Brakes unless at high speed - what to tackle?
 

Well, I found out luckily without any loss that the brakes on the FR-S are no good at highspeeds. At ~130kph and higher they feel non-existent if you need to stop the car and anyone who doesn't engine brake hard is in trouble.

Pads felt greased! Haha. So - what's the first couple steps that will improve this particular sort of braking?

Was this the first time you have ever fully used the brakes since you bought it?

Heh, this is kinda strange. The car will feel a little different under high speed braking than low speed, but it shouldn't feel anything like "no brakes". 130kph is only 80mph, that's not crazy high speed by any means, but we need more info...

What were the circumstances, were you out cruising around, on twisty mountain roads, on a track? How many miles are on the car? Was the pedal soft? Was ABS activated? Were you actually pushing the pedal firmly or it just didn't brake as hard as you thought it should?

Its possible the pads were glazed, fluid boiled etc... If you really need an upgrade, better pads and fluid would be the first step. It's the final step for most, the stock braking system is pretty solid until it's pushed to its limits, which should only be achievable at a track, not on the street.

engine braking does not change the acute stopping power at all

His point is that engine braking helps bleed speed. He said nothing about engine braking making the brakes better or worse.

Speed is not the primary concern with brakes, it is heat that you need to worry about. Just going 80mph and stepping on the brakes should be no problem for the stock brakes. If you did something to get them hot (riding the pedal, repeated hard stops) they will be equally weak at any speed until they cool down to regular operating temperature. Higher speeds will obviously heat brakes up faster, so there is some speed at which the stock brakes will no longer be effective, but they should have no problem with 80mph during regular driving. I think you need to give us more information about the circumstances and what happened. Were you using the brakes a lot before this happened? Were you running summer tires in cold weather? Did the ABS activate?

I had the same thing on a WRX once at high speed but only because the brakes were cold. Cruising at 120kph for 20min without touching the brakes and then went flat out on a secluded straight stretch. Crested a hill at 230kph and saw 80kph signs and an intersection but had no brakes, the pedal just hummed under my foot. I thought I knew the road but got it wrong! I changed down, got the brakes back at 180kph and took the bend fast.

If it was like that at 130kph on cold brakes I would take to the dealer under warranty.

my point is that if your brakes arent enough to stop the car, your engine wont save you. he said if you dont engine brake you are in trouble (or something to that effect). if you get yourself in trouble, and its not from overheating your brakes, engine braking is not going to help you at all. actual brake systems have not been the bottle neck of stopping power since the sixties.

Yeah engine braking on a RWD car with a 2 liter engine is not going to provide much stopping force at all.

Brakes are so easily and cheaply upgraded. A good pad choice and fluid change alone will make a night and day difference.

You can go even above that and do rotors and lines, remove backing plates for extra cooling. So many options on the stock system to get improvement.

Start with pads and fluid. We noticed a huge increase there. We recently added our stage 2 package to our car for this weekends time trial.

http://ft86speedfactory.com/images/brakeupstg2.jpg

With 12.5:1 compression a 2L will provide similar engine braking to a 3L with 8.5:1 and be a lot lighter vehicle to stop too.
When you lose your brakes, engine braking is fantastic, almost as good as the hand brake if you don't lock it up and more stable.
I tend to use the engine to slow down and enjoy the gear changes, then use the brakes for coming to a stop only. That way you are less likely to get caught out when things go wrong.

Yeah but he said

If you are engine braking hard, you are already in trouble. If you try to "engine brake hard" in a RWD car you will spin. When you engine brake you are just braking the rear wheels, combined with the fact that you are shifting the weight forward by braking, you're not going to get much done that way and you'll end up in a ditch. Sure it can be done to bleed off some speed on the highway or coming to a red light but the idea of "engine braking hard" is pretty foolish.

http://en.wikipedia.org/wiki/Lift-off_oversteer

My brakes feel fine (for a few laps anyways with stock pads) at higher speeds. :shrug:

Which brake fluid did you guys use?

The condition was a 0-until I need to start braking (around 90 mph) on a straight stretch of road. I saw the road about to run out so I was on the brakes first step was light and they did almost nothing. Second was hard braking. No lock-up / ABS .. it felt really greasy. I had to engine brake hard like I said to grease off the speed.

Car has 5k miles and has otherwise performed well.

We swapped in the Motul 5.1 for now.

For increased heat capacity, upgrade brake pads and brake fluid. :)

But on the cap it say use a dot3 brake fluid only.

Motul 5.1 is certified for DOT 3, 4, and 5.1 systems.

how does 5.1 act in severe cold?

Like most fluid. -40F is the point in which to worry about it. Honestly if it is -40 outside, I'd be staying inside. :happy0180:

If it's -40, just use the snow drifts to slow down. ;)

At least it wasn't like this:

[ame="http://www.youtube.com/watch?v=9UkXvXsFO50"]How to ALMOST crash your Subaru in style!! - YouTube[/ame]


But anyway, if you're going to be braking hard like that, you need better performance brake pads which are properly bedded in, better brake fluid (DOT 5.1), and better tires.

It'll happen, and I'll be driving

haha me too

The OP seems to have the exact opposite issue of the rest of the sporting world, his brakes were BELOW their minimum operating temp if you are to believe his scenario played out as described...

I for one have had ZERO issues off track with this car and even on track this weekend i had no problems with repeated stops from 100 mph with or without engine braking, I could engage ABS anytime I would have liked and I had a fresh set of Hankook Ventus RS-3's mounted in 225 flavor just for this weekend....

blame canada

I don't see the point in "upgrading" brake fluid for street use. Same with lines and rotors. The OP was driving on the street, people. He doesn't need upgraded heat capacity, just more friction.The stock pads are a little silly. I changed them to Hawk HPS for street use - much better. Good bite, good modulation, don't need any time to warm up. Beware of vendor posts encouraging you to "upgrade" systems that don't need upgrading.

Maybe the problem is in the master cylinder?

He was in an emergency situation with no brakes and had to use high rpm engine[hard] braking but normally you would use lower rpm and it wouldn't be enough to unsettle the rear end.
If you are driving hard you would be using both the engine and the brakes.
Clearly you could drop it into a low gear going through a tight bend in the wet and spin out but there are lots of stupid things which would also put you in the ditch, you just don't do them.

Bit of a weird sounding problem.

The brakes on my car are definitely better once warmed up to temp (5 minutes of driving or so) but I've never had a problem with stopping power even from speeds much higher than 130km/h.

If it's persistent then try re-bedding your pads perhaps?

:iono:

The brakes on these cars do suck compared to a lot of other things available. The feel is also squishy and vague.
My first planned mods are HP+ front pads/HPS rear pads and stainless lines and fluid. I hope this takes care of the issues I have, because frankly it's saddening to have such a responsive car thats SO GOOD at so many things but still has lackluster brakes.

theres no point in having a sports car for street use either. its hard to criticize people for not being entirely rational considering many of us are using it for street use since thats not rational at all

I ran RBF600 on my Corvette and swap between ATE yellow and SuperBlue?
Why on the street? 3 reasons...
1 - if you do a track day, chances are you're not gonna change fluid after the race, maybe before but usually not after.
2 - There's ZERO harm in running better fluid on the street
3 - It's like $4 a pint more for ATE fluids than DOT3 crap ($8 more for RBF) - if you're that cheap you need to drive a Corolla.

Brakes are never usless. its always the driver that is

Stock pads are perfect for the street. I'm shocked you like the HPS pads, I tried them a long time ago and they were some of the worst pads I've ever used (next to discount one-stoppers).

I agree on fluid on the street, stock is fine. Same with the pads, I never had a problem on the street with them. Sure, on the track they sucked, but on the street they were fine. Hell some members here have used them on the track for a good bit without issue.

Mine feel fine. They aren't 911 hard, but they are less squishy than a lot of OEM setups.

Maybe you guys with issues should do some bleeding? My car had some air in it but that was after a few laps on the track, but perhaps you guys have air in the lines from the factory?

His point eliminates track use. I don't disagree with the other two points, but it's not at all required. If people are generating enough heat to boil fluid on the street then they are doing something wrong.

oh we got a tough guy here.

I know how to brake in a straight line ya mook. My Soarer has Project Mu all around so I know what it feels like to have proper brakes.

Well, sounds like some people need to learn the limits of their vehicles SLOWLY rather than just going act like an F1 driver and get in a horrible situation. Just my opinion, but don't do something that you don't know the consequences are... Just sayn. Don't be a douche. And as far as the Vendors tryn to sell their parts, well, the guy said his brakes didn't work, so they were tryn to be safe and for his system to work correctly.

I'll most likely get the StopTech pads when the time comes, i haven't noticed any need yet but this in the description makes me think they may work for you.

Street and high performance pads to fit both OEM calipers and StopTech® Big Brake Kits

Para-aramid composites provides linear response regardless of pad temperature

100% positive molded for uniform friction material density

Specially engineered for pursuit, rescue and emergency driving

Scorched to raise initial cold effectiveness and easy bed-in

100% Asbestos-free formulas