ZX vs S12w Calipers on s00zx vented rotors

[tsheldon]

Hi brake Gurus,

 

I am collecting parts to begin brake conversion on a 72 that will see limited track time.

 

Rears are set with the 240sx caliper ross c brackets and 300 zx rotors.

Master cylinder is 15/16

 

My question is this : Why would I want to use the s12w calipers on the 300 zx rotor instaed of the setup posated on terry O's webpage with 280zx caliper on turned down 300zx rotors, It seems that the zx caliper should yield more than enough clamping pressure and retain the solid pedal feel with the 15/16 master.

 

Has anyone weighed the two caliper/bracket setups to see if there is a difference in unsprung weight ??? looks like the zx setup should be way lighter.

 

Am I missing something????

 

Tim

[zgeezer]

Two matters come to mind:

1. A fully functional hassle free parking brake, using your Z's cable and

2. A rear rotor that you can replace anywhere anytime without looking for a machine shop.

 

g

[zgeezer]

Two matters come to mind: 1. the sx calipers allow simple fully functional parking brakes using your stock cables and two extension links and 2. a stock rotor means you or your shop can replace it without looking for a machinist.

 

g

[Pop N Wood]

Doesn't Terry's set up require you to drill out the threads on the caliper mounting bosses on the strut itself? Means once you put those on you are committed to that set up (if I remeber correctly)

 

I have the exact vented S12 front and 240sx rear set up in my garage waiting to be installed. The front calipers are heavy pigs. But they will allow me to upgrade to a lighter set up at some future date if I wish (Ross's or JSK/wilwoods)

 

As for stopping power, I know that has been discussed in depth in previous threads. I think the answer will be somewhat inconclusive. A lot of "it seems to me", and "my set up works fine" but not nothing like "this set up stops 10 feet shorter than the other".

[tsheldon]

Yes the strut bosses due need to be drilled out, but this seems to be the only downside of this swap.....

 

Is anmyone aware of any inherrent problems with the zx caliper??? sticking binding etc.......... if not it seems like this is a slam dunk solution

 

As I see it :

 

Firm pedal feel with 15/16 bore master

Lower unspring weight

No hub adapter

Good Pad Selection

Increased Rotor Swept area

Vented rotor

All Nissan parts

 

Whats not to like, especially if combined with the 240 SX rear conversion???

[JMortensen]

The only real "problem" with the ZX caliper setup is the rotor. Rotors are a part that is going to wear out. The harder you drive it and the more aggressive your pads are, the more rotors you'll have to replace. So you might be setting yourself up for a lot of lathing. If that doesn't bother you then I say do it. If it does then you might consider moving the bosses out 1/8" or whatever it is like Terry did. It's a PITA, but you only have to do it once, then your off the shelf rotors work fine.

 

I've got some friends that run ZX struts and brakes on very fast 510's and do lots of track days and I can't remember any of them ever having a bad caliper.

[tsheldon]

Thanks for the feedback...

 

I'm leaning towards the rotor triming only because I am not all that thrilled about having my braking and thus my life depend on my welds...

 

 

Any thoughts on adj proportining valve with the 280zx front and 240 sx rear I would think it should be damn near dead on ...

 

tim

[JMortensen]

The stock ZX rear discs were 10" IIRC, and I think your 300ZX rear rotor is 11". Might need the prop valve to dial back the rears a bit, but I guess there's only one way to find out...