GR86 upgrade stock brakes or wait for Performance Pack?

[Dylans47]

Originally Posted by CSG Mike

Braking power is determined by tires, not brake calipers. To a lesser degree, by pads, by making sure you're maximizing brake utilization.

Are you sure about this? I mean imagine you put a single piston caliper in front and compared stopping power to a 6 piston caliper. Of course the 6 piston caliper will offer more braking power due to the increased surface area of the larger brake pad alone. Not to mention the difference in clamping force.

So in my case, going from the stock two piston to a four piston will increase braking power, given my tires aren't the limiting factor.

[EAGLE5]

What pads did you have? What fluid? What symptoms did you experience? 5 minutes into the session or 15?

[Dylans47]

Originally Posted by EAGLE5

What pads did you have? What fluid? What symptoms did you experience? 5 minutes into the session or 15?

I had GLOC R10 pads all around, motul rbf600. This was on a 2019 brembo package Miata, which are four piston calipers and 11.75" rotors on a 2300 lb car. It was a proper setup. So I have no doubts that something similar will occur on a stock two piston caliper and 11.6" (I think?) rotors on a 2800 lb GR86 with pads and fluid. I know you need to fish out those that don't really track their car, or know anything about their setup. Not the case with me and my miata.

The biggest issue was I felt abs kicking in noticeably earlier than usual. Just felt like braking ability was reduced significantly. Towards the end of some later sessions, I would feel the brake pedal need to go further to the floor to actually get any braking out of it. I believe that was more because of air in the lines, so I bled and replaced the fluid again. Still felt the same reduced braking ability issue at another event.

It's just hard to get around brake fade when driving on track in 90+ degree F weather.

Edit: The miata also had coilovers and 225 section RE71R tires. I was definitely stopping on a dime.

[CSG Mike]

Originally Posted by Dylans47

Are you sure about this? I mean imagine you put a single piston caliper in front and compared stopping power to a 6 piston caliper. Of course the 6 piston caliper will offer more braking power due to the increased surface area of the larger brake pad alone. Not to mention the difference in clamping force.

So in my case, going from the stock two piston to a four piston will increase braking power, given my tires aren't the limiting factor.

If the surface area of the pistons is unchanged, and caliper rigidity is unchanged, the clamping force is unchanged.

[Dylans47]

Originally Posted by CSG Mike

If the surface area of the pistons is unchanged, and caliper rigidity is unchanged, the clamping force is unchanged.

Gotcha. So it just comes down to surface area and rigidity. That makes sense, thanks Mike.

[CSG Mike]

Originally Posted by Dylans47

I had GLOC R10 pads all around, motul rbf600. This was on a 2019 brembo package Miata, which are four piston calipers and 11.75" rotors on a 2300 lb car. It was a proper setup. So I have no doubts that something similar will occur on a stock two piston caliper and 11.6" (I think?) rotors on a 2800 lb GR86 with pads and fluid. I know you need to fish out those that don't really track their car, or know anything about their setup. Not the case with me and my miata.

The biggest issue was I felt abs kicking in noticeably earlier than usual. Just felt like braking ability was reduced significantly. Towards the end of some later sessions, I would feel the brake pedal need to go further to the floor to actually get any braking out of it. I believe that was more because of air in the lines, so I bled and replaced the fluid again. Still felt the same reduced braking ability issue at another event.

It's just hard to get around brake fade when driving on track in 90+ degree F weather.

Edit: The miata also had coilovers and 225 section RE71R tires. I was definitely stopping on a dime.

You need more pad.

[CSG Mike]

Originally Posted by Dylans47

I'm very likely going to be buying a GR86 on launch, but the only thing making it very likely and not definitive is the stock brakes. I track about 5 times or so a year and like to canyon drive, so I would like a nice set of brakes. Unfortunately just some pads wont cut it with the stock 2 piston front and 1 piston rear setup.

Reading around the forum, it sounds like AP Racing or CSG's Brembo GT kits are great options for someone looking for an upgrade in the current toyota 86 platform. But, those kits run $2000 and don't upgrade the rear calipers. The current performance pack for the BRZ runs $1200, and include wheels and dampers (which to be fair I would be replacing anyways, but still).

I haven't been able to find a post discussing brake bias alterations when only adding a BBK in the front, leaving the rear calipers stock. Perhaps I still have a lot to learn, but would that not alter the brake bias?

So I guess my questions come down to brake bias confusion and value considerations.

Thanks everyone.

I think ultimately your best option is to just put on proper pads, like the CSG C2, use Endless RF650 fluid, and you won't even need to worry.

You're worrying about problems you don't yet have, and may never have.

[Dylans47]

Originally Posted by CSG Mike

You need more pad.

What do you mean by this? Like I need R12s? I believe thats GLOC's most track ready compound. Never would have thought I would need those since R10s already slot over R6 and R8, both of which are lower rated track pads.

Edit: Gotcha. Just saw your post about the pad and fluid recommendation. I'll definitely give those a try before switching to a BBK then. I trust your HPDE knowledge much more than my own haha. I've also heard a lot of good things about Endless fluid.

Thanks Mike, appreciate it.

[EAGLE5]

They go up to R18 on their website.

[Dylans47]

Originally Posted by EAGLE5

They go up to R18 on their website.

I stand corrected then! Not sure where I got R12 being the highest. It definitely could be just that I wasn't running a high enough temp compound. Thanks for the clarification.

[Dylans47]

@CSG Mike, will you becoming active on the GR86 forum as well? What are your plans with the GR86? Purchasing, testing with CSG, etc?

Sounds like the 86 platform will finally outperform the S2000 on the track. Excited to see the Tsukuba racers in Japan mod the GR86. The RX7 and S2000 seem to be the most popular and successful time attack cars over there. Never see the 86 or BRZ.

[churchx]

Originally Posted by Dylans47

Although, why do you say the PP is unreasonably expensive? I found it's only 1200 and includes the front/rear calipers, dampers, and wheels.

When optioned in new car. If one wants to retrofit, all PP brake parts alone will cost you 2.5K (unless sourced used from some crashed PP twin), and by then aftermarket offerings seem more competitive. Probably another 2-3K for new PP dampers & wheels. When buying PP in new car, it's price difference between PP and "normal" parts .. later you'll never get anything near to that full price for selling stock wheels/dampers/brakes used to recoup part of costs of PP kit parts.

[CSG Mike]

Originally Posted by Dylans47

@CSG Mike, will you becoming active on the GR86 forum as well? What are your plans with the GR86? Purchasing, testing with CSG, etc?

Sounds like the 86 platform will finally outperform the S2000 on the track. Excited to see the Tsukuba racers in Japan mod the GR86. The RX7 and S2000 seem to be the most popular and successful time attack cars over there. Never see the 86 or BRZ.

There's a GR86 forum?

I've had the car on order from day 1, and I think CSG will also be picking up a few.

[soundman98]

Originally Posted by churchx

When optioned in new car. If one wants to retrofit, all PP brake parts alone will cost you 2.5K (unless sourced used from some crashed PP twin), and by then aftermarket offerings seem more competitive. Probably another 2-3K for new PP dampers & wheels. When buying PP in new car, it's price difference between PP and "normal" parts .. later you'll never get anything near to that full price for selling stock wheels/dampers/brakes used to recoup part of costs of PP kit parts.

the PP used parts were going for at least $2-5k used on ebay.