Yet another 930 brake upgrade question

[911-lightning]

So I am thinking about doing the 3.6 conversion to my 80 SC. I want to get this approved by the DMV in Norway and I then need to do a brake upgrade as well.
My first plan was to go with the 993tt brake upgrade since the engine hopefully will come from a 993. The only problem with this is that the 993tt is equipped wit ABS. The person I talked to at the DMV said that this could be a problem regarding the approval of the conversion.

So then I thought to go for the 930 brake upgrade. Or did the 930 (1979) also have ABS? Anyway. I have the narrow body SC and I understand that the conversion isn't a bolt on conversion.

- There need to be a spacer between the front caliper and spindle
- The rear calipers need to be machined to fit the rear trailing arms and need a spacer between the caliper and trailing arm
- The rear trailing arms need to be modified to fit the 930 caliper
- I need to upgrade the master cylinder to the 23mm
- I need to bend new brake lines
- I need to remove the dust shield from the rear rotor

When it comes to the rotors.
Is it correct that I can use the stock 930 rear rotors without any other modifications than the ones I have listed?
If i go for the floating front rotors. Is the rotor then the stock 930 rotor or is it a "custom" design?

if I buy a kit. For Instance the kit supplied by VCI. Do I need to buy the rotors from them when they wear out or could I just order form anywhere else?

[newms]

You have done your homework well. I have a full 930 set up on my 82 with. ROW 3.2. In front you need a 'spacer' or hat to attach to the hub which aligns the front caliper correctly. The front calipers bolt on. I buy slotted not floating front rotors from Coleman racing for around 350 pair. The rear are OE Zimmerman 930 rotors. Yes you have to remove the dust shield mounting tabs from your trailing arms and machine the rear calipers and new brake lines all around and 23.3 mc. Once it's all sorted the performance is ridiculous. Not cheap and if you do track, IMO, the first money to spend. Also unlike some mods 930 brakes all set up for SC/Carrera will hold nearly full value forever.

[911-lightning]

@ newms

So the rotors you buy from Coleman racing, are these stock 930 or modified to fit as an conversion piece? It was to my understanding that if you use stock 930 rotors they are designed to be offset? So this will "push" your wheel out by 22mm or something like that?

Just a thought. If i use unoriginal wheels that require spacers could i then use original 930 spacers but adjust the offset with the wheel spacer?

I am thinking about running some 8 and 9 inch RUF rims (yes I know there heavy and this is stupid. Stupid is what stupid does).

Sorry for my English, try to use the spell check

[Bill Verburg]

Originally Posted by 911-lightning

@ newms

So the rotors you buy from Coleman racing, are these stock 930 or modified to fit as an conversion piece? It was to my understanding that if you use stock 930 rotors they are designed to be offset? So this will "push" your wheel out by 22mm or something like that?

Just a thought. If i use unoriginal wheels that require spacers could i then use original 930 spacers but adjust the offset with the wheel spacer?

I am thinking about running some 8 and 9 inch RUF rims (yes I know there heavy and this is stupid. Stupid is what stupid does).

Sorry for my English, try to use the spell check

Stock 930 rotors for '78-80 930 are 2 piece floating and can be used w/ stock SC hubs Stock '80 up 930 rotors are 1 piece and have a built in os that the earlier versions had a wheel spacer for. W/ the earlier setup the spacer is simply not used on an SC. '80 was a transition year.

I am unclear as to what spacers you referred to in your posts, there are caliper spacers that are used to center the caliper on the rotor and there are wheel spacers that are used to move n/b wheels outboard when they are used on w/b cars.

The 930 caliper bolt to the 3.5" SC struts but usually a small caliper spacer is needed to center it on the rotor.

You can use oe 930 hardware or buy aftermarket, VCI is a popular supplier of the rotors and accompanying adapters and hardware. They can also machine the rear calipers to convert them from 3.5" 930 trailing mount to 3" leading SC mount.

You can use either floating or non, the main complaint about the old style floating is noise at normal speeds.

[Fly911]

PM sent in Norwegian!

[911-lightning]

Originally Posted by Bill Verburg

Stock 930 rotors for '78-80 930 are 2 piece floating and can be used w/ stock SC hubs Stock '80 up 930 rotors are 1 piece and have a built in os that the earlier versions had a wheel spacer for. W/ the earlier setup the spacer is simply not used on an SC. '80 was a transition year.

I am unclear as to what spacers you referred to in your posts, there are caliper spacers that are used to center the caliper on the rotor and there are wheel spacers that are used to move n/b wheels outboard when they are used on w/b cars.

The 930 caliper bolt to the 3.5" SC struts but usually a small caliper spacer is needed to center it on the rotor.

You can use oe 930 hardware or buy aftermarket, VCI is a popular supplier of the rotors and accompanying adapters and hardware. They can also machine the rear calipers to convert them from 3.5" 930 trailing mount to 3" leading SC mount.

You can use either floating or non, the main complaint about the old style floating is noise at normal speeds.

So if I am looking for something that is original and will bolt on at the front I need to go with floating rotors from '78-80? To look at it another way. If I want to use solid rotors at the front. What are my options? Is it possible to change the SC hub for a 930 hub? Do I need to buy aftermarket rotors that are adapted to the 930 caliper?

I wondered if the offset that is created by using the stock 930 rotors could be corrected with the "wheel spacers". I probably got this all wrong but is the problem not that the integrated offset will push the rim/wheel out by 22mm?

I this is the case and you run a rim that dont have the correct "ET" so that you need to use spacers to align the wheel with your fender. Is it then possible to use a 22mm shorter spacer and still use the rotor?



I am using 993 targa at the moment.

[Bill Verburg]

Originally Posted by 911-lightning

So if I am looking for something that is original and will bolt on at the front I need to go with floating rotors from '78-80? To look at it another way. If I want to use solid rotors at the front. What are my options? Is it possible to change the SC hub for a 930 hub? Do I need to buy aftermarket rotors that are adapted to the 930 caliper?

there are no 1 piece options for use w/ 930 brakes and SC/Carrera fenders unless you use wheels w/ large off set.

Here's what is is used oe on a '78-80 930, 911 hub(same as used on SC) multipiece 304x32mm rotor/hat assembly the bolts to the hub, and a 21mm wheel spacer. Discard the 21mm wheel spacer and then 7ET23.3 to 8ET30mm wheels fit on an SC fender car.

here's what is used on a 930 from '80 on, 930hub which has the 21mm spacer built into it, 1 piece 304x32mm rotor that bolts to the hub, 7ET23.3 wheel

So in order to use the late 930 hub and rotor you would need a custom o/s wheel 7ET45 to 8 ET51, Now interestingly 964 and 993 and 996 used 8ET50 front wheels, but it would be exceedingly fifficult to fit a 9 or 9.5 wheels from those cars in back to match. In back you want 8 ET10.6, 9 ET15 or 9.5 ET19.5. Say you used a 964 8 ET52 CupI wheel in front then a 964 CupI in 9.5 ET68 would need ~49mm spacer to fit the back of an SC/Carrera fender car.

Originally Posted by 911-lightning

I wondered if the offset that is created by using the stock 930 rotors could be corrected with the "wheel spacers". I probably got this all wrong but is the problem not that the integrated offset will push the rim/wheel out by 22mm?

I this is the case and you run a rim that dont have the correct "ET" so that you need to use spacers to align the wheel with your fender. Is it then possible to use a 22mm shorter spacer and still use the rotor?



I am using 993 targa at the moment.

Ok 993targa wheels, these 7ET55 and 9ET55?



those wheels on the 930 Hub hat woud be equivalent of 7ET34 so you would need an additional spacer to bring them down to ~7ET24

in back the 9ET55 would need ~40mm spacer to bring it down to ~9ET15

[911-lightning]

Originally Posted by Bill Verburg

there are no 1 piece options for use w/ 930 brakes and SC/Carrera fenders unless you use wheels w/ large off set.

Here's what is is used oe on a '78-80 930, 911 hub(same as used on SC) multipiece 304x32mm rotor/hat assembly the bolts to the hub, and a 21mm wheel spacer. Discard the 21mm wheel spacer and then 7ET23.3 to 8ET30mm wheels fit on an SC fender car.

here's what is used on a 930 from '80 on, 930hub which has the 21mm spacer built into it, 1 piece 304x32mm rotor that bolts to the hub, 7ET23.3 wheel

I see, so the one piece rotor for the front that VCI provides with their kit is custom made? That answers my question about not being able to use a one piece original part.




[/QUOTE]Ok 993targa wheels, these 7ET55 and 9ET55?



those wheels on the 930 Hub hat woud be equivalent of 7ET34 so you would need an additional spacer to bring them down to ~7ET24

in back the 9ET55 would need ~40mm spacer to bring it down to ~9ET15[/QUOTE]

I have the targa wheel the one on the bottom of the two.

I know you are the man to talk to regarding the brakes. So insted of me trying to understand do you think that the VCI kit (930 Brake Upgrade 911 - Carrera - 914 - 914/6)
is the way to go or is there another better solution for my build? I plan to go for the 3.6 conversion, the car will be a street car but once a year we try to go to the Nürburgring and some other track use.

[KTL]

Yes there are spacers used between the caliper and the strut mounting "ears" depending on what your rotor hats require to center the rotor.

930 Calipers is there a more desirable year?

On my current setup I have 930 front calipers, 32mm thick rotor with zero offset (Wilwood HD40 11.75" x 1.25"), 1/4" thick flat hats that are fixed/non-floating bolted. I needed to space my caliper to align it with the rotor so I bought the four Porsche spacers instead of stacking 1/2" dia. grade 8 washers or making my own spacer from 1/8" plate steel. They were only $4 each and I was placing an order anyway. The part number is 930.351.553.01

[Bill Verburg]

Originally Posted by 911-lightning

I see, so the one piece rotor for the front that VCI provides with their kit is custom made? That answers my question about not being able to use a one piece original part.

Ok 993targa wheels, these 7ET55 and 9ET55?



those wheels on the 930 Hub hat woud be equivalent of 7ET34 so you would need an additional spacer to bring them down to ~7ET24

in back the 9ET55 would need ~40mm spacer to bring it down to ~9ET15[/QUOTE]

I have the targa wheel the one on the bottom of the two.

I know you are the man to talk to regarding the brakes. So insted of me trying to understand do you think that the VCI kit (930 Brake Upgrade 911 - Carrera - 914 - 914/6)
is the way to go or is there another better solution for my build? I plan to go for the 3.6 conversion, the car will be a street car but once a year we try to go to the Nürburgring and some other track use.[/QUOTE]
VCI doesn't not supply a 1 piece rotor for use w/ 930 brakes they they only offer floating or no floating rotors which bolt to a hat which bolts to the SC hub. The rotor annulus for all of the 930 fronts is 304x32mm

I think that the VCI kit is a great off the shelf solution

So w/ the 993 wheels what size spacers are you using now? The rear spacers should be the same to use the 993 9s whether you have stock or 930 rears as they have the same o/s

so maybe you could get away w/ using the late 930 hub and rotors by just getting 2 new front wheel spacers, it looks like ~10mm spacers would do it.

[newms]

I do have small spacers to center the caliper on the rotor. I have the VCI setup and sent a rotor to Coleman years ago and they made rotors for me. After that first time they have all info on file and I call and they make! If you want I have a set unopened in box and can get the Coleman info for you. You still need the hats don't forget. I run 8x9 x 15 fuchs with 7mm spacers for autocross; 7 x8 x 16 bbs rs with no spacers for track; and 6x7 x 16 fuchs with a little bigger spacers for street (just for the look!). street and AX spacers needed to clear caliper face and keep the right rear from rubbing on oil line.

[stein johnsen]

Get in touch with Steve Werner at Rennsport for your 930 brakes brakes .

[opie]

+1 on what Stein said, Had my 930 brakes 0n my 86 for 8 years, Steve did my conversion,