GX470GT

I know the OEM brakes are more than good. However those folks here who have done the upgrade to a BIG BRAKE KIT, are they better than OEM in everyday city/highway driving? Any preference on 4 vs 6 piston? Or should I just stick with the stock setup? How does it affect weight and handling?

Phamboogie

iTrader: (3)

It's not a necessary mod, but it would definitely shorten 19"+ wheels' braking distance. 6-piston is a bit excessive, in my opinion. I plan to get a 14" BBK in all corners sometime in the next five years. :lol:

GSteg

iTrader: (15)

Braking distance is practically the same. What you do get is better brake feel, but your brake bias may be thrown off a bit depending on what brakes you get.

GS FONZy

iTrader: (6)

Are you sure braking distance stayed the same from oem to 4pot LS/TT set ups? I am 100% sure I can stop in a shorter distance from oem. It may not be much, but it sure feels like a big difference. However; I don't know if my results were different do to the fact that I compared only with 20s. Although, I felt safe with my oem brakes and 20s, I can see the difference with the 4pot TTs.

JeffTsai

iTrader: (1)

Braking distance from around 50-60mph for the stock brakes is gonna be as good as BBK. For ONE stop. And I don't mean granny style slowing down. I'm talking about mashing on the brake pedal as hard as you can till either ABS kicks in, or if you're good the threshold right before it activates. Try it a second time and the stock brakes aren't going to clamp as well as the first time but will still be good enough. Try it the third, fourth, fifth....and it will start to get worse each time after that. With a BBK you can keep doing the 60-0 stop all day long with no problems and performance degredation.

Now where BBK really comes into play is when you're cruising 150+ and need to come to a stop abruply because of certain vehicles parked on the side of the road. The stock brakes fade terribly at those speeds. Don't ask me how I know that lol. BBK on the other hand has no problem slugging the car back down to sane speeds over and over again.

As you all know I'm not the average Lexus driver. Most people here probably have no business putting BBK on their cars according to how they drive. They do it mostly for looks. As I said the stock brakes are perfectly adequate at stopping the car from any sane speeds in a emergency situation. Most people here just put BBK on for the looks.

And because I'm not the average Lexus driver...for me, the 4 pistons 14" in the front are not cutting it. I'm going to upgrade to 8piston 15" or 6piston 14" soon.

GS FONZy

iTrader: (6)

Braking specs for the Supra NA from 60-0 is 118ft
For the turbo version is 109ft

So there is a difference, a bigger rotor with more pad braking surface will have a better bite, whether stopping from 60 or 100mph. It might not look as significant at lower speeds because both do the job, but when you start pushing the limits of the smaller system, you will definitely see and feel the difference.

GSteg

iTrader: (15)

I'm pretty sure its about the same, otherwise it would be defying physics

It feels like we're stopping shorter only because the more linear feel. I too feel the same way sometimes, until reality comes in and smacks me. Full on stop, both OEM and BBK brakes have enough force to lock up the wheels. What's stopping that from happening is the ABS modulation, but the ABS activation does not depend on the calipers..it only detects lockup. So it doesn't matter if you have 20 pistons or 1 pistons, once you reach that threshold, it'll kick in. Ultimately, tires and weight will determine the braking distance. Of course fading is a whole different topic My OEM brakes with upgraded pads had less fade than my LS400 with OEM pads. I can't wait to switch these out.

DaveGS4

iTrader: (2)

Source please. If it wasn't the same exact test day / conditions / surface and (most importantly) with the same tires on the car this isn't an apples-to-apples comparison. The two cars came with very different rubber if I remember correctly... Your tires are going to be the most important factor in your stopping distance under any circumstance. Just googling finds 60-0 on the Supra TT at 120ft

I agree with Jeff, you're going to get the same stopping distance with both OEM and big brakes. The difference is primarily three things:
1) brake fade
2) pedal feel
3) how cool you look

This has been covered in past threads many times; I'd suggest using the search feature to dig some of those threads up for research. There is a comparison of weight for several big brake options as well - that's a fair point on handling and unsprung weight difference.

GSteg

iTrader: (15)

The TT has a good amount more rubber than the NA

NA:
Front: 225/50/16
Rear: 245/45/16

Front: 235/45/17
Rear: 455/40/17

GS FONZy

iTrader: (6)

Edmunds.com


You know that's only about 3/8" more surface contact, right?

GSteg

iTrader: (15)

yes per tire, but apply 0.4" to all 4 corners and you're going to have significantly more rubber.

If the OEM calipers have enough power to lock up the wheels, what good does it do to have more clamping force if the wheels are already stopped? Certainly not stopping distance. You can always try to take our your ABS fuse out and test this theory To keep it from locking up, add more rubber or get stickier tires to make use of the more powerful clamping force.

DaveGS4

iTrader: (2)

Links if you would please, hopefully they'll also tell if they used the exact same tires on both models I can't seem to find any braking distance there when I look.

Edit, just looked it up in the brochure on toyotareference.com. The turbo came with Z rated performance tires and NA had lesser V rated. That also has a significant impact on this in addition to the tire size.

GS FONZy

iTrader: (6)

I don't want this to go on forever, I understand all your point and they all take part in brake prformance. My only point, probably did not make it clear and that is why we keep going back and forth. A car equipt with bbk needs less effort to stop over oem. All cars can lock their brakes, that's not the point, nor is it safe to do. A desirable brakes systems is the one that stops without having to smash the pedal inorder to slow down or stop the vehicle.

Clifton

Brakes don't stop the car, the tires do. Tire width although important, isn't as important as compound. Most tires are for mileage or sporty street driving with wet weather considered, not grip. Throw some R comp DOT's on with stock brakes and you'll stick your passenger to the dash at 50 mph. As said a BBK will be better at repeated high speed stops with out brake fade as they can dissipate the heat better but I've only known one GS400 that did regular track days (road coarse) and he ran stock brakes with better pads and RA1's (Toyo R comps) without brake problems. One or two hard stops at 100 don't count as hard use. On a GS a BBK is more for bling unless it's being tracked, not that there is anything wrong with that. Keep the caliper piston area the same on a BBK and the front to rear bias and pedal feel won't change. I won't run a high friction pad on the street either. Arizona Performance (not my business, just a friend) makes a bunch of BBK's for Supras. I think they are the same as GS's though.

Alexus_300

iTrader: (4)

I believe jeff and dave has pretty much covered up the basics between OEM and BBK. I can attest to some true test data that was conducted by myself and a few friends. I will try to find the videos and test data that I have stored somewhere about the differece and post them for all. Before going further into the topic, what most people don't address is the tire internal air temps of the tire, rubber compound temperature, and the cold inflation pressure for all corners. Next is the type of tire used. For most that drive daily, you would choose to run a street compound (the reason I am stating street compound is that I know that R-compounds stops better in dry condition but you must consider how they react with a little moisture on the roads). Lastly, the brake proportioning of the BBK to the OEM brakes. With all these covered, I did 10 multiple consistent back to back 62-0 MPH stops and recorded my data between the OEM brakes and BBK and have found that the variance between the BBK and OEM is that with every stop, the variance between stopping distance for the BBK is within 3 ft. with no fade while the OEM would fade after the second hard braking and braking distance would increase by roughly 4-6 ft. for each additional stop. All of this was conducted in a fairly controlled environment where tire choice, road condition and weather were all the same. Intervals between each run is timed for 30 seconds.