Anyone have any brake questions? - Page 43 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


General Miata Chat A place to talk about anything Miata

Reply
 
 
 
LinkBack Thread Tools
Old 07-14-2016, 02:17 AM   #841
Elite Member
 
codrus's Avatar
 
Join Date: Mar 2007
Location: Santa Clara, CA
Posts: 3,473
Total Cats: 283
Default

Quote:
Originally Posted by ryansmoneypit View Post
I understand that, but I thought it would have the ability to flow 100% or less. Not some random amount and less.
(edit: was confusing two posts).

If you removed the stock prop valve and installed an adjustable one that you can dial all the way down to zero, then yeah, you should probably be able to lock the rear brakes. This depends on a bunch of things though, one that's not totally obvious is that the stickier tires you have, the more weight transfer you get, and the less rear bias you want. At one point my car was perfectly stable on street tires, but would lock the rears with R comps.

I have two brake pressure sensors, one of these days I'm going to get around to installing them at various points in my system and measure what's what.

--Ian
codrus is online now   Reply With Quote
Old 07-14-2016, 09:27 AM   #842
Supporting Vendor
Thread Starter
iTrader: (1)
 
OGRacing's Avatar
 
Join Date: May 2014
Posts: 1,650
Total Cats: 64
Default

Quote:
Originally Posted by gtred View Post
Thxs for the great info OG.

Unfortunatly, I still do think that I'm screwed. You see, I've "upgraded my brakes"... and now my shiny BBK's won't stop the car.

There are various opinions on whether or not a 2004 MSM has ABS with EBD. It sounds like if it does have EBD, then I can turn that prop valve all I want and the car still may not stop.

Here's what I did to a nice set of your PFC's at the end of an enduro. The sad thing is that I really couldn't tell much difference in threshold braking... just that same vague "step on the pedal like a gorilla kind of feeling" ... without stopping much. ...that is until my wheel caught fire d//t a hydraulic failure.


I've tried mult suggestions of using different pad manufacturers and combo's. Hawk, PFC, Carbotech's, ect. Still, the car will only stop a -.78 g. (while I gleaned the happy side of -1.0 g with OEM's on an old set Hawk Blues).



I think that much of the problem has arisen form the dynalite having a much smaller caliper piston size (3.00 sq in) that the OEM caliper (3.54 sq in). Willwood doesn't make a 3.5 dynalite or dynapro in a lug mount (only a radial mount dynapro)My Wilwood prop valve is installed just off the MC ( and before the ABS pump). Willwood specs that this will cut off all line pressure to the rear until the pressure reaches 100#. I then has an adjustable knee. They don't specify the slope of the pressure ratio's. I've never been able to adjust this adequately.

I did even test out using a smaller piston (non-sport) rear caliper... which was a fail.




After reading your article on prop valves, If my car does have EBD, then I might just turning that **** in futility.
hello gtred,
you used up all of those PFC pads... and then some!
If your finding a limit of .78 with all of those pad manufacturers where seeing -1 with blues. the limit in braking G is not in the pads. I did mention before that the brakes don't stop the car, the tires do. do take some time a re-read the first few pages as we cover that topic in detail. i'ts hard to diagnose what changes have been made to the car from your first test to now.


from my experience .78G in braking is very low, on our data we see consistently see 1.03g on the PFC 10/11 combination maxxis rc-1 tire.that's using my driving and i'm not very good or aggressive. what device are you using to measure? if your using a hand held device like a phone or even a AiM solo. moving it's mounting point in the chassis will change the data. oh and if your going to have wine in the garage man rules dictate we use a mason jar :P JK.

Last edited by OGRacing; 07-14-2016 at 09:40 AM.
OGRacing is offline   Reply With Quote
Old 07-14-2016, 10:21 AM   #843
Elite Member
iTrader: (6)
 
Join Date: Feb 2013
Location: Staunton, Va
Posts: 1,972
Total Cats: 145
Default

I see now, that I was duped into thinking that a proportional valve, was going to actually be able to control flow in a proportional manor, from full pressure to zero.
ryansmoneypit is offline   Reply With Quote
Old 07-21-2016, 09:13 AM   #844
Junior Member
 
Join Date: Jun 2016
Location: Dousman, WI
Posts: 116
Total Cats: 10
Default

All right, here's a kind of unusual question - I'm looking at floor mounted reverse type pedal box, which is to say the sort with the master cylinders pointing rearwards, on the theory that I can get everything spaced farther towards the firewall that way. It looks like the only ones that aren't megabucks are the OBP and Tilton 600 series ones. Are there any others I should be considering? Not to put too fine a point on it, but stretching the budget to an AP pull type box isn't in the cards.
mekilljoydammit is offline   Reply With Quote
Old 07-21-2016, 11:17 AM   #845
Junior Member
 
Join Date: Apr 2011
Location: Oregon
Posts: 233
Total Cats: 6
Default

Quote:
Originally Posted by OGRacing View Post
hello gtred,
you used up all of those PFC pads... and then some!
If your finding a limit of .78 with all of those pad manufacturers where seeing -1 with blues. the limit in braking G is not in the pads. I did mention before that the brakes don't stop the car, the tires do. do take some time a re-read the first few pages as we cover that topic in detail. i'ts hard to diagnose what changes have been made to the car from your first test to now.


from my experience .78G in braking is very low, on our data we see consistently see 1.03g on the PFC 10/11 combination maxxis rc-1 tire.that's using my driving and i'm not very good or aggressive. what device are you using to measure? if your using a hand held device like a phone or even a AiM solo. moving it's mounting point in the chassis will change the data. oh and if your going to have wine in the garage man rules dictate we use a mason jar :P JK.
Yes, I was thru the PFC's, the backing plate and was testing the mu of my caliper piston on that lap.

I'm using an AIM solo that's mounted on the steering wheel hub. Any better placement suggestion?

Thank you for giving me your baseline numbers of 1.03g. This is what I'll shoot for..

I've re-licensed / insured the car now, so I can try some "back road" tuning. Perhaps my problems stem from trying to dial in the brakes during a raceday...it's just too cumbersome to have to come into the hot pits, unbuckle the net, belts and Hans, then lift the hood to adjust the brakes during qualifying. And, you really can't get the speed you need just driving around the paddock without upsetting the Pit Marshal. The Rose cup race is at the end of the month, and I'd really like to participate; but it's a chicane race and I will need good brakes.

My set-up is: 225 Hoosier r's on 9" rims. 800#/425#/MCS/Eibach bars. I've got an 11.75 TSE BBK kit that I'll replace my std 11" Wilwood kit with. I'll probably use a set of Carbotech pads that I have; I think 8/10. OEM rear sport brakes. I've got some hydraulic bits + pieces ordered from Good-win, so hopefully I can assemble and tune the brakes without any more drama. l can try to tune the prop valve with ABS fuse pulled, or I might even remove the ABS completely, just to simplify.


gtred is offline   Reply With Quote
Old 07-21-2016, 01:19 PM   #846
Junior Member
 
Join Date: Oct 2010
Location: LI, NY
Posts: 79
Total Cats: 9
Default

GTRed,

Have you thought about relocating the proportioning valve to the cabin with goodwin's kit?
BMWidmer is offline   Reply With Quote
Old 07-27-2016, 09:05 AM   #847
Junior Member
 
Join Date: Apr 2011
Location: Oregon
Posts: 233
Total Cats: 6
Default

Quote:
Originally Posted by BMWidmer View Post
GTRed,

Have you thought about relocating the proportioning valve to the cabin with goodwin's kit?
Great suggestion!

gtred is offline   Reply With Quote
Old 07-28-2016, 09:17 AM   #848
Supporting Vendor
Thread Starter
iTrader: (1)
 
OGRacing's Avatar
 
Join Date: May 2014
Posts: 1,650
Total Cats: 64
Default

Quote:
Originally Posted by mekilljoydammit View Post
All right, here's a kind of unusual question - I'm looking at floor mounted reverse type pedal box, which is to say the sort with the master cylinders pointing rearwards, on the theory that I can get everything spaced farther towards the firewall that way. It looks like the only ones that aren't megabucks are the OBP and Tilton 600 series ones. Are there any others I should be considering? Not to put too fine a point on it, but stretching the budget to an AP pull type box isn't in the cards.


I went with the tilton600 Reverse mounts. they sit a little closer. i have done one autocross since the install and the closer pedals weren't an issue. hardly noticed.
OGRacing is offline   Reply With Quote
Old 07-28-2016, 11:32 AM   #849
Junior Member
 
Join Date: Jun 2016
Location: Dousman, WI
Posts: 116
Total Cats: 10
Default

Exactly the box I was looking at, thank you. I can kinda wish there was a trunion version that was reverse mount, but then I likely wouldn't be able to afford it, the same way I really really can't afford the pull type AP box. I did however see a setup on ebay once that had machined adapters to fit the 77 series master cylinders to a 2-bolt flange with a modified brake pedal to accept the Tilton trunion style balance bar - is that something off the shelf and do you have any idea how much better the 900 series pedal stuff is than the 600 series?
mekilljoydammit is offline   Reply With Quote
Old 08-12-2016, 12:20 AM   #850
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 16,823
Total Cats: 1,251
Default

Getting what look like cracks in the rotor. Should I get new rotors? Or is this normal.



aidandj is offline   Reply With Quote
Old 08-12-2016, 03:09 AM   #851
Elite Member
 
codrus's Avatar
 
Join Date: Mar 2007
Location: Santa Clara, CA
Posts: 3,473
Total Cats: 283
Default

That's normal. Replace when the cracks go all the way to the edge, like this:



--Ian
codrus is online now   Reply With Quote
Old 08-12-2016, 09:45 AM   #852
Sadfab Union President
iTrader: (3)
 
Join Date: May 2014
Location: Kansas
Posts: 2,690
Total Cats: 114
Default

Quote:
Originally Posted by aidandj View Post
Getting what look like cracks in the rotor. Should I get new rotors? Or is this normal.

$20 rotors still? Do you remember how many track days you've got from them?
deezums is offline   Reply With Quote
Old 08-12-2016, 09:51 AM   #853
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 16,823
Total Cats: 1,251
Default

Like 8 now. Went through 1 set of pads.
aidandj is offline   Reply With Quote
Old 08-14-2016, 05:51 PM   #854
Newb
 
Join Date: Feb 2016
Posts: 26
Total Cats: 0
Default Hydrolic E Brake

I have a question.. I just got a ASD Hydro E brake (Pass through style) for my 91 miata (1.6) and see the OEM e brake is ran by cable. Is it the same process to install as all of the other install DIY's i found; which is basically finding the brake line that goes from the master cylinder under the car and cut into/flare it before it splits off into the rear?

Just want to make sure this will work before i start cutting into lines.

Thanks!
Mikey
boriicuaz is offline   Reply With Quote
Old 08-14-2016, 11:00 PM   #855
Supporting Vendor
iTrader: (3)
 
emilio700's Avatar
 
Join Date: May 2005
Posts: 4,852
Total Cats: 992
Default

Just received a pre-production Stoptech radial mount bridge bolt ST42 280mm (11") kit for an NA8 for evaluation. It comes with a 15/16" Sport master, Sport rear calipers, 1 piece rear rotors and race pads. ST42 is a burly caliper with staggered 36/30mm pistons.
The intent is to allow any generation chassis be it NA6, NA8, NB1 or NB2 and upgrade path that balance torque ratios front and rear. The system is modular so you can get it without the master or calipers or however you need it. The OEM stuff is all Centric new or reman. In the next few weeks I'll start a new thread with more pics and info as I get it. We'll stick this in Taxi with the 180whp race engine, Quaife sequential.

Pads are DR22 which is almost identical to a Wilwood 7816 in pad volume, around 3.0 inches. Piston area is between the small Superlight and the 1.38" Dynapro and Dynalite that most every else uses. Front rotors are nice 8 bolt 2 piece with left and right directional friction rings. By my math, the torque ratios should be pretty much spot on. Preliminary retail pricing looks attractive considering the caliper makes even the Dynapro 4 look flimsy. I'd equate it more to the Superlight in terms of apparent mass/rigidity.

Last edited by emilio700; 08-15-2016 at 08:11 PM. Reason: updates
emilio700 is offline   Reply With Quote
Old 08-14-2016, 11:04 PM   #856
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 16,823
Total Cats: 1,251
Default

Is that any different than the kit available here: StopTech Big Brake Kit for Mazda Miata | Garage Star
aidandj is offline   Reply With Quote
Old 08-14-2016, 11:27 PM   #857
Mr Broke Pants
iTrader: (8)
 
thumpetto007's Avatar
 
Join Date: Sep 2010
Posts: 1,329
Total Cats: 64
Default

Quote:
Originally Posted by emilio700 View Post
Just received a pre-production Stoptech radial mount bridge bolt ST42 280mm (11") kit for an NA8 for evaluation. It comes with a 15/16" Sport master, Sport rear calipers, 1 piece rear rotors and race pads. ST42 is a burly caliper with staggered 36/30mm pistons.
The intent is to allow any generation chassis be it NA6, NA8, NB1 or NB2 and upgrade path that balance torque ratios front and rear. The system is modular so you can get it without the master or calipers or however you need it. The OEM stuff is all Centric new or reman. In the next few weeks I'll start a new thread with more pics and info as I get it. We'll stick this in Taxi with the 180whp race engine, Quaife sequential.

Pads are DR22 which is almost identical to a Wilwood 7816 in pad volume, around 3.0 inches. Piston area is between the small Superlight and the 1.38" Dynapro and Dynalite that most every else uses. Front rotors are nice 8 bolt 2 piece with left and right directional friction rings made by Coleman it looks like. By my math, the torque ratios should be pretty much spot on. They also have a 300mm (11.75") waiting in the wings but I'm not sure if that will make it to production. Preliminary retail pricing looks attractive considering the caliper makes even the Dynapro 4 look flimsy. I'd equate it more to the Superlight in terms of apparent mass/rigidity.
I need to get in the habit of calling you before ordering anything. I just wasted 2500 dollars with the radial mount dynapro.
thumpetto007 is offline   Reply With Quote
Old 08-15-2016, 01:43 AM   #858
Supporting Vendor
iTrader: (3)
 
emilio700's Avatar
 
Join Date: May 2005
Posts: 4,852
Total Cats: 992
Default

Quote:
Originally Posted by aidandj View Post
Is that any different than the kit available here: StopTech Big Brake Kit for Mazda Miata | Garage Star
Looks like it. We have two other two other radial mount kits that we are playing with now to compare it to on track. We're hoping we can come up with some conclusions and share that information in a new thread later.
emilio700 is offline   Reply With Quote
Old 08-15-2016, 01:47 AM   #859
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 16,823
Total Cats: 1,251
Default

Quote:
Originally Posted by emilio700 View Post
Looks like it. We have two other two other radial mount kits that we are playing with now to compare it to on track. We're hoping we can come up with some conclusions and share that information in a new thread later.
:Bigtu:
aidandj is offline   Reply With Quote
Old 08-15-2016, 10:49 AM   #860
Supporting Vendor
Thread Starter
iTrader: (1)
 
OGRacing's Avatar
 
Join Date: May 2014
Posts: 1,650
Total Cats: 64
Default

Why does it look like your only using the upper 2/3's of the rotor? if your pads are using the full swept area you have some major rotor coning going on.

Quote:
Originally Posted by aidandj View Post
Getting what look like cracks in the rotor. Should I get new rotors? Or is this normal.

OGRacing is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Project Gemini - Turbo Civic on the Cheap Full_Tilt_Boogie Build Threads 55 05-06-2017 08:18 PM
15x10 - 15x11 6UL @ 949 Racing emilio700 Wheels and Tires 148 04-25-2017 09:41 AM
1994 Spec Miata Race Car SM/SM2/SSM For Sale Quinn Cars for sale/trade 6 10-23-2016 07:58 AM
Raleigh: Fiberglass headlight scope, 1.6L ECU, AFM, Hardtop latches, more bigmackloud Miata parts for sale/trade 9 11-07-2015 11:58 PM
Leaky Wilwoods mx592 Suspension, Brakes, Drivetrain 1 10-01-2015 12:45 AM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 02:08 AM.