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-   -   Stock brakes too small for stock wheels (https://www.ft86club.com/forums/showthread.php?t=55784)

ndsleep612 01-16-2014 02:38 AM

Stock brakes too small for stock wheels
 
I've owned my FR-S for over 6 months and every time a big "oh sh*t" event happens it's related to the stopping power of the brakes. It got me thinking if the car should have came with larger rotors or smaller wheels.

I drive conservatively, but once in a while I'll gun in on a freeway entrance to match the speed of traffic. When I step on the brake pedal, it feels that there just isn't enough bite to the stock brakes when you're trying to slow down when traveling 85 or doing emergency braking. The BBK looks so tempting whenever i see the small donut of a brake rotor on my FR-S engulfed by the stock 17's.

Does anyone else feel that the stock brakes "could" be better? Such as a stock 4-piston caliper for the front wheels?

wootwoot 01-16-2014 02:43 AM

Get better tires. The brakes are more than sufficient. The Prius rubber is the weak link.

IAmNotTheDriftKing 01-16-2014 04:10 AM

Get better pads as well. No need to get bigger rotors unless you track the car every weekend. Plus those are expensive.

wparsons 01-16-2014 08:34 AM

Go do this simple test on an empty road.

Get up to speed and slam on the brakes, does the ABS get engaged? If so, you don't need more stopping power at all. If you feel the car doesn't stop fast enough, you need more grip (better tires).

SkAsphalt 01-16-2014 10:57 AM

Stop speeding up to 85mph in moments when you need to "oh shit" hit your brakes. Just stop doing that.

Suberman 01-16-2014 11:25 AM

Brakes are possibly the most misunderstood mod out there.

Whenever you're tempted to "upgrade" your brakes go out and see if ABS can be activated on warm dry pavement. If it can your brakes are already stopping the car as quickly as possible.

Then fit grippier tires. If the ABS does not activate then and only then do you need "bigger brakes".

Brakes generate heat by slowing the wheels. Brake discs need to be big enough and vented enough to keep the brake pads from fading by dissipating that heat quickly enough to maintain the designed operating temperature for the selected pads. Larger rotors are mainly about improved heat capacity and dissipation rates. It is rare that a road car has brake rotors that are too small. Small is beautiful because brakes are unsprung weight, remember that, unsprung weight.

It is critical to recognize that brake pads only work well over their designed temperature range. Cold brakes don't work very well at all. You MUST fit brake pads that run neither too cool nor too hot, with the "too cool" aspect of primary importance on the street. Often brakes that look too cool are and don't stop you as well as they need to on that first cold emergency stop of the day.

The number of pistons in the caliper is not relevant in the real world. Basically, total caliper piston area has to match the pressure multiplier required by the size of the master cylinder piston. Go too big and the MC won't work effectively. Caliper piston area is mainly a function of pad area. Big pads might be needed for very demanding braking but they will likely be useless on the street. So, start with pads before you decide you need bigger calipers with more pistons or more piston area.

If you find your brakes are fading on the street then you need to modify your driving. You should NEVER experience an "oh shit" moment when driving. If you do, then you need to be more observant.

For track work the best solution is a set of track optimized pads you put in and take out at the track. Using track pads on the street is pretty stupid actually and can kill you.

Don't mess around with brakes until you've read up enough to know you don't mess around with brakes. Buy only from a reputable brake specialist AFTER reading everything you can about their products to ensure it will do what you need it to do (NEED, not want brakes are not a styling option).

Any factory brake upgrade will also work fine. Note there isn't one for these cars as yet. The factory brakes are very, very good for most driving. Only repeated hot lapping shows up any fade. That's due to the chosen pad material and designed that way.

Vonsamhain 01-16-2014 11:34 AM

The biggest reason for BBK isnt stopping power or bite anyway, the difference is ussualy quite small. It's more about disapating heat from constant use. The hotter your brakes become the less useful the are.

andrew5826 01-16-2014 12:14 PM

i've had my brz for a little over 6 months as well and i've never found the stock brakes to be lacking. It actually does a better job with better pedal feel compared to other heavier cars w/ BBKs ive driven. the key is to be on the verge of locking up. you can only stop as fast as friction allows you

wparsons 01-16-2014 12:40 PM

Quote:

Originally Posted by Suberman (Post 1455229)
Small is beautiful because brakes are unsprung weight, remember that, unsprung weight.

Bigger doesn't always mean heavier, the AP racing spring kit has bigger discs but cuts a significant amount of weight from each corner.

Quote:

Originally Posted by Suberman (Post 1455229)
It is critical to recognize that brake pads only work well over their designed temperature range. Cold brakes don't work very well at all. You MUST fit brake pads that run neither too cool nor too hot, with the "too cool" aspect of primary importance on the street. Often brakes that look too cool are and don't stop you as well as they need to on that first cold emergency stop of the day.

For track work the best solution is a set of track optimized pads you put in and take out at the track. Using track pads on the street is pretty stupid actually and can kill you.

Not all track pads are unsafe on the street, saying they will kill you is a huge stretch. Even a hardcore high temp pad will have some bite in the cold.

My "summer" pads (Ferodo DS2500) have more bite at 0* than my stock pads do, the only reason I took them out is they're much noisier in the winter temps and I don't need higher heat capacity so I might as well run down the cheaper stock pads.


Quote:

Originally Posted by Suberman (Post 1455229)
The number of pistons in the caliper is not relevant in the real world. Basically, total caliper piston area has to match the pressure multiplier required by the size of the master cylinder piston. Go too big and the MC won't work effectively. Caliper piston area is mainly a function of pad area. Big pads might be needed for very demanding braking but they will likely be useless on the street. So, start with pads before you decide you need bigger calipers with more pistons or more piston area.

The only real benefit to going to a 4 piston caliper from ours is that you'll get a fixed (non sliding) caliper which is more rigid and offers better feel at the pedal. You're right that you won't gain a drop of stopping power from an upgrade like that.

One other thing to consider is that there are two types of fade... pad fade and fade from boiling the fluid. Pad fade happens when the pads are too hot to stop you and you lose bite, but the pedal stays firm. If you boil the fluid the pedal goes soft and you have zero braking power. If you're going to upgrade the pads, you NEED to upgrade to a higher temp fluid as well.

Another consideration with a BBK is that they can actually reduce your consumable costs if you track the car a lot. The rotors will last longer, and two piece ones are cheaper to replace the rings. Pads are also generally cheaper than the same pad for the OEM caliper.

For a street driven car that sees the odd autoslalom, the biggest braking upgrade you'll need from a functional standpoint is better pads and fluid.

BlueDubbinTDI 01-16-2014 12:51 PM

I'll say it again, you think these brakes suck? Drive a Golf, you'll change your mind.

CSG Mike 01-16-2014 12:54 PM

Quote:

Originally Posted by ndsleep612 (Post 1454758)
I've owned my FR-S for over 6 months and every time a big "oh sh*t" event happens it's related to the stopping power of the brakes. It got me thinking if the car should have came with larger rotors or smaller wheels.

I drive conservatively, but once in a while I'll gun in on a freeway entrance to match the speed of traffic. When I step on the brake pedal, it feels that there just isn't enough bite to the stock brakes when you're trying to slow down when traveling 85 or doing emergency braking. The BBK looks so tempting whenever i see the small donut of a brake rotor on my FR-S engulfed by the stock 17's.

Does anyone else feel that the stock brakes "could" be better? Such as a stock 4-piston caliper for the front wheels?

Are you hitting ABS? Braking distance is determined by your stock tires. Better pads will get you more bite, so you can get more braking force applied to the tires with less pedal pressure. A BBK's primary purpose is to allow you to sustain lots of back to back braking without overheating.

Other than telling us that the brakes suck, tell us WHY they suck, and I can point you in the right direction.

"Doctor, I'm sick" - your first post
"What are your symptoms" - my post

Quote:

Originally Posted by wparsons (Post 1455009)
Go do this simple test on an empty road.

Get up to speed and slam on the brakes, does the ABS get engaged? If so, you don't need more stopping power at all. If you feel the car doesn't stop fast enough, you need more grip (better tires).

This.

Hit ABS? Get better tires
Can't hit ABS no matter how hard u step on the pedal? Get better pads
Pedal is spongy? Bleed the brakes.
Want to drop a nuke on the problem? Get a BBK with high performance pads.

DarkSunrise 01-16-2014 01:00 PM

Quote:

Originally Posted by ndsleep612 (Post 1454758)
I've owned my FR-S for over 6 months and every time a big "oh sh*t" event happens it's related to the stopping power of the brakes. It got me thinking if the car should have came with larger rotors or smaller wheels.

I drive conservatively, but once in a while I'll gun in on a freeway entrance to match the speed of traffic. When I step on the brake pedal, it feels that there just isn't enough bite to the stock brakes when you're trying to slow down when traveling 85 or doing emergency braking. The BBK looks so tempting whenever i see the small donut of a brake rotor on my FR-S engulfed by the stock 17's.

Does anyone else feel that the stock brakes "could" be better? Such as a stock 4-piston caliper for the front wheels?

Before spending money on an expensive BBK, try Stoptech SP pads + fresh DOT 4 brake fluid. That'll cost less than $150. Make sure to bed-in properly.

It'll be subjective to some degree, but with that setup, I had an issue with the brakes almost have too much initial bite on the street.

m.wood0213 01-16-2014 01:15 PM

I have never had an issue with the stock brakes. Ive driven on some twisty backroads pushing the car about 75% and heavy braking with ZERO fade. I have only occasionally engaged ABS. When an "oh shit" moment happens try a different reaction on the brakes. Dont just slam on the brakes and hold it on the floor. I am no track day expert but you have to transfer the weight to the front. If you gradually (but quickly) press down on the brakes will help out. Then when you feel they are about to lock up, let up just a hair on the peddle to minimize your braking distance.

Like I said Im no expert and havent driven track days or race cars but my last car had no ABS and when those "oh shit" moments happened I knew how to deal with them. You should have more confidence in yourself and your NEW car with WRX brakes. At least upgrade the front tires to something more grippy the leave the back as they are so you can get them loose when you want! :burnrubber:

DR 86 01-16-2014 01:31 PM

Stock brakes are great. 3 track days on then with zero issues no fade on Motul brake fluid before upgrading to track pads. Just learn to drive properly.


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