LSOHOLIC

I have a few questions about brake rotors on my C5 ZO6. I'm a weekend warior/street car. Meaning I do a couple auto-x events and take it to the road course about twice a year. I also put my drag pack on and hit the drag strip a couple times a year. I drive the car to all the events, so the rotors need to be street worthy. I know all of this sounds like a lot but......she only saw 1200 miles last year....total. Shes just a Friday/Saturday night car.

Unsprung weight is my main concern. And I would also like them to work with stock calipers. I've worked real hard to get this thing down to 2880lbs (not gutted at all) and it would great to bring the unsprung weight down also.

I've been reading a lot and here are a few of the choices i've looked in to;

Coleman with AFX/Zip hats
DBA 5000
StopTech
AP Racing
Brembo
PBR
Baer Eradispeed
Wilwood
Hitco
HardBarUSA

Any input would be appreciated..

Thanks....

MJM

Your needs are a bit different than most who modify their brake systems. Most people want to get rid of the stock calipers to improve their braking. Many of us keep the stock rotors because they work and are inexpensive.

If all you want to do is decrease unsprung and rotational mass, then go with the lightest rotor that is the stock dimension. Just realize you will get zero improvement in braking and if the rotor surface material is thinner than the stock rotor you will get less life out the rotor. Most of the high tech replacement rotors are pretty pricey to replace.

LSOHOLIC

So your saying if I went to a Performance AFX rotor with Cobalt XR1's or 2's I would see no performance gain ??

LSOHOLIC

30 lbs of unsprung weight plus the loss of rotational mass seems like a huge performance gain to me !! Plus the write ups on those rotors with the Cobalt pads seem to be pretty good also.

So you were saying without a caliper change I will see no improvement in braking ?? My car is at 2880lbs and brakes great IMHO, I'm mainly after less rotational mass with a bonus being better breaking.

I know the guys in this section know the brake options as well as anyone. So this is where I began my search for knowledge and recomendations.

Thanks...

Jason

Light, strong, cheap. Pick 2.

VetteDrmr

The latest issue of GRM has an article on wheel weight and its effect on the autocross course. The test vehicle is a fairly new Miata, which would amplify the effects of rotational mass. Also the wheel's diameter has a bigger effect on rotational inertia than a rotor.

Short version? They couldn't hardly measure the difference, either on the stopwatch or on a chassis dyno.

MY conclusion? Reducing unsprung weight and rotational mass is good bench racing fodder, but for us weekenders I don't think you'll see any significant difference. I'm highly confident I won't.

NOSLO6

Great magazine, great article. I've been hoping they'd put this one on the website...

LSOHOLIC

Could I run the AFX 2 piece rotors forward and aft with my factory C5 ZO6 pads ?? If so what would be the out come (what kind of pedal feel/durability) ??

And about the rotating mass statement, I strongly disagree. I can personally say rotating mass is a huge thing. But I do agree that the closer the mass is to the center the less effect it has on the outcome. I ran some replica wheels and the car slowed down in all aspects of performance. Example, my current rear wheel setup weights 51lbs and the china replicas weighted 66lbs=15lbs per corner. If it didn't matter then whats with all the R&D the race teams perform ?? It does matter, the drag strip will prove it !

Thanks...

0Vector Vette

LSOHOLIC,
When it comes to autocross and tracking, the majority of the stopping performance gain is from the race pads, not the rotors. The major advantage of the rotors is that they last longer then stock ones do, on a racetrack with racepads. The weight loss/reduced rotating mass is harder to measure for sure but is very real. There is no doubt that the further away from the center the reduction is, the more the gain will be. That doesn't mean there is no gain though, there certainly is. Just like a liteweight crankshaft or a smaller diameter liteweight clutch help an engine rev quicker, a liteweight rotor is easier to turn as well. At the dragstrip, the weight savings will help. In fairness though, the 32 pounds you are talking about saving is for the C6 Z06, the C5 does not save that much.

If you are interested in our products or have any further questions, give us a call.
Robert Finlayson
Performance AFX Motorsports
815-254-2631

Olitho

The lightest rotors I have seen are the AFX on the rears if you remove the parking brake, and they last a long time, too.

For the front, the lightest rotors I have weighed are the Hardbar/AP rotors, but they don't work with stock calipers.


Oli

LSOHOLIC

Thanks everybody....Thanks Robert....I have some more reading to do.

Again thanks..

MJM

The lighter rotors might help on the drag strip....for accelerating the rears. They won't provide any additional braking power though.

If you go to a more aggressive brake pad (regardless of what rotor you are running) you will get more braking power but shorter rotor and pad life.

Matt

UstaB-GS549

Are you sure? I thought they were interchangeable.

I'm using blank rotors with my Hardbar AP caliper kit and they work fine. I did have to shim calipers outboard 1 mm to center caliper, but that might be my car.

mountainbiker2

I have Performance AFX rotors for C5.

Front savings. 2 lbs. each rotor.
Rear savings with parking brake. 3 lbs. each rotor.

They work fine.

Steve A.

RX-Ben

I would not recommend street pads on a road course unless you have little experience (i.e. won't be taxing the brakes too much). Get good pads (PFC 01, DTC 60, Cobalts, etc.) and good fluid. Bleed as needed. Rotate pads regularly. Add DRM ducts and a Quantum kit once you get serious. Then start stocking up on cheap rotors. Once you start competing, then think about getting fancier stuff.