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.

lendaddy · 06-05-2003, 06:50 AM

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

beepbeep · 06-05-2003, 07:01 AM

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 $$$...

lendaddy · 06-05-2003, 07:18 AM

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

don911 · don911's Garage

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

lendaddy · 06-05-2003, 07:56 AM

Sounds like $1650 for the front from VCI. Hmmm

lendaddy · 06-05-2003, 08:00 AM

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

beamonk · 06-05-2003, 08:10 AM

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.

beepbeep · 06-05-2003, 08:20 AM

Quote:

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

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.

Bruce M. · 06-05-2003, 08:34 AM

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

lendaddy · 06-05-2003, 09:01 AM

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

Bruce M. · 06-05-2003, 09:14 AM

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.

widebody911 · widebody911's Garage

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

rdane · rdane's Garage

Private mail sent....

dean · 06-05-2003, 11:12 AM

Pelican Parts sells big Reds I think

lendaddy · 06-05-2003, 11:18 AM

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.

widebody911 · widebody911's Garage

Quote:

Originally posted by lendaddy
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

lendaddy · 06-05-2003, 12:02 PM

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.

widebody911 · widebody911's Garage

Quote:

Originally posted by lendaddy

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.

Have you done the other basic brake stuff, ie changed fluid, bled them, new lines, etc?

They do not pull, shudder, or act weird in any other way just not very powerful.

What are your expectations?

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.

"Sucky" implies comparison. Sucky compared to what? Your GT3R?

Again, we need to examine your expectations. When I drove Jack's car @ TH last summer, I thought his non-boosted brakes sucked, even though his car could probably have out-braked 98% of the cars on the track.

Pad wear seems to be even.

Almost irrelevant except in terms of assessing the condition of each corner to the others

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.

This is indicative of a failing master cylinder.

Before your blow your next few paychecks on Big Reds (sorry Wayne!) get yourself a new master cylinder, some ATE Super Blue, and some decent pads. I would also vote for braided lines, but that's a whole other debate. You might also consider rebuilding your existing calipers. If you decide to upgrade later, you can always sell them.

Look thru previous posts and read about the epiphanies others have experienced once they've rebuilt the stock components.

When your stock brake system is restored to proper working order, then - and only then - can you determine if it sucks.