Cracks in rotors

danegrey

Ok, old, but still learning about cars and tracking..

After my last track night, looking at the rotors and I have noticed cracks in both front rotors. My assumption that they need to replace. They are Z1 Motorsport - Z1 (Sport) Performance Brake Rotors - Akebono. They have seen about 10 track events.

Also when putting on the brakes a lot of vibration, on most corners (street driving no vibration)

Not sure what is going on, looking to be educated on all of this...

(probably will reorder the Z1 (Sport) Performance Brake Rotors - Akebono, would look like the 2 piece rotors, but not time yet)

thanks for all the help/education/insight...
Cheers

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Lots of Changes
the Z needs to be driven and driven hard for the car lives for it

Rusty

Pictures?

Mirco surface cracking or cracks?

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BGTV8

Cracks that extend to the edge of the rotor mean the rotors are toast.

Brake judder on the track and no judder on the road usually means you have hard spots on the rotor from heat soak at the end of a track session.

When a session ends, don;t park the car and leave it, you need to move the can forward 2 feet every minute or so such that no single spot on the rotor stays under the hot pads for more than a minute of so - which leads to differing hardness in the rotor

Also, what pads are you using on the track .... same as DD pads ?

And do you have any rotor cooling set up ?

danegrey

Carbotech XP10 front/Carbontech XP 8 rear

yes I have stillen braking cooling in place

Thanks all for helping and the education

pictures:

IMG-3691 (1).jpg

IMG-3694 (1).jpg

IMG-3692 (1).jpg

IMG-3693 (1).jpg

IMG-3690 (1).jpg

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Lots of Changes
the Z needs to be driven and driven hard for the car lives for it

Rusty

Your rotors are toast. You got cracks in the drilled holes. You should know better then to track with drilled rotors. They always start to crack at the holes.

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danegrey

I known now, I young and foolish

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Lots of Changes
the Z needs to be driven and driven hard for the car lives for it

Rusty

Learning the hard way gets $$$$

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Tractionless

Same could be said about removing the steering lock fuse. Fact of the matter is no one listens then wants to complain and send out an SOS when it all goes south.

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Toys Not Tots

Spooler

Yeah, if you track, slotted only is the only way to go.

JARblue

Be careful with the Z1 2-piece rotors. I know a few people who regretted their purchase when the rotors didn't stand up to their track abuse. Brake rotors act as a heat sink for cooling so more mass is not necessarily a bad thing. The unsprung weight reduction of the Z1 2-piece is really nice but the downside they run much hotter under extreme conditions.

You keeping an eye on DarkJak's rotor and caliper thread?

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Rusty

RacingBrake rings have some mass to them. They're thick.

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2011 Nismo#91

Yeah you need new rotors unfortunately. If you only had short cracks at the drilled out parts I would say you are OK; But you would need to check them regularly to make sure they didn't grow into the long cracks that extend to the edge. Those mean the rotor can break apart at any moment under hard braking.

I have had a lot of luck with FrozenRotors, they are cryogenically treated rotors, they are relatively inexpensive and hold up to a lot of abuse. Simple blank rotors are what I use, sure they don't look fancy but they work well and don't break the bank.

There are many good rotors available. Two piece rotors are good bit they are very pricey and I don't feel the weight savings, increased performance, is there for the average user. For competition sure take every edge you can to win and have the sponsors share the cost or replacing them. Slotted rotors are good too but wear the pads down unnecessarily quickly for no real gain, unless your using pads from the 90s.

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danegrey

thanks all for the input and help, definitely teaching me a few things, and what to think about next year... Will probably redo the rotors totally based on the comments provided.

I order the same as before, Z1 (Sport) Performance Brake Rotors, with holes and slots, but was able to change my order just to slots. Doing another track event a week from Saturday, so figure ahead of time need to get them...

Thanks again

__________________
Lots of Changes
the Z needs to be driven and driven hard for the car lives for it

OptionZero

isn't this exactly why cross-drilled is a poser mod?

less structural integrity due to how they're manufactured and less mass do soak heat, minimal advantage in airflow

two-piece for the weigh reduction and most versions have superior internal venting

or

upsize to bigger setup that has more mass (and other features)

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Rusty

What's funny. With cast iron. You drill holes at the end of the cracks to stop the cracks. Here, you already have the holes. And the crack starts at the holes. Unequal thermal expansion and contraction of cast iron.

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