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vchengap

Pad/rotor recommendation for stock NC calipers

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At ECR this past weekend and I think I got some irregular pad deposit on my front rotors due to heat issues (with the resulting steering wheel judder upon braking).  Gear is Carbotech XP10 pads, standard Centric rotors, and Castrol SRF fluid. 

I'm thinking of trying a more aggressive compound (XP12 or XP20?) and possibly adding a vent kit from Goodwin.  What are all the NC folks using for pads and rotors on stock calipers?  Any recommendations?

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Use the brakes less.  Miatas don't need to slow for corners.  😛

 

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1 hour ago, Matt93SE said:

Use the brakes less.  Miatas don't need to slow for corners.  😛

 

😆 Seriously though - I do wonder if I'm being overly aggressive with the brakes considering I'm running pretty gnarly pads already.

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26 minutes ago, vchengap said:

😆 Seriously though - I do wonder if I'm being overly aggressive with the brakes considering I'm already running pretty gnarly pads already.

What compound tires are you running?

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The stock brake package can handle heavy use, but they require ducting.  Backing plates that cover the ID of the rotor, ducted to the front bumper are necessary (I think the Goodwin kit is fine).  Don't use a 2-piece rotor (worse performance), the Centric blanks are good.  The best pad combo we landed on with our IMSA cars was Pagid RS 29 front / RS 44 rear, but everyone has a favorite brand.  Having tested the brake package to its limits and well beyond, in hot endurance racing, this combo is pretty good.

Andris

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1 hour ago, Hollywood said:

What compound tires are you running?

200 TW.

Federal 595 RSR in front.  Hankook RS4 in rear.  Will switch to the Hankooks all around once the Federals wear through.

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Carbotechs demand stringent bedding before running them on track. Been there, done that. The judders sucks. Can skim rotors and restart the process.

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18 minutes ago, El_Tortuga said:

Carbotechs demand stringent bedding before running them on track. Been there, done that. The judders sucks. Can skim rotors and restart the process.

Yeah - that could definitely be a contributing factor. There's a story there. When I did my last front brake job, Carbotech sent me pads that were the wrong dimensions. I bedded those per their instructions before realizing they were faulty units. They then sent me the correct pads which I may have half-assed in bedding because I assumed the transfer layer from the first set would work just fine. 

Who knows. Probably just need to start over to your point.

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19 hours ago, El_Tortuga said:

Carbotechs demand stringent bedding before running them on track. Been there, done that. The judders sucks. Can skim rotors and restart the process.

This is the most truth thing ever written. I hated them on my Miata, just couldn't ever get them to work well and consistently. Of course, I have GLOC on the Lexus now and they seem fine. <shrug>

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On the topic of brakes, I went back through some of my data and compared with data from Sam (BRZ4Science) and Skip. The peak g-force I'm hitting on deceleration is considerably less than Sam's and Skip's even though they're running similar cars with similar setups.  

vchengap    -0.70g
BRZ4Science    -1.25g
865        -1.10g

I'm consistently peaking at about -0.70g (verified by both AiM GPS and internal accelerometer) whereas Sam and Skip are seeing considerably higher forces (-1.25g and -1.10g respectively). I appear to be losing precious time because I can't shed speed quickly enough.

There's only a couple possibilities I can think of:
- I'm not braking hard enough. Seems unlikely because I'm pretending it's leg day on the pedal in some corners.
- I'm not braking quickly enough. Am I being too smooth with brake application thereby reducing the g forces? Again, seems unlikely.
- My tires/brakes are not optimally set up. Not sure about this one. I went back through several years of data across several tracks and my peak deceleration is about -0.8g. Seems low for 200 TW tires, racing pads, and a light car.

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either you have a major bias issue causing ABS to kick in early and reduce total braking ability, or you're simply not braking hard enough..  ???  

not like you can go out and try it immediately, but next time you go to the track, certainly work on threshold braking technique.   get out on a straight and make sure there's nobody behind you, and STAND on the brakes.  also play around a little and see how the ABS feels at 60-70-80-90-100-110% braking effort.

I know if I go into a corner and stomp the brake pedal in my Infiniti, the ABS will kick in and actually reduce overall braking.  But if I tip into the pedal and give the car a little time for the front end to settle and then stand on the brake pedal, I can really get on them hard.  squeeze the pedal vs. kick it.

Previously, I hadn't tracked a car with ABS until I did the first day with my FRS back in January..   I was still gaining confidence every lap, but I could feel the ABS pump engaging (vibration in my foot) while going into diamonds edge even at 60-70% braking effort.  but I kept getting on them harder each lap and the car kept stopping harder.   going to take a lot of time to get used to since I've been tracking/ racing cars for almost 20 years with no ABS!!!

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13 minutes ago, vchengap said:

On the topic of brakes, I went back through some of my data and compared with data from Sam (BRZ4Science) and Skip. The peak g-force I'm hitting on deceleration is considerably less than Sam's and Skip's even though they're running similar cars with similar setups.  

vchengap    -0.70g
BRZ4Science    -1.25g
865        -1.10g

I'm consistently peaking at about -0.70g (verified by both AiM GPS and internal accelerometer) whereas Sam and Skip are seeing considerably higher forces (-1.25g and -1.10g respectively). I appear to be losing precious time because I can't shed speed quickly enough.

There's only a couple possibilities I can think of:
- I'm not braking hard enough. Seems unlikely because I'm pretending it's leg day on the pedal in some corners.
- I'm not braking quickly enough. Am I being too smooth with brake application thereby reducing the g forces? Again, seems unlikely.
- My tires/brakes are not optimally set up. Not sure about this one. I went back through several years of data across several tracks and my peak deceleration is about -0.8g. Seems low for 200 TW tires, racing pads, and a light car.

have someone else drive your car (maybe even one of those guys) with the data on, it'll answer all the above.

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Quick update on the peak g-force during braking.  I did some testing in an empty parking lot today and may have found my issue.  It seems that I may not be braking hard enough.  I really put some leg into it after warming up the tires/brakes and was able to get near -1.1g.  I crosschecked the g's with the brake pressure readout from my ECU and confirmed that I needed a much higher brake pressure to breach the -1.0g mark.

It's definitely an odd feeling to discover something like that after 8 years of HPDE events. Potentially game changing in terms of gaining a couple easy seconds at the track. I'll do some more testing at MSR-C this weekend on the 3.1. Just weird to think that I may have to retrain my brain on braking after all these years. Wish I had noticed this flaw in my technique years ago.

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it's always a bummer to figure out the problems with the car were driver-induced. 😕

 

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I'm using Hawk DTC60 front and 30 rear, mainly because that's what the Playboy Cup cars ran

Like the stopping and other characteristics but hate the dust.  And they don't last very long as compared to PF97 I ran on my NA

Do get the GWR brake duct kit.  I have it and so does Skip, but he now has Wilwood front brakes

At the recommendation of a couple of people, I'm soon going to try the Raybestos ST43.  Skip has them now.  One user calls them the "magic pad"

At the recommendation of MER, I'm using Centric blanks.  Sign up with Rock Auto for their "closeout" sales emails.  Recently got a set for $22 each.

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Have you done any checking to find the max pad temperature you're getting to?   the higher the temp, the faster the wear on the pads.  so if you're getting the pads too hot, they will wear quickly and obviously make lots of dust.

I've run the DTCs on my cars for a long time, but usually stick with the DTC70 on the Nissan due to the higher temp capacity.  They dust, but not awful- then again, it's wilwood Superlites on a 150hp car so it's not a ton of heat.  Pads last >40hrs/set on that car.

The RX7 can only get the DTC60 but needs better.  it dusts like mad.  inside of wheels are black and pour dust out after a race weekend.  pads last about 4-6 hours/set.

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On 5/14/2020 at 8:39 AM, Matt93SE said:

Have you done any checking to find the max pad temperature you're getting to?   the higher the temp, the faster the wear on the pads.  so if you're getting the pads too hot, they will wear quickly and obviously make lots of dust.

I

No I haven't.  I have ducting so not much more I can do.  Depending on which track(s) I run, I get between 400-600 track only miles per set.  I've gone to the thicker ones as used in Playboy Cup to cut down on the labor part.

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On 5/14/2020 at 8:14 AM, nealb said:

I'm using Hawk DTC60 front and 30 rear, mainly because that's what the Playboy Cup cars ran

Like the stopping and other characteristics but hate the dust.  And they don't last very long as compared to PF97 I ran on my NA

Do get the GWR brake duct kit.  I have it and so does Skip, but he now has Wilwood front brakes

At the recommendation of a couple of people, I'm soon going to try the Raybestos ST43.  Skip has them now.  One user calls them the "magic pad"

At the recommendation of MER, I'm using Centric blanks.  Sign up with Rock Auto for their "closeout" sales emails.  Recently got a set for $22 each.

I ran the Hawk DTCs a couple years ago and was really disappointed with how quickly I burned through them.

Are the Raybestos ST43 available for the stock NC calipers? I don’t have the budget to pony up for Skip’s setup at the moment. Thinking about trying a higher temp pad like GLOC 12 or 14 to see if that helps with the fade issues I’m having. I also run cheapo Centric blanks and never had any issues with them. 
 

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I have carbotech xp12s up front and RS4 tires. I tend to see about .8G under braking as well, with max a bit over .9G. I know my braking isn't great, and it sounds like I may be in the same boat as you on brake force. I guess I really need to get on it more and see what happens.

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On 5/16/2020 at 10:24 PM, vchengap said:

I ran the Hawk DTCs a couple years ago and was really disappointed with how quickly I burned through them.

Are the Raybestos ST43 available for the stock NC calipers? I don’t have the budget to pony up for Skip’s setup at the moment. Thinking about trying a higher temp pad like GLOC 12 or 14 to see if that helps with the fade issues I’m having. I also run cheapo Centric blanks and never had any issues with them. 
 

Yes, I got ST43 for OEM calipers from Porterfield.  If you are SCCA member, 10% discount

 

Haven't installed them yet, still going thru some DTC60 I had stockpiled

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