I get so excited about this stuff…
I guess it goes back to the years when I remember having a 911 with the lowly T-struts (which I actually love now). I remember searching high and low for a caliper upgrade but around every corner there was no true bolt on upgrade for the 3" spacing.
Although I no longer have any cars with the 3" struts, I finally found a "real" upgrade, a "real" bolt on solution that meets my entire criterion for an acceptable swap from the stock M-Caliper.
Here's the low-down: These Brembos have a 3" bolt spacing and the exact same offset as the M-Caliper. This means they'll simply bolt right on. When I say bolt on I mean... all the way. They even fit with the standard dust shields. The fluid inlet is aimed right up at the tab on the strut for a direct in.
They have the same 48mm piston as the M-Caliper, S-Caliper and the later A-Caliper. What's cool about this is, they are the later "cup" type piston with no knock-back mechanism to deal with. The cup design offers better cooling with much more surface area than the standard M and S-Caliper pistons. Also nice is the fact that this won't throw off your fluid dynamics with your current Master Cylinder. Again, Bolt on!
The pad size is much larger than the M-Caliper pad. They are the same width as the A and S-Caliper pads but not as tall... (only slightly, like 2mm or so). If anyone is familiar with the BMW 320i pad size, these are the same. Another nicety, as I mentioned that these add up in all areas as a true bolt-on upgrade is; with this basic pad size (which has been proven with the S-Caliper and A-Caliper) there is no over stress of the standard 20mm rotor which obviously lived on all 911's through 1983.
They weigh in a full 4lbs lighter than the M-Caliper so there goes a good chunk of un-sprung weight (yes, they're aluminum!). Did I say "Bolt on upgrade!"?
You simply take your M-Calipers off and stick them on the shelf (in a plastic bag of course) for posterity sake, bolt these on, bleed the system (you know you should do that this year anyway) and you'd be good to go!
These calipers are sold on an "As-Available" basis. Here's what you get:
* Freshly anodized caliper cores (clear or black available).
* Freshly plated fasteners.
* New seal kits and caliper ½ seals throughout.
* Pistons reconditioned with new heat resistant paint
These calipers will be like new when they arrive at your door. Be sure to ask about Speed-Bleeders and Porterfield pads (and rotors and bearings and…)
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http://www.pmbperformance.com/catalog/item...552/6862358.htm