JEFF1988RX7SCOTTSDALE

I have the 88 S4 Convertible and I'm looking to replace the brake pads. I don't have any experience with the RX-7 so I'm hoping to get some recommendations. I'm not going to be racing the car, just some spirited driving on occasion...basically pushing it once in a while to see what it will do. I have used PBR Deluxe with good results on a few Bimmers. Any thoughts?

Jeff

87 t-66

iTrader: (133)

hawk

clokker

iTrader: (2)

Hawk HPS.

JEFF1988RX7SCOTTSDALE

I probably have to be more specific, but I did look into the Hawk HPS. Unfortunately, the reviews or comparisons etc. don't give engineering data which would allow me to make a better decision. Reading the "sales" description of a specific pad is just too subjective.
Here's what I want and what I think the PBR Deluxe achieved. Very good initial brake response (e.g. high coefficient of friction when cold), VERY low dust...I know because my 735, 635, etc. had stock wheels similar to the RX7 which were very time consuming to clean. Reasonable hot/hard braking conditions with very minimal fade (keep in mind a 3800 lb 735 with 4 people racing through the Blue Ridge mountains for 20-30 minutes is not a real track test, but I never had a fade issue.
So, from what I'm gathering, the Hawk HPS are popular, but I'm basically reading they don't have that great of an initial grip when cold. And frankly, I will probably pop the car up to 120 and back it down in a hurry a lot more than I will be in the mountains getting them real hot for any extended time period. Also, I'm not hearing they are very low on dust, and I would prefer that over the high speed/high heat characteristics.
Finally, are ceramic compounds new and "actually' improved? Does anyone use any ceramic pad and have some experience. They are advertised as "better"...like that means anything without some specs...

Jeff

openrx

hi jeff

there are calculators for brake pads IF you know the basic info like coefficient of friction and pad size.

i agree it helps to have data to balance the 'they are great' reports...

one characteristic to understand about the OEM brakes on your car is how their performance maps out...

but that i mean pedal travel/effort vs braking power.

AS NEW the setup is this...

~70% of the pedal travel brings ~25-30% of the braking force.

with the last 30% of travel and pedal effort delivering 70+% of the braking force.

THIS curve feels like "oh **** where are the brakes, ah finally grip and wow great grip!"

lots of new drivers are spooked by the need for so much travel BEFORE stopping power happens.

especially compared to newer german cars that have IMMEDIATE braking power with very little pedal travel.

but that's the 7 design, and i've got the graphs to support it.

so imo using a pad that needs to be warm or engages late is a bad idea.

'ceramics' might be ok on the rears because of the lower dust feature and the minimal value of the rear discs for stopping power.

ALL of the semi metallic pads will throw ~ the same amount of dust,

so stats should be the guide and matched to driving (street vs track) styles.

your car came with organic (asbestos) pads. THESE are still available from mazda dealers made to ORIGINAL specs.

my car has the ORIGINAL OEM pads still in use at 21 years.

objectively, they are great pads for heat, stopping, longevity and EXTREMELY low dust.

but dealing with the asbestos (wet cleaning) is an issue.

otoh the pads WORK really well, throw almost no dust and don't leave iron frags on the rotors to RUST...

mazda oem pads are available in 2 versions the original (organic/asbestos) and a 'shorter life' version that is organic/asbestos free.

i typically use the friction data and formula to calculate STOPPING power when buying pads for other HIGH performance cars...

but with the 7 i'm hanging on to oem for now.

here are pics of the 21 year old original pads and rotors there is STILL a lot of life left in both...

henry

JEFF1988RX7SCOTTSDALE

Thank you for providing some actual information. I'm going to go with the Axxis Deluxe Plus (I understand they are now selling them as "Advanced"...name change maybe only, used to be PBR), but they are basically organic with very little dust and I don't think they are asbestos. I'm an engineer and definitely appreciate the numbers WAY more than the hype.

Jeff

clokker

iTrader: (2)

I was not "spooked" by this characteristic of the brakes but never cared for it either.
It's useful to realize that the kinesthetics of a car are not engineering decisions but instead, ultimately fall to the preference of some test driver (or a cadre of test drivers) who makes decisions based on personal preference, just like we do.
There is no hard and fast data-based rule concerning "brake feel", although there may be an organizational bias towards one preference or another (hence the perception that German cars favor immediate braking power over the longer travel found in the RX).

Having spent the better part of the summer experimenting with my car's brake "feel", I can definitely say I much prefer the shorter travel, firmer pedal that a larger booster/MC provides...fully aware that the actual braking performance isn't measurably better, just my perception of it is more favorable.

This has nothing to do with being a "newer" driver (which I am decidedly not), more a personal preference thing.

As an engineer surely you're aware that "numbers" divorced from real world application can be extremely deceptive.
Two drivers in the same car can generate a completely different data set of performance numbers due to their personal style and methods...it's the price you pay for introducing the human element.

I don't believe anyone was trying to "hype" you- I certainly wasn't...what you were getting was subjective,personal opinions as opposed to numbers from data acquisition which, being an engineer you may prefer but who here has their car wired like that?

JEFF1988RX7SCOTTSDALE

Got it, and the "hype" I'm talking about generally comes from the sales end of things in the description of a product that too often can never be described by the engineer who designed it. Nuff said, I got the information that I needed, ...a set of brakes to start my experience with the RX7. I will not judge the car by any means on this one element. Already I'm impressed (if not theoretically, but emperically also).
Just getting some experience from the site, and enjoying the fact that after 9 years it's starting to purr.

Jeff

Absolutely, much appreciated.

openrx

the reference was to new folks (even 20 years past) hopping in for a test drive and responding to the brake characteristics...

i've also heard drivers say "what's wrong with the brakes/boost, get new pads or put on some stainless lines"

and MY own sensory experience slowing from 130 before a hard curve.

these cars are PRE abs which may play into the way the system was designed as well.

i've almost NEVER locked them up and suspect the design helps me on that issue.
___________________

having read your thread about revolving master cylinders, it's really amazing stuff and entertaining.
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i don't have a sweeping PERCEPTION about german car braking characteristics, because they are each different.

but currently own 3 (newer audi s cars) and they ALL have narrow pedal ranges from NO brakes to FULL ON.

and new drivers of THESE cars often comment "wow these brakes are really touchy" which translates into a LOT of erratic stopping.

our proprioceptive sensory input and muscle/motor response adjusts as we adapt at the foot/leg/hip/brain level.

this is called neuromuscular learning.

driving one design, then the other, tests this system and adds to the enjoyment of driving each.
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a lot of personal reports and endorsements of a given pad are biased, that's not bad but common...

the reports are further confused by tire and rotor variations.

so using the hard data about pads can be useful, WHEN it is available.

when someone reports THESE PADS ARE GREAT and really stop me good! it helps to know the m for that pad.
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best of luck with the new pads jeff!

henry

funkjaw

iTrader: (3)

I have driven many pads, been recommended many pads, and have heard bad things about many pads.

For the type of driving you are talking about:
Porterfield R4-S
OR
Project MU B-Force