I was in the RS/RZ brake caliper and custom rotor group buy and wanted to share some pics. The rotors came today and I though I would do a little comparison between the stock rotors, new precision custom rotors, and the massive Porche/Movit rotors.

Here ya go:













The new precision front rotors are really nice and think, probably never fade, but as you can see the porche/movit ones have mouch more swept area.

 

by the way, i had planned to sell my kit to help offset some of the cost for the cym car I just purchased, but they look so good I may have to keep them :-)

ohh well, more debt ....

 

Wow those look really nice. Makes me wish I was in that group buy.
M-P

 

They look sweet! How much were they with the group buy?

 

Those really do look good. Thanks for reminding me to change my brake pads today

 

Excellent pics. Do you mind adding these in our Suspension Forum with a link back to this thread? That way people searching brakes in the future are certain to find it.

 

Not necassarily. The Porsche/Movit ones are full of holes. Holes don't count as swept area

 

Not to mention that if it's not being swept by a brake pad (hence the term), it's not swept area...

Swept area is total friction area contacted by the brake pads during one revolution of the rotor.

Imagine two circles, one corresponding to the inside edge of the pad, and one corresponding to the outside edge of the pad around the circumference of the rotor. If the the pad width does not increase, increasing the distance of the pad from the rotor centerline (with a larger rotor) increases the area inside the two circles. If the pad is wider, even mounted at the same distance from the rotor centerline the area inside the two circles increases. Either way, that constitutes an increase in swept area.

Without seeing the pads and calculating the area covered, it's not so easy to determine that the Movit rotors have more swept area than the Precision Brake rotors, although they are about 1/2" larger in diameter, and therefore one would expect at least some increase in swept area. However, Damon is right. Holes do not constitute swept area because they are an "absence of friction surface".

 

Keep in mind that you can't count the slots in the Precision rotors as swept area either. Regardless of what is "swept" or not, those Movit brakes do look like they have more mass to dissipate heat.

 

sweet as pics. thanks. i need to upgrade my brakes also.

 

here is the thread on teh group buy with all the info (its looong):
https://www.rx7club.com/showthread.p...hreadid=219291

 

good idea, just added it to sus/brakes forum

 

all good points guys.... I should have mentioned (and pictured) the pads, the pads for the proche/movit kit a re MUCH bigger than the rs/rz pads....I'll try to get some pics of the pads up as soon as I get the caliper/pad set in.

 

here is a stock front FD pad (on bottom) compared to a porche 993 Turbo pad (on top).

obviously the 993 pad has a ton more 'potential' swept area, I can almost fit the entire stock pad (frictionmaterial AND backing plate) inside the the frictiona material area of the 993 pad.....however as mentioned above you have to consider what is lost by the holes/slots on the rotor face.

 

ur welcome daedelGT :-)

 

Any of those choices definitely seem to be big improvements over stock. Glad to see the Precision Rotors are merely slotted

.mmmmmm.....big brakes... Now I have additional fuel to envy Damian with

 

:-) thanks damonB, just dont envy my debt for all these fun toys :-) (heheheh)

 

 

No offense, but the Movit rotor looks like someone cut the center out of a drill press table... Man that sucker looks HEAVY.

 

It is. It weighed 21.5 lbs on my bathroom scale.

 

Jim: hahaha funny... maybe not a drill press table, maybe a manhole cover!

Damian: Excellent pictures showing the differences! Let us know how the install goes.

Brian

 

hahah jim, yeah its big and heavy,....

wargasm... the porche/motiv kit was already on my track car, but i will post when i start the rs/rz kit install on my street car... and post many pics as always :-)

mr.stock, you run the same porche/motiv 993 kit on your car too? do you know if those are custom motiv rotors or stock porche rotors

 

No. I don't run the Movit kit.

However, the kit that is on your car used to belong to me. I bought them from Steven D'Gerolamo of Ultimate Garage many moons ago. I weighed all the parts of that kit and have that recorded in my RX7 log. I never installed them but rather, I sold them to Steven S. whose car you bought(via Fabian).

The Movit kit rotors are stock Porsche 993 rotors as far I know.

 

ahh, thanks for the info mr.stock
i though they were stock porche rotors too, but not positive.

why did you end up selling the kit? too heavy?

(Fabian suggested making aluminum hats to reduce weight, and I may when I get the funds/time to do it)

 

Yes.

Although mass is good for heat dissipation, the entire kit weighed too much.

Here are the numbers:

Rotor 21.5 lbs
Calipers 8 lbs
2 brake pads 2.75 lbs
bracket 1.5 lbs
----------------------------
Total per side 33.75 lbs

When the M2 Performance AP racing kit came out, I bought those instead.