77 930 upgrade to non-turbo 993 calipers

[77turbocarrera]

Hi guys, I have a 1977 930 and I 've gone through all the posts about brake upgrades but is seems a little grey when it comes to the (non turbo) 993 black caliper adaptation.

I see that most shops sell the adapters for the 993 TT red caliper, I found msroadrace on ebay and he sells the adapter for the non turbo 993 caliper (front).

Porsche 911 993 Caliper Adapter Bracket Custom: eBay Motors (item 390146475389 end time Oct-18-10 16:38:47 PDT)

Are there any other sources for this adapter? Is the adapter for the 993TT caliper the same dimensions as the non turbo 993 black caliper? He has it listed that way.

If I use these 993 calipers what rotor style will will work best? It seems that some people have used the mid 80's 930 rotor which looks similar to the 77 rotor. is this correct?

Now do I leave the rears alone? it would seem that the braking would be mismatched with factory 77 rears.

I have a complete set of 993 non turbo brake calipers and i already have the 23mm master installed.

Thanks for your help on this.

[Bill Verburg]

Originally Posted by 77turbocarrera

Hi guys, I have a 1977 930 and I 've gone through all the posts about brake upgrades but is seems a little grey when it comes to the (non turbo) 993 black caliper adaptation.

I see that most shops sell the adapters for the 993 TT red caliper, I found msroadrace on ebay and he sells the adapter for the non turbo 993 caliper (front).

Porsche 911 993 Caliper Adapter Bracket Custom: eBay Motors (item 390146475389 end time Oct-18-10 16:38:47 PDT)

Are there any other sources for this adapter? Is the adapter for the 993TT caliper the same dimensions as the non turbo 993 black caliper? He has it listed that way.

If I use these 993 calipers what rotor style will will work best? It seems that some people have used the mid 80's 930 rotor which looks similar to the 77 rotor. is this correct?

Now do I leave the rears alone? it would seem that the braking would be mismatched with factory 77 rears.

I have a complete set of 993 non turbo brake calipers and i already have the 23mm master installed.

Thanks for your help on this.

The same caliper adapter is used for either 993 or 993RS/tt fronts, the 993 is used w/ a 304mm rotor the taller 993RS/tt is used w/ a 322mm rotor. Be sure that the caliper adapter that you use has the correct o/s for the rotor o/s. The 3 most commonly used rotors are the flat '78-80 930 304s, 964 322, 928S4 304, 993 304 and 993 322

the 964 and 928 have the same rotor o/s the 993's is a few mm different

[77turbocarrera]

Hi Bill, thanks for replying so fast. He said the adaptor was made for an 11 3/4 rotor (298mm with some quick math)

Knowing this, will his adaptor still work with the 304mm size rotors? Can you recommend an adaptor that you know has the correct sizing for the 304mm rotors ?

Also I just read a post about using the 996 rotor and 993 caliper for the rear. Is this a bolt on for my 77? What do you recommend for the rears?


thanks

[Bill Verburg]

Originally Posted by 77turbocarrera

Hi Bill, thanks for replying so fast. He said the adaptor was made for an 11 3/4 rotor (298mm with some quick math)

Knowing this, will his adaptor still work with the 304mm size rotors? Can you recommend an adaptor that you know has the correct sizing for the 304mm rotors ?

Also I just read a post about using the 996 rotor and 993 caliper for the rear. Is this a bolt on for my 77? What do you recommend for the rears?


thanks

VCI will have what you need, just be sure that you know what rotors you will use. the adapter has to match the rotors

[77turbocarrera]

I see, so its the caliper (993tt vs 993) that dictates the rotor size not the adaptor. Do you have any opinion on using the wilwood rotors? they seem like a quality part and the price is right.

This was the rear set up I read about:

Rear - 996 299x24 rotors with 993 34/30 calipers (need to modify caliper ears to fit 3" Carrera trailing arms)

Any idea of the complexity of this mod to the caliper ears?

[Bill Verburg]

Originally Posted by 77turbocarrera

I see, so its the caliper (993tt vs 993) that dictates the rotor size not the adaptor. Do you have any opinion on using the wilwood rotors? they seem like a quality part and the price is right.

This was the rear set up I read about:

Rear - 996 299x24 rotors with 993 34/30 calipers (need to modify caliper ears to fit 3" Carrera trailing arms)

Any idea of the complexity of this mod to the caliper ears?

I'm sure that the wiloods will be fine, I think that they are 309x32 and are used by a # of folks here

I've never used 996 rotors in back, they aren't much bigger than 290x24 3.2 Carrera rears. I've always used 930 309x28s w/ either 965 or 993 rear calipers(both are 30/34)

the 993 and 993RS/tt calipers are hydraulically the same and both use 132mm long pads, the difference is the height, both the RS/tt caliper and pad are ~10mm taller than 993, hence they use the bigger rotors. There is a version of the 993 caliper which was used on 964RS and 965 that has a raised mounting boss, these calipers would use the same adapters as the other 2, but because of the rasied mounting boss's they need 322s too. Additionally you can use an extended adapter to allow the use of the 993s on 322s, though this isn't usually done

[spuggy]

Another alternative to the VCI route is the Instant-G kit to use 993, 993TT, 996 or 996TT calipers together with the stock factory rotors designed for each of those calipers via a kit that includes a custom hub, all bolts and new bearings.

If you supply your own calipers, just buy the front 993 kit, your choice of pads, rotors.

Here's the 993 page:

Instant-G Big Red Conversions

Wear items are then widely available - and cheap. I bought a set (all 4) of German-made 996 rotors drop-shipped for $200 - cheaper than the aftermarket pads. Blew me away.

Is that as good a solution, technically, as a fully-floating front rotor? Probably not, in theory. But the brakes work very, very well (used them in anger the other day).

[77turbocarrera]

I got under my car today and noticed I have 2 sets of mounting pads on rear trailing arms. The rear set of holes are spaced about 3.5 inches and are UNTAPPED. Do you know if these can be tapped to mount the 993 rear caliper instead of filling and drilling the caliper?

thanks

[77turbocarrera]

some pics of the mounting pads and caliper