280ZX rear caliper Race Pad?

[duragg]

Installing the 280ZX rear calipers on my 240 and trying to pro-actively avoid some of the Bias problems associated with the Toyota S12W front caliper combination.

I've never bought "race pads". 

I was going to try to install some very aggressive rear pads to help improve the bias.

 

Wo what are good "race pads"?

Porterfield the way to go??

They have a Full Race R4 pad, or a Hi-performance Streed R4S pad?

 

Any input on which would have maximum stopping power without needing to get warmed up or be filthy / noisy?

[beermanpete]

We have used the R4 in the front (stock brakes) and they make a lot if noise until hot. Street use will not get them hot enough to quiet down. Try the R4S pads instead, they are the recommended street pad.

[Miles]

I tried Porterfield RS4 pads on my 240Z (Toyota vented front, 240SX rear brakes).  Even though they are  street pad, they didn't have enough cold bite for street use. Even after making a number of "warming stops" they still didn't do well on the street.

 

By the way, I could never get the Toyota S12W vented and 240SX rear brake setup balanced. The rear 240SX calipers (similar to 280ZX) can not keep up with the S12W vented front brakes. It is a known problem discussed many times in the brake forum. Research this before you pull your drums off and change the master cylinder etc.

 

I have since gone  back to stock front brakes with the 240SX rear calipers using  Hawk HPS pads (Hawk Blues) front and rear. The Hawk HPS pads  have good cold bite and I don't have to heat them up.  They are a bit more dusty though and they are quiet.

[duragg]

I'm for sure committed to S12W and 280zx rears no matter what.

Have to make something work.

 

Thinking....

Why not run an end-mill into the front pads to degrade them a little?

Why bother putting in my Wilwood PV at all?

Or I will just start cross drilling hole in the rotors...

 

Thx for ur input. Sounds like no easy kill with pads.

[RebekahsZ]

I have stock front system and Maxima rear disc conversion.  Running R4S all 4 corners and am happy with how it stops-no squeeling.  I have drilled out the stock proportion valve and installed a Wilwood adjustable prop valve.  Even with the prop valve all the way open, I cannot get the rears to lock in either wet or dry.  I have tried Ceramic pads and R4 pads on my drifting handbrake caliper in the back (another Maxima caliper).  I can't get it to lock with either pad material unless I am already in a turn.  I wasn't happy with the R4, so I tried the ceramic hoping for improved cold performance, but they are worse than the R4.  I think that the dust on the rotor is important, so the mixed pad type may actually be compounding the problem.  It is on my list to go back to 100% porterfield.  They are dusty as heck, but I'm happy with how the car is stopping, even though I need more rear bias.  The Porterfields do improve with heating.  The slow-down portion of all my local tracks is really short, so I'm standing on the brakes from 126mph and am having no trouble.  Hoping for similar performance going around cones in the parking lots this spring. I haven't found anybody yet who could lock their Maxima, 240sx, or 280zx rear calipers.

[duragg]

Its fun to search all the other car forums and see what other guys are doing.

We aren't the only car with bias issues.  The Miata guys seem to be in the same boat, and the ones that race in certain classes have front excess bias.

They are limited to the mods and from reading between the lines only a few will admit to exactly how they are cheating.

 

But, They mill a large or larger slot or slots in the front pads.  Reduces pad area and helps them change bias.

Seems a bunch of guys in the "stock car" forums do the same thing to get heavy rear bias and more tail happy.

 

So, yea spend Bucks on perfectly balanced Wilwoods or other options like Silvermine.

Or live with crappy unbalance.

Or get creative and see how it goes.  Not much to lose I guess.

[duragg]

Interesting test:  http://www.stockcarracing.com/techarticles/scrp_0412_race_car_brake_bias/viewall.html

[h4nsm0l3m4n]

I run S12Ws on the front and 280zx rear calipers.  I've tried a couple combinations with varying results.  I used this with an adjustable proportioning valve fully open and a 15/16 master cylinder.  All of them dust a bit but thats fine for me.  I havent heard any of them produce much/any noise.  These are all more aggressive "street" pads.  In my opinion these are actually harder to figure out because there is less information available from manufacturers and some pads work better than others for regular everyday driving.  Pretty much none of the below pads would work well from real road race applications.  Finding an optimal autox setup is what I'm going for here. 

 

If youre interested in running real road racing brake pads I would recommend Carbotech or Hawk.  Both have a lot of compounds to choose from so by talking with them and some trial and error you should be able to get a setup that works well.  We run Carbotech XP10s on our RX7 chumpcar, the brakes are awesome and have been bulletproof so far.

 

Front - Hawk HPS, Rear - Hawk HPS

As you would expect, pretty heavily front bias

 

Front - Hawk HPS, Rear - Hawk HP+

This was interesting.  Dead cold this felt really good, however once up to temp the HP+ pads have so much initial bite that the rears would lock up really quickly.  It was difficult to modulate the brakes to prevent lock up.

 

Front - Hawk HPS, Rear - Axxis ULT

My compromise setup.  Internet reports ULTs having a bit more bite than the HPS.  The front bias has returned but may be a little less pronounced.  ULTs are also a ceramic pad so are a little more heat resistant than the HPS.  Could be useful for some of the high speed autox events I attend.

 

Things I'd like to try:

Front - Axxis ULT, Rear - Hawk HP+

The HP+ pads are still probably to aggressive relative to the ULTs but may be worth a try.  I actually have the pads to do this but have not bothered yet.

 

Carbotech AX6s are supposed to be a good pad too but I havent tried them.

 

Redesign my brake brackets to use NA z31 rear rotors (instead of 280zx) and 280zx rear calipers

These rotors have a bit more diameter which would increase braking torque by quite a bit.  It could really help with getting the most out of our 280zx rear calipers and could really improve brake bias.

Edited January 7, 2013 by h4nsm0l3m4n

[duragg]

Is your Parking Brake hooked up?

I haven't rigged mine yet.

 

How effective is the parking brake?  If you reef on it can you lock up the rears?
Tj

[h4nsm0l3m4n]

Yes, it is hooked up and seems to work well enough to hold the car on a hill.  Its not that great but if I adjusted the parking brake right I may be able to get it to lock the rears.  To be honest I've never tried to use the parking brake to lock up the rears.  I've never needed to use this method to make the rear come around...

[duragg]

I guess I miss the days of my 48hp 1979 Diesel Rabbit whose parking brake was used extensively for maneuvering (I was 16...).

Saved my ass several times..

 

Now that I think of it,  my Gen2 Rx7 had a great parking brake too.

 

On several occasions a rapid course reversal was advantageous.  I am older now and don't get into the same crap I used to.

 

jT

[duragg]

I bled the rears proper and today I was getting nearly simultaneous 4 wheel lockup.

From reading the rotors, the pads aren't anywhere near fully seated yet, so all this will probably change.

 

Indicator that I may be close enough on bias to not require any special steps.

[duragg]

Wow. I switched to Hawk HT10 pads in the rear early 280ZX caliper and rotor and now barely pulling the e-brake locks up the backs EASILY.  I have my Brake Proportioning valve turned about 3/4 out (less rear).

 

Front are Toyota S12W / Vented with Hawk Ceramic pads. (wanted good heat resistance but less "bite" in front).

 

This is primarily a track car now and the stock pads were RUINT after a few HPDE sessions.

This should give me more heat resistance along with with Hawk Blue juice and some adjustability.

Pads made a huge difference on this setup.

Tj

Edited April 29, 2013 by duragg

[m1ghtymaxXx]

What year 280ZX calipers are you using?

[duragg]

I have the 79-81 style giant King Crab looking ones.

For the record I also replaced the hard lines from rear junction to rear wheels and installed -4 stainless hydraulic flex lines. I also have deleted to stock BPV and plumbed the Wilwood BPV.

 

I got the rear HT10 from Porterfield. They had one set on the shelf by chance.

Bedded in and blasted off.

[RedNeckZ]

   I am running the 300zx up front and 280zx early model calibers with later model rotor (short hat) on the rear.  I moved the rear brake pressure (above the rear axle) over and reattached to the brake line.  I run stainless steel brake hoses on the front and standard rubber brake lines on the rear.  On the street I run a semi-metal on the front and standard organic pads on the rear.  I do not have a adjustable valve on it.  I track it a lot and haven't had a problem with it overheating on me.  It gives me a very neutral feel with the brakes.  So try to run a better pad up front and a lesser pad on the rear.  With the old brakes (stock) I would come off the track with no brakes at all.  I would have to bleed them before I could go back out on the track.  Your front brakes take up most of braking action, so do as much as you can to cool them (brake cooling duct).   I got my info for this a few years back from the old president of the texas club.  He gave a paper out on this subject during a Z car convention.  About the rear hand brake, what I did was moved the brake cable to each other side and attached.  I then added a small section of small round pipe to the adjustment area, it went between the adjusting nuts and the adjusting rod.  If you need a copy of that paper, just contact me and leave a address to send it to.  Good Luck with it, Rich.