300zx brake cover. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Drift Style S14 · 06-21-2003, 12:26 AM

just wondering if you guys thought it would be worth it to do the coversion on all the brakes (fronts and rears). would there be a noticable difference than just haveing stocks in rear?

*AceInHole* · 06-21-2003, 05:49 PM

when I did the Q brakes on my car I did all 4 to make sure not to ruin my brake bias...

my thoughts on the z32 brakes: people do just the fronts and claim it works fine (a friend of mine runs z32's up front and stocks in the rear and likes it), but then they'll say not to change the master cylinder as it'll ruin brake bias a lot. After having swapped the MC myself and noting the huge difference, I personally wouldn't want to do just the z32 fronts and not swap the MC, but then again, I've already done the hard part to the rear conversion (the e-brakes).

in the end: the rears aren't a necessity, but IMO, it's worth it.

theronin · 06-21-2003, 11:58 PM

I (like Ace said) have swapped only the fronts to z's... however i am one that chose to also swap the master cylinder! it wasnt terribly hard and it made my brakes feel so much better! i drove them with the stock mc and with the new mc and it is night and day. Asad over at freshalloy broke the bais down numerically and showed us that the difference was miniscule at best between our master cylinders! i however didnt do the rears seeing as how i dont think right now i want to dive that deep into the world of messing with my ebrake. one day i will though.... one day.

Drift Style S14 · 06-22-2003, 09:37 AM

whats the problem with the e-brake??? so when doing the covertion i need to remember to change the master cylinder also.

old_s13 · 06-22-2003, 01:47 PM

I had Z32's up front on my `90 S13 and it worked, but the pedal feel was very vague and at the same time, it was very sensative. Locking up the front brakes was TOO easy.. even with 225/50/16 wheels with sticky tires, those calipers are just too strong for that master cylinder.

I then installed the rear Z32 brakes and noticed a good difference, however, there was too much power in the rear now and the back would lockup under extreme braking -- NOT SAFE, NOT GOOD.

I then installed the larger of the two Z32 MC's and the car works perfectly. In retrospect, I wouldnt do the front Z32 brake upgrade unless I did the ENTIRE 5-lug, wheel/tire, and brake upgrade -- on all fours -- plus MC.

With the current setup, I have NO complaints.

- Mike

AKADriver · 06-22-2003, 07:11 PM

The bias issue is a bit nebulous since it's due a lot to preference.

Whenever this comes up, I like to point out the stock S14 Silvia K's/200SX turbo brake system:

Front caliper: OPF25V - identical to 300ZX iron 30mm
Rear caliper: CL11H - identical to S14 240SX, larger piston than S13 CL9H
Master cylinder: 15/16" bore (1" with ABS), 3.9 kPa split, 0.4 reducing ratio

Now this explains a lot...

Softness is simple. 240SX master cylinders are one size smaller (7/8", 15/16" with ABS). The only exception are '97-'98s with automatics, which got the 15/16" with or without ABS.

The split point and reducing ratio are the SAME as the 240SX master cylinders. So why did Mike feel front bias?... Because S13 REAR calipers have tiny little pistons! The S14 rear caliper piston is just a smidgen bigger, even though the rotor and pad are the same.

My personal plan for a budget brake upgrade is to replicate this S14 Silvia K's system, though I might use the 26mm aluminum Z32 caliper since the rears will still fade first. I will be swapping on S14 240SX rear calipers as part of it to keep my bias in check, and I'll use a 15/16" or 1" master cylinder with the 3.9/0.4 bias setup, whatever I can get one from.

The S15 Silvia Spec-R/200SX turbo also used that same system, so hey, if it was good enough to stay in production for 9 years, it's good enough for me.

old_s13 · 06-22-2003, 07:27 PM

AKAdriver> I did not have a problem with the front/rear brake ratio until AFTER I installed the rear Z32 brakes.

The original MC was 7/8" and worked "decently" with the 300Z front calipers. When upgrading to Z brakes, I feel you NEED to upgrade the tires. Using Z brakes with 15" rims is unacceptable unless you are running some wide and sticky 15" wheels/tires, which I dont think are too common. Back then, I ran 225/50/16x7.5 and it was acceptable.. much better grip than that of the old 15" setup. At high speeds, this setup worked fine.. but once you hit the streets, I would have a VERY tough time being able to modulate the pedal.. especially at lower speeds/panic stops.

I later upgraded to my current setup: 245/45/16x8 wheels and tires, front and rear Z32-TT brakes. As soon as I installed the rear caliper setup, THAT was when I had a serious problem with the f/r proportioning -- the rear was just TOO strong. Having the rear end of your car break-out while slowing down to exit the freeway will DEFINATELY wake you up during your morning commute! That is when I knew I had to do something with that issue, either get another MC or proportioning valve, etc.

So I got a Z32 MC and installed it, it was 100% bolt on.. all I had to do was unplug one of the ports, it was already threaded and had a seat for the fitting. Bled, installed, and test it out -- what an AMAZING improvement. That is when I learned JUST how much better the MC can improve the feel of the brake system. Now, the brake pedal is ROCK HARD. If you jab the brakes, they wont lockup.. it takes some serious muscle to lock up the brakes -- EXCELLENT.

The 7/8" MC had more pressure but less pedal travel. The larger 1 1/16" Z32 MC has less pressure going to the calipers, correct proportioning, and more useable pedal travel. I can jab the brakes and have a very firm pedal with excellent feedback, I am extremely pleased.

So, thats my experience.. good luck!

AKADriver · 06-22-2003, 07:39 PM

Ah. I misinterpreted "locking up the front brakes was TOO easy" - I thought you meant you were experiencing slight front bias. Yeah, my current tire setup is basically just enough for the stock brakes, any multi-piston front caliper/11" rotor setup would overpower the 205/60-15 street tires with ease. Thankfully (?) Z brakes force you to upgrade wheels anyway. Probably at that point I'll run 225/50-16 R compounds at the track.

The 7/8" master cylinder is the achilles heel of any simple upgrade. If anyone takes anything away from all this it's that it's just not enough for big stuff. Even the basic upgrades like the Maxima/180SX setup should at least go to 15/16" to keep the pedal feel up.

Drift Style S14 · 06-22-2003, 09:47 PM

ok from what i have read here, its very clear that when doing the 300zx brake swap, regardless if its the front or all four, that i am going to also need to swap the master cylinder from the 300zx.

Now where can i find the master cylinder? would a working one from a junk yard be ok? is there a certain year i should look for?

06-21-2003, 12:26 AM	#1
Drift Style S14 Zilvia Addict Join Date: Sep 2001 Location: ............ Age: 42 Posts: 602 Trader Rating: (0) Feedback Score: 0 reviews	300zx brake cover. just wondering if you guys thought it would be worth it to do the coversion on all the brakes (fronts and rears). would there be a noticable difference than just haveing stocks in rear?

06-21-2003, 05:49 PM	#2
AceInHole Autox Technician Join Date: Dec 2001 Location: New Haven, CT Age: 44 Posts: 3,961 Trader Rating: (0) Rides Gallery: AceInHole Feedback Score: 0 reviews	when I did the Q brakes on my car I did all 4 to make sure not to ruin my brake bias... my thoughts on the z32 brakes: people do just the fronts and claim it works fine (a friend of mine runs z32's up front and stocks in the rear and likes it), but then they'll say not to change the master cylinder as it'll ruin brake bias a lot. After having swapped the MC myself and noting the huge difference, I personally wouldn't want to do just the z32 fronts and not swap the MC, but then again, I've already done the hard part to the rear conversion (the e-brakes). in the end: the rears aren't a necessity, but IMO, it's worth it. __________________

06-22-2003, 09:37 AM	#4
Drift Style S14 Zilvia Addict Join Date: Sep 2001 Location: ............ Age: 42 Posts: 602 Trader Rating: (0) Feedback Score: 0 reviews	whats the problem with the e-brake??? so when doing the covertion i need to remember to change the master cylinder also.

06-22-2003, 01:47 PM	#5
old_s13 BANNED Join Date: Nov 2001 Location: Los Angeles, CA. Posts: 2,824 Trader Rating: (0) Feedback Score: 0 reviews	I had Z32's up front on my `90 S13 and it worked, but the pedal feel was very vague and at the same time, it was very sensative. Locking up the front brakes was TOO easy.. even with 225/50/16 wheels with sticky tires, those calipers are just too strong for that master cylinder. I then installed the rear Z32 brakes and noticed a good difference, however, there was too much power in the rear now and the back would lockup under extreme braking -- NOT SAFE, NOT GOOD. I then installed the larger of the two Z32 MC's and the car works perfectly. In retrospect, I wouldnt do the front Z32 brake upgrade unless I did the ENTIRE 5-lug, wheel/tire, and brake upgrade -- on all fours -- plus MC. With the current setup, I have NO complaints. - Mike

06-22-2003, 07:11 PM	#6
AKADriver Post Whore! Join Date: May 2002 Location: Springfield, VA Age: 43 Posts: 3,517 Trader Rating: (1) Feedback Score: 1 reviews	The bias issue is a bit nebulous since it's due a lot to preference. Whenever this comes up, I like to point out the stock S14 Silvia K's/200SX turbo brake system: Front caliper: OPF25V - identical to 300ZX iron 30mm Rear caliper: CL11H - identical to S14 240SX, larger piston than S13 CL9H Master cylinder: 15/16" bore (1" with ABS), 3.9 kPa split, 0.4 reducing ratio Now this explains a lot... Softness is simple. 240SX master cylinders are one size smaller (7/8", 15/16" with ABS). The only exception are '97-'98s with automatics, which got the 15/16" with or without ABS. The split point and reducing ratio are the SAME as the 240SX master cylinders. So why did Mike feel front bias?... Because S13 REAR calipers have tiny little pistons! The S14 rear caliper piston is just a smidgen bigger, even though the rotor and pad are the same. My personal plan for a budget brake upgrade is to replicate this S14 Silvia K's system, though I might use the 26mm aluminum Z32 caliper since the rears will still fade first. I will be swapping on S14 240SX rear calipers as part of it to keep my bias in check, and I'll use a 15/16" or 1" master cylinder with the 3.9/0.4 bias setup, whatever I can get one from. The S15 Silvia Spec-R/200SX turbo also used that same system, so hey, if it was good enough to stay in production for 9 years, it's good enough for me.

06-22-2003, 07:27 PM	#7
old_s13 BANNED Join Date: Nov 2001 Location: Los Angeles, CA. Posts: 2,824 Trader Rating: (0) Feedback Score: 0 reviews	AKAdriver> I did not have a problem with the front/rear brake ratio until AFTER I installed the rear Z32 brakes. The original MC was 7/8" and worked "decently" with the 300Z front calipers. When upgrading to Z brakes, I feel you NEED to upgrade the tires. Using Z brakes with 15" rims is unacceptable unless you are running some wide and sticky 15" wheels/tires, which I dont think are too common. Back then, I ran 225/50/16x7.5 and it was acceptable.. much better grip than that of the old 15" setup. At high speeds, this setup worked fine.. but once you hit the streets, I would have a VERY tough time being able to modulate the pedal.. especially at lower speeds/panic stops. I later upgraded to my current setup: 245/45/16x8 wheels and tires, front and rear Z32-TT brakes. As soon as I installed the rear caliper setup, THAT was when I had a serious problem with the f/r proportioning -- the rear was just TOO strong. Having the rear end of your car break-out while slowing down to exit the freeway will DEFINATELY wake you up during your morning commute! That is when I knew I had to do something with that issue, either get another MC or proportioning valve, etc. So I got a Z32 MC and installed it, it was 100% bolt on.. all I had to do was unplug one of the ports, it was already threaded and had a seat for the fitting. Bled, installed, and test it out -- what an AMAZING improvement. That is when I learned JUST how much better the MC can improve the feel of the brake system. Now, the brake pedal is ROCK HARD. If you jab the brakes, they wont lockup.. it takes some serious muscle to lock up the brakes -- EXCELLENT. The 7/8" MC had more pressure but less pedal travel. The larger 1 1/16" Z32 MC has less pressure going to the calipers, correct proportioning, and more useable pedal travel. I can jab the brakes and have a very firm pedal with excellent feedback, I am extremely pleased. So, thats my experience.. good luck!

06-22-2003, 07:39 PM	#8
AKADriver Post Whore! Join Date: May 2002 Location: Springfield, VA Age: 43 Posts: 3,517 Trader Rating: (1) Feedback Score: 1 reviews	Ah. I misinterpreted "locking up the front brakes was TOO easy" - I thought you meant you were experiencing slight front bias. Yeah, my current tire setup is basically just enough for the stock brakes, any multi-piston front caliper/11" rotor setup would overpower the 205/60-15 street tires with ease. Thankfully (?) Z brakes force you to upgrade wheels anyway. Probably at that point I'll run 225/50-16 R compounds at the track. The 7/8" master cylinder is the achilles heel of any simple upgrade. If anyone takes anything away from all this it's that it's just not enough for big stuff. Even the basic upgrades like the Maxima/180SX setup should at least go to 15/16" to keep the pedal feel up.

06-22-2003, 09:47 PM	#9
Drift Style S14 Zilvia Addict Join Date: Sep 2001 Location: ............ Age: 42 Posts: 602 Trader Rating: (0) Feedback Score: 0 reviews	ok from what i have read here, its very clear that when doing the 300zx brake swap, regardless if its the front or all four, that i am going to also need to swap the master cylinder from the 300zx. Now where can i find the master cylinder? would a working one from a junk yard be ok? is there a certain year i should look for?