Jump to content
Please check your junk folder for registration emails ×
  • Current Donation Goals

    • Raised $0.00

Cracking rotors at Trackdays


Recommended Posts

So, for the second consecutive trackday ive managed to crack a rotor. They were new about a year ago, OEM type ones from Subtech. Original pads were bendix ultimates, just swapped to pagid RS-29 ones. I was braking pretty heavily, sometimes activating abs i guess which probably didnt help things either.

Anything I can do to help stop this happening in future? Less aggressive on brakes is an option I guess, but a bit hard to do when trackday adrenaline kicks in. Ill look at removing the ABS fuse as well.

Ducting?

Proper aftermarket rotors?

???

Link to comment
Share on other sites

whats the car, its weight, the track, weather conditions, your overall treatment of braking application, power, current brakres installed..

What do you define as less aggressive? often its the opposite, more aggressive cracks less... think about it and let me know what you think.

Link to comment
Share on other sites

Hampton downs: maybe high teen degrees air temp, dry, main straight braking from 200kph

Taupo: similar conditions/braking I guess.

Cars stock, 1300kg version 6 sti? Brakes are stock 4 pots with pagid rs-29 pads. RE11 road tyres. Taupo only really has the 3 main braking zones I guess which are in a straight line, so braking heavily for 50-75m then turn into corners.

This time as well i made sure to rotate the wheels a bit when parked up every so often to rotate the heat. Did a cool down lap after each stint barely using brakes.

Link to comment
Share on other sites

on road tires i dont see you getting to the cracking point, even at factory weight.

do you have an unrestricted front air dam area?

some times people think that being softer on brakes = better.. the nana them but sit on them for longer .. this often cooks them more.

get on them hard, slow down, and get off them. = better technique imo.

potentially your 294mm rotors might have heat soaked to much and could do with larger ones but thats working around the problem.

maybe those pads are causing it too. could also be bad luck - ive never cracked one yet, pushing more power, but on brembos, but we\'ve never run ducting yet #touchwood.

Link to comment
Share on other sites

Yeah im on the brakes as hard as I can be tbh, to the point of the abs sometimes coming on a bit. The front end of the car is all stock, so i dont know how good that is for airflow. Cracked a rotor with both the pagids and bendix ultimates.

Sigh, maybe its time to do a bembros upgrade....

Link to comment
Share on other sites

 AdamOst said:

Yeah im on the brakes as hard as I can be tbh, to the point of the abs sometimes coming on a bit. The front end of the car is all stock, so i dont know how good that is for airflow. Cracked a rotor with both the pagids and bendix ultimates.

Sigh, maybe its time to do a bembros upgrade....

i dont think you should need to honestly. are you rotors going a gross blue color before cracking? are you getting pad material left on the rotors?

also what fluid are you running.?

Link to comment
Share on other sites

i\'ve been through this exercise with a fairly stock sti.

i don\'t think there is a one-size-fits-all remedy. this is what i\'ve tried anyway, i still ruin the 4pot/1pot setup with bendix ultimates over a trackday but no major failures recently.

-pay extra attention to warming them up on the outlap, and cooling them on the inlap. ie. not using the brakes AT ALL to allow an airgap between pads and rotors in the pits. some pit entries are interesting to coast into, but i just nudge the handbrake if needed

-whilst in pits, i push the car to help cool the rotors evenly

-made sure front wheel bearings are good. ruined many many rotors until i sorted this. 2nd hand hubs are asking for failure, i pressed in genuine new bearings

-adjusted my braking style. i tend to brake about 80% of the available brake... this doesn\'t mean i don\'t brake hard, but as the car slows into corner entry i just dont brake harder while everything is red hot. (at that point there is more braking available just dont use it) i brake a little earlier to compensate. its a bit weird as people say i do brake late?

-loose all the extra car weight possible

-bring extra rotors :)

have managed a dozen spirited laps of manfield at good pace. ran out of fuel and stamina before the brakes gave up

Link to comment
Share on other sites

 kamineko said:

i\'ve been through this exercise with a fairly stock sti.

i don\'t think there is a one-size-fits-all remedy. this is what i\'ve tried anyway, i still ruin the 4pot/1pot setup with bendix ultimates over a trackday but no major failures recently.

-pay extra attention to warming them up on the outlap, and cooling them on the inlap. ie. not using the brakes AT ALL to allow an airgap between pads and rotors in the pits. some pit entries are interesting to coast into, but i just nudge the handbrake if needed

-whilst in pits, i push the car to help cool the rotors evenly

-made sure front wheel bearings are good. ruined many many rotors until i sorted this. 2nd hand hubs are asking for failure, i pressed in genuine new bearings

-adjusted my braking style. i tend to brake about 80% of the available brake... this doesn\'t mean i don\'t brake hard, but as the car slows into corner entry i just dont brake harder while everything is red hot. (at that point there is more braking available just dont use it) i brake a little earlier to compensate. its a bit weird as people say i do brake late?

-loose all the extra car weight possible

-bring extra rotors :)

have managed a dozen spirited laps of manfield at good pace. ran out of fuel and stamina before the brakes gave up

Did most of that really :( Might have gone a bit rough on the outlap on one of my stints. I now have a spare for future issues, was only 75$ each fomr partmaster. Thankfully Taupo had some in stock so I flicked the old one off, put the new one on, did a few shakedown laps to bed it in and off i went again.

My final session at taupo was 13 laps, with a big off but had no real problems with fade or anything. Same the first time i went to hampton downs

Link to comment
Share on other sites

"This time as well i made sure to rotate the wheels a bit when parked up every so often to rotate the heat. Did a cool down lap after each stint barely using brakes."

What does rotate the wheel a bit mean?..how often? how many turns? and for how long?..IMHO this is probably where they are cracking from.

Link to comment
Share on other sites

noticed the first one on the drive home, it was a bit wobbly in the steering wheel under braking but i thought ti was just the pads being low. Went to drive ot work the next day and it felt like a wheel was loose so checked them all and saw the crack. This time i noticed it when i went to swap the marshalls around the track. So both times its been after hot laps, not during.

Link to comment
Share on other sites

Have you looked into the sloted discs on t.m?

No info on how those would crack tho,iv seem discs red hot and no cracking

Almost as if the breaks were that hot and got cold water on them id say somthing like that could be possible?interesting to see the outcome

Link to comment
Share on other sites

  • General Member

Being after laps not during would make me think it might be a problem with our warm down process. I know its mentioned above but in the pits no handbrake and pushing the car forward and back seems fairly effective.

Do some reading into slotted, dotted etc. but seems to be a strong school of that that they arent much help and crack easier. I\'m considering a slotted set to replace my cracked one I have on the front currently.

Link to comment
Share on other sites

I wonder if it\'s just because you\'re doing 10+ laps at a time and your rotors aren\'t handling the strain of this. Becoming weakened and brittle so they crack once cooled/while cooling down. There\'s a lot of difference between doing spirited road driving and doing 200km->60km hard braking over and over again

I\'ve done ~6 trackdays, 1 with two pots, two with 4-pots and three with brembos and have never cracked a rotor, but I only do 5 laps per session generally.

Ducting as previously suggested is probably your best bet

Link to comment
Share on other sites

What Rob said is pretty much the cause 90% of the time when people take their road cars to track days. They stay out there for a whole session beating on the car. Generally this is more laps than an actual sprint race!

While having good pads and fluid certainly helps, there just isnt enough capacity in those rotors to take the prolonged heat generated lap after lap.

Add some brake ducting to help, or just dont do as many laps per session.

If you want to build some really effective ducts, you need to seal the back of the rotor off so that all the air you are forcing in goes to the centre of the hat, so it can be forced out the vanes and provide even cooling. I dont know if you want to go this far or not, but it is the best way to keep the discs cool... here is how I did mine:

Bumpsteer1.jpg

Its a lot easier to do this on Subarus as their front caliper is in the trailing position rather than leading. Just have to be careful when running the duct hose, as on the drivers side, it will be very close to the headers and can get burnt/damaged easily.

Fixed :)

Link to comment
Share on other sites

Might be the long stint, though i did a 13 lap stint at the end of the first trackday I went to at HD, then did an entire trackday with no issues at taupo, then did another TD at HD and did 3 normal stints, and felt the crack driving home again, then 8 months later did this trackday at taupo and felt it after my first session. These sessions are usually 1 warmup, 5 flying, 1 cooldown.

I never leave the handbrake on and always do a warm down lap at least not really using brakes. Generally my warmup lap is mostly tame, though once or twice I did go a bit hard I guess, dude to there only being a 20min gap since the last session. Ill try make more use of the warmup lap then, and for any long distance stints at the end of the day maybe take a slow lap or two in the middle.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recent Status Updates

    • MrSg9Sti04

      Afternoon team,
      im new to the group first time posting. Im hoping some body can help me get my launch control all dialled in on my link g4x. Ive had the computer and car all tuned from chris at prestige awesome knowlegable guy super happy with the results but now im wanting to get my launch/anti lag all dialled in. Ive been reading multiple different forums etc all with different conflicking information which has made me nervious with what do i listen to this or that if you get what i mean. Now ive started to make myself familiar with my PClink software etc the past few weeks and im eager to learn how to do minor setups or tweaks etc so im not relieing on my tuner so much and obviously saving myself abit hurt in the back pocket. 
      Now back to the question at hand.... Im wondering if theres and one who could please share there knowledge and wisdom with setting all my values, timing, fuel etc when i have launch control armed and engaged, or even a launch tune file they can possibly send me to load onto my tune. Ive figured out the setup of my digital inputs turning launch control on etc and its obvisously on its pre set factory settings. It engages but doesnt sound the greatest or as angry as it should i feel. Hence reaching out to you good buggers. 
       
      Cheers in advance for any info and help yous maybe able to give me.
       
      Cheers Shaun
      · 0 replies
    • Joker  »  gotasuby

      updated your DP's too : hope that's ok!
      · 0 replies
    • Joker  »  SAS

      Updated your DP's to reflect your business page  
      · 0 replies
    • Joker  »  Nachoooo

      Updated your Avatar : couldnt help myself  cheers!
      · 0 replies
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Forum Statistics

    40.9k
    Total Topics
    573.5k
    Total Posts


×
×
  • Create New...