Results from single track day after full brake rebuild. What now?

[SterlingShelby]

Pretty disappointed with my brake results after 1 track day at UMC on the outer course. I had completely rebuilt the brakes on this car this winter and upgraded to dtc60 pads, ti shields, vorshlag brake deflector kit, homemade ducts from the lower valance, and new rotors, on top of already having stainless lines and amsoil dot4 fluid. I never really experienced brake fade which is good but the brakes didn't seem to be nearly as aggressive on the bite as when I had my HP+ pads. And my anti-locks seemed to be activating way more this time around. I was also running about 10mph slower coming to end of the big straight which I think would help with temps(my previous best was 164). Running the same Michelin ps4s on both setups but with obviously more wear this time. Could all of that be tire?

And to top if off my brand new "high temp" OPMustang brembo seals gave out after 1 track day .

For the rears, I'm running just some generic ceramic power stop pads.

What would you guys do next? More aggressive rear pads? Different rotors?

 

[TMSBOSS]

Are the pistons/calipers leaking? It appears you are referring to the dust boots as failed. Is this correct?
If the ABS is working more than before, the brake pads are a bit more aggressive so that sounds right. You may need to work on threshold braking a bit more.
The rotors look fine.
Hawks are not a "Popular" pad with a lot of track folks. GLOC, Raybestos, Pagid, carbotech and other get better reviews.
Did the Amsoil fluid boil? Color? Soft pedal? Do you know the dry and wet boiling points for your fluid?

 

[Norm Peterson]

For the rears, I'm running just some generic ceramic power stop pads.

I doubt they've got enough bite to match DTC-60 front pads (mu likely less than 0.4 vs DTC60 a bit beyond 0.7). Fronts sound like they're being overworked, and I wouldn't doubt front ABS activity.

What would you guys do next? More aggressive rear pads? Different rotors?

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Definitely got some heat checking going on.

Norm

 

[Mad Hatter]

Is your car a 2013+ gt500? Are you on a stock tire size (skinny)? Not a huge Hawk brake pad fan because they tend to eat disks way more then other more expensive pads (and last less as well). Have you thought about swapping some of the Brembo S550 6pt brembo calipers?? Much bigger pad and a better caliper. Gave up on the dust boots a long time ago... they don't last very long.

 

[SterlingShelby]

Are the pistons/calipers leaking? It appears you are referring to the dust boots as failed. Is this correct?
If the ABS is working more than before, the brake pads are a bit more aggressive so that sounds right. You may need to work on threshold braking a bit more.
The rotors look fine.
Hawks are not a "Popular" pad with a lot of track folks. GLOC, Raybestos, Pagid, carbotech and other get better reviews.
Did the Amsoil fluid boil? Color? Soft pedal? Do you know the dry and wet boiling points for your fluid?

yes, brand new "high temp" boots failed. Not sure if that is from extreme heat or what at this point. I thought with the ti shims that wouldnt be a problem. I had forgotten to purchase some of those temperature strips before hand so i don't know what they got up to must it must have been extremely hot cause it cooked the paint coating right off the pads.

That cracking on the new rotors look normal?!

No leaking. pedal is firm. I didnt realize Hawks weren't that popular for track. How come? Ill have to ask around at the local track some more but i thought they were popular out here. maybe i'm wrong.

I know its 580 degrees dry but i dont recall the wet rating. ill have to look tonight. I have yet to bleed them again to see what the color looks like.

 

[JDee]

As Norm indicated, I also think not having a racing pad on the rear is a mistake, you're asking the fronts to do an awful lot of work. I run DTC50 front and DTC30 rear and have very good modulation and wear with them. I do not find they are hard on rotors in warm weather, cold they will eat rotors. Hawks are not popular around here but I have had very good results with them, they are moderately priced and readily available where I live.

If we ever get out of lockdown I'll be running the set of rotors and pads I put 8 track days on last year, they've got at least another 4 days in them. I use the OP dust boots and find them problem free though as others have mentioned you don't need dust boots for track work anyway.

I come from an endurance racing background where brake management is critical, there are techniques that cost you a second or two a lap but increase pad life by a huge amount. The 60s have a very high heat threshold (1400 degrees) and it may well be beyond what production car parts can deal with. I don't have that issue with 50s which have a lower temp threshold (1100 degrees). Your rotors look fairly beat up for one day but there's nothing there that's a problem going from the pictures.

Start with putting some 30's on the rear and see what happens.

 

[JAJ]

Pretty disappointed with my brake results after 1 track day at UMC on the outer course. I had completely rebuilt the brakes on this car this winter and upgraded to dtc60 pads, ti shields, vorshlag brake deflector kit, homemade ducts from the lower valance, and new rotors, on top of already having stainless lines and amsoil dot4 fluid. I never really experienced brake fade which is good but the brakes didn't seem to be nearly as aggressive on the bite as when I had my HP+ pads. And my anti-locks seemed to be activating way more this time around. I was also running about 10mph slower coming to end of the big straight which I think would help with temps(my previous best was 164). Running the same Michelin ps4s on both setups but with obviously more wear this time. Could all of that be tire?

And to top if off my brand new "high temp" OPMustang brembo seals gave out after 1 track day .

For the rears, I'm running just some generic ceramic power stop pads.

What would you guys do next? More aggressive rear pads? Different rotors?

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So, having owned a 2014 GT500 and tracked it a lot, here's what happened in your outing:

1. Rear brakes - the '13/14 GT500 ABS is calibrated to increase rear brake bias when the car's in track mode. It uses the rear brakes to improve brake balance in the braking zone and corner entry. By putting nondescript pads out back, you cancelled out some very helpful programming in the ABS and forced the front brakes to do all the work.

2. Front brakes - with no rear brakes to help them, you overloaded them. The miracle is that you didn't overheat the calipers and boil the brake fluid. The damage to the piston dust boots is a warning, so pay attention.

3. Hawk DTC-60's - they're ok and can handle a lot of heat. I had a set for my GT500 and I used them exactly once. I didn't like their weird behavior so I threw them away after one track day, but hey, maybe that's just me.

4. Rotors - you said they were new, but you didn't say who made them. They look okay, but with all the heat you're generating, a two-piece rotor set up front might be a worthwhile upgrade. It'll take some of the load off the front calipers.

The biggest gain you can make is to run real race pads at the back. PFC97's are good, although there are other choices as well.

 

[stevbd]

I don't have any experience with the Hawk DTC-60 but if they don't have good initial bite, you likely were compensating by pressing them harder and harder, and longer, causing more heat and problems.

 

[67GTA]

A lot of good suggestions already posted, however I still don’t see what size PS4’s you’re running. The most aggressive race pad is only as good as the effective contact patch of your tires. Once you pass that threshold, the ABS has to step in because the tire just won’t hold the force of the brakes. With the non-race rear pads not helping, the fronts quickly become overwhelmed - especially if you’re on a staggered street tire setup with smaller tires up front.

The common misconception is that you can just throw race pads on a street car and it will brake like a race car. Not the case. The tires need to be considered, otherwise as suggested above the driver needs to adapt inputs to not overwhelm the contact patch of the tire.

 

[Ewheels]

Simply put, your car is not balanced. Good news, it's easily fixable.
You have no rear brake and matched aggressive track front pads with 300tw street tires. Get some track pads in the rear and a quality set of track tires. I would suggest GY Supercar 3 or NT01. You'll be getting those lap times down in no time

 

[blacksheep-1]

FWIW the dust boots are pretty much sacrificial, no worries there, I've seen them melted to the caliper before, sounds like the seals worked just fine. So OP definitely gave you the good stuff.
For a barometer, this is my T4 car, John Heinricey (google it) used to drive it, and he ran stock pads on the back and these on the front. Now this car is a lot lighter than yours and uses a lot less power BUT John is an outstanding driver and gets the most out of the car. So everyone is different, but this info might help you in your journey as a reference.

 

[TMSBOSS]

yes, brand new "high temp" boots failed. Not sure if that is from extreme heat or what at this point. I thought with the ti shims that wouldnt be a problem. I had forgotten to purchase some of those temperature strips before hand so i don't know what they got up to must it must have been extremely hot cause it cooked the paint coating right off the pads.

That cracking on the new rotors look normal?!

No leaking. pedal is firm. I didnt realize Hawks weren't that popular for track. How come? Ill have to ask around at the local track some more but i thought they were popular out here. maybe i'm wrong.

I know its 580 degrees dry but i dont recall the wet rating. ill have to look tonight. I have yet to bleed them again to see what the color looks like.

Your brake fluid may be able to give you some info. Brown or dark and it cooked. I always bleed some off between events. Any air or discoloration will tell you some of what happened at the lase event.
The rotors do have "Heat Checking", no cracks. Would a rotor upgrade help?? It always helps. Did your rotors fail, crack or warp? It does not appear they have. One of the best rotors made, in America BTW, is the Girodisc. They are fantastic, but pricey.
I stopped worrying about the dust boots when I track a car. They may survive, may not. Their best purpose is to keep water and dust out. Some folks do Not run these because they will "Cook" early.
Pads. I went from stock Boss pads to Pagid pads. I never looked back. If budget is a big concern, you will have to adjust driving techniques to accommodate a "Lessor" pad, rotor or fluid. If not, replace the rotors with Girodisc, the pads with Pagid, GLOC, Carbotech or other top of the line pads. Brake fluid is another "Spend" that can hurt a bit. The "Good Stuff" can be north of $60.00 a liter. Look for wet and dry numbers as high as your budget will allow. Get with Tim at OP or the folks at KNS and ask for advice on a "Complete Package" front and back rotors, pads, lines and fluids. A compromise with one will cause the others to be over worked.....until failure. Then expensive brake parts wont look so expensive.
Tire sizes??

 

[JAJ]

I don't have any experience with the Hawk DTC-60 but if they don't have good initial bite, you likely were compensating by pressing them harder and harder, and longer, causing more heat and problems.

They've got pretty good bite. What I meant by "weird behavior" is that they have a strong rising torque curve - brake torque increases with temperature. When you're in a series of shorter runs from corner to corner, they're great. However, at the end of a long straight where the brakes have cooled, you get a brief moment of "where did my brakes go?" before they come back. I'm sure for those who like them, they're fine, but I'd been a Pagid user for years by then and these just didn't suit me. I also don't like the corrosive dust they make, although the one time I used them it didn't rain and I got the dust off the next day before it welded itself to my rims.

 

[stevbd]

They've got pretty good bite. What I meant by "weird behavior" is that they have a strong rising torque curve - brake torque increases with temperature. When you're in a series of shorter runs from corner to corner, they're great. However, at the end of a long straight where the brakes have cooled, you get a brief moment of "where did my brakes go?" before they come back. I'm sure for those who like them, they're fine, but I'd been a Pagid user for years by then and these just didn't suit me. I also don't like the corrosive dust they make, although the one time I used them it didn't rain and I got the dust off the next day before it welded itself to my rims.

JAJ, I was referring to the OP's comment in the first post about the Hawks not being "as aggressive on the bite...."

 

[JAJ]

JAJ, I was referring to the OP's comment in the first post about the Hawks not being "as aggressive on the bite...."

Ahh, I see. Good point. I'd skipped over it because I read it as just another part of OP's overall dissatisfaction with the braking. I figured the lack of bite wasn't actually a problem with the front pads as much as it was caused by weak rear brakes at the exact moment when the ABS system was shifting braking effort to the rear brakes to help the fronts and balance the car. I think if the OP sticks with the DTC60's and puts real race pads at the back, he'll be pleasantly surprised by the bite.

 

[SterlingShelby]

sorry its taken a bit to respond, works had me running like crazy.

The more I think about it the more I think that everyone is correct about needing more aggressive rear pads to balance out the car. I didn't know these cars throw more bias to the rear upon braking, I just assumed the little single piston brakes in the back weren't doing shiznit to begin with, so that makes sense. Ill try that for our track day in June.

As for the tire sizes, 265 front and 285 rear. Believe me, i know, these aren't nearly big enough and will hopefully be changed out soon. All that being said i was still matching track times of friends in TT4 so i was pretty pleased with that on 300 wear tires.

 

[RodS197]

Some great info here, especially about the GT500 brake bias logic. You probably got bad info from the fleet of 3V mustangs as we typically run a very mild pad in the rear and more aggressive in the front as a matter of course for our cars.

There are many different pads available. One thing I would recommend is don't go too aggressive to early in your driving. Tends to teach over braking and over slowing. Plus if you really liked the HP+, I would stick with them for a while until you feel like they are holding you back. I ran them for about 2 years. I have some great videos of me going to a pad that was over my head, a great spin into Black Rock hairpin... Led to about 2 years of crappy braking until I mellowed the pads out and reset my technique.

Also, get with us in WDG 15 and let's send an instructor out with you just to check your braking technique. Heaven knows it helps me from time to time.

See you in June,
Rod

 

[SterlingShelby]

Some great info here, especially about the GT500 brake bias logic. You probably got bad info from the fleet of 3V mustangs as we typically run a very mild pad in the rear and more aggressive in the front as a matter of course for our cars.

agreed. And to be fair, I ran the same type of setup on my 3V with great results! I immediately jumped to just thinking the problem was from the added weight and speed, I didn't think about the difference in bias for this car.

Thanks for the advice! always great to hang out with you guys!

 

[JAJ]

agreed. And to be fair, I ran the same type of setup on my 3V with great results! I immediately jumped to just thinking the problem was from the added weight and speed, I didn't think about the difference in bias for this car.

Thanks for the advice! always great to hang out with you guys!

Back in 2014 when I had my 2014 GT500, there was a lot of data and media coverage on the way that SVT, now FP, had rethought the chassis and engine to make the car truly road-track capable. Shifting the brake bias in Track Mode was just one of the changes. There's a great video, if you can find it, of a lap at the Nürburgring, and another of the high speed run that established the 202MPH top speed. It's great stuff to watch, and the main point was to make it clear that the latest S197 GT500 was truly a sports car for any track, not just a drag strip.