kmagvette

I need to improve my brakes in the rear, have AP 6 pot up front and stock C5 Z06 singles out back on a C5Z. This makes for a very unbalanced system.

Cash is a concern. I am being taunted by the 4 pot Alcons (and many Wilwoods) on eBay. Has anyone been able to mount them on a C5?

Many of them are lug mount on 3.50" centers. The adapters I see are too small for the C5 knuckle.

There are a few radial mount Alcons as well. Any experience with these?

The back-up plan is to put the old front 2 pots out back, but I would prefer a solution whereby I get to keep the parking brake - comes in handy at state inspection time.

ibjamin

How about putting the C6 Z51 rotors and brackets on the rear. Go from a 12" rotor to a 13" one on the rear to better balance the 14" front. Use same stock calipers.

kmagvette

That was the question that just got me out of the rack. Are there rotors available that allow me to keep the parking brake, use my stock fronts, and avoid a screw around project slicing up my rears (backing plate, sticking cables somewhere, etc)? I will look at that option...now, back to sleep.

Sidney004

Easiest and cheapest solution is to increase the coefficient of friction in the rear. Ferado racing pads go up to .72
http://www.federal-mogul.com/en/Afte...03+Brake+Pads/
assuming of course they carry C5 rears and if you can get them up to operating temp. Ferado lists the Cf and carries Alcon pad sizes; by knowing the exact Cf you can calculate the increase in rear bias. Increasing the radius of the rotor will yield 8% greater braking force, which is useful along with being a better heat sink but if you were to switch your pad Cf from .5(average racing pad) to .62(DS 3000) that would be a 24% increase in rear braking force. What pads are you using front and rear right now?

AU N EGL

if Cash is a concern then put the stock C5Z FRONT calipers and rotors on the rear. and Use HAWK DTC-70 brake pads back there too.

beerkat

So you can put the front rotors and caliper on the rear, is it a straight bolt on?

kmagvette

Cash is a concern to the extent that I don't have 3K laying around, unallocated, to do AP's in the rear. I am not willing to dig into the cage fund. If there is something I can do that is in the $800 range and it is a better solution than stock fronts to the rear, that would work. Especially if it is a non-destructive solution with respect to the parking brake.

I am intrigued by ibjamin's suggestion of putting C6 Z51 brackets and rotors back there and using my stock fronts. Does everything fit? I almost is too convenient if it does.

JVetthead

yep.. allmost. You use the front brackets and front rotor. Have to lose the parking brake tho.. I cut away the backing plate for better cooling.

Oh... and allways carry around a 2x4 block for those not so level padocks

Lan.Jet

Just put the C6Z06 back brakes on. that's around $800 and it has the parking brake.

ghoffman

What model Alcon? Is ther an Ebay link?

NemesisC5

I installed C6 Z51 size DBA 4k rotors on the rear of my C5Z. Just buy the C6 Z51 brackets and the calipers bolt right up, basically plug-n-play. Cash is tight for me now...

coffey

Maybe get the ebay calipers, use an off the shelf big rear rotor that keeps the parking brake and mount up your calipers as you see fit. Adapters aren't too hard to make.

gkmccready

Do the ebay calipers have the right pistons sizes or are you still in for a bias problem compared to the fronts and now you've bought yourself a master cylinder upgrade, too?

kmagvette

Long winded PM sent.

kmagvette

Sure, make me take stuff off the car ...

The stock front pistons are 1.6", stock rears are 1.75". Ignoring rotor size (I know you really can't), assuming the stock master is retained, and identical pads are used...

Stock fronts have a piston area of 4.02 sq in.
Stock rears have a piston area of 2.41 sq in.
Rear piston area is 60% of the front piston area.

My AP Fronts have 2 sets of 3 pistons, each set is {1.5", 1.25", 1.0"} yielding and effective piston area of 7.56 sq in per caliper...gee, I wonder why the stock rears feel useless

So, more assuming, the front rotor got about 1" bigger, and my best guess is that the rear will be about 1" larger when all is said and done. So call that a wash. Maintaining the stock 60% rear piston area to front piston area with the AP's up front would dictate a 4 pot rear with 1.2" pistons. The stock setup is a bit weak in the back, so slightly larger pistons might not be all that bad.

Things that screw up all the above elementary calculations and assumptions:

1. Relative pad area
2. Real impact of different rotor sizes
3. Other stuff I managed to miss mostly because I really don't know what I'm doing...but am willing to learn.

With all the variables out there, including the wants of a particular track, I see and adjustable master in my future. My current goal is to get something that is much closer to matched than the AP fronts and stock rears without depleting my cage fund.

gkmccready

Maybe the cheapest way out is the DRM master cylinder? Randy@DRM has been asking me if I have a high, hard pedal with my Wilwood SL6Rs (1.62, 1.2, 1.2 pistons)... I think he's looking at the MC angle but I haven't really asked him because my pedal feels "okay" and the car stops well.

Where'd you get the AP fronts? They should be able to help you figure this out. :-)

J.R.

I was running Wilwood 6 piston front and stock c5 rear with the stock master cyl. and it seemed to work o.k.

When I added the Wilwood 4 piston rear (SL4R) I needed more volume and went to the DRM master cylinder with proportioning valve adjustment built in and it works like a dream.

However, be aware, as you increase brake sizing it may possibly create some ABS issues with the C5 stock brake system. Seems to be more of an issue on pre 2001 units.

coffey

Yeah talking to the mfgrs is helpful. I second that.

2MCHPWR

can you get the Baer Eradispeed Brake Rotor for C5 and Z06 Corvette?
"...the 2pc 14 inch rear rotor kit requires slight modifications."

NemesisC5

Yes, they are available with smooth or slotted (without holes) rotors as well. The abutment brackets are part of the kit.