tazswing

I think my rear brakes need to have the slide pins re-lubed. Does it matter what I clean them out with? I have the correct junk to re-lube them but was not sure if there is "too harsh" a cleaner/de-greaser to use.

Cheers.

OGRacing

iTrader: (1)

i used brake clean. just blast it out and make sure your grease is clean. tiny stones can band and cause the caliper to drag.

Voltwings

So i'd like to talk about a topic that i know has been covered in this forum, but not in this thread yet, which is brake ducts.

I'm not new to road courses and track days but i just do them for fun, i don't "race" so i'm not bound by any specific limitations. Previously we were running two mustangs, my ~400 whp / 3600 lb 5.0 and my fiance's ~300 whp / 3400 lb v6. On both cars i was running 13.2" rotors with 3" brake ducts and carbotech XP 10 / 8 pads. Our typical schedule is 1 weekend every 2-3 months, so not super often, but often enough that we go through some wear items.

So, to save money my fiance' and i are now sharing a Miata, and since this car will really only get ~20 minutes rest between our sessions, i am trying to address all cooling and efficiency mods upfront. I understand the design of the miata hub seems to limit how brake ducts can be designed, but on the mustangs (and maybe it mattered more there due to the weight and horsepower) it was always stressed that the duct should be aimed as close to the rotor hat as possible. This makes sense to me, it cools the hub, and allows the air to pass up through the vanes and cool both faces of the rotor evenly - in theory.

All the Miata ducts i have found have very large gaps between the duct and rotor, again a design i understand is limited by what we are working with, but combined with the small rotor hats we're working with it basically just seems like all the air is blowing on the rear face of the rotor? I am probably over thinking this, as apparently people are running these kits with success, but the "science" of it doesn't make sense to me. You would think that basically ducting 2.5 - 3" worth of air at the rear face of a rotor and not really getting much into the hat / vanes to cool the front would lead to a warped / cracked rotor since different parts of it are heating and cooling / expanding / flexing, whichever at different rates?

I still have a lot of my 3" brake duct hardware left over, so i am looking to put 3" ducts on our car - which is otherwise just a basic bolt on NB2 with some very mild weight reduction and suspension, we've only had it for a few months at this point and are just getting it all set up - since i already have the parts. I understand 3" is overkill for our application, but like i said, since we're both driving this car, i would hate for a weekend to get ruined by some cooked brakes when that issue can be very easily addressed beforehand, i'm just not sure how i feel about a lot of the duct options out there ... Thanks.

For example, these were the backing plates / dust shields we were running on the mustangs: Vorshlag S197 3" diameter Brake Duct Backing Plates (Pair) - Vorshlag LLC

ThePass

iTrader: (3)

You're right on the money that there is simply no way with the dimensions of the Miata spindle to move the outlet closer to the hub unless you want to cut parts of the spindle off.

But in short, yes you are overthinking it. These factors were all considered in the design of our ducts.

First, the sort of design that you see in Singular ducts place the outlet of the hose about 1/2" away from the inward rotor face, and then the shape of duct itself is designed to serve as three sides to a box that allows the airflow to flare out from there towards the center of the rotor. The duct direction is angled towards the rotor center. You seem to be thinking of the air exiting that duct as if it exits the hose end, contacts the rotor and then vanishes. In practice, with a Singular duct, the inwards rotor face serves as the fourth wall to the box that channels air from the hose exit to the rotor center. Air pressure is lowest at the center of the rotor hat - an effect facilitated by the design of the rotor and internal vanes as they spin - so this is exactly where the cool air delivered by the hose from a much higher pressure source will go. The rotor gains a bit of cooling from the initial contact of cool air fed by the duct, but the majority of the thermal transfer IS indeed from the air feeding into the rotor hat and then traveling outwards through the rotor veins.

Many, many cars running these ducts these days, reporting lower brake component temperatures, longer pad/rotor life and no adverse effects. All our testing during development showed the same, but the sample size that exists now reinforces that.

-Ryan

Voltwings

I think you're exactly right, thanks for clearing that up. You can see looking at those Vorshlag baking plates what i was expecting coming in, and seeing all the miata offerings i was kind of hesitant. Thanks for the reply.

OGRacing

iTrader: (1)

fixed it for you but yes exactly right.

sixshooter

iTrader: (12)

Straight vein rotors move air from the center outward, too. See: turbocharger

OGRacing

iTrader: (1)

true true...

tazswing

Here are two:

1) What is the diameter of the small-*** tubing that fits over the bleed screws for four piston dynapro calipers?
edit: read it is a .170" inside diameter. I will confirm tonight after getting some different tubing.

2) Why are one-way check valves not used for bleed screws or can one swap those out to make bleeding easier (more reliable?)?

Leafy

iTrader: (1)

Have you ever bled with speed bleeders? Its terrible they never work right, and once you give up on them actually sealing and working sometimes they dont even work out for you when you treat them like normal bleeders.

aidandj

iTrader: (5)

<p>@tazswing here is the tube I use.</p><p></p>

tazswing

Nice. The .170" worked well for me.

I guess short-cuts are just that then. Good to have friends...to pump your brake peddle.

Eric W

Okay 95% of all this brake info I've just read has gone completely over my head, so I'll just ask my question straight forward.


1996 1.8L. turbo'd Miata making approx: 250whp. 230tq.
Stock 1.8L rotors & pads (so so bad)


Car will never ever see any track time BUT my daily driver situation is very different then most......
The car is a business use city delivery only
car, meaning 5-days per week 10am-10pm delivery driving 1,000 delivery miles per week on this car.


I'm looking for a rotor and Pad combination that has minimal dust, Extremely longevity an will stop my turbo'd Miata from 100mph. to 0 for 10 hours a day 5-days per week.

I'm unwilling to swap to a BBK. at this time, cost being the set back


My current delivery car 02 civic has burned through (gone nothing left) EBC Redstuff pads in 6 months, then switched same car to fresh EBC blank rotors an Yellow stuff pads they wore down to the backing plate in 9 months. This is unacceptable.


Is what I'm after Possible, staying with the oem 1.8L calipers & rotor size?
Thanks

Eric W

*double post

OGRacing

iTrader: (1)

i got nothing for ya. If you had a mail truck i could do something that lasts a long time. Good performance and dust come hand-n-hand.

sixshooter

iTrader: (12)

Run cheap stock pads. For delivering pizzas it is all you need.

If you are more interested in stopping the car than looking hot for all the potential boyfriends you may encounter then you can use real performance pads, which will dust. If you aren't gay you need to realize girls pay very little attention to cars. If you are gay you need to realize gay guys pay very little attention to cars. Straight guys pay attention to cars. But straight guys think the Miata is pretty faggy, even if lowered and placed on cute wheels (called rimz if you dropped out of school).

The only pads with light dust are ceramic ones from the local parts store. They don't stop as well as ones that do dust.

Six months? Nine months? And you are complaining? Mine last two weekends, maybe three. And I am happy they last that long.

You should consider a job in cosmetology. They don't go through brake pads quickly.

OGRacing

iTrader: (1)

that quote needs to get immortalized somewhere.

OGRacing

iTrader: (1)

ftjandra

iTrader: (6)

I never figured they'd stay glowing for that long, especially with brake ducts.

--Ferdi

tazswing

WTF??