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S12W/maxima calipers brake bias


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Hi, im doing my brake setup on my 280z build using S12W calipers front and maxima calipers rear, 15/16 front master, stock proportioning valve delete.

 

I tought i had to put my proportioning valve on the rear brake lines as usual but now ive read on another thread that the maxima calipers are not well matched to the S12W resulting in too much front bias........

 

Any confirmation on this and is there a fix for the problem?

 

Thanks in advance!

Edited by mforget
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3 hours ago, mforget said:

Hi, im doing my brake setup on my 280z build using S12W calipers front and maxima calipers rear, 15/16 front master, stock proportioning valve delete.

 

I thought i had to put my proportioning valve on the rear brake lines as usual but now ive read on another thread that the maxima calipers are not well matched to the S12W resulting in too much front bias........

 

Any confirmation on this and is there a fix for the problem? 

 

Thanks in advance!

 

 

Should have researched this more. Lots of info in the brake section.

 

Stock brakes are fine.

 

The Toyota vented/solid  front and Maxima/240SX rear is biased towards the front 60% front and 40 % rear.  This is based on my own calculations and actually experimenting with  the following:

 

  • Stock front 240SX rear
  • Stock front Maxima rear
  • Solid Toyota Stock rear
  • Vented Toyota stock rear
  • Vented Toyota 240SX

 

 

Is there a fix? No, but people have tried putting more aggressive pads on the rear to achieve better front - rear balance.  Probably ok for racing.

 

No, you can't put a proportioning valve on the front - that would be dangerous.

 

Recommend that you use Carbotech AX6 pads front and back. They have excellent cold bite for city driving and get better as they heat up.

 

 

My current  set up is Toyota solid front, 240SX rear, 280Z 8.5 in booster, 79 280ZX MC and Carbotech AX6 pads.  With the Carbotech pads, 280Z booster and 15/16 MC my brakes are like stock.

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1 hour ago, Miles said:

 

 

Should have researched this more. Lots of info in the brake section.

 

Stock brakes are fine.

 

The Toyota vented/solid  front and Maxima/240SX rear is biased towards the front 60% front and 40 % rear.  This is based on my own calculations and actually experimenting with  the following:

 

  • Stock front 240SX rear
  • Stock front Maxima rear
  • Solid Toyota Stock rear
  • Vented Toyota stock rear
  • Vented Toyota 240SX

 

 

Is there a fix? No, but people have tried putting more aggressive pads on the rear to achieve better front - rear balance.  Probably ok for racing.

 

No, you can't put a proportioning valve on the front - that would be dangerous.

 

Recommend that you use Carbotech AX6 pads front and back. They have excellent cold bite for city driving and get better as they heat up.

 

 

My current  set up is Toyota solid front, 240SX rear, 280Z 8.5 in booster, 79 280ZX MC and Carbotech AX6 pads.  With the Carbotech pads, 280Z booster and 15/16 MC my brakes are like stock.

 

Do you run any proportioning valve at all?

Edited by mforget
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Do you run any proportioning valve at all?

 

Yes.  I installed a Wilwood proportioning  valve only because I was experimenting with different caliper and pad configurations.   I now leave it wide open.  I would remove it, but I am too lazy to crawl under the car.

 

A proportioning valve reduces pressure to the rear brakes.  All of these brake swaps are biased towards the front not rear (60%F 40%R to 70%F 30%R) so a proportioning valve makes no sense UNLESS you plan on racing with aggressive pads on the rear which you "dial-in" while racing.

 

You have a 280Z with the larger 8.5in booster which will help with the stiffness caused by the larger bore 15/16 MC.

 

Go with the Carbotech AX6 pads and you should be ok.  Don't waste your money on Hawk or Porterfield street pads - they do not perform well in traffic.

 

See attached brake bias data:

 

BRAKE BIAS CALC INPUT and RESULTS.docx

Edited by Miles
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45 minutes ago, walkerbk said:

If you use the s12+8 calipers from the later years, they were machined to fit vented roters like the s12w ones but have smaller cylinders making for more of around 57% to 43%. This is what I run and am very happy with the setup.

 

Good point. 

 

SW12 VS S12 8 CALIPER.jpg

Edited by Miles
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  • 5 months later...
On 9/16/2018 at 1:46 PM, Miles said:

Do you run any proportioning valve at all?

 

Yes.  I installed a Wilwood proportioning  valve only because I was experimenting with different caliper and pad configurations.   I now leave it wide open.  I would remove it, but I am too lazy to crawl under the car.

 

A proportioning valve reduces pressure to the rear brakes.  All of these brake swaps are biased towards the front not rear (60%F 40%R to 70%F 30%R) so a proportioning valve makes no sense UNLESS you plan on racing with aggressive pads on the rear which you "dial-in" while racing.

 

You have a 280Z with the larger 8.5in booster which will help with the stiffness caused by the larger bore 15/16 MC.

 

Go with the Carbotech AX6 pads and you should be ok.  Don't waste your money on Hawk or Porterfield street pads - they do not perform well in traffic.

 

See attached brake bias data:

 

BRAKE BIAS CALC INPUT and RESULTS.docx

So based on the spread sheet you supplied wouldn't it be best to run the toyota vented up front and the toyota solid on the rears.  If I understand this correctly, that would give a 55/44 brake bias. So I wonder how hard it would be to mate the toyota solid fronts to the rear of a 280z?

My numbers may be skewed because I was focusing on the front line PSI. Not sure what the rear would be or if the volume from the master affects the overall numbers

Thanks

Edited by rabrooks
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Not sure how you arrived at Toyota front and back.  Won't work.

 

The Toyota calipers only go on the front because they have no parking brake function. 

 

The 240SX calipers have a parking brake function.  So they only go on the back.

 

 

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