bandsmalter

Looking for real world feedback on the Wilwood brake kit now offered for the 911.

https://www.wilwood.com/BrakeKits/Br...axle=Front+Kit

How does it all work on the track? Bias OK with stock brake master cylinder? Did everything bolt up nicely?

I am thinking of installing this kit and running some track days. I have a Garmin Catalyst so could do some before and after comparisons on braking points and Gs pulled etc... Would be interesting, right?

Thanks

budge96

Overkill , unless you have doubled your horsepower magically these components won’t come into play , if you were to go ahead and bite the bullet your stock M/C would need upgrading at least to turbo 23 MM …Bert

Spyerx

what front struts do you have / what year car?

RennPart

I guess print advertsing still works- that add in Panorama was great.

I spoke with a long time engineer and sales rep from Wilwood about this at VIR a few years ago. At the time they are working on edging into the European market. Apparently they chose to start on the G body cars- we're all for it and excited to see what they come up with for the late model stuff.

We sell Wilwood, give us a call and let's get some real world feedback.

--Aaron

Wilder

I looked into them in depth and called the company a few times. My primary concern was unsprung weight reduction. Their calipers weigh about half the weight of the Carrera calipers and there are few options out there for these cars. If you buy the four corners, it doesn't come with rear rotors so you have to use Zimmerman or OEM in the rear. I asked about bias and they said they come set up with OEM bias and that you can change it. The price is right and they have a good reputation on the track as "off-brand Brembos". I'm building my car in Germany and brake upgrades have to be TUV approved so went with Cargraphics instead but would've otherwise gone with the cheaper Willwoods. Not the answer you were looking for but hope it helps.

Bill Verburg

They really don't publish enough technical specs to have an opinion one way or the other, Their attitude seems to be trust me it's ok

I refuse to deal w/ people like that.

If you are only running a few track days then most brake upgrades aren't going to be worth the cost of entry

What you should do id learn to use the existing brakes more sparingly

use fresh Castrol SRF brake fluid, the best there is for stressed brakes

use high temp track oriented pads which will usually have a thermal brake built in.

add 964/99 style scoops to direct cooling air to the rotors

KNSBrakes

I'm sure it bolts up nicely. Wilwood makes kits that fit.

As far as bias - those calculations vs. stock are pretty easy - have you run them? I'm sure WW did - the ****ty WW kits are where idiots used WW parts and 'designed' there own kits.

I'm less happy with the 32 vane solid mount non GT37 rotor. It's already a smallish 300x28mm disc with a Superlite 16mm pad, that's 200 WHP/sub 3000 lb car range or so.

Bill Verburg

That was my point, yes i's easy enough to 'run the numbers' but the numbers need to be provided by the supplier. w/o complete valid specs you get to trust them, I wouldn't as I've seen too many poorly speced 'kits'

The point of a BBK is t enlarge the thermal envelope of the brake system, you don't need a huge increase in brake torque as the limiting factor there is the tires' ability to grip.

while increasing the thermal envelope it's important to keep bias and pedal feel as optimized as possible.

the easiest way to increase the thermal envelope is to increase cooling air flow, rotor size, rotor air flow characteristics and of course lighten the load through weight reduction w/ better technique.

stock 911 from '69 thru '83 use 284x20 and 290 x20mm rotors, in heavy use the fronts will tend to overheat much more than the rears, this can be moderated w/ good fresh fluid, track oriented pads and cooling air flow improvements and/or increasing front rotor size.
first step up in front rotor size is to use the '84-89 911 fronts 284 x24mm, the usual max is the 930 304x32 though bigger can be fitted, the nice thing about the '84-89 fronts is that bias and pedal are unaffected. For rotors thicker than 24mm a bigger caliper is required. Besides being larger the 930 rotors feature improved internal architecture that greatly improves cooling.

another strategy to alleviate front overheating is to move bias back, but there is a limit as to how far back bias can safely be moved, stock brake torque bias used through '83 is very close to the max useable. The only penalty for too much front is wasted resources.

usually but not always a bigger front rotor is accompanied by a bigger rear rotor. heat is much less of an issue in back, so bigger rotor is more of a tool to help keep bias where you want it though it does help keep the thermal balance optimized as well.

bandsmalter

Thanks for the comments.

The car is an 85 911. I have owned the car over 30 years and done a a number of track days in those that time. It has cooling ducts leading to backing plates, stainless lines, and has used various track pads and ATE blue / gold fluid. I've pretty well maxed out the things you can do with stock pieces.
My front calipers need to be rebuilt (again) as the boots a crispy, and my front rotors are warped. So time for some maintenance. Bolting up new parts for $1500 that are lighter, and increase the diameter and width is pretty appealing.

Sam-Son

Was also curious about these compared to those 930 ERX kits.

A friend just bought a willwood kit for his Miata and was very impressed with the quality and how light they are.

Bill Verburg

The cooling ducts/backing plates are useless way too small to move any meaningful amount of air, use 964/993 type A-arm scoops


Ate is a fine street fluid but it's boiling points are 388/536 wet/dry

Castrol SRF is 518/608 this is the one to use for thermally stressed brakes

warping rotors is a myth, most likely the pads have left uneven deposition this is normal and can be cleaned of w/ emory cloth

there are several different types of common rotor issues

holey rotors will crack most easily


It's also natural to develop hotspots

If these hotspots a re blued when they cool the rotor is toast

Lighter means little in this context

if you want better brakes that work and bolt up out of the box and have great parts/pad availability but a set of Elephant Racing 930s and a 23.8mm m/c to run them.

wildcat077

You should try to find a OEM 930 setup, my friend who's a PCA instructor installed that in his 88 Coupe and he loves them.He bought the whole kit from Steve Weiner many years ago when they were still
somewhat affordable at the time.Nothing wrong with Wilwood, but if you can get a set of 930 brakes it would be perfect.Bill is the brake guru, good advice ...
As for my car,an 89 Coupe i got a smoking deal on a near new set of 996TT complete all around brake kit.The bias was completely front minded and it was dangerous when the road or track were wet.I ended up setting up
my brakes with a Fabcar dual master and Tilton bias valve setup and it was a bunch of fun outbraking GT3's in the black run group when i was doing PCA DE's !
It's gone back to street duty only now and i'm going to tone down the brakes a little and make them more user friendly.

Cheers
Phil

RennPart

Wilwood has 14 "variations" of the kits.

Just select the year/model of whatever hubs you're running.

Basically there are "M" and "S" hub front kits- options are calipers only, 11.1" one piece rotors, and 12.9" 2 piece ultralight HPS 32 vane rotors.

The rear is pretty easy, 20 or 24mm thick factory rear rotors- calipers only or choose your 1 piece rotor (blank or slotted)

Not sure what size wheels most of you run- but this must be taken into consideration.

rennpartbrakes.com until this becomes rennpart.com

--Aaron

bandsmalter

For fun I looked at the cost of 4 options:



The OEM package is ATE, Zimmerman, Textar from a well known Porsche online site.
The Porsche kit is the same site, but using all Porsche parts and an stainless brake line kit
The Elephant racing kit is the street kit.
The Wilwood kit is the higher cost 12" front rotor kit and the complete rear kit with rotors.

So if you are doing a mild restoration and want to refresh your brakes what to do.... what to do. If originality is not a consideration the Wilwood kit is awful compelling. It has to be a step up for the original set-up.

Bill Verburg

The last thing to consider is cost
the first is what do you need

here's a survey of the brake stress index for a most stock 911 variants

For track you you really want to be under 325

If just modifying bakes the rotor sizes and cooling ae the main considerations

here are the thermal indexes for most stock rotors


here a survey of bias, torque and thermal performance


a historical perspective of brake stress


again Wilwood isn't included because they don't provide enough information

like piston sizes and do they have outer seals like stock, effective rotor diameter vs actual etc.