aznpoopy

thats a myth.

the limit to your braking is the ability to lock your wheels. if your stock brakes can lock your wheels, then guess what, you won't get any more stopping power from a bigger brake set-up. what you will get is the ability to lock your wheels with less pressure from your foot.

that's incidentally why 300zx brakes 'feel' like they stop harder. in reality, they stop the same, but you are just don't need to step on the pedal as hard.

the advantage of bigger rotors is more mass to absorb heat and more surface area to dissipate heat. once again, if you are using stock brakes and they don't fade for wahtever motorsport you're doing, bigger rotors is also just a nice but fairly pointless upgrade.

now if you ARE fading your stockers, and you are already using high temperature racing brake pads, then you have a reason to go change to a bigger brake set up.

remember, your brakes do not come in contact with the road! if we are both in s13s with identical shitty tires, and i have stock brakes and you have z32 brakes, are you telling me you are going to stop faster then me? of course not. what you will be able to do is lock your brakes quicker then me. but if we both threshold brake perfectly, we'll both stop in the same distance.

if you want to improve stopping distance, what you should be looking at is brake bias and gripper tires.

MARTIN

I am familiar with the way stopping works... Well, if you have better tires then it becomes harder to lock your tires and therefore puts more strain on the brakes... To be honest in city driving I prefered the stock brakes(refering to my other car) but once you got on the highway, it became apparent which ones brake better. noone needs to upgrade their brakes if they do daily driving and an oocational race. The way you make it seem, is that you dont need upgraded brakes. But there must be a reason why high performance cars come with bigger brakes than normal non performance oriented cars..

RETed

Gee, stupid enough to spam here too?

What is "more braking power"???
Do you have problems locking your tires up???
If so, something is WRONG with your stock brakes.

You don't know what you're trying to describe.
You don't want "more braking power" - more braking power just locks up your tire FASTER.
I bet you want "better braking feel".

Changing over to some other brakes will most likely make it worse.

You want MORE BRAKING FEEL, get a larger bore brake master.

Or change out your brake pads...



-Ted

ilike2eatricers

I dont consider this spam at all. This is a legitimate thread about a potential upgrade for the FC. I ust figured some gurus in the suspension forum might chime in also with their opinions.

You're probably right I guess I want better braking feel. Right now I have powerslot rotors, project mu pads, and stainless braided lines.

What larger bore brake master would you recommend? The only upgrade I ever heard of was the 929 cylinder upgrade but I think k2rd is gone now. Does the 929 cylinder change the brake bias much?

RoadRaceJosh

If the rotors were of significantly larger diameter I could see doing a 300ZX brake swap, but .2" in diameter doesn't cut it. The 5 lug, 4 piston brakes are quite good and bolt right on. In fact I didn't pay anything for mine. I wouldn't mind a significantly larger front rotor for the sole reason I could run more laps on streetable brake pads. It just might keep me from swapping brake pads at the track for driver training events. Working instructors get to take their own car on track during the lunch break.

jacobcartmill

iTrader: (6)

this "upgrade" would be a waste of time.

s5 TII brakes are excellent.

get some stainless brake lines and some nice pads. i have stainless lines and some decent cheap pads and i can lockup all 4 tires instantly.

cafcwest

do I HAVE to get S5 TII brakes?

Can I get S4 TII brakes? What about 88-91 Convertible brakes? 86-91 GXL brakes? 86-87 Sport brakes?

Like y0 dAwG, I want crazy tight yo braking.



/end sarcasm

ilike2eatricers

.

Snrub

iTrader: (1)

That's exactly what I was thinking. Do some research first and second think about spending your money one something that would be a good bang for the buck.

Anyone who's interested in cutom a 300ZX brake kit please PM me. Florida swamp land also available for a terrific price.

Nihilanthic

Guys, you know that friction is coefficent of friction * the normal force, right? Surface area only helps with heat dissipation. (which is a good thing!)

Piston area might change the mechanical advantage you get from the hydraulics system, but youre still limited by the pads heat range ultimately. and yeah if you can lock up your tire sooner it means you can squeeze harder at higher speeds, which is a good thing on the track.

But, in the end, I still fail to see how 300ZX brakes would be worth the expense! Its hardly bigger, the 4pot brakes are already...4pot, and good discs and pads would work just fine.

Remember, FCs are 2700 lbs cars! Youre not trying to stop a 300ZX or a camaro here.

I Hate Ricers

So...you can't lock up the 4 pot brakes at high speed? I'm just wondering, haven't tried.

And yeah, theoretically the increase in surface area won't change anything. But if the thread starter is using the larger 300zx rotors with the calipers, his leverage and heat dissapation are both going to go up, increasing the effectiveness and life of his pads and rotors. Too bad the tires won't last longer!

RETed

Check your brake master.
Most of the T2 brake masters are actually 7/8" - it's "embossed" on the bore.
The ABS units are 15/16"???
Don't quote me on this, as I haven't messed with this sorta thing in a long time!
The problem is that the ABS brake master is 2 channel, while the non-ABS brake masters are 3 channel; it's get to be a custom plumbing nightmare!

The bias valve is *outboard* of the brake master itself.
It is not built into the brake master.


-Ted

Nihilanthic

Higher speed = higher momentum. Try to lock at 100 vs... in a parking lot (assuming the pads are hot, cold pads wont grab for **** most likely). BTW 2x speed = 4x energy, and as fast as your rim/rotor/tires are spinning, thats a lotta energy.

And, I dunno if it applies here though - but the power vs torque relationship.... if braking power is the same it would imply that you should be able to lock it at lower speeds vs higher ones. But, if thats not the case I apologize in advance. However, if TORQUE is the constant, you still run into issues with the fact that you have so much more angular momentum in the wheels.

Anyway, the 300ZX brakes arent really much bigger AT ALL, so it would be a marginal advantage. Id rather just get some slotted or dimpled rotors and some good brake pads, and maybe air ducts, and leave it at that.

Has anyone actually DONE this swap yet to give an impression? lol. Remember, FCs are very light cars, and the 4pots have proven themselves on tracks. What real advantage do you get from getting some 300ZX brakes, assuming you used good rotors and pads on both? Id say its so marginal its not really worth the time. But, hey, I could be wrong :P

ilike2eatricers

Thanks for the info. I'll look into this as an option. Seems like it'd be alot easier if I got rid of the ABS.

It's apparently done on several FC's in Japan and is seen in many Japanese rx7 magazines. It would be great if I could understand Japanese and listen to the commentary on the FEED FC with the Z brakes. Appears they spent several minutes talking about the brakes in the vid.

theloudroom

Guys, Ted is right here.

The 5 lug FC brakes are awesome for normal driving.
The only REAL reason to swap them out is if you're having fading problems from repetitive high speed stopping.

I could see changing master cylinder bore size for driver preference, or adding an adjustable proportioning valve like I have done to my own vehicle, but swapping on brakes from ANY other car isn't going to improve your 60-0 stopping distance, assuming both systems are properly balanced/biased.

The only thing you could improve is going to be brake fade from overheating, and only if the new brakes are significantly bigger.

What type of driving was this FC with Z brakes set up for?

theloudroom

It is the case.
Locking the brakes means you apply enough force to the pad such that the force required to turn the rotor is more that the force to cause the tire to loose grip.

This should be do-able at any practical speed.
And since your brakes are now locked, heat doesn't come into play.
The heat is busy destroying your skidding tires

....of course you don't actually want to lock your tires, but it should be possible.
In reality, you're at the edge of lockup and all that heat is going into the brakes.
The bigger they are, the more heat they can absorb/dissipate before fading, but beyond a certain size, you're not going to hit a critical temp unless you perform repeated high-speed stops.

It is amazing to think about the energy involved in a typical stop:
2600lbs * 60 MPH = 1180 kg * 26.8 m/s = 31624 joules of energy
over the course of 2.73 seconds is 11583 Watts!.
(This is why you don't see fully regenerative brakes on a hybrid.)

Of course, let's ballpark your specfic heat capacity at 400 Joules per kilogram and degree Kelvin. And the boiling point of Castrol synpower is about 500 deg F = 260 deg C.

233 degress of availible temp rise
31624 joules of energy
400 joules per kilogram degree

79.06 kilogram degrees

gives you
.34 kg = .75 pounds

so really, for a typical 60-0 stop your temp rise doesn't seem like it would get anywhere near critical

even 120-0 MPH only brings the minimum mass up to 3 pounds.

jacobcartmill

iTrader: (6)

if you have all that stuff and still need more braking, check your master cylinder. all i have is pads and brake lines and i am way past the limit of my tires.

edit: i think ted just said that. oh well.

RETed

If this is a vid, I can try and translate it for you.
If it's a mag, anyone got a scan?


-Ted

ilike2eatricers

It's a vid. It's 475mb though. Let me see if I can just chop that one section with the FEED FC so the download wont take long. I think my buddy has some of the mags I'll see if I can get some scans.

MPLSrx7

sorry if this is a stupid question but, could i get TII brake calipers on my base without converting to 5 lug?

Nihilanthic

I still dont see how the 300ZX brakes are going to appreciably make it have a harder braking force. The difference in area is negligeable so heat isnt an issue, and the clamping force isnt going to be much different as far as I know... and it comes down to the pads and the tires anyway!

What does the 300ZX brake calipers have that the FC's dont thats going to fix anything? Is the piston area different? Would changing the M.C. do the job?

RoadRaceJosh

If you want more brake "feel" (harder pedal) and more pedal reserve then use the larger 929 master cylinder. The 300ZX calipers have larger pistons and therefore apply more force for a given pedal pressure and therefore have a lighter pedal feel. For most people the stock brakes with good pads are just fine. If you want a little better feel and pedal reserve use stainless braided brake hoses. Your hoses are probably original anyway so consider it for safety reasons too.

ilike2eatricers

theloudroom

The proportioning valve is external to the master cylinder.
Getting a larger master cylinder is going to do nothing but give you less brake travel.