Big Brakes

[tonycharger72]

Wanted to get some opinions from follow members on a brake setup for my 260z,

 

Fronts:

314 by 30mm Rotor - Vented & Slotted

R32 GTS-T Caliper (4 Piston - 41mm Pistons)

or

320 by 32mm Rotor - DBA4000 Slotted

R32 GTR Caliper (4 Piston - 41mm Pistons)

Or,

Use the above rotor with OUTLAW 2800 series with even 41.5 pistons to suit 32mm discs (got offered some new for $400AUD),

I like the idea of using new Calipers, but dont know if the 2800's would be good to use with the following rear brake kit,

 

Rears:

XF Falcon Rear Brake Kit

286 by 24mm Rotor - Vented & Slotted

Single Floating Caliper (40mm single floating piston - from memory)

This is a rear brake setup from an XF Ford Falcon and has a provision for the handbrake,

[Jsquared]

I'm pretty sure the R32 GTS-t brakes are the same as USDM Z32 brakes (seeing as I have a set that are about to go onto my 240SX), so the front rotor is 280mmx30mm (unless you meant using the GTS-t caliper on a larger rotor). Piston size is 40.45mm as well, but that's just nit-picking, sorry. I can help though Go to the forums on Freshalloy.com and go to the "Best of 240SX" section, and look for a thread about brake bias by Asad. Great info there, you can use that guideline to calculate your own brake bias (compare to stock) and see what kind of brake torque increases (percentage-wise) you'd get.

[tonycharger72]

Thanks heaps for the link mate,

 

This is what ive figured out, there are some approximations, as im not 100% certain about the falcon rear brakes pad size or piston size, but i think they would be pretty close to what ive put down - also, the GTR calipers are thicker, but they have the same sized pistons as the Z32/GTS Calipers, but i dont know if they use bigger pads???

So, the info below is probably not 100% correct, it should be close enough to be useful,

Option 1:

314mm Rotors & R32 GTS Calipers

 

- 4 piston fixed caliper

- 40.45mm piston diameter

- 314mm diameter rotor

- 50mm wide pad

 

Effective rotor diameter: 314-50 = 264

effective piston area: 40.45^2 x 4 = 6545

"brake torque": 1727880

 

Stock 300zx/240sx rear brakes:

 

- Single piston sliding caliper

- 34mm piston diameter

- 290mm diameter rotor

- 40mm wide pad

 

Effective rotor diameter: 250

effective piston area: 34^2 x 2 = 2312

"brake torque" = 578000

 

Front Brake Bias = 1727880/(1727880+578000) = 0.75%

Rear Brake Bias = 1-0.75 = 0.25%

 

Option2:

 

314mm & R32 GTS Calipers

 

- 4 piston fixed caliper

- 40.45mm piston diameter

- 314mm diameter rotor

- 50mm wide pad

 

Effective rotor diameter: 314-50 = 264

effective piston area: 40.45^2 x 4 = 6545

"brake torque": 1727880

 

XF Falcon Rear Vented Rotor Modified to suit (286mm by 24mm)

 

- Single piston sliding caliper

- 40mm piston diameter

- 286mm diameter rotor

- 45mm wide pad

 

Effective rotor diameter: 286 - 45 = 241

effective piston area: 40^2 x 2 = 3200

"brake torque": 771200

 

Front Brake Bias = 1727880/(1727880+771200) = 0.69%

Rear Brake Bias = 1-0.69 = 0.31%

 

Option 3:

 

320mm Rotor R32 GTR Calipers

 

- 4 piston fixed caliper

- 40.45mm piston diameter

- 320mm diameter rotor

- 50mm wide pad

 

Effective rotor diameter: 320-50 = 270

effective piston area: 40.45^2 x 4 = 6545

"brake torque": 1767150

 

XF Falcon Rear Vented Rotor Modified to suit (286mm by 24mm)

 

- Single piston sliding caliper

- 40mm piston diameter

- 286mm diameter rotor

- 45mm wide pad

 

Effective rotor diameter: 286 - 45 = 241

effective piston area: 40^2 x 2 = 3200

"brake torque": 771200

 

Front Brake Bias = 1767150 / (1767150+771200) = 0.69%

Rear Brake Bias = 1-0.69 = 0.31%

 

Option 4:

 

320mm Rotor & OUTLAW 2800 Series Calipers

 

- 4 piston fixed caliper

- 41.2 piston diameter

- 320mm diameter rotor

- 42.8mm wide pad

 

Effective rotor diameter: 320-42.8 = 277.2

effective piston area: 41.2^2 x 4 = 6789.76

"brake torque": 1882121

 

XF Falcon Rear Vented Rotor Modified to suit (286mm by 24mm)

 

- Single piston sliding caliper

- 40mm piston diameter

- 286mm diameter rotor

- 45mm wide pad

 

Effective rotor diameter: 286 - 45 = 241

effective piston area: 40^2 x 2 = 3200

"brake torque": 771200

 

Front Brake Bias = 1882121/(1882121+771200) = 0.71%

Rear Brake Bias = 1-0.71 = 0.29%

 

 

So, there isnt much difference at all between any of the above setups - goes from about 75% front bias to about 69%

[tonycharger72]

I suppose to compare the above setups, i would need the original 240-60-80z brake bias, anyone know that???

[JMortensen]

It doesn't really matter what the original brake bias was, unless you want to match it perfectly for some reason. As long as you can get it in the neighborhood you should be fine, then use an adjustable proportioning valve to fine tune from there. You might be able to use this spreadsheet: http://sth2.com/Z-car/Brakemath.xls It is set up for a full race car with dual masters, but if you plug in the same value for the masters it will give you an idea of where the balance will be with respect to braking g forces.

[BlackBeaut]

Hope you don't mind if I slightly hijack this thread but on the topic of adjustable bias valves, are these use in conjunction with the OEM bias valve or does it completely replace the OEM valve? Strikes me that it should just replace it.

 

And... once in place how do you go about setting it up? Is it a matter of finding a quiet road and slamming the anchors on until the fronts lock just before the rear, or is there a more technical approach? I've currently got a homebrewed front set up (4 pot brembos on a 305x28mm disc) and I'm planning on using Z32 rears, 297x18mm.

 

Cheers,

Rob

[JMortensen]

You have to remove the original valve, then test as you describe. Better to test when it's wet for a street car, otherwise you might be in for a surprise at the first rain. If it just isn't raining, figure out where the front locks first, then give a little bit of a safety margin.

[BlackBeaut]

You have to remove the original valve, then test as you describe. Better to test when it's wet for a street car, otherwise you might be in for a surprise at the first rain. If it just isn't raining, figure out where the front locks first, then give a little bit of a safety margin.

 

Thanks Jon, much appreciated.

 

Cheers,

Rob

[Phantom]

Jon,

I assume just gutting the OEM proportioning valve and then adding the APR in the rear brake line will accomplish the same thing as a complete removal of the OEM valve?

Bill

[JMortensen]

Yes it will. The 240's are easy to gut. You can unscrew the guts right out of the side of the valve, cut them off, and put the bolt back in. Not sure about the 280's.

[tonycharger72]

Jmortensen, thanks for the spreadsheet mate,

 

 

Just curious, the bloke from the freshalloy.com brake link said the pedal will start to get a bit mushy if you start going bigger than 300zx 4-spots up front and 300zx 2-spot calipers out back, i would assume this is with the stock 240sx Master Cylinder - which probably wouldnt be 1"

But,

I was speaking to an Australian Wilwood distributor and he said that if i go 4-spots on all four corners, and if i use any bigger than 41.2mm pistons on the 4-spots, a 1" Master Cylinder just aint going to cut it, i will need to go to a bigger master cylinder,

 

He said that i would need to go to the master cylinder that the VT commodore uses (1 1/16") or something like that,

or use two, 7/8" & 15/16" for front and rears,

 

Any thoughts?

 

 

Also, which is better, Outlaw or Wilwood or are they much of a muchness in-comparison to one another???

[JMortensen]

I'm trying to figure out master cylinder sizes myself right now. It's a tough one. I know that a 15/16" master works well with Toyota 4 piston calipers in front and 280ZX calipers in back (my old setup) but I can't say how the bigger caliper in the back changes that. The smaller the master the less pedal pressure required, but if it is too small then there is too much pedal travel.

 

What does the 300ZX use? At least if you knew that you could take a guess at what size you need.

 

I think the Wilwood and Outlaw calipers are pretty similar. Never seen a head to head test. I bought Wilwood because that's what the brake setup I bought suggested, not because of any allegiance to Wilwood.

[tonycharger72]

Dont know about the 300zx Master Cylinder, but i'd be surprised if it wasnt a 15/16" or 1" master cylinder, just because the 280zx used a 15/16" and it had smaller brakes than the Z32 300zx,

 

The Wilwood bloke in Aus said that he was helping a guy with a BMW brake upgrade and he said when they went to 4-spots on all four corners and used 44.45mm Pistons on the front Calipers the pedal was really really mushy, so the guy had to upgrade and he went to the 7/8" and 15/16" setup, but the bloke said you could also use the 1 1/16" (it may have been bigger) master cylinder from a VT commodore, which is of a Holden, so it is probably on some Chevy cars in the states?,

 

This is the setup im thinking off,

 

Fronts: OUTLAW 4000series

- 4 piston fixed caliper

- 47.8 piston diameter

- 320mm diameter rotor

- 46.5mm wide pad

 

Effective rotor diameter: 273.5

effective piston area: 47.8^2 x 4 = 9139

"brake torque" = 2499517

 

Rears: OUTLAW 2800 Series

- 4 piston fixed caliper

- 35.05 piston diameter

- 280mm diameter rotor

- 42.8mm wide pad

 

Effective rotor diameter: 237.2

effective piston area: 35.05^2 x 4 = 4914.01

"brake torque" = 1164618

 

Front Brake Bias = 2499517 / (1164618 + 2499517) = 0.68

Rear Brake Bias = 1-0.63 = 0.32%

 

That, or maybe go to a 300mm rotor in the rears,

Than use a Wilwood mechanical spot caliper for the Hand-brake, like the guy from this website, www.datsport.com, check out his rear brakes,

 

 

What are you going to do about the rear caliper bracket for the 4-spot calipers???

 

I figure the best way to do it would be to have a flat bracket, kinda like the ones that ArizonaZcar uses with his Wilwood setup - just because it would be the easiest to make,

But before i go out and buy the calipers i think you would have to know what rotors were available so you could get the correct overall height...............because if you use a flat bracket, the caliper is going to have a certain offset that will put the caliper in a certain position over the rotor,

so overall rotor height would be pretty important,

1 - so you dont increase your track

2 - so the caliper centres itself under the rotor

Unless you get a custom made hat made up for the rotor to get the correct overall height, but i would really like to avoid this expense,

[JMortensen]

What are you going to do about the rear caliper bracket for the 4-spot calipers???

 

I figure the best way to do it would be to have a flat bracket' date=' kinda like the ones that ArizonaZcar uses with his Wilwood setup - just because it would be the easiest to make,

But before i go out and buy the calipers i think you would have to know what rotors were available so you could get the correct overall height...............because if you use a flat bracket, the caliper is going to have a certain offset that will put the caliper in a certain position over the rotor,

so overall rotor height would be pretty important,

1 - so you dont increase your track

2 - so the caliper centres itself under the rotor

Unless you get a custom made hat made up for the rotor to get the correct overall height, but i would really like to avoid this expense,[/quote']

I bought a setup with a custom hat and caliper bracket from JSK Innovations. Unfortunately the guy who made them screwed up on his measurements and has since gone out of business from what I can tell, so it looks like I'll need a fairly thick wheel spacer in the back to get the wheel to clear the caliper. No big deal as I've got longer studs, but it shouldn't be this way. I'm just hoping the wheels stay under the fenders with the spacers on.

 

You're right that the rotor position is everything, and that making a straight caliper bracket is easier, but it is possible to weld up a bracket that isn't flat if the caliper needs to be offset in or out. My old setup with the 280ZX rear disc was like that. It had a caliper bracket that set the caliper ~3/8" inwards. It didn't look terribly complicated to make.

[Pop N Wood]

I bought a setup with a custom hat and caliper bracket from JSK Innovations. Unfortunately the guy who made them screwed up on his measurements and has since gone out of business from what I can tell..

 

Someone recently posted that he still actively sells on ebay. sure hasn't been on this board much.

[JMortensen]

Hasn't been answering emails either. His website is down. Maybe he is just selling the few fuel rails and TB spacers he has left...

[tonycharger72]

That sucks about the bracket mate,

Ive tried his website and the fonebooth one, but they both appear to have dissapeared,

 

Im betting that there will be about 1-5 rotors available that will fit all the requirements for the right caliper offset, width for the caliper..........etc,etc, on the rears, if im lucky ,

 

Just of the top of my head, i was thinking of doing this for the rears to find out what Caliper and Rotor should be easiest to fit,

 

Start by removing everything from the rears,

Then maybe use the backing plate as a guide of where you want the caliper to mount (as i want to try and use a flat caliper mounting bracket), and the caliper mounting bracket will mount were the backing plate used to,

Then take measurements of exactly where the rotor will centre itself under the caliper,

Then you will be pretty close to knowing what overall height rotor you need and then start checking places like DBA.com.au to see if they make anything close,

 

Which means you should be able to find out which calipers and rotor should work on the rears before you buy them,

[tonycharger72]

These are the prices i was quoted,

 

4-Spot with 4 equal 1.75" Pistons - Forged billet superlites to suit (1.25") rotor = $235/caliper ($470/pair)

 

& for the rears

 

4-Spot with 4 equal 1.38" Pistons - Forged billet superlites to suit (0.81") rotor = $235/caliper ($470/pair)

 

 

Wilwood Mechanical Spot Caliper to suit 15mm Disc = $129/each ($258/pair)

 

These are all Australian Prices, thats $1198AUD or $900US for 4 Brand new 4-spot calipers and 2 Mechanical spot calipers,

 

I spoke to the nice folk at the Brembo & AP racing and was quoted about $1500AUD/pair for 4-spots with 41mm & 38mm pistons, and these are like the lower end of what they sell,

But was wondering with the Wilwoods, which ones would i want???

Lug mount or radial mount calipers???

[JMortensen]

You can make your bracket for either lug mount or radial mount calipers. Lug mount would be easier, and the front caliper bolt pattern is "narrow mount" which means 3.5" between the mounting holes. If you keep the narrow mount spacing then the caliper bracket is a lot smaller. The Arizona Z Car setup http://www.arizonazcar.com/brake.html uses Superlites on the front and Dynalites on the rear. I found my calipers for ~$450. Places like http://www.behrents.com and http://www.pitstopusa.com have pretty good deals. I bet you could save some money if you could get them to ship to Oz. I didn't buy the spot calipers for my car, but I can't imagine they cost $500.

 

I think the "standard" setup is 1.75" pistons in the front and 1.38" pistons in the rear. I believe that is what Arizona Z Car sells in their kit for use with the 15/16" master.

[Jsquared]

I've only skimmed the latest bit, as you guys are getting a bit more in-depth than I needed to, but I will address the Master Cylinder question:

 

In the FreshAlloy thread, the mushy feel with Z32 calipers at all four corners is due to the small size of the stock 240SX master cylinder, which is 7/8" (ABS cars had 15/16"). The Z32 had various sizes, 15/16", 1", and 17/16"... varying by year and turbo/nonturbo, with the 1" being most common, then the 17/16"... with the 15/16" not being that common (there is also a variance in that some were Tokico and some were Nabco, and to date nobody has been able to figure that part out, since they're the same part number Sometimes Nissan just does things weird). Look at the percentage increase in piston area at the calipers, and I think you'd want to shoot for a similar percentage increase in master cylinder size.