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Brake Pads and Prop. Valves - Paging SaulSpeedwell

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#1
bmarshall1

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 I was reading a thread about pad compounds, weight transfer and such, and Saul had raised a very good point that wasn't addressed regarding proportioning valves and brake pressure.
 
Saul had mentioned 'knee' of the prop. valve chart.  I assume that he meant if one were to use very high brake pedal pressure, once past the apex of this curve, proportioning results would change.  Can anyone tell me what the change would be, ie: more or less brake power sent to the front/rear?  Or did I totally miss the intent of the post.
 
The reason I ask is that I run DTC 60/30 and have no problem with rear (or front) lock - meaning I may be leaving some time under braking on the table.  Some folks were saying to use the same pads front and rear, others said not to, and there seemed to be good arguments for both sides.
 
Having said all that, given my mediocre skills and based upon what I have read into the arguments.  If I were to use a less aggressive pad, I will be using more pressure to achieve the same stopping power and also using more large muscle groups.  This abundance of pressure may take me "over the curve" on the proportioning valve leading to ??
 
If I were to use a more aggressive compound, or even the same f/r compound, perhaps I could use more 'finesse' of foot and calf pressure, less pressure overall, and stay under the proportioning valve curve, leading to a difference of ?? vs. going past the curve.
 
I am most definitely overthinking this but now it is more of a point of curiosity regarding the prop. valve and what happens with excessive brake pressure.


#2
Steve Scheifler

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Some very good questions. I won’t attempt to answer your specific question about the prop valve but I will remark that there are probably five or more versions so to answer your question you might first confirm which you have (anyone buying a used race car beware that many were swapped for what people believed to be one with a better balance. No, that is not allowed by the rules.) If the other thread didn’t post a link to a post detailing the versions (as of that point) you can likely find it searching miata.net.
Bona fide - A bonafide Spec Miata driver

#3
bmarshall1

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Thanks Steve, good point about the version that I have.  My car is a 99 and I assume it is stock, but having bought the car used, there is no telling.






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