By the way what does all this cost?

 

On the Wilwood, they are MAP priced so everyone sells them for the same price. So use a vendor you can earn/use points or get a coupon with. I got mine from Jegs with free shipping and $150 off, so the rotors were right at $2K even. Pads were Hawk GT 5.0 pads from Redpants for $400. So $2400 all in I think.Only about 2K miles so far but no issues.

Rotors
https://www.jegs.com/i/Wilwood/950/140-13106/10002/-1
Current $100 coupon if you sign up with email, makes them $2072.00

 

Racing Brake is similar price 4 rotors and street pads $2300. You can upgrade pads in the package for more $

 

Nothing of value to add here but I wish those rotors had the hardware with the clips where the two pieces attach.

Similar to these:

 

Brembo, makers of our OEM brakes, also do lightweight 2-piece rotors that have those clips, or some very similar.

The front ones are #102.8013A (or E for track day discs with different vanes). Rear are #202.6001A.

In UK they are around £1600 front & rear, but I can't find the weight of them, have written to Brembo to ask, but they are closed down for most of this month.

 

Yes but I've not studied it yet and I have braked hard. I thought maybe it was because we ran them new on the track and are switching pads between track and street.

The rotors provide reduced unsprung weight as well as reduced rotating mass. Lateral weight transfer thru the unsprung mass is immediate when cornering. Because of 'jacking effect", load is transferred thru the suspension linkage (sway bar, control arms) laterally from the inside tires to the outside. Lateral weight transfer increases scrub force at the contact patch of the outside tires. Since the weight cannot be kept from moving across, reducing the unsprung weight reduces the weight that is transferred laterally to the loaded side. Since less weight is transferred laterally (horizontally) to the outside, scrub force is reduced on the outside tires and vertical weight is conserved on the inside.

The sprung weight rolls around the center of gravity and adds vertical force to the outside tire which would be optimized at the "engineered limit" of the tires vertical load. This is a timed event which is delayed from the instantaneous lateral weight transfer that occurs thru the suspension links, as it takes some time to compress the spring once the car starts to roll. Sports cars are engineered and tuned to optimize these two events (bushings, springs, dampers, tires, roll bars). Since the lateral transfer is instantaneous, we stiffen the resistance to roll such that centrifugal force acts much quicker vertically on the contact patch.

As a plus, the lighter rotors reduce rotating mass at the hub. 18" magnesium wheels provide another means to this end for race cars. It is much easier for the spring and shock to control the contact patch if the weight at the end of the lever (control arm) is reduced. All things equal and resolution to measure it, a car will corner faster with less unsprung weight and will accelerate and brake faster with lighter rotating mass. IMO two piece rotors are a great value for any sports car, provided they are engineered for the task.

Removing insulation is reducing sprung weight. I like what Rich did with his car removing the sound deadening in the liners, but that is as far as I would go. If I didn't not track my car, I wouldn't bother. We have the liners in and out enough it just simplifies things.

Not trying to sing to the choir. It just seemed odd to go from two piece rotors to insulation

chr

 

Do they need someone to test fit the 6-piston rotors? I just ordered a brand new set of factory rotors that they can use to duplicate if I can get a deal on the final product?

 

"The sprung weight rolls around the center of gravity"

This is not correct. The centrifugal force acts thru the center of gravity. The car rolls around the roll center axis which is created between the front and rear roll centers. The greater the distance between the CG and the roll center axis the easier the car will roll.

chr