Brake Pads

[Harold Flescher]

I use "cans" that duct air to both sides of the rotor. Avail at Winners cCircle and probably elsewhere. To work well, what is avail isn't optimized as the can should only have .060 clearance, and you will have to hand fit and reweld to make that happen.
H

Jay and others:

Do you use a device to bring part of the ducted airflow to the front side of the rotor or do you get the end of the duct as close to the inside of the rotor as you can?

Thanks,

John

 

[Chris Schaafsma]

Jay and others:

Do you use a device to bring part of the ducted airflow to the front side of the rotor or do you get the end of the duct as close to the inside of the rotor as you can?

Thanks,

John

With vented rotors I direct the air towards the center of the rotor - not to that general area, but right down close to the open center area. With solid rotors I would take the can approach.

 

[Jay Lutz]

I knew my "nobody ever believes me" bellyache would stir the pot.........in fact I've worked with/talked with/consulted with some of you to help improve your brake system. Some have listened and some have not.......your choice of course and I'm always learning as well.

Harold is a person who observes, listens and applies ideas from a variety of sources so I'm not surprised he has employed many of these tricks already....I think I recall some of our conversations but maybe I'm hallucinating again.

On the brake can you would like the clearance between the slot to be minimal so that rapidly moving, highly turbulent, non laminar air (that removes more energy (aka heat) from the system must spend as much time as possible adjacent to the hot rotor. There might also be some stripping of hot air away from the leading edge external to the can. But be careful less you restrict the slot too much....maybe let a thermouple DAQ channel help you decide?

A counterbored disc brake piston insulator keeps heat away from the fluid to prevent boiling but can cause friction material overheating as it has one less place to go

One hose to a can, another hose to the caliper to cool it. Center of the rotor eye is excellent if you can package it and are lucky enough to have ventilated rotors on your old production car.

Couldn't find a pic of the ventilated disc brake piston but maybe someone else can post one. You can either mill slots (my favorite) or drill holes if slots with sharp corners make you nervous.

Initial bite, feel, pedal effort, CF.......are important but are all second order issues once you make sure you actually HAVE breaks ALL of the time.

Make sure during a test session that you can actually lock hot brakes (either axle) if you push on the pedal too hard. Lots of people can't and are leaving lap time on the table.

Finally, and I know you won't believe this as I didn't , but Buddy Fey told me this and I've proven it to myself over and over again, straight line high decel braking including trail braking is the LAST thing club racers really learn how to do well (me too even though I know better). Data AQ proves it over and over again even though your gut says this can't be right. This little trick is how I coached Bob Boig to win the Runoffs for this first EP Miata win.....this allowed him to consistently pass going into 7 at Mid Ohio. Even Bob will concur this new "ability" is what won him the race.

That's enough of my unwanted ramblings for now.

Thanks, Jay

 

[Matt Blehm]

Make sure during a test session that you can actually lock hot brakes (either axle) if you push on the pedal too hard. Lots of people can't and are leaving lap time on the table.

My problem is that is all too easy to do, and I often throw away tires that have lots of rubber and one shiny spot. to keep from doing that, I leave a lot of time on the table in order to keep the tires under the car.
I would say much of my issue stems from suspension "sticktion" and a car that's easy to upset on bumpy tracks. hit a tiny bump under braking, or have any sort of curvature in your line and it easily locks a wheel.

 

[Harold Flescher]

Jay,
I agree completely that braking is the most improvable skill and one of the hardest to master. There are so many things that can lead to locking a brake that the tendency is to soften up braking even once you know the proper braking point, which is also hard to define and learn differently for each corner. One of the reasons building "feel" into the system with pads so one can sense/feel lockup and soften the pedal just an RCH and have the wheel unlock. It is the skill I have to work at the most and constantly. It's a thinking skill requiring great focus.
H

I knew my "nobody ever believes me" bellyache would stir the pot.........in fact I've worked with/talked with/consulted with some of you to help improve your brake system. Some have listened and some have not.......your choice of course and I'm always learning as well.

Harold is a person who observes, listens and applies ideas from a variety of sources so I'm not surprised he has employed many of these tricks already....I think I recall some of our conversations but maybe I'm hallucinating again.

On the brake can you would like the clearance between the slot to be minimal so that rapidly moving, highly turbulent, non laminar air (that removes more energy (aka heat) from the system must spend as much time as possible adjacent to the hot rotor. There might also be some stripping of hot air away from the leading edge external to the can. But be careful less you restrict the slot too much....maybe let a thermouple DAQ channel help you decide?

A counterbored disc brake piston insulator keeps heat away from the fluid to prevent boiling but can cause friction material overheating as it has one less place to go

One hose to a can, another hose to the caliper to cool it. Center of the rotor eye is excellent if you can package it and are lucky enough to have ventilated rotors on your old production car.

Couldn't find a pic of the ventilated disc brake piston but maybe someone else can post one. You can either mill slots (my favorite) or drill holes if slots with sharp corners make you nervous.

Initial bite, feel, pedal effort, CF.......are important but are all second order issues once you make sure you actually HAVE breaks ALL of the time.

Make sure during a test session that you can actually lock hot brakes (either axle) if you push on the pedal too hard. Lots of people can't and are leaving lap time on the table.

Finally, and I know you won't believe this as I didn't , but Buddy Fey told me this and I've proven it to myself over and over again, straight line high decel braking including trail braking is the LAST thing club racers really learn how to do well (me too even though I know better). Data AQ proves it over and over again even though your gut says this can't be right. This little trick is how I coached Bob Boig to win the Runoffs for this first EP Miata win.....this allowed him to consistently pass going into 7 at Mid Ohio. Even Bob will concur this new "ability" is what won him the race.

That's enough of my unwanted ramblings for now.

Thanks, Jay

 

[Jay Lutz]

If you have a DAQ system (if you don't, you should) , and you fear locking a wheel...........just instrument wheelspeeds on all wheels, write a calculated channel to compare all 4 and display an alarm (maybe 4. I'd advise something big and bright as drivers tend to be kind of inert on these things) on the dash telling you one is locking, maybe even which one (probably too complicated).

Then back off on the brake pedal a bit to save your tires. Hopefully you won't drive off the track at the same time ;^(

To quote "Tropic Thunder" and Robert Downey Jr..........ain't no thang.

Thanks, Jay

 

[Matt Blehm]

Good idear. I just need to convert all my hubs to ABS hubs with the sensors mounted on the knuckles, then buy a DAQ unit and wire it all up. sounds easy enough.
(actually that's the easy part. figuring out what to do with the data is the hard part!)

 

[Jay Lutz]

Matt,

That's quite a bit of stuff to replace and add.............but it will solve your problem. I have no doubt you'll figure out what to do with the data.

 

[Matt Blehm]

It was more of a tongue in cheek comment.
But it wouldn't be THAT hard. Wheel hubs on these cars are a consumable item. usually I buy junkyard hubs and put new bearings in them, then get 3-4 years out of them until the bearing fails and eats the hub. Next time I replace them, junkyard hubs with ABS rings are the same price as non-ABS.
Same with rear diff output shafts, where the rings are on the rear end. I have a couple sets of them with rings already.

Then it's a matter of stripping the ABS sensors off a junkyard car and running wires. could probably just yank the whole ABS computer and harness out and then cut the connectors off and you'd be done with the wiring.

It's probably a day's worth of work to get it all installed.
honestly you wouldn't even have to run it through a DAQ if you could code a PLC. just look at four inputs and do a frequency count on each one. if any one is, say 10% slower than the others, then you fire an output pin that goes to a dummy light on your dash.

I've actually put a small amount of thought into it before this thread and figured I would be better off fixing the bigger issues, like having suspension bind, junk shocks, and being 100hp down on the competition.

..... Back to brake pads and air ducts.

 

[Al Seim]

Finally, and I know you won't believe this as I didn't , but Buddy Fey told me this and I've proven it to myself over and over again, straight line high decel braking including trail braking is the LAST thing club racers really learn how to do well (me too even though I know better). Data AQ proves it over and over again even though your gut says this can't be right. This little trick is how I coached Bob Boig to win the Runoffs for this first EP Miata win.....this allowed him to consistently pass going into 7 at Mid Ohio. Even Bob will concur this new "ability" is what won him the race.

Interestingly enough (maybe) my current brake kick is coming directly from data.

Our (Race Technology's) data analysis software now has a "simulation" channel which essentially functions by inferring the cars max capabilities from the overall data and then constructing a simulated lap using everything to the max. I was frankly skeptical as to how valuable this might be, until I had a chance to review some data late last year with our chief software engineer. Looking at my best lap ever at Summit Point (comparing my real lap to the sim lap), and with him knowing nothing about my car or the track, he zeroed in immediately to the main brake zones - where, on close analysis, I'm obviously giving up maybe 0.5 secs or a bit more due to not really trusting / underutilizing the brakes.

Until the brakes get too hot, they WILL lock up - but I'm obviously unconsciously babying them even when trying to go fast...

 

[JohnMcNaughton]

I never saw anyone comment about brake bias. You could be using way too much front bias, and underusing the rears. Spread the workload.

I am firmly on Jay's side, you can never get too much air to the brakes. Use front brake ducts to funnel more air into the hose. Use good ducting, 3" or 4", in the front brakes, to increase air volume and pressure in the air hose. Small tire friction cuts in the air hose will bleed off a lot of air flow from the brakes. Carefully construct the release of the air to the calipers and discs. If you have ventilated discs, seal the air flow at the center of the disc, to force it to exit thru the vanes outer dimensions. Others have offered comments & sources for cans to use on solid discs.

I have found I can go faster if I stay off the brakes. Something you may not even be aware of, are you holding a hesitant foot over your brake pedal... Even a little drag is not good, just more heat.

 

[Larry Frankenstein]

Been reading this and have been planning a brake upgrade. Could youse guys post up some pics of your ducting etc.

Thank you,
L

 

[loopracing]

here's some brake scoops for vented discs. Uses 3" hose from air dam down to 2.5" hose. By having air directed with no loss, 2.5" is adequate.

 

[Al Seim]

Lucky so-and-so's with newfangled cars w/ ventilated discs.......

Jay - speaking of getting air to the right places - am I correct in assuming that vented discs would be a lot as opposed to a little better in terms of thermal shedding? (Assuming sensible airflow management in both cases)

 

[Jay Lutz]

Al, a LOT better, not a little better

The white duct pics look like the set I initally made from styrofoam insulation glued together with Elmers glue, sanded to fit including an aluminum insert for the bolt, paint with ordinary latex wall paint as a solvent barrier, coat with polyester (aka cheap) filberglass, let harden, dissolve foam in gasoline.......pretty it up, paint it up, mount, attach hose.

Most of you won't support this (reason soon obvious) but a #303 can (yes a 15oz green bean can from the pantry) is the perfect size to make a cheap cooling can for 3" OD hose.. Just weld on bolt flange to attach to the knuckle, cut the appropriate slot for the rotor, attach hose. I actuall ran tin can ducts on my Hcar for 5 years with no problem.

Admittedly........... they were a little hillbillyish looking.

 

[Greg Nagy]

It's probably a day's worth of work to get it all installed.
honestly you wouldn't even have to run it through a DAQ if you could code a PLC. just look at four inputs and do a frequency count on each one. if any one is, say 10% slower than the others, then you fire an output pin that goes to a dummy light on your dash.

I can't wait for the 'DNF - Stuxnet'

 

[joecam96]

Most of you won't support this (reason soon obvious) but a #303 can (yes a 15oz green bean can from the pantry) is the perfect size to make a cheap cooling can for 3" OD hose.. Just weld on bolt flange to attach to the knuckle, cut the appropriate slot for the rotor, attach hose. I actuall ran tin can ducts on my Hcar for 5 years with no problem.

Jay, I'm not laughing, somewhere I had a photo of soup cans over rotors on an early pro Trans-Am car.

 

[mg_john]

Most of you won't support this (reason soon obvious) but a #303 can (yes a 15oz green bean can from the pantry) is the perfect size to make a cheap cooling can for 3" OD hose.. Just weld on bolt flange to attach to the knuckle, cut the appropriate slot for the rotor, attach hose. I actuall ran tin can ducts on my Hcar for 5 years with no problem.

Admittedly........... they were a little hillbillyish looking

.

Jay:

My kind of modification! Cheap and effective! And maybe I can get someone to make me a green bean casserole!

And, living in Walhalla, SC hillbilly fits right in.

Thanks,

John

 

[racerbob4]

.

Most of you won't support this (reason soon obvious) but a #303 can (yes a 15oz green bean can from the pantry) is the perfect size to make a cheap cooling can for 3" OD hose.. Just weld on bolt flange to attach to the knuckle, cut the appropriate slot for the rotor, attach hose. I actuall ran tin can ducts on my Hcar for 5 years with no problem.

Admittedly........... they were a little hillbillyish looking.[/quote]


Do you leave the labels on?

 

[Al Seim]

Maybe time to write another "please let me run vented rotors" letter, brake rotors off a GTI Rabbit bolt straight on.

Then I can make some cool fiberglas ducts like above instead of aluminum bean cans...

If I do I'll have to provide some documentation of what I believe but do not know for sure, which is that the 1600cc VW has an abnormally high axle weight / swept area brake loading for a non-vented brake Prod car.

Some may disagree but I've never really come to grips with "performance limitation via brake thermal dissipation"..... Coupled with the fact that the 1600cc VW HP car is hardly a current overdog.