Lightest weigh caliper/rotor combo?

[JohnJL]

I'm sofa-building my next project while the knee heals. The theme of the next project is a lightweight narrowbody outlaw. I am going for a tasteful sprinkling of modern upgrades with old-school originality. Singer stole my idea.

I have become curious about brake options. I have cars with VCI/Big Reds, Early S, A and M calipers but no experience with non-oem options.

I see some very interesting ads in Racecar Engineering and other mags and sites showing FEA-focussed designs and exotic materials. They look very light and interesting.

There are threads on some options;

C12

73T - C12 Big Brakes

AP Racing



Stoptech


Wilwood
These have 3.5" lugspacing.
Wilwood High-Performance Disc Brakes - Billet Calipers Superlite 4 Lug Mount



Performance Friction


Its probably not perceptible on its own, but I'll take any weight savings. Perhaps there are some options out there with a lower profile to allow a bigger rotor if desired without needing to bump up wheel sizes with the associated rim and tire weight?


Does anyone want to share their non-OEM calipers and rotors?

Thanks!

[wildcat077]

I would think it's the weight of the rotors that will kill you ... the six piston alloy calipers wouldn't be the issue here !

Cheers !
Phil

[JohnJL]

Understood, I am looking for how successful others may have been with the weight/thermal capacity/clamping force/packaging/reliability/longevity/cost tradeoffs

[Mahler9th]

The folks at Jerry Woods Enterprises have some recent experience with an AP set up on several Spec 911 and other cars. I am not sure how light it is, but if they are complete with development and testing you can bet it works really well. They may be selling or plan on selling everything as a kit.

I use 930 rear calipers in front and Boxster rear calipers in the back. My car is very light at about 1950 pounds without driver. I use Wilwood rotors front and rear and they are pretty light. And relatively inexpensive. Here are the part numbers so you can get the detes:


FRONT:

UL- 32 Curved Vane
Front Left 160-2898
Front Right 160-2899

REAR:

Hat: Part number 170-0032

UL Straight Vane
Rear 160-1949

This set up is one a number of our local lightweight GT racing cars, and at least one Spec 911 has a similar set up. I can give you details on the cars if you want. Those details matter, obviously.

- Mike

[winders]

What's there to gain here except for a massively lighter wallet? What are you putting these brakes on? Weight? Engine? Wheel size?

Scott

[JohnJL]

Thanks Mike.

Scott,
The car is a 1978 tub with a narrowbody CF/composite body. The motor is a 3.0 I built for another car and am transplanting over to this new project. I got 240hp from it with a carrera intake, now with DR60 cams and I am working on an ITB intake. The target weight for the car is 850kgs. Only glass will be the windshield. I am building it as a bare-bones toy, I'm sure it will occasionally see Mosport or Cayuga, as the others do.

I'm not making the assumption it involves a lighter wallet yet, I have 2 sets of good condition early S and SC calipers and rotors to sell to offset the cost. I'm looking at the whole package too, tires, wheels, rotors and calipers altogether. I have a couple of sets of 16" Fuchs which I may use, sell, or cut up for 3-piece wheels.

[winders]

John,

930 brakes would look and work great on the car....and would work with 15" wheels if you went that route.

Scott

[JohnJL]

Thanks Scott.

I dont expect I'd directly notice a couple of pounds on each corner, but it seems to me particularly with a light car you want the suspension to react as quickly as possible since the rest of the car has less mass to dampen vibration. I wonder if, through careful caliper/rotor/wheel/tire selection its possible to drop 25% of the unsprung weight. That might be a noticable difference.

[JohnJL]

Maybe some of these for the calipers...

[LJ851]

Don't forget to consider the weight of the tires you choose, some are much heavier than others!

[911pcars]

S brakes and rotors for lightness.

4-piston calipers? Depends on the rotors you choose to use. Bigger and thicker = heavier.

Carbon rotors will probably meet your objectives of lightness with no expense spared (in line with Singer's philosophy).

Street, track or display purposes?

Sherwood

[JohnJL]

I dont really like my S calipers. I've "S"d everything else about the 1971T so I plan on leaving them on there, but I've never been really thrilled with the firmness and feel of the S fronts. I've tried different MC, different pads and different fluids. PR Technology did the same and came to the same conclusion.

I already have a dedicated track car, this will be a car to put the smile back on my face to/from work occasionally and on the weekends, and will find its way to Cayuga and Mosport on occasion.

[chrismorse]

I put C discs on an auto x speedster, S vented brakes on a pumped 914 and F-50 calipers and 355x32 fronts and 330x28 rear discs with Lotus calipers and brembo parking brakes on a 308 gtb. I love brakes. Driving hard, you gotta have the ability to get rid of the heat or you are going to pay for a lot of rotors, pads and caliper rebuilds. It is imperative to stay out of the eating up the brakes zone.

IMHO, improving the brakes is a lot cheaper than paying for more HP in reducing lap times + Better brakes makes you feel almost invinceable - I hate having to back off early and baby really hot brakes.

So you want to have "just enough" brake heat dissipating ability to stay out of the "non-linear" Zone.

Assuming you have the air ducting close and once you get the diameter as big as you can front and rear, have a good F/R balance, (just not locking the rears), probably need a cockpit adj prop valve for this, THEN you can start reducing the disc mass/experimenting with pad and disc material, (titanium, aluminum, CF, unobtanium).

You can always substitute $$$$ for mass.

I went WAY overkill with the 308 giant brakes - i was dealing with ebay used parts and trying to get a close F/R balance, having hats and caliper adaptors made and used parts, but i still spent 7 k with me doing all of the install and brake line fab stuff. Martin at Girodisc was instrumental in making this happen.

Even with these huge calipers and discs, i have less total brake component "weight" than the stock ATE brakes, (identical to early 911 vented brakes).

But, i have huge flywheels at the front and probably a lot more disc than i need at the rear - if i trip over a huge barrel of money, i will start downsizing the mass and maybe the material, (but not the diameter) of the discs. I think, once you have the gross size of the disc set up, you might be able to go with a lighter version of the 355x32 disc, or, even a different material without irreparably changing the brake balance. You might need to do the same front and rear, so the thermal throughput remains the same. This is even more complex than i simplistically thought. Ah well, yet another shortcoming.

chris




As we speak, (or rather i blather on), i am rebuilding the brakes and suspension on my dad's 74 911, (including zinc plating the spring plates and calipers, new rotors, stainless lines and doing the elephant suspension bushings, late adj spring plates and bilsteins, hopefully being able to borrow scales to corner balance. Dunlop direzzionales on the stock refinished Fuchs, Carrera bars...TIGHT.

[JohnJL]

Cool car Chris, thanks for posting that.

Yes, I've played with venting a bit on the track car. I forget who made them but I have a set of those CF ducts another Pelicanite made, I may reuse those.

[winders]

When it comes to brakes, there is only one thing worse than too small a brake setup: way more brakes than you need.........

Scott

[chrismorse]

Originally Posted by JohnJL

Cool car Chris, thanks for posting that.

Yes, I've played with venting a bit on the track car. I forget who made them but I have a set of those CF ducts another Pelicanite made, I may reuse those.

I think you have to build for the most demanding situation you will put THIS car through, so you don't wind up short, or out of brakes - i hate that :-)

I like Brembo calipers for light weight and parts availability, but i haven't any experience with any current calipers.

I still like the full floating set up for lightest weight and ability to change rotor mass for heat rejection.

Looking forward to seeing what you come up with for this specific use.

:-) chris

[chrismorse]

Originally Posted by winders

When it comes to brakes, there is only one thing worse than too small a brake setup: way more brakes than you need.........

Scott

What????

Never enough brakes, horsepower.

Younger women, older whiskey and faster cars :-)

chris

[winders]

Too much brakes means too much weight.....weight is the enemy, especially if it is rotating weight.

Scott

[ShakinJoe]

John

I have exact weights on rotors and calipers from a stock 1987 set up to 993 F/R calipers combined with 930 rear rotor and renn sport front rotor.

You can have too much brake which would result in not getting enough heat. If you are oing with 15 or 16 inch wheels, it will be difficult to get enough brake under the rims to qualify as too much.

[JohnJL]

Thanks guys.

So to narrow it down for discussion purposes, lets say I plan on using 7x16 front and 8x16 rear Fuchs.

Now, I admit not doing or even venturing a guess as to how to do the math, but I wonder if stock calipers and rotors, with judicious use of venting, would have trouble keeping up with a car 200+ kgs lighter than new? The car will not run slicks, but r888's or similar and the longest track stints will likely not exceed 20 minutes.

So I guess I'm saying I'd still like to see what options are out there that are lighter than the stock ATE anchors, fit under 16" fuchs, fit or can be adapted to fit Bilstein struts and fit or can be adapted to fit stock or carrera rotors or aftermarket alternatives.