[TrackClub]

Originally Posted by GunMetalGrey

Haha well I respectfully disagree, it depends on the car, the track and the driver and the format of the open lapping (how long the sessions are and how long the breaks between the sessions are). In this case all of these variables are different

GMG, your home track layout is extremely hard on brakes imo. After a session, do NOT park the car (except to check tire pressures) but unlatch the hood (to help release hot air trapped there from motor and F brakes) and drive it around the paddock, or access road to provide air flow until oil comes down to sane temps. Then park and open the hood fully. If you come off and just park you will create a heat sink situation for all components, which may not recover for the next session.
Cheers!

[GunMetalGrey]

Originally Posted by TrackClub

GMG, your home track layout is extremely hard on brakes imo. After a session, do NOT park the car (except to check tire pressures) but unlatch the hood (to help release hot air trapped there from motor and F brakes) and drive it around the paddock, or access road to provide air flow until oil comes down to sane temps. Then park and open the hood fully. If you come off and just park you will create a heat sink situation for all components, which may not recover for the next session.
Cheers!

I hear you, my father had the same advice, use the long open road highway just outside the track to cool it down right after a session

[Pcormier66]

Originally Posted by TrackClub

The corner entry speed has little to do with brake pads, but much to do with how much grip given tires (and aero if present) will provide and to what extend a driver can maintain best balance regarding weight transfer to get the most out of all 4 contact patches. This is where effective trail braking comes in (including moving the whole braking sequence forward closer to apex aka "late braking").

Also, low/medium torque pads provide easier modulation of brakes during the entry phase, as a driver has a wider band of pressure available to them before locking up (or inducing ABS), or over slowing. And hence it is easier to vary pedal pressure and achieve better results balance and hence pace wise.

What matters much more for lap times is not where threshold braking begins, but how much SPEED is carried from turn in to apex. Because, one will spend much more time in that phase vs the former.

If one reads brake and brake pad descriptions by manufacturers who provide hardware to pro series (vs resellers focused on retail market), it is easily evident that: high torque pads apply only to full racing slicks and full aero cars (prototype, open wheel types) where tire grip is insane in comparison to any street track car, hence a lock up is unlikely.

Smooth initial application (vs on/off switch offered by many high torque pads) is seen as a *must have* quality for any pro GT type cars, including those on harder spec skicks etc, basically cars with less grip vs full aero cars.

PAGID has been providing pads to many pro GT level teams incl IMSA, LeMans, Porsche Cup, etc etc. Check their mu tables.

PCF has also been providing pads (and whole braking assemblies) to top level series including IndyCar, Conti series, IndyLights, etc. Bottom line, they know brakes. This is how they describe a couple of their pads and their intended applications (shortened version to make a point):

"08 Compound gained immediate favor in Endurance Sportscar and GT racing due to its performance in applications where smooth initial bite is a must"

"11 Compound... The result is ultra-smooth braking with reduced wheel locking at the end of a stop. 11 can be used in a large spectrum of temperature ranges...It is ideal for use in medium- or low-grip situations such as hard spec tires or light cars with no downforce.

Basically, all pro pad manufacturers recommend specific pads to pro teams based on: venue, tires, downforce, duration, heat management of related components, etc.
You will never seen them pushing a highest mu pad as "the best". Because, based on the application it may be "the worst"!

Unfortunately, it seems the current retail marketing has discovered that high mu = "race" marketing = sales.
(And not only pads, but after market "race" BBK, enhanced "race" components, "race" cooling solutions, etc as now ppl have to deal with HIGHER HEAT.

As such, i am sure some folks are spending thousands ONLY becase of a pad choice. Ridiculous proposition in my book anyway.

Imo running extreme level torque pads on a non aero car with street (or R comp) tires on, with brake components not designed for, nor capable of dealing with high temp "sweet spots" of such pads is counterproductive on many levels.

But, we live in a free world and this is supposed to be fun, so i will retire from this subject now. Let's just not confuse retail marketing of "race" vs real racing.

Cheers!

I tried to caveat my experiment with all things being equal. The only variable is pad choice. For every - very relevant variable - you have added, has confused the basic principle that pad choice is generating more heat because driving technique will change to adapt to faster engagement and higher decel.

[Norm Peterson]

Originally Posted by Pcormier66

Is there some chemical reaction going on to create more heat with race pads?
If the clamping force between the rotor and pad is the same, the heat generation is the same. Race pads will activate ABS sooner, and more consistently, lap after lap. That's why lake braking is so much more effective, and fun, on race pads. And that's what causes higher temps, which leads to more heat soak. Said another way, you need less pedal pressure with race pads to generate the same braking performance as OEM.

I use high torque pads on all my track cars. Have for 15 years. Probably tried very brand under the sun. No fancy aftermarket cooling or parts. Just good, fresh fluid.

As for catching cars in the corners, just because you late brake doesn't mean you are not also able to trail brake. Good technique involves both. It's not one or the other. I would agree that your consistency to trail brake after a late braking event is lower. But if you get it right, the rewards are huge. And isn't that why we are doing this?

My guess - and at this point it's strictly a guess - is that high-mu pads conduct heat better than lower-mu pads. This would be inherent with the specific formulation, things like metallic content, and exactly what metal.

That amounts to making the pads behave somewhat less effectively as either heat sinks or insulation, as more thermal energy - heat - is passing through them more quickly. It's a problem in thermal transient behavior.


Incidentally, I came across some slightly different mu curves for some of Hawk's pads, only a couple of weeks ago. And information that Hawk has reformulated at least the HP+.

DTC60


DTC70



Norm

[RUQWIKR]

Originally Posted by Yanbags

I managed to get a set of the Garage Therapy ones before they discontinued them

I'm also running the girodisc front rotor rings; the directional vents look smoother and larger than OEM so I imagine it's better at air evacuation but that is just pure speculation from my eyes.

If you measure the cross-section of the 3D-printed duct adapter, it's less than the hose. Not saying it's not of some benefit, but, I got one of the first kits and promptly sent it back. If they or someone comes out with one again, I would hope they would do a better job at the design. Understanding that the hose is a wear item with large wheel / tire combos at full lock.

[RUQWIKR]

Originally Posted by NickyRacerBoy

I run stock SS1LE ducting DTC70 front DTC60 rear Racing Brakes stainless steel pistons with Castrol brake fluid with ZERO fad. Not to tune my own horn but if I am not having issues you should be fine. Change to another caliper brand and your more likely to run in issues.

As a note, he's using the VENTED stainless pistons from Racing Brake...

[TrackClub]

Originally Posted by GunMetalGrey

I hear you, my father had the same advice, use the long open road highway just outside the track to cool it down right after a session

Super! Keep in mind ya dont have to go fast to cool down the car effectively. Even paddock speeds help here (with unlatched hood). Cheers!

[TrackClub]

Originally Posted by Pcormier66

I tried to caveat my experiment with all things being equal. The only variable is pad choice. For every - very relevant variable - you have added, has confused the basic principle that pad choice is generating more heat because driving technique will change to adapt to faster engagement and higher decel.

I think we are saying the same thing? Clearly if you decelerate the same mass, but from a higher speed and in a shorter distance more heat will be generated.

What i have attempted to convey, is that a pad torque should be matched to essential variables such as venue type, tire type, aero level, cooling, etc.

Another consideration is that race pads (regardless of their torque levels) are designed with race cars in mind. That means, on average 2600lb. Nascar stock cars excepted (3400lb) i am not aware of a single pro race car scaling close to 4000lb. If there was such an animal, it would require tremendous cooling capability plus components designed to withstand tremendous heat: much higher than an average 2600lb GT type car.
So, no wonder folks are smoking their brakes (especially at venues offering limited cooling opportunities).

[TrackClub]

Originally Posted by RUQWIKR

As a note, he's using the VENTED stainless pistons from Racing Brake...

Yes, SS 1LE doesnt come with vented pistons, but ZL1 does from a factory.

[RUQWIKR]

Originally Posted by TrackClub

Yes, SS 1LE doesnt come with vented pistons, but ZL1 does from a factory.

No, the ZL1 calipers do not. The caliper body up front is the same as the V3 CTS-V (J6H) and J57 CCB calipers (C6 / C7 and Gen5 Z28).

My J6H ZL1 1LE front calipers have the J57 vented pistons in them - put in there by yours truly. As FYI, J57 rear calipers for the above vehicles do not have vented pistons.

[TrackClub]

Originally Posted by RUQWIKR

No, the ZL1 calipers do not. The caliper body up front is the same as the V3 CTS-V (J6H) and J57 CCB calipers (C6 / C7 and Gen5 Z28).

My J6H ZL1 1LE front calipers have the J57 vented pistons in them - put in there by yours truly. As FYI, J57 rear calipers for the above vehicles do not have vented pistons.

Got ya! So ZL1 and ZL1 1LE calipers are the same and both have unvented pistons? I swear somebody posted ZL1 were indeed vented, so my bad here.

[Yanbags]

Originally Posted by R3ctivision

How are DS1.11s in terms of pad life, driving to and from the track, and pad taper? And caliper “brownbo” issues with them with the SS ducts?

Originally Posted by TrackClub

Indeed! I used them on my C5Z then moved on to DSUNOs and frankly cannot recall how they compared except for the 1.11 having much flatter torque. They are noisy, dusty and when cold not recommended. To/from would be ok, but nothing DD wise imo. And of course Ferodo website warns against it. Never had any taper issues except for xp10 i tried once on my SS.
GMG, a pad you may wanna try is DS2500. It should give you a bit more torque without frying things. I think Strano sells them (at good prices). Might be worth a try and see? Cheers!

PS Hope Yanbags chimes in here as well re his SS experience. But again, when considering pads one MUST also consider the venue. I had run ST43 which cooked my fluid and almost set my wheels on fire (seriously) on a tight track in just few laps, but they did ok at Mosport where apart from 2 corners out of 10 braking is rather light and a long straight cools things pretty good between laps. So it all depends...

I am here! On my second set of DS1.11 because I loved them so much the 1st time around. In my personal experience, I am finding that they have really great pad life and are not harsh on rotors. Pad taper does happen with track use, but I think it's going to affect any pad with this caliper if you are hard threshold braking. The car is not my DD but has plenty of street miles and I think they are totally fine for it. They are 100% usable in colder temps. Definitely dusty and a bit noisy but not an outrageous amount like the school-bus-esque set of Pagids a friend of mine has on his 997. I did experience "brownbo" on my 1LE letters, but IIRC - it was from when I tried out the ST-43 pads.

Similar experience to TrackClub - I was not happy with ST-43 performance. They lasted long, but temps seemed too hot (did not measure), had pad fade, and I just didn't jive with the overall pad behavior.

[RUQWIKR]

Originally Posted by TrackClub

Got ya! So ZL1 and ZL1 1LE calipers are the same and both have unvented pistons? I swear somebody posted ZL1 were indeed vented, so my bad here.

Other than color & marking.

[TrackClub]

Originally Posted by RUQWIKR

Other than color & marking.

Great to know and to correct my erroneous assumption here.
Thanks!