Laguna Seca Track Day Brake Issue
 

Hi everyone,

I currently have a base, manual 2013 370Z with 18k miles. All I have done to it is replace the tires to wider 275R, 245F Michelin Pilot Super Sports.

The first time I went on a track was in Feb. on stock everything (except tires) to Laguna Seca and I noticed that after running 5 sessions throughout the day, my front brake pads were still great but my rear brake pads were completely worn to the backing plate. This was to the point that the TCS light on my console turned and stayed on. I decided to upgrade my stock OEM pads to something better, EBC Red Stuffs and also upgrade and flush my brake fluid with Motul RBF600. This combination initially felt great and pedal feel was amazing!

However, yesterday I went to Laguna Seca again (having flushed my brake fluid with Motul again and brakes still with a lot of pad left) and noticed that after three sessions, I started getting steering wheel vibrations whenever I braked from high speeds. I also drove the car around the paddock after every session to cool the brakes. Usually for the first 10 mins of every session, I didn't have the vibration issue but it would come back towards the second half to the point it got really violent and make it harder to control the car.

I inspected the car afterwards and noticed that my front pads held up fine and barely weared, however, my rears had again worn down almost close to the backing plate! There was also a lot of black crusty (burnt pad material I believe?) that I found on the wheels.

I was wondering, if the braking power of the car comes from the front:
-why did the rears wear down exponentially faster than the fronts?
-what could be the root cause of the vibration when braking?
-Should I use better (Carbotechs?) next time for track and also have the rotors resurfaced?

Your inputs would be greatly appreciated!

-Nik

something doesn't sound right about brake bias. seems like rear is grabbing way too hard for OEM 370Z. I hardly wear out the rear pads with Carbotech XP10/8 front/rear combo. I have no idea about red stuff but I doubt that pads caused the rear to wear fast.

someone needs to chime on this.



edit: steering wheel shaking is probably warped rotors, but sometimes uneven pad material transfer onto the rotors could cause vibration. it happens when you don't bed in the pads properly for carbotechs, it's hard to detect. usually steering wheel vibratio is for the front rotors most commonly. on your next run at the track, you might not notice any vibration if it was the pad issue.

Not bedding the brakes properly is what i was also thinking

If you are driving with the traction control on (and I recommend this for a newbie), you will cause more wear to the rear brakes. If you are accelerating hard out of a corner and the rear starts to slide, the traction control will step-in and try to keep the rear of the car from getting away from you. This will happen even to a lesser degree on a street driven car if you accelerate hard from a turn.

I don't know if you are using an instructor, but I would guess that you need to be more smooth in your application of power and try to apply the power gradually as you are unwinding the wheel.

VDC will eat rear pads guaranteed. :( Best to turn it off and get used to running without it, or look into getting your car tuned with EcuTek, which includes a track-oriented replacement for VDC. Laguna Seca is one of the harder tracks on brakes, so it's not too surprising that you ran into this issue.

Your rotors likely have a lot of deposits on them after a track day with street pads. I would recommend replacing them entirely versus resurfacing. OEM blanks are fine -- otherwise you might try StopTech slotted.

Carbotech (XP10 front, XP8 rear) is a good option for a track pad. Still streetable too, so long as you're willing to deal with some noise.

With the VDC on. If the rear starts to step out. It will apply a rear brake to straighten the car out. First time this happen to me. I had a instructor with me. He chewed my butt off for hitting the brakes mid-turn. I had to show him on the video that I didn't do it. It scared the crap out of me when it happen.

Thanks guys for the suggestions and comments!

I was planning to just replace the rear brakes (same brake pad: EBC Red Stuff) for now and I will buy a set of track pads next time I go.

As for the rotors, I'm wondering if resurfacing / replacing is necessary if I just drop in a new set of brake pads and bed them in properly? Maybe, I should get them looked by a professional to determine the severity.

As for the VDC issue, how does the car behave on track if it's turned off? Is the difference quite significant with handling/braking?

Word of warning, If you don't know what the car will do with VDC off you shouldn't turn it off. Play around in a really large parking lot with the VDC off and try to pitch it sideways and hold it there while your making a turn (foot on the gas and about 25 mph). Give yourself lots of room (like 150 ft all around you) because the car will wip around the other way when it recovers and you'll be going backwards with your foot on the brake trying to stop before you hit something.

This is what an upgraded LSD fixes. Stiff swaybars help make it more controllable.

Cars dangerous with everything left on! It's way to violent at applying brakes and killing engine power. Kill the VDC and YAW.

PS you're nuts running Laguna first on OEM pads!

If you're tracking. Turn the VDC off. That should be the first thing you do. With it on, it will get you into trouble quicker then if it was off. :shakes head:

I run with VDC off on the Dragon due to it's stupid activities. I hate VDC.

VDC always off...

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Guys: I don't wait to start another debate on VDC, but if the OP is wearing out a set of rear pads that quickly, he is way too aggressive on the throttle. If he turns VDC off, this will be a guaranteed spin (hell, I have spun on track with VDC on!). Hopefully, he isn't being followed closely or doesn't hit anything until he learns the 'feel'.

OP: Feel free to turn the VDC off, but do it in a safe place. Maybe this is what you need to learn how hard you are pressing the gas and the power that your can can put down with very little throttle.

Good luck and stay safe!

I think that you are spot on, regardless of if you track or drive it hard just for fun he needs to know how the car behaves with the VDC on and off. As you well know measuring the amount of slip, speed and braking in the first half of the turn is were bad stuff is most likely to happen.

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What could be happening is with the VDC on. It's applying a rear brake trying to keep the car straight. OP, did you notice if the traction control light flashes coming out of the turns?

Buckeye, when you say too aggressive on the throttle, do you mean when applying power at the apex? I brake in a straight line before the turn, turn in and hit the power at the apex. You're saying I should apply light power here?

Rusty, Yes. I noticed the TCS light came coming out of turns. It was especially noticeable at turn 11 on Laguna Seca which I feel is the hardest on brakes and shifting to second gear (hard to get that combo right).

What do you guys suggest to improve my next track day with regards to TCS, braking and applying power with this car? I'm on the base 2013 model so no LSD :(

Yes he's saying you're to aggressive power on at the apex. You're forcing the cars VDC to kick on and that's why your lights flashing and the cars applying the rear brakes to keep you straight. He's saying if you turn the VDC off and drive the same you're gonna spin in the same turns you're cooking your brakes in and killing your pads. Turn it off next time but drive slower unless you know how to drift.

:iagree:

Yes. Each turn at each track is different so there is no 'rule'. You can start applying light throttle as you start to unwind the wheel, and the more you unwind the harder you can accelerate. I would expect that you would not be flat-on-the-floor until the steering wheel is straight.

I missed the fact that you were in base model. No LSD makes your brake wear situation even worse.

The inside tire is spinning.

All the nanny gadgets make folks feel as if they can drive well when in fact that is not the case. They make it harder to learn the true way the car needs to be driven.

Will the VDC eat the rear Carbotechs just as easily as EBC Redstuff or OEMs? I've never seen burnt brake material in my life until post Laguna Seca sessions :D

:iagree:

11 is a slow turn anyway. What you want to do is line up on the right edge, brake hard, then turn in and slowly unwind after the apex. The goal is to get the car straightened out quickly so you can get on the gas coming onto the straight. Feel free to use that green strip on the right side. I always have my right tires on it coming out of T11. My buddy always has his left tires on it, LOL.

There are two messages here for those that track mostly, learn to drive the car with the VDC turned off to avoid the helpers from helping you not to crash by cutting power and adding brake bias to the rear and learn how to break properly. We all use our brakes differently and so brake ware will very because of that. If you do threshold braking you will get burnt breake material as you call it on the edges of your brakes regardless of material. The OP would have same results with different pads, in fact he may put himself in real bad situation if he was running race pads as they may just lock up or cause the car to spin out as mentioned before due their aggressive nature.

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Thanks guys! I appreciate your insightful responses. I will work on that before my next track day.

As for the steering wheel vibration I had, I took my car into the dealership and they said they would take $80 just to inspect! So I didn't want to do that but the service advisor said that if the vibration is happening at the steering wheel, it probably means the front rotors are "warped" and said resurfacing should fix the issue. Most people have said that rotors are never really "warped" just brakes are not bedded in properly. Also the vibration now only happens at hot temperature. I stopped seeing it on freeway braking. Resurfacing/buying new rotors are basically the same cost and my car is only 20k miles!!

When do you guys usually get rotors replaced? ( I have 20k miles and tracked the car twice at Laguna Seca).

I get at least a dozen track days on a set of StopTech rotors. They tend to vibrate for a lap or two when bedding in a new set of pads, but no issues beyond that. I just check for minimum thickness and look for cracks to make sure there's nothing on the edge.