300zx Brakes. If you have them, POST HERE!

[Jeff240sx]

This thread was inspired by a post in another thread. I just didn't wanna hijack the other thread, so here's mine.

Originally posted by Tyler Durdan
Quick question:

Is your brake pedal real mushy feeling? I just put mine on, and have bleed the fronts pretty damn well, and the brake pedal feels incredibly mushy...I know it's the norm for them to be mushy feeling, but I don't know if it's supposed to be this mushy. Any thoughts or suggestions would help.

I have always wondered why people have mushy brake pedals from a z32 swap. So I figured that if we put our minds together, we can figure it out.

First off, my setup is on a s14 (1996)
Calipers:1991 z32 TT calipers. Aluminum, 30mm.
Rotors: X-drilled and slotted Brembo rotors.
Pads: EBC Greens and currently Hawk HP.
Lines: PDM-racing conversion lines.
Master Cylinder: Stock

As far as mushyness goes, it's not at all mushy. I have only bled my lines once, and that was during the install.

I am also against using a z32 Master Cylinder, because it was setup for a z32, and not a 240sx with a super-heavy front bias in braking. It is usually required to swap all 4 calipers to use a z32 MC safely.

If everyone else could post their setup, and mushyness level, and we can (hopefully) figure out a solution or cause.
-Jeff

[Foxcolt]

26 mm Z32 brakes. Stock modified lines (To cold to put right one's on) Brembo blank rotors.

Little bit mushier than stock. Not something that was noticable enough to not like. No biggie

[Dousan_PG]

mine:
30mm TT front brakes
stock z rotors
earl's SS brake lines
oem pads (?)

rear: stock
KVR pads

mine are slightly mushy but not HORRIBLE. i have to add my rear ss lines still but fronts are SS lines, stock z rotors and i dont know what kind of brake pad (oem?). anyways, i like it how it is. if its too firm it can be TOO responsive. especially on the track. idont want to lock up the fronts when i just need slight slowing down. i like them how they are. more pressure means moer braking power. slight pressure just slows it down a bit, which can be perfect depending on situation.

[Foxcolt]

I did notice how easy it is to lock up the fronts. I deffinatly don't like that.

I do think the z32 MC is a good idea. That's what I plan on doing once I get my rears in. Fooking drum brakes...Hate em

[Tyler Durdan]

91 300zx front aluminum calipers
front 30mm Stock Rotors
Stock 300zx Lines
OEM Pads
Mushy as hell.

One thing I'm noticing is the ss lines...maybe that's the solution to my problem. I'm gonna bleed the rears to see if it cures the problem. I'll let you know.

On a side note, thanks to Jeff for the start of this thread.

Mark

[brage]

I installed mine, and the mushyness factor is VERY low... A common problem is people installing the calipers upside down (with the bleeder screw at the bottom as opposed to the top which causes problems. There have been numerous posts regarding this on twinturbo.net!


SO... MAKE SURE YOUR BLEEDER SCREWS ARE ON THE TOP OF THE CALIPERS WHEN INSTALLING THEM!!! otherwise it is nearly impossible to bleed the top half pistons!

-jeff

[Tyler Durdan]

Bleeder screws are installed on top...my thought is the air got into the system during the install, and somehow made it's way through the rear brake lines...so I'm gonna give those a bleeding to see if it cures my problem.

[uiuc240]

You always have to bleed ALL brakes...not just the fronts. When you do the swap, the lines get disconnected...that's all you need for a reason to bleed all the lines.

I have:

26mm calipers, KVR pads, SS lines, KVR rotors, Russell speed bleeders.

My pedal is very firm except for the bit of play at the top of the travel...and I'm used to that now. I *do* want the rear brakes and a Z32 MC, though.

Eric

[Kid Zelda]

Set up on an 89 S13

Z32 front Aluminum 30mm calipers

Z32 rear Aluminum calipers (Also, I think all rear Z32 calipers are aluminum, does anyone know if Nissan changed the material to iron, when they changed the front calipers to iron ? )

Rotors are brembo blanks that need to be replaced soon
Pads are OEM Nissan pads

SS custom brake lines.

Need to bleed the brakes a bit more, but the pedal feel is a bit mushy. I only drove the car around the block, since I just got the car running


Can't wait for Z32 M/C, new rotors and good pads

[AKADriver]

I've noticed that noone is mentioning if they have ABS or not.

It makes a difference... there are different stock master cylinder sizes.

AFAIK:
'89-'96 non-ABS: 7/8"
'89-'96 ABS, '97-'98 all: 15/16"
300ZX: 15/16" and up (most are 1")

The 15/16" master cylinder should be a-ok. The 7/8" might be a bit overworked...

For those who want a M/C upgrade for your non-ABS cars using 300ZX fronts and stock rears, a '97-'98 non-ABS M/C might be the ticket.

ABS and non-ABS master cylinders have a different number of ports and won't swap...

[brage]

I have ABS+VLSD BTW

-j

[91s13coupe]

is this upgrade really worth it??? you only get 8ft greater (60 to 0) stopping distance than the stock setup. my guess is if you by some quality crossdrilled/slotted rotors, some good pads and stainless steel lines you would get similar results (if not better) for alot less $$$$. plus a floating caliper setup has more stopping power than an equivilent fixed caliper setup. im not flaming anyone who has done this upgrade just trying to justify the price difference. to me it just seems like a "bandwagon" fad. sorry if i piss anyone off, thats not my intent!

[AKADriver]

Stopping distances should really be completely unaffected. I can lock 'em up from 70mph with the stock brakes equipped with even just decent pads.

The main benefit isn't stopping power, but the immense heat sinking capability of the bigger pads and rotors.

The extra stopping power and definitely the extra heat capability come into play when you have sigificantly more power than stock and you take your car to the track.

The S14 Silvia K's and S15 Silvia Spec-R came equipped with "300ZX brakes", stock...

[240 2NR]

There's more to brakes than simply, if you can lock them you don't need anymore. The feel from the 300zx brakes is inspiring, drive some and then decide, I think you'll be convinced. Sure, the stock brakes are competant, but they still leave room for improvement. A sportier pad helps and once warm I find the KVR's pretty amazing though they still fall behind the Z brakes. I think the larger rotor and stronger caliper allow for greater modulation in addition to the heat capacity it adds (which may or may not get utilized). Either way there is room for improvement in the stock system, you may not need it, but the Z's are a very "affordable" and easy upgrade.

[hooter]

Originally posted by 91s13coupe
is this upgrade really worth it??? you only get 8ft greater (60 to 0) stopping distance than the stock setup. my guess is if you by some quality crossdrilled/slotted rotors, some good pads and stainless steel lines you would get similar results (if not better) for alot less $$$$. plus a floating caliper setup has more stopping power than an equivilent fixed caliper setup. im not flaming anyone who has done this upgrade just trying to justify the price difference. to me it just seems like a "bandwagon" fad. sorry if i piss anyone off, thats not my intent!

I use the stock S13 brakes with good pads and good fluid with no problems so far. Have yet to experience any brake fade.

It really depends on how you drive. Some people swear by the 300zx upgrade, some can live without it. I personally don't think I could live with the mushy pedal and would want to upgrade the MC while I'm at it, which adds to the cost and complexity of the swap.

-Charlie

[91s13coupe]

thats my point. usually when i do somthing (especially when it comes to my 240) i do it right. so money is just not a factor when it comes to my car. if i have to wait to do it right because it costs more, then ill wait! but unless you seriously race your car im not convinced its worth the $1000+ dollars to convert to 300zx brakes (w/ mc, etc). granted i havent driven a 240 with the conversion,so i may be dead wrong but it just seems like alot of people are doing it cause everyone else is! and a good majority of those that have spent the bucks DONT race their cars (legally). for a potent STREET machine(or even a weekend warrior scca solo racer) i think its overkill and money that could be spent better elsewhere!

[Jeff240sx]

Ok. How about we don't hijack this thread with crap. Start a new topic in chat.
I started this thread to figure out why some people had a mushy pedal and others have a very firm pedal, minus about 1/4" of softness at the top.
Also, where did you get the distance of 6'? Is that some imaginary number to try to make a point? AFAIK, nobody has done a 70-0 stop series with stock brakes, then swapped to z32 brakes, and done a comparison 70-0 series.
And what the hell is a "floating caliper setup?" I unbolted the 240sx calipers from the 2 bolts holding them in, and installed the z32 brakes in those same 2 bolts. The calipers are installed very much the same. Are both "Floating calipers?"
It's also not $1000+ for the conversion. I did my fronts for $450, and the rears can be had for $250. The MC is a junkyard item, or AutoZone. Most people only do the fronts, but even the whole setup isn't near $1000.
Finally, brakes are the most important aspect of any sports car. I don't car about what races you participate in, or anything like that. If you drive fast, or even modify your car for more power, you need brakes.
-Jeff

[91s13coupe]

sorry we got "off topic" but i said 8 ft and actually the project silvia in i think sport compact car had a braking comparison between the stock 240 brakes and the 300zx upgrade (they did front and rear 300zx brakes) and the stopping distance was "only" 8ft less 60-0 than the stock 240 brake setup! and the 240 uses a floating caliper setup while the 300zx uses a fixed caliper setup. search and you will find an explanation of each. that little "bar" that you have to remove to do the upgrade(its called a torque member) that surrounds the calipers on the stock setup is the major component of a floating caliper setup (which are proven to be more efficient than a fixed caliper setup) because that component basically multiplies the clamping power of the brakes by providing some leverage for the caliper. sorry for the off topic stuff but i was just voicing an opinion for what its worth. im not flaming anyone for doing the swap just pointing out there are viable options without having to drop all that $$$ on the conversion!

[mrmephistopheles]

8 feet is an eternity when you REALLY want to stop.
Like Jeff said, brakes are the most important aspect of a sportscar. I add a caveat to that: Tires are the most important aspect of a braking system. You can have either stock or Brembo brakes, but if they're stopping a skinny 15" tire, it's gonna suck.
Big, wide wheels and sticky tires are not just for bling factor.

[SlowEXd]

93 NON ABS

fronts
26mm Z32
Brembo slotted
brembo pads

rear
stock calipers w/ Brembo slotted, and Brembo pads
Stainless lines all corners

Mushier than stock! Not firm enough for me.
I have bled more times than my driveway can handle,(always a little splatter)

1" Z32 master cylinder going on hopefully this weekend.
Keep you updated.

[Tyler Durdan]

Fixed the mushy problem with my setup...91 300zx fronts only.
When I bled the rear lines, there was a lot of air trapped inside. I have about a 1/8 - 1/4" of mushiness, then it's firm. I absolutely love the setup...as for the price issue...be patient and shop local junkyards. I did my entire setup for less then $200.

91 300zx calipers and rotors pulled at local junkyard: $80.00
Rotor Turning and new oem pads: $42.00
Brake fluid: $6.00
New Seal Kit for DIY Caliper Rebuild: $24.00
Total Cost: $152.00
Being able to stop constantly with no brake fade: Priceless.

Granted you can add another $100 for ss lines I'm gonna pick up, but it's still a cheap and damn good brake upgrade. An extra eight feet stopping distance is a hell of a world of difference at scca events, especially when one turn that leads right into another, and then into a sloam.

A fast car only needs a throttle...fast drivers need throttle, brakes, clutch, and a steering wheel. Quote me on that.

[Jeff240sx]

WOOT! I helped someone with this thread!
-Jeff

[Tyler Durdan]

Originally posted by Jeff240sx
WOOT! I helped someone with this thread!
-Jeff

Boowah...damn we are post whores.

*Hangs head in shame*

[LanceS13]

IIRC, SCC said their car had a rear bias (locking the rears before the fronts). If they get the proportioning right and make the fronts work harder than the rears like they're supposed to, I bet they'll cut another 10ft.

[AKADriver]

The proportioning was messed up IIRC because they were using a 240SX master cylinder with 4 wheel Z brakes.

I'll have to go back and reread the article... did they do the test of the stock braking system with fresh high-performance pads and good tires or with the worn-out stuff? I know their 300ZX brake upgrade also included a 5 lug swap with Volk GT-Ns and sticky rubber.

[LanceS13]

I'm pretty sure it was all old stock stuff. But I think they had some Spec V 17x7" wheels (assuming decent tires) on it before the GTNs. I'd like to see what happens with the Z MC and maybe a decently tuned adjustable proportioning valve.

(Sorry Jeff, I know this isn't exactly what this thread's about)

[Halz]

The SCC project car changed tires and wheels at the same time it changed brakes.. If they could lock up the wheels with the stock brakes, the 300ZX brakes would not be able to improve upon that.

[Jeff240sx]

Sure you can... The initial force 300zx brakes create is much, much more than the 240sx brakes. This means that in less pedal travel, you generate much more clamping force. And why does everyone insist that the first stop that you make should be the shortest? Sure, shorter is good, but repetition is much better. The main reason for the 300zx brakes. Initial force and fade resistance. It's not complicated people!
-Jeff

[91s13coupe]

but dont you get increased fade resistance and heat dispersion from a cross drilled and/or slotted rotor in the factory issue size?!
i bet its right there with the 300zx coversion except in the MOST EXTREME instances! which 95% of us here will never see!

[uiuc240]

cross drilling is for aesthetics ONLY. if you don't believe me, ask those who race. pads are either outgassed from the factory or made from non-gassing materials (which was the main reason for drilling in the first place). the MINOR addition of surface area for braking does not outweight the loss of material for heat absorption/radiation.

i have cross drilled. i won't get them again. extra money for basically nothing. but they DO look cool.

Eric