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SUNNY Z

Brakes! Who is running what?

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JMortensen    235

The problem is that the stickier the tires, the more heat you can put into the brakes. For tracking a Z with sticky tires I think you need some pretty serious ventilation to allow the stock calipers and rotors to keep up. I've been on the track with slicks and half-assed ventilation and boiled Super Blue brake fluid in less than 5 laps with 4 piston front on solid rotors and 280ZX rear disk. When this happens the pedal goes straight to the floor, no warning, pumping doesn't do much, you're pretty well screwed. Getting a vented rotor in the front seems to be the key to running on the track without a lot of ventilation (vent tubes tend to get torn up on the street so not the most desirable fix). Toyota calipers on stock rotors is better than stock in terms of increasing heat capacity, but not by much, and can really screw up the bias and lead to less effective braking even if it works for another lap or two before it fails. Pads help a lot, but you still need to be able to dissipate the heat, and if you can't get the heat out of the system you're still going to have trouble, although you might put it off for a couple more laps because your pads didn't give up before the fluid boiled.

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Leon    35

The problem is that the stickier the tires, the more heat you can put into the brakes. For tracking a Z with sticky tires I think you need some pretty serious ventilation to allow the stock calipers and rotors to keep up. I've been on the track with slicks and half-assed ventilation and boiled Super Blue brake fluid in less than 5 laps with 4 piston front on solid rotors and 280ZX rear disk. When this happens the pedal goes straight to the floor, no warning, pumping doesn't do much, you're pretty well screwed. Getting a vented rotor in the front seems to be the key to running on the track without a lot of ventilation (vent tubes tend to get torn up on the street so not the most desirable fix). Toyota calipers on stock rotors is better than stock in terms of increasing heat capacity, but not by much, and can really screw up the bias and lead to less effective braking even if it works for another lap or two before it fails. Pads help a lot, but you still need to be able to dissipate the heat, and if you can't get the heat out of the system you're still going to have trouble, although you might put it off for a couple more laps because your pads didn't give up before the fluid boiled.

Jon, I understand that. However, the ITS racers must use stock brakes and don't lose the pedal during a race. I'm sure they utilize brake ducting but it appears as though stock brakes are good enough when properly maintained and set up.

 

In fact, after reviewing the thread, you made essentially the same comment in post #17. You have also divulged that your brake ducting was inadequate.

 

I think we can conclude that the stock brakes, with aggressive friction material, high-temp brake fluid and good ducting will work just fine, even on extended track sessions.

Edited by Leon

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JMortensen    235

I agree, but think you're underestimating the hassle of proper ducts. Do some searching on that and you'll see that you probably won't be able to turn the wheel all the way to lock and you'll lose some ground clearance. If you put ITS ducting on a street car I think it would be ripped off in a couple hundred miles.

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SleeperZ    3

Fortunately we don't need ducting on the street. Vented rotors are very nice, and definitely help with keeping the brakes cool during extended sessions. For other uses like the street, strip or even autocross, there is not time to develop much heat, so heavier components and/or better pad materials are just about all that is required as upgrade.

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ablesnead    0

I have many years racing ITS datsun 240s....our brakes suck , if you need to use them , ( particular tracks ) , then you are at a distinct disadvantage..ducting carbo tech rear lining , latest porter field ....they still suck , I have finished 1 hour enduros with the calipher piston all the way thru the pad metal...no brakes , but we expect that, still won !

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SleeperZ    3

@ablesnead -- I absolutely agree that vented rotors are very nice to have on a road course, and more pad area distributes the heat better. But in terms of single braking events or low speed/short duration like autocross and street driving, stock brakes can do the job as well as any of the "upgrades".

 

And I wonder whether brake rotor cooling is impaired when such large rotors are fit so tightly inside the wheels. I use 15" wheels, and the Silvermine rear disks may fit some and not others - I question whether they would perform any better than the 280ZX solid rotor in a 15" wheel...

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johnc    724
However, the ITS racers must use stock brakes and don't lose the pedal during a race.

 

Yes they do. Depends a lot on the track and how aggressive the driver is. Ran a 6 hour enduro and we had to do a front pad change halfway through. Try changing brake pads quickly when they come in smoking.

 

The Silvermine kit is probably the best bang for your buck ready-made kit available. It also has good balance as shipped. The 280ZX and Maxima rear calipers tend to not have enough rear bias when used with the Toyopta S12W caliper up front.

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Leon    35

Yes they do. Depends a lot on the track and how aggressive the driver is. Ran a 6 hour enduro and we had to do a front pad change halfway through. Try changing brake pads quickly when they come in smoking.

 

The Silvermine kit is probably the best bang for your buck ready-made kit available. It also has good balance as shipped. The 280ZX and Maxima rear calipers tend to not have enough rear bias when used with the Toyopta S12W caliper up front.

Ok, I'll concede that stock brakes may be inadequate for 3 hours of endurance racing. :P

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galderdi    0

I am running hydraulic handbrakes in both my track cars.

 

I had a close call yesterday when I had a complete hydraulic brake failure. It occured at the fastest part of a Motorkhana test (similar to your Autocross) coming in to the finish. I went for the foot brake, it went to the floor, I went for the hydraulic handbrake, it offered no resistance. By this time I was well past the finish line and was looking for gaps between the parked cars waiting for their turn. I managed to apply the standard cable handbrake which started to slow me as I threaded the needle between a parked car and a trailer. The gap was actually narrower than my car which meant I had to clip the trailer but it was only the ramps so no damage was done.

 

So it turns out there was nothing wrong with my installation of the system. It was perfectly suitable for the purpose and had been operating well up to the incident. The problem was that I must have placed pressure down on the handle at some stage during my run. All that was holding it back was the standard circlip which popped out allowing the brake to explode and lose all its fluid.

 

So finally here is my point. If you run a Hydraulic handbrake make sure it rests on a stopper when not in use. That way if you do happen to lean on it the stopper will take the weight not the circlip.

I have now installed a stopper under my handle and I feel more comfortable with the setup. Personally I think these Hydraulic handbrakes should have a stopper built in as standard.

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Zinpieces    1
post-6289-015156000 1352082924_thumb.jpgI am using stock Q-45 rear brakes mated to a T3 rear suspension setup. For the fronts I am using 12.2 in Wilwood rotors and lightweight 4 piston calipers on T3 five lug front hubs. Technotoytuning has developed a five lug hub for 240Z spindles that really is sweet!

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Racin_Jason    0

A belated thank you for this thread!

 

I am about to get around to 'refreshing' the brakes on my V8Z (425ish @ crank) and I was about to purchase upgrade kits for the F&B that wouldve set me back over $1200. This is a street car and nothing more (well..drags).

 

This opened my eyes to the idea of putting good pads on my stock front brakes and doing a basic pieced-together rear disk setup - apparently it'll do the job! This will save LOTS of money and ease installation.

 

How is the balance on a system like I just described? Can I even use the stock proportioning block?? Oh..do I need to upgrade the MS for added capacity in the rear calipers?

 

Thanks!

Jason

Edited by Racin_Jason

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duragg    18

S12W with vented rotors and the pads that came with them.

280zx rear calipers and a solid rotor with stock pads.

Proportioning valve removed, lines running straight through.

 

I have 2 track days (7.25 sessions @20m each) and some street driving and few complaints yet. Its a cheap setup and scratched my itch for more heat capacity and disc bling. Bias seems fine at the moment. 15x10 wheels with street tires so for now that is the limiting factor. After each session all the wheels are covered in dust so at least I know the backs are contributing. Real track tires will want real pads- and the bleeding financial spiral begins.

 

The mechanical handbrake on ZX rears is fine for emergency or parking, but won't come close to locking the rears. Its geometry and how I integrated the ZX cable to the Z mechanism isn't ideal, but works and is safe.

 

The big king-crab looking ZX calipers can hit the body and stock brake mounting brackets, so pay attention to clearance with an eye towards full squat.

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tooquick260    4

Did the Z32 front brake swap Looks awesome and works better than stock with original BMC. Have the Z32 master cylinder and plan on installing once I get the turbo install sorted out.

 

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I am also working on getting the Z32 rear brakes adapted to the rear. I have to say thanks to my brother. He threw the idler bearing on his 300zx ruined the motor, bent all the valves and the auto tranny was slipping. So he has given me all these parts to use.

Edited by tooquick260

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John Scott    0

Stock hardware, but in great shape, Hawk HP+ up front, MSA's perfomance shoes out back. Rarely driven hard, but seems to do the job at the strip to haul it down in a hurry with no drama, even on hot lapping.

I used to run the Dot 3 Ford HD Truck fluid. NLA

Wondering what peformance Dot 3s are still out there on a budget.

Edited by John Scott

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duragg    18

Wondering what peformance Dot 3s are still out there on a budget.

Same here.

What is the best bang for the buck when upgrading fluid.

 

I like to have a gallon at a time, so with that quantity pricing is probably reasonable.  Leaves enough to soak my clothes and the floor without feeling pinched.

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Gregmatic    10

Wagner DOT 5.1  is my new favorite.  Its a 5.1 NOT a 5 which means it isn't silicone based, basically the next step above DOT 4.  Also it is inexpensive, easy to find and has the highest high boiling point of any shelf fluid I have found yet.

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