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SleeperZ

280Z with 280ZX front calipers, maxima rear calipers

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I've been using the 280ZX front calipers for years with some track use.  I think most people that run the S30 on the track realize that increasing brake capability on the front without balancing it on the rear will not get much benefit.  The benefit I do get is just the vented 300ZX rotor and Porterfield pads last for a few more laps even though they do most of the braking.  Of course the stock rear drums do next to nothing with this much front bite, and the diving into turns is extreme.

 

So I am now, finally, doing a rear disc conversion using the '86 Maxima rear caliper and '82 280ZX rear disc.  I think this caliper has the easiest interface to the parking brake, even though the late model 280ZX rear caliper has slightly more pad area to the disc.

 

So I'd like to solicit thoughts on this with regard to braking balance.  I have less braking grip on the front than if I had used the Toyota caliper.  My setup should resemble a late model 280ZX, but with slightly less grip on the rear, assuming the same brake pad compound.  I'd thought I should replace the 280Z proportioning valve with the 280ZX valve, but after reading some recent threads in this sub-forum, perhaps I should consider removing the proportioning altogether.  My main purpose for the car is casual track use, and not much street use, but I just don't want to rear bias the braking to the point where it becomes unsafe.

 

Maybe my best option is an adjustable proportioning valve, just to be sure?

 

TIA

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The Maxima swap will not improve stopping performance.   And you may end up having to install a larger diameter master cylinder.

 

Do not remove the proportioning valve until you have  estimated  your front to rear balance/bias based on your final selection of calipers, rotors etc. 

 

The Maxima,  and similar 240SX rear brake swaps,  don't improve performance.  Just less drum maintenance.

 

Remember that a proportioning valve reduces pressure. All of the Toyota, 280ZX, 240SX and Maxima brake combinations end up with too much front brake bias i.e, the rear brakes can't keep up with the front brakes. So adding a proportioning valve to the rear brakes will not help unless you are experimenting with front and rear pad choices for off-street racing events.

 

 

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Rear discs should give me better performance because I intend to use Porterfield pads.  I do not believe the factory drums can be fitted with a shoe of an equivalent compound, and the factory material is crap.

 

I am already planning to install the 280ZX 15/16 master.

 

My thought on the balance is since my caliper solutions for both front and rear are both essentially stock 280ZX, the brake balance with a 280ZX proportioning valve would be acceptable, but more balanced than a bigger (than 280Z factory) front brake and drums.  And if I need more pressure in the back for the track, an adjustable proportioning would be appropriate.

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I recall others talking about installing a 280ZX braking system in a 240Z/280Z,  but never heard back how it  worked out.

 

Hope you will take pictures and report back when you finish the swap.

 

I wonder if there is room to squeeze in the larger 1979 280ZX booster. 

 

I am now using Carbotech AX6 pads on a Toyota - 240SX set up on my 240Z.  The Carbotech AX6 pads have excellent cold bite and grab hard when hot. They are suitable for street and auto x.

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Personally, looking back on my Maxima caliper install, I would now build a custom adapter and use something like GM PBR aluminium calipers off Third and Fourth Gen Camaro's. ( 1989 through Mid 200's )  These are designed for an 11.8" rotor ( 300mm ) .  Will have full pad coverage over the disc ( unlike Maxima calipers ) , they are extremely reliable, dirt cheap, easy to find and have a huge Pad selection.  You should be able to get buy with the stock M/Cyl as the piston volume is close to a Maxima Caliper.  You may need to upgrade to a 1" M/Cyl but that is not a big deal. 

 

I would eliminate the stock proportioning valve and run an adjustable one on any Track or Autocross use vehicle. So nice to be able to alter the amount of rear brake bias. Can be used to help car rotate on initial turn-in. Very effective for Autocross.  

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I have seen your thread on that, and it looks like a good option, especially that it allows more braking torque on the rear with the ability to reduce it with the adjustable proportioning valve. I am not yet certain that will fit inside 15" wheels, although my current solution easily fits inside 14" wheels...

Edited by SleeperZ

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Yeah... 15's would be really tight. The 280ZX rear rotors are not 300mm though. Only 256 mm. The PBR GM calipers should clear with that rotor. You'd have to try them and see what the clearance is.

 

Here are a couple of Pictures from my Third gen Camaro. First picture is GM 1LE rear rotors ( 300mm / 11.8"  ) with PBR Calipers. This required 16" rims to clear. 

 

Second Picture is same rear rotor with WilWood Forged Superlites. The Super Lites actually had more clearance than the PBR's. 

 

S3000002.thumb.JPG.099d9119cb7c5f462a0ade99d64141e8.JPGS3000004.thumb.JPG.837398656193267d6f5724120051592f.JPG

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On 9/17/2018 at 7:45 PM, SleeperZ said:

Rear discs should give me better performance because I intend to use Porterfield pads.  I do not believe the factory drums can be fitted with a shoe of an equivalent compound, and the factory material is crap.

 

FYI,

 

Porterfield offers shoes for the factory drums.

 

https://www.porterfield-brakes.com/product_info.php?productID=3986

https://www.porterfield-brakes.com/product_info.php?productID=12839

https://www.porterfield-brakes.com/product_info.php?productID=3985

Edited by bradyzq
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Thanks for that link, very informative and encouraging.

 

The silvermine kit looks great, but it requires 16" wheels, and I already have all the parts but rotors and pads for the rear.  I've got about $200 spent on this so far so I will definitely try it before changing parts again.

 

Interesting about the Porterfield equipped shoes, I would not have thought that would be supported.  I've already been driving for years with the 280ZX front calipers and vented rotors, so I'll probably have to mess with proportioning in any case, and I really don't like drums.  Ah well.  I do appreciate the input.  If I ever get this thing back on the track, I will give some more feedback, and eat as much crow as necessary.  :)

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