Sitting here in the doldrums of Winter and this is the thought that came to mind... - ZR-1 Net Registry Forums

Mystic ZR-1 · 01-24-2020

An idle mind is......

Wilwood Forged Narrow Superlite 6R Big Brake Kit (front)
140-8337
Any one using them?
Older posts here say 13 inch fit OK under 17" A-Molds?
Worth the $? Street, occasional track day... (damn, they look nice!)
Dust?
Change rear to same compound pad D413.
Wilwood says they work w/stock master cylinder?
Change bias spring in MC?
They look like they'd stop a freight train?
Looks like best $ @ Jegs or Summit?.

tnova · 01-24-2020

I put the complete 140-8337 front brake kit on my '91 with the 140-8314 hat and rotor kit on the back, retaining stock calipers in the rear. Wilwood originally said would work with the stock master cylinder however I could not dial out enough rear brake with the the bias valve I installed to keep them from locking up first. The spring replacement is the opposite of the direction you need to go because it puts in more rear brakes. Called Wilwood and they corrected themselves that '90 and '91 had small bore master cylinders and they aren't big enough to push the volume needed on the front for balanced braking. They added that even with a later model C4 master cylinder, I would still need a bias valve to take out rear brakes but it works. Again, no bias spring as that goes in the opposite direction needed.

My solution was to use the old school C4 racer's solution and put on a later model Camaro master cylinder that has a 1" bore. You need a spacer to between the mounting ears and brake diaphragm housing to keep piston rod depth correct. You also need to clearance the inner fender edge slightly so it doesn't hit the master cylinder reservoir. Brake end fittings and lines need to be changed too. A lot of work but my car now stops fantastically.

Instead of going through the Camaro master cylinder swap, just use the later C4 larger bore master cylinders and it should work according to Wilwood but don't use the bias spring upgrade and you still may have to put in a bias valve unless you use the Wilwood rear calipers too.

Tony (Tnova)

tnova · 01-24-2020

And yes, they fit under my 17" sawblades.

secondchance · 01-24-2020

Quote:

Originally Posted by Mystic ZR-1

An idle mind is......

Wilwood Forged Narrow Superlite 6R Big Brake Kit (front)
140-8337
Any one using them?
Older posts here say 13 inch fit OK under 17" A-Molds?
Worth the $? Street, occasional track day... (damn, they look nice!)
Dust?
Change rear to same compound pad D413.
Wilwood says they work w/stock master cylinder?
Change bias spring in MC?
They look like they'd stop a freight train?
Looks like best $ @ Jegs or Summit?.

Doug,

I’m running Wilwood Narrow Superlite 6R up front. I couldn’t check A mold on the front because I installed 14” rotors. But, I tried A mold wheel on the rear with 13” rotor and it fit.
Also, check Wilwood site and perhaps talk to their rep to be sure.
I’m running stock MC but did not change bias spring. The set up works great!

http://www.zr1.net/forum/showthread.php?t=24546

Mystic ZR-1 · 01-24-2020

.

EvanZR1 · 01-24-2020

I keep thinking one of these days I'm going to pull one of my front Shelby wheels off and see if they will clear the 14" Wilwood setup (using the Wilwood template).

-=Jeff=- · 01-24-2020

I have the 13" kit int he front.. still using the OEM Master as well. I have a 92 master with the Bias Spring, but never got it installed.. I had a camaro master on my 89.. Wow that one worked well..

Still might do the master upgrade at some point

secondchance · 01-25-2020

I installed Wilwood 6 piston Superlites up front w/ 14” rotors and 4 piston Superlites in the rears w/ 13” rotors.
I think later ZR-1s had 15/16” bore MC. I bought a Camaro MC w/ 1” bore but concluded that I would have to rig up another brake fluid reservoir because Camaro reservoir did not have a nipple to accommodate ABS pump priming. Also, did not want to mess with re-routing brake lines to the opposite side.
OEM MC works fine. I thought 1” would reduce the pedal travel and firm up the pedal but concluded it to be too much work considering all worked very well as is.

Mystic ZR-1 · 01-25-2020

.Here’s the rear set-up...

tnova · 01-25-2020

Here's the C4 master cylinder bore sizes. I thought '92s were smaller also but they're not. My 7/8" bore '91 didn't handle it. Putting a 1" Camaro MC on is a lot of work as has been pointed out. I have a lot of "if I were to do it again" stories on my '91 and one of those would be going to a 15/16" bore with no line or fitting mods. Then again, my brakes with the 1" bore are really, really good.

Tony (Tnova)

87 master Brake Master Cylinder
Bore Size : 7/8"
Line thread Size : M12-1, M10-1

The '88-'91 master cylinder
Bore size: 7/8"
Line thread size 12M x 1 and 10M x 1

The '92-'94 master cylinder
Bore size 15/16"
Line thread size 12M x 1 and 10M x 1

The '95-'96 master cylinder
Bore size 15/16"
Line thread size 12M x 1 and 10M x 1

98-2002 Camaro = 1" bore
Bore Size 1"
Line thread size 11mx1.5 and 12mx1

01-24-2020	#1
Mystic ZR-1 Join Date: Jan 2010 Location: Mystic CT Posts: 2,597	Sitting here in the doldrums of Winter and this is the thought that came to mind... An idle mind is...... Wilwood Forged Narrow Superlite 6R Big Brake Kit (front) 140-8337 Any one using them? Older posts here say 13 inch fit OK under 17" A-Molds? Worth the $? Street, occasional track day... (damn, they look nice!) Dust? Change rear to same compound pad D413. Wilwood says they work w/stock master cylinder? Change bias spring in MC? *They look like they'd stop a freight train?* Looks like best $ @ Jegs or Summit?. Last edited by Mystic ZR-1; 01-24-2020 at 07:12 PM.

01-24-2020	#2
tnova Join Date: Oct 2013 Location: Spokane Valley, WA Posts: 115	Re: Sitting here in the doldrums of Winter and this is the thought that came to mind. I put the complete 140-8337 front brake kit on my '91 with the 140-8314 hat and rotor kit on the back, retaining stock calipers in the rear. Wilwood originally said would work with the stock master cylinder however I could not dial out enough rear brake with the the bias valve I installed to keep them from locking up first. The spring replacement is the opposite of the direction you need to go because it puts in more rear brakes. Called Wilwood and they corrected themselves that '90 and '91 had small bore master cylinders and they aren't big enough to push the volume needed on the front for balanced braking. They added that even with a later model C4 master cylinder, I would still need a bias valve to take out rear brakes but it works. Again, no bias spring as that goes in the opposite direction needed. My solution was to use the old school C4 racer's solution and put on a later model Camaro master cylinder that has a 1" bore. You need a spacer to between the mounting ears and brake diaphragm housing to keep piston rod depth correct. You also need to clearance the inner fender edge slightly so it doesn't hit the master cylinder reservoir. Brake end fittings and lines need to be changed too. A lot of work but my car now stops fantastically. Instead of going through the Camaro master cylinder swap, just use the later C4 larger bore master cylinders and it should work according to Wilwood but don't use the bias spring upgrade and you still may have to put in a bias valve unless you use the Wilwood rear calipers too. Tony (Tnova)

01-24-2020	#3
tnova Join Date: Oct 2013 Location: Spokane Valley, WA Posts: 115	Re: Sitting here in the doldrums of Winter and this is the thought that came to mind. And yes, they fit under my 17" sawblades.

01-24-2020	#6
EvanZR1 Join Date: Nov 2010 Location: Omaha Posts: 402	Re: Sitting here in the doldrums of Winter and this is the thought that came to mind. I keep thinking one of these days I'm going to pull one of my front Shelby wheels off and see if they will clear the 14" Wilwood setup (using the Wilwood template). __________________ Evan 2023 70th C8 HTC, 94 Admiral Blue ZR-1 SOLD - 2012 Carlisle Blue Metallic ZR1 - 800HP SOLD - Steel Blue 91 391cid ZR-1 #391 SOLD - Black 91 ZR-1

01-24-2020	#7
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,136	Re: Sitting here in the doldrums of Winter and this is the thought that came to mind. I have the 13" kit int he front.. still using the OEM Master as well. I have a 92 master with the Bias Spring, but never got it installed.. I had a camaro master on my 89.. Wow that one worked well.. Still might do the master upgrade at some point __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - 3" Magnaflow Bullet cats - LT4 Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978

01-25-2020	#8
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,704	Re: Sitting here in the doldrums of Winter and this is the thought that came to mind. I installed Wilwood 6 piston Superlites up front w/ 14” rotors and 4 piston Superlites in the rears w/ 13” rotors. I think later ZR-1s had 15/16” bore MC. I bought a Camaro MC w/ 1” bore but concluded that I would have to rig up another brake fluid reservoir because Camaro reservoir did not have a nipple to accommodate ABS pump priming. Also, did not want to mess with re-routing brake lines to the opposite side. OEM MC works fine. I thought 1” would reduce the pedal travel and firm up the pedal but concluded it to be too much work considering all worked very well as is.