Cracks in rotors

thekinn · 07-19-2021, 07:45 PM

Good on you OP for keeping a close eye on your car.

(assuming this is a hobby and you aren't racing professionally) I don't think I can subscribe to moving my car every two minutes after pulling in to the pits.. I've been tracking my car for over fifteen years and have never done this. Yes, I'll get pad deposits caked on a section sometimes, and after my next session.. its gone. Do your best to cool the brakes on your cool down lap.. (stay off the brakes and roll at a good pace, not a crawl.) you'll be fine.

JARblue · 07-19-2021, 11:16 PM

Ok so why would you ever engage any braking method after hot lapping? Just stop it on a flat surface or chock the wheels?

Rusty · 07-20-2021, 12:00 AM

Quote:

Originally Posted by JARblue

Ok so why would you ever engage any braking method after hot lapping? Just stop it on a flat surface or chock the wheels?

Many do. Or just leave in first, or in park.

Spooler · 07-20-2021, 01:14 AM

Quote:

Originally Posted by rusty

many do. Or just leave in first, carry a brick for a tire chock, or put it in park.

fify

tRidiot · 07-20-2021, 11:38 AM

Opinions are like aholes... plenty of 'em around here.

thekinn · 07-20-2021, 12:03 PM

I have never heard anyone at any HPDE, OTD, Race, say 'use the e-brake' when you park.
Unless you want to chisel your e-brake pads off the drum or call a tow truck..
drifting off topic..

DarkJak · 07-20-2021, 01:03 PM

Getting back on topic....

Definitely replace, and start monitoring rotor temps so you can figure out if ducting or better rotors are necessary.

Being able to run OEM style rotors is awesome (on the wallet) if you can make them work, because even the cheapest 2 piece rotor's rings are more than a set of Centric premiums.

DarkJak · 07-19-2021, 10:04 PM

Quote:

Originally Posted by JARblue

OP has a MT so there's no need to move the car every few minutes after hot laps. The e-brake is not leaving any deposits on the rotor surface.

For AT, I don't know why anyone would put it in Park after a hot lap. Just leave it in N and apply the e-brake.

I avoid applying the E brake with my 7AT. Rear rotors get to 650F after cool down and the hat piece is right next to it, which is where the drum brakes are, too.
I have no idea how hot the stock drum pads can get before fusing but have always heard to not use the e-brake after getting off the track.

The 7AT has a parking pawl that locks so you get a transmission brake which has no chance of fusing due to heat.

That said, I don't move my car after it's parked either. Nor do I do it with my E36, which gets almost to just 100F less on rotor temps. While I worry a bit on uneven cooling due to the caliper trapping more heat, it hasn't been enough to crack a rotor.

Tractionless · 07-22-2021, 08:20 AM

Quote:

Originally Posted by DarkJak

I avoid applying the E brake with my 7AT. Rear rotors get to 650F after cool down and the hat piece is right next to it, which is where the drum brakes are, too.
I have no idea how hot the stock drum pads can get before fusing but have always heard to not use the e-brake after getting off the track.

The 7AT has a parking pawl that locks so you get a transmission brake which has no chance of fusing due to heat.

That said, I don't move my car after it's parked either. Nor do I do it with my E36, which gets almost to just 100F less on rotor temps. While I worry a bit on uneven cooling due to the caliper trapping more heat, it hasn't been enough to crack a rotor.

I wouldn't keep my foot on the brake neither. I don't even do so on the street as you can see where the marcel builds up on the rotor which causes shuddering etc. that will then be diagnosed as warpage by someone trying to sell you parts. Can simply have the rotors turned to remove the marcel as long as they are within the service limits.

Rusty · 07-22-2021, 08:25 AM

Quote:

Originally Posted by Tractionless

I wouldn't keep my foot on the brake neither. I don't even do so on the street as you can see where the marcel builds up on the rotor which causes shuddering etc. that will then be diagnosed as warpage by someone trying to sell you parts. Can simply have the rotors turned to remove the marcel as long as they are within the service limits.

Marcell?

What's hair have to do with it.

Think you mean material.

Rusty · 07-19-2021, 10:44 PM

Quote:

Originally Posted by JARblue

OP has a MT so there's no need to move the car every few minutes after hot laps. The e-brake is not leaving any deposits on the rotor surface.

For AT, I don't know why anyone would put it in Park after a hot lap. Just leave it in N and apply the e-brake.

Never apply the e-brake after coming off the track and parking. The e-brake shoes can stick the their drum.

JARblue · 07-20-2021, 09:12 AM

Quote:

Originally Posted by Rusty

Never apply the e-brake after coming off the track and parking. The e-brake shoes can stick the their drum.

For the record, this is what the Nissan rep instructed me to do at the Nissan Performance Academy at COTA years ago. He said find a flat spot (make sure car isn't rolling in N) and then lightly apply the e-brake

Rusty · 07-20-2021, 10:22 AM

Quote:

Originally Posted by JARblue

For the record, this is what the Nissan rep instructed me to do at the Nissan Performance Academy at COTA years ago. He said find a flat spot (make sure car isn't rolling in N) and then lightly apply the e-brake

I've had a couple of instructors tell me not to use the e-brakes. There are a couple of different opinions it.

07-19-2021, 07:45 PM	#1 (permalink)
thekinn Base Member Join Date: Sep 2009 Location: Michigan Posts: 206 Drives: 06 350Z LS MT Rep Power: 6862	Good on you OP for keeping a close eye on your car. (assuming this is a hobby and you aren't racing professionally) I don't think I can subscribe to moving my car every two minutes after pulling in to the pits.. I've been tracking my car for over fifteen years and have never done this. Yes, I'll get pad deposits caked on a section sometimes, and after my next session.. its gone. Do your best to cool the brakes on your cool down lap.. (stay off the brakes and roll at a good pace, not a crawl.) you'll be fine. danegrey likes this. __________________ 06 Enthusiast MT - v2

07-19-2021, 11:16 PM	#2 (permalink)
JARblue A True Z Fanatic Join Date: Mar 2011 Location: Austin, TX Age: 44 Posts: 36,450 Drives: 11 Z34, 98 E36 M3 Rep Power: 2684441	Ok so why would you ever engage any braking method after hot lapping? Just stop it on a flat surface or chock the wheels? Hotrodz likes this. __________________ 2011 370Z 6MT Sport Gun Metallic \| ARC \| CJM \| Ecutek \| FI \| Fujimura \| R2C \| SPL \| Stillen \| TWM \| Z1 \| ZSpeed \|

07-20-2021, 12:03 PM	#6 (permalink)
thekinn Base Member Join Date: Sep 2009 Location: Michigan Posts: 206 Drives: 06 350Z LS MT Rep Power: 6862	I have never heard anyone at any HPDE, OTD, Race, say 'use the e-brake' when you park. Unless you want to chisel your e-brake pads off the drum or call a tow truck.. drifting off topic.. __________________ 06 Enthusiast MT - v2

07-20-2021, 01:03 PM	#7 (permalink)
DarkJak A True Z Fanatic Join Date: Jun 2011 Location: Madison, WI Posts: 1,397 Drives: 2009 370Z Rep Power: 16804	Getting back on topic.... Definitely replace, and start monitoring rotor temps so you can figure out if ducting or better rotors are necessary. Being able to run OEM style rotors is awesome (on the wallet) if you can make them work, because even the cheapest 2 piece rotor's rings are more than a set of Centric premiums. __________________ @stupidtoycars \| My track vids 09 7AT\|MCS 2WNR\|Topgunz Rotrex\|Ecutek (Eugene)\|Maxxis RC1\|Titan-7 TS-5\|OSG LSD\|Rear Mount Derale Oil Cooler (WIP)+25 Trans Cooler\|Fismo\|G-LOC R12/R10\|Zeta III L\|NLR Wing and Splitter\|CJM Pan and Fuel Hat\|Radium Surge Tank\|AP Racing CP9668

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07-20-2021, 11:38 AM	#5 (permalink)
tRidiot Base Member Join Date: Oct 2013 Location: OK Posts: 178 Drives: '09 370Z Sport Rep Power: 9972	Opinions are like aholes... plenty of 'em around here.