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Old 12-08-2012, 07:24 PM   #501
thewilfred
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more brain power to me!
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Old 12-14-2012, 12:19 AM   #502
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Hi, I haven't been on here a lot in a couple years and just stumbled on this thread.

Great write-up, curious to see some of the posts in the 21 or so pages.

I agree with the 1st post, 100%.

For street use, most brake systems are perfectly fine UNLESS you really don't know how to use them.
Yes, tires (and proper inflation....) make a bigger difference.
Not carrying around lots of extra weight also helps....all other things being equal.

I run basically stock brakes (rotors were replaced at one point, nothing special) with SS lines and nice semi-metallic pads.
Yes, I can get brake fade. Usually that is either:
-Running in the hills
-Driving waaayyyyyy too fast on public roads

The pads I run have a consistent feel.
The SS lines improve the SYSTEM a bit since the 1998 ABS systems had a strange pulse that rubber lines aggravated. The SS lines changed the pulse frequency which helped.

I learned to drive in a 1968 Plymouth Fury III with a small V-8, bias ply tires and 4 wheel drum brakes. You LEARNED to manage brakes to help fight fade.

I like others that run some BBK's. They added rotational mass (hurts performance) and weight on the wrong end of the springs (which hurts handling). It helps even out the performance.
LOL.
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Old 12-16-2012, 02:55 PM   #503
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Thank you for the post! It seems to be such a common misconception. Brembos sure look nice thought!
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Old 12-22-2012, 12:30 AM   #504
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Best source of info I've found so far : ) Thanks!
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Old 12-22-2012, 05:56 PM   #505
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Thumbs up I Know a little about brakes

I didn't read anything in the otherwise brilliant post about ABS brakes. We aren't talking about systems that lock up so there might still be something to the increased surface areas of larger rotors.

But, with that said, I once made a full pass in an 11 second Chevy II with original drum brakes on all 4 corners. Very Scary and dodgy but I didn't die!
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Old 12-23-2012, 12:25 AM   #506
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Quote:
Originally Posted by prncnhorse View Post
I didn't read anything in the otherwise brilliant post about ABS brakes. We aren't talking about systems that lock up so there might still be something to the increased surface areas of larger rotors.

But, with that said, I once made a full pass in an 11 second Chevy II with original drum brakes on all 4 corners. Very Scary and dodgy but I didn't die!
From what I understand of the subject, the abs system is actually modulating the brakes so that the wheels don't lock. They do this because the braking distance of a rotating tire is lower than that of a sliding tire. This actually doesn't factor into the question of brake capability much though, mainly because it is trying to account for the different coefficients of friction (static, as in the rotational situation, and kinetic in the sliding situation).

The system that we are discussing doesn't include the tire and road interface. The brakes locking are an ideal condition for a system where an idealized rotational mass is being studied. In this situation the important forces involved are between the disk and the brake pad. The force equations here are actually less dependent on brake pad contact area than they are on brake pad material. Which would indicate that as long as the stock brakes are using a sufficient material they should do the same job (on the first stop) as the more expensive brakes. They will be much less fade resistant than better brakes because of the geometry of the brake interface, but that is another story.

There are just too many variables to account for if you look at the whole system while simply comparing brake capability. ABS actually plays an important role in stopping the car, but it doesn't factor into the comparison of actual brakes.
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Old 12-25-2012, 01:07 PM   #507
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good post
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Old 01-11-2013, 03:51 PM   #508
T.W.E S.o.h.c
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Cool well said

well said but lines pads rotors are very important
Quote:
Originally Posted by Davenow View Post
READ THIS FIRST

The point of this thread, since no one seems to be able to get this, and I will add it to the first post is








99% of people, with increased power, the only time they are going to need stopping power greater than what a bone stock brake/tire setup can offer, is when they are going down the road and have an "OH ISHT" panic brake situation.

And in that situation, there is no brake setup on the planet that will stop you any faster than the OEM pads/rotors/lines/fluid will.
The ONLY thing that will shorten that distance, is a stickier tire.


And for most people, they mod their car and they go out and rail on it from a stop or roll, usually in a straight line. The braking power they have to worry about is going to come into play

when they see a cop
When they hit a red light
When something is coming out in front of them
When there is some reason they need to get on the brakes hard and fast to avoid hitting something.

None of those things would see any benefit whatsoever, from upgraded pads,rotors, lines, or fluid, or any combination of them. Only a stickier tire is going to make the car slow down or stop in a shorter distance.

So, to be clear, if in an effort to make the message of this post look incorrect, you are posting something completely irrelevant if you

1. You bring up power gains
2. You bring up racing
3. You bring up anything other than the type of street driving that 99% of people actually do.
---Most people don't do canyon runs or anything similar to that.

Unfortunately, those 3 points above, encompass at least half the responses in this thread
Point is, stop trying to come up with situations that I am not talking about, just to make this post look incorrect, to justify what you spent on your brake kit. Maybe you do something that requires it, most people however, even with 400+whp, don't, and won't.



And just to make it clear once again.

For 99% of people with increased HP, the main brake performance issue is going to be

Panic braking in an emergency situation (be it a cop, old lady pulling in front of them, or just oh **** a red light)













When people talk about modding their car to make more power, someone almost always comes in and tells them that with more power, they need more handling and more braking.

While this is solid reasoning, its not always a necessity.

My personal philosophy is that when upgrading a vehicle, address everything, to maintain a nice balance.

However, there is a flaw with part of the logic of "if you upgrade one you must upgrade all 3 in order to remain safe"

If you go from stock, to 400whp, upgrading the brakes, IS NOT NEEDED AND YOU WILL BE NO SAFER THAN YOU WOULD BE ON STOCK BRAKES.

Now, I know a lot of you are now no longer reading this and are already forming your replies, and unfortunately many of you will base them on beliefs you have formed by reading what others have said on the internet, who only said what they said, because they read it on the internet. Or based on misconceptions. (some of you may have well thought out and solid arguements as well) Those of you about to say I am wrong, I assure you, are wrong. Please do me and yourselves a favor, and make sure you UNDERSTAND WHAT I AM SAYING before replying.

Here is the thing.

A WRX with @170whp (stock 2.0L typical) traveling at 10, 40, 60, 130mph, will take the exact same force to stop, as a fire breathing alcohol fueled 800whp WRX traveling 10, 40, 60, 130mph.


Take either of those cars, put a $14000 stoptech 8 piston f/6piston r setup, and do the same full boogie panic stops, and what do we get?

THE EXACT SAME STOPPING DISTANCE.

(now, lets leave heat induced fade off the table for now, as it isnt something that 90% of people that would argue that you have to upgrade the brakes would ever run into on stock brakes anyway) For the sake of this discussion, lets look at what people are really talking about. Panic stops, someone pulls in front of you OH ISHT nailing the brakes to avoid hitting them, stopping or the rate at which you can slow down enough to avoid impact (since you dont always have to stop)

Why is that?

What stops cars? What is the ultimate force that determines what point the traveling vehicle will no longer be traveling?

Friction. Not the friction between the pads and the rotors, but the friction between the tire and the road.


Now, lets take 2 cars again.

First WRX, 170whp, bone stock brakes. 225/45/17s in a dot legal R compound.

Second car, whatever WHP, and $7k in brake upgrades. Stock tires. Heck lets even say they went to stock STI 225/45/17 RE070s.

Send both cars down the same road, in the same weather conditions at the same speed. Have someone pull out in front of them.

Tell me, which one will stop short enough, or be able to slow down fast enough to avoid a wreck?

I bet more than half of nasioc would pick the car with $7k in brake upgrades. Those people would all be in an accident.



How does a car stop? Well, how does it move? What moves, that causes the big hunk of metal to move?

TIRES.

What gets a car off the line faster? Less wheelspin. WHat gets you less wheelspin? Stickier tires.

What gets you through a corner faster? More traction, what gets you more traction? Stickier tires.

Just like when you are trying to accelerate a vehicle, the amount of grip the tire has on the road, will determine how fast you can get moving forward (or backwards if you are a launch in reverse type of guy ) Its the EXACT SAME THING when trying to slow or stop.

OEM brakes have FAR more than enough power to lock up even a big wide sticky r compound tire.

People like to cite that the STI has a shorter stopping distance with its Brembos. The brembos have nothing to do with it. The RE92s have everything to do with it.



So a lot of people at this point, will argue that "well then why do they put brembos and big brakes on sports cars if they dont stop you any shorter"

The answer is intended purpose, and as much as many people dont want to believe, LOOKS/CUSTOMER PERCEPTION.

The "intended use" for the STI is hard performance driving. Track days, racing, its a car with actual motorsport use in mind. Even if they have watered it down and softened it for normal day to day use, its still a car that was built for motorsport use.

Big fixed mount calipers with lots of pistons, and large diameter rotors offer something a floating caliper with normal sized rotors dont offer. Mass. More mass=more resistance to heat induced fade. They also offer a more consistant and precise pedal, which allows finer braking control into corners.

They also offer a look. Like the new WRX, look at how many people complain that they "downgraded" the brakes. When in fact, from a stopping distance standpoint, there is no change.

Look at the competition for the STI, the EVO. What would happen to STi sales if they removed the brembos and the EVO kept them? That would sway those people who are on the fence, a little more towards the EVO.

Finally, lets look at the group-N STI rally cars. What brakes do they run?

That's right, not the Brembos. They run the older FHI 4 pot/2 pot setup in order to clear the smaller rally wheels. Yet they stop JUST FINE.



Lines, well lines are, from a stopping distance and fade standpoint, completely useless. Nail the brakes, things lock up rubber or steel lines makes no difference. Heat the brakes up, stainless lines have nothing to do with anything.

What lines DO get you, is a more consistant pedal, allowing more precise control.



Fluid, unless you are doing repeated hard braking enough to boil normal fluid, going to "upgraded" fluid, is a waste of money, and $18/bottle motul wont get you anything that $3 autozone fluid wont.




Rotors? NEVER an upgrade unless your factory rotors are damaged/very worn. Or if you go to a larger diameter rotor. Even then, that will only increase the amount of force per bit of pedal travel, to the point where they just lock up. Which would have happened on OEM sized rotors anyway. Slotted/drilled, at this point, is pointless and is for looks. Modern pads dont off gas like they used to, so having the slots/dimples/holes to vent off the gasses, well there is no need. Not only that, but 90% of drilled rotors will end up cracking. So if you want the look, GO FOR IT!, but buy a rotor that was cast with holes, not a solid that was drilled after. Break out the wallet though, and be prepared to search, not many people carry them and they arent cheap. If you do shows, do what I did, carry a set of $99 ebay cross drilled rotors with you and slap them on at the show. It takes 20 min.





"BUT MY BUDDY PUT BREMBOS ON HIS WRX WITH WTFBBQ ALLOY PADS, SUPERBUTTSEKS INCREDITAINIUM LINES AND CHUCK NORRIS BRAND FLUID AND IT STOPS WAY HARDER."


No, it doesnt. It has a lot more INITIAL BITE.
95% of people will mistake initial bite and/or decreased pedal travel, for the ability to stop shorter.

A locked tire is a locked tire. And while big brakes can lock a tire without having to push the pedal as hard, stock brakes can still lock the tires instantly if you nail the pedal. Therefor, stopping distance and rate of slowing down, is unchanged.,




So what can you do to make the car safer if you up the power?

Well, for one thing, if you are driving responsibly and within the law, why do you need to upgrade the brakes at all? Ok so obviously that is a dumb point to bring up

No but seriously, you upped the power and you want the car to be able to stop shorter


Well, as we have established, the grip of the tire on the road is the ultimate determining factor, so you want wider and or stickier tires. Preferably, both.

There is another aspect to look at too. Weight. A heavy object takes more force to accelerate or decelerate than a lighter one.

Put your car and yourself on a diet.

I think its hilarious that someone adding 50whp, and refusing to upgrade the brakes, is shunned and flamed, yet someone adding 200lbs of stereo gear/other things, no one even mentions the brakes. Rest assured that 200lbs of weight WILL increase stopping distance measureably.






Handling, thats another story altogether. A car that handles better is always safer than one that doesnt. In fact if you are so worried about safety, handling should be your first priority. Guess where the very first place you should look when it comes to handling Yup, those same black round things that will make you stop shorter.





This is a bit of a mind dump, so forgive me if it jumps around a bit or if I missed something or repeated myself.

Ill add more or edit it as needed when I get a minute.
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Old 01-11-2013, 05:13 PM   #509
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I'm just going to keep quoting this line since it makes me laugh my ass off no matter how many times I read it:

"BUT MY BUDDY PUT BREMBOS ON HIS WRX WITH WTFBBQ ALLOY PADS, SUPERBUTTSEKS INCREDITAINIUM LINES AND CHUCK NORRIS BRAND FLUID AND IT STOPS WAY HARDER."
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Old 01-16-2013, 10:51 AM   #510
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Great post (even though I'm commenting years later), I just picked up an 06 WRX wagon so I've been going through all the stickys; I've owned many vehicles in my 29 years (mostly Fords, it's OK though I'm wearing my Flame-Proof suit); example vehicles and brake "upgrades"
1966 Mustang - 4 wheel drum, went to front disc to reduce fade (also the springs inside the drum fell apart a lot) - this car is under the knife again, I want to turn it into an open track vehicle, so thats a whole other ball of wax.
1992 Mustang 5.0 - disc/drum - swapped SN95 rotors & calipers in front because the fade was evident on the stock brakes in normal driving conditions (well normal teenager driving conditions) also I ran wider tires that were quite sticky.
1993 Impreza - disc/drum, 1.8L FWD Auto - it had 14" rims so you can imagine how small the factory discs were, I replaced front axles more often than I replaced front brakes, great little car minus the axle chewing issue, used the cheapest brakes I could find, fade was never evident (no upgrade).
2003 SVT Focus - disc/disc brakes were massive, went to centric "premium rotos" because the rim/hub conact points were anodized and I ran a summer & winter set so I swapped wheels a lot, I should note I did front brakes at 75k and rears at 98k; that car was easy on brakes
2002 Honda CBR F4i - EBC HH pads and stainless lines adjustable levers - pads were for track days, lines were for better lever feel (bike had really long rubber lines) adjustable levers were because the stock brake lever was uncomfortable
2007 Toyota Yaris (my wifes car) disc/drum - centric "premium" rotors - she has a winter set and a summer set, the anodized contact points make it easier to swap wheels. I only did her fronts at 60k miles, and the pads had plenty of life, that car is easy on brakes too, I pulled the drums apart and the shoes look brand new still
I've owned an 88 and a 93 F-150 (disc/drum) , 2002 Explorer (disc/disc), 88 Buick regal (dont even know what it had for brakes) all of them have had enough braking power and I never noticed fade, even when I over-loaded my 93 F-150 to the point of blocking the rear suspension to keep the wheel wells off the rear tires.
With the exception of the mustangs (sub-standard brakes) and the motorcycle (intended track use) I have found no reason to upgrade brakes, with the WRX, since its my DD, I will most likely stick with stock pads and fluid, maybe do centric rotors for the anodized surface, but I don't think these brakes for DD use will need an upgrade.
Unrelated but related - "AWD is soo much better in the snow" FALSE! AWD gets you moving in the snow but doesnt do dimp to help you stop or handle; its your freaking TIRES!
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Old 01-25-2013, 02:27 PM   #511
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thanks for the help, blowing through these stickies is helping a ***** ton
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Old 02-01-2013, 03:15 PM   #512
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Default Good post OP, but....

"Well, as we have established, the grip of the tire on the road is the ultimate determining factor, so you want wider and or stickier tires. Preferably, both"

Stickier tires yes indeed, but as far as stopping distance goes width is not a factor AT ALL (goes for surface area in a braking system as well), unless you were talking fade, which you clearly were not.

With regards to stopping distance and friction force there are two different coefficients of friction, static and dynamic. Static friction is when there is no slippage between the two friction surfaces (tire and road in this case). Dynamic friction is when there is slippage between surfaces (i.e., lockup situation). With any two friction surfaces being the same, the coefficient of static friction is always greater than the coefficient of dynamic friction. That is why ABS is so good. It keeps the road and tire in a state of static friction, rather than dynamic.

Think of putting a piece of wood (or anything else for that matter) on a flat surface and slowly raising one end of it to create an angle. You will be able to get that angle pretty steep before the wood begins to slide. Once it starts to slide you will have to decrease the angle dramatically to get the wood to stop moving. That is the static/dynamic coefficients of friction at work in a physical application that anyone can test themselves. It is always the case no matter what two friction surfaces you are talking about. Always.

The equation for friction force is: (friction force)=(coefficient of friction) times (normal "vertical" force)

That is it. Notice there is no variable for surface area anywhere in that equation because the surface area does not matter. Sticky tires just increase that coefficient of static/dynamic friction. Ever wonder how a locomotive can pull such huge loads on knife edges that are the steel wheels and tracks? The coefficients of friction are poor with steel on steel, but the normal force is massive.

Other than this slight oversight, your OP is spot on regarding everything else. I am happy to be able to clear this up and add to a wonderful discussion.

Signed,

Old egg-headed engineer that loves him some good physics talk

Last edited by Hoon Goon; 02-01-2013 at 03:23 PM. Reason: Didn't do the quote thing right, but oh well.
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Old 02-01-2013, 05:40 PM   #513
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So if stopping a vehicle is negative acceleration, and width of tires don't matter when it comes to negatively accelerating, then why does a wider contact patch matter so much during positive acceleration?

I am not trying to be rude or argue...I am just curious why in drag racing, road racing, etc., wider and stickier is better than skinnier and stickier. I feel that if you were correct, then every race car out there would be buying 165 width slicks instead of tires twice that width because the extra width is only gaining them weight instead of grip. It just seems to me that you are missing a variable in your equation somewhere...
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Old 02-01-2013, 10:44 PM   #514
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Tires are a somewhat special case in the frictional force world. Here is an interesting article that explains why a wider tire (and therefore surface area) is better for stopping:

http://www.physics.sc.edu/~rjones/ph...efriction.html

The basic premise is that the tire road surface is not an idealized coefficient situation. The tire has the ability to shear at the contact point with the road and therefore the wider the tire the more shear resistance is available.

There are also deformation issues based on road conditions. If the road was extremely flat and the tire shear issue was solved then surface area wouldn't affect the situation as much (or at all).
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Old 02-06-2013, 09:33 PM   #515
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Op is saying all we need for a brake upgrade it this,

http://www.ebay.com/itm/3D-SILVER-BR...item2a28c58eaf

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Old 02-06-2013, 10:08 PM   #516
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nice point so i guess the only point upgrading your brakes is by going faster than the factory top speed but who goes faster than that on a daily basis anyway so i guess upgrading your brakes is till useless
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Old 02-10-2013, 09:32 PM   #517
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Quote:
Originally Posted by amalgrover View Post
So if stopping a vehicle is negative acceleration, and width of tires don't matter when it comes to negatively accelerating, then why does a wider contact patch matter so much during positive acceleration?

I am not trying to be rude or argue...I am just curious why in drag racing, road racing, etc., wider and stickier is better than skinnier and stickier. I feel that if you were correct, then every race car out there would be buying 165 width slicks instead of tires twice that width because the extra width is only gaining them weight instead of grip. It just seems to me that you are missing a variable in your equation somewhere...
Quote:
Originally Posted by JRCrutc View Post
Tires are a somewhat special case in the frictional force world. Here is an interesting article that explains why a wider tire (and therefore surface area) is better for stopping:

http://www.physics.sc.edu/~rjones/ph...efriction.html

The basic premise is that the tire road surface is not an idealized coefficient situation. The tire has the ability to shear at the contact point with the road and therefore the wider the tire the more shear resistance is available.

There are also deformation issues based on road conditions. If the road was extremely flat and the tire shear issue was solved then surface area wouldn't affect the situation as much (or at all).
I can dig it. I learn something new every day (at least try to). I did not consider the shear forces working on the tire at the interface. My old Statics and Dynamics professors would righfully give me an F. Thanks for the replies fellas!

****NOTE FELLOW NASIOCers: A GUY JUST ADMITTED HE WAS WRONG*****

I am a hydraulics/hydrology guy, but I still love the cars and thinking about this stuff!
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Old 02-14-2013, 01:30 PM   #518
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Awesome article and great refresher as I'm getting back into the hobby (been driving a Yaris for 2 years now, shoot me! - waiting on a new STI now)

I'm surprised how many people don't realize this though! 18x10s here we come! :-D
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Old 02-28-2013, 06:21 PM   #519
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Quote:
Originally Posted by STirocket View Post
I like Dave's post, and think this whole discussion is a good read. But his sentence about having a 400 WHP car and not needing to upgrade the brakes is a bit misleading. He goes on to say if you're driving 10, 20, 40, or 60 MPH it's going to take the same time/distance to stop your car. That's absolutely correct, but the reason people upgrade cars to make 400 WHP is not so they can go the same speed as they went in their stock car. It will DEFINITELY take bigger brakes, better tires etc. to decelerate from 150 MPH than it does with your stock car at 60 MPH.

A lot of other people have mentioned brake fade, which is a condition that you will rarely experience on the street unless you do a lot of canyon carving. However, if you do ANY track time, it's a VERY real concern that needs to be addressed. Stock brakes aren't designed to dissipate the heat generated on the race track, period. On my local track, decelerating from over 135 at the end of the main straight to go through turn 2 at 80 MPH, then accelerating up to 110 going down hill into turns 3A and 3B at 40 MPH over and over again for a half hour at a time will most definitely cause stock brakes to fade if not outright fail. So if you have a stock car that might only be able to get up to 100 MPH on the main straight it's not nearly as hard on the braking system to decelerate to 80 to go through turn 2, and if you only get up to 60 or 70 going down the hill into 3A and 3B you may be able to do that all day without your brakes fading.

Just sayin' having a lot more than stock HP can certainly mean you should upgrade your brakes if you aren't driving the speed limit...

Rocket's two cents
Thank you!
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Old 03-14-2013, 11:29 PM   #520
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Default help please

2013 New Impreza sport 5 speed noises
Ok, So Id like some advise. Dealer changed factory oil at 1k miles per their recommendation to remove break in metal etc deposits they billed me and serviced the vehicle with 0w20 oil synthetic subaru oil. The car had a moderate engine clacking noise, but now after the oil change its significantly louder, to the point i can hear it under acceleration even with the radio on, and on decel its loud as heck too. This is my first Roo, and need advise. I truly love everything else about this functional and fun car, but none of my previous 16 cars have ever had these noises (not that can be heard like this) and they have all been used. Thanks.




Quote:
Originally Posted by Davenow View Post
READ THIS FIRST

The point of this thread, since no one seems to be able to get this, and I will add it to the first post is








99% of people, with increased power, the only time they are going to need stopping power greater than what a bone stock brake/tire setup can offer, is when they are going down the road and have an "OH ISHT" panic brake situation.

And in that situation, there is no brake setup on the planet that will stop you any faster than the OEM pads/rotors/lines/fluid will.
The ONLY thing that will shorten that distance, is a stickier tire.


And for most people, they mod their car and they go out and rail on it from a stop or roll, usually in a straight line. The braking power they have to worry about is going to come into play

when they see a cop
When they hit a red light
When something is coming out in front of them
When there is some reason they need to get on the brakes hard and fast to avoid hitting something.

None of those things would see any benefit whatsoever, from upgraded pads,rotors, lines, or fluid, or any combination of them. Only a stickier tire is going to make the car slow down or stop in a shorter distance.


So, to be clear, if in an effort to make the message of this post look incorrect, you are posting something completely irrelevant if you

1. You bring up power gains
2. You bring up racing
3. You bring up anything other than the type of street driving that 99% of people actually do.
---Most people don't do canyon runs or anything similar to that.

Unfortunately, those 3 points above, encompass at least half the responses in this thread
Point is, stop trying to come up with situations that I am not talking about, just to make this post look incorrect, to justify what you spent on your brake kit. Maybe you do something that requires it, most people however, even with 400+whp, don't, and won't.



And just to make it clear once again.

For 99% of people with increased HP, the main brake performance issue is going to be

Panic braking in an emergency situation (be it a cop, old lady pulling in front of them, or just oh **** a red light)













When people talk about modding their car to make more power, someone almost always comes in and tells them that with more power, they need more handling and more braking.

While this is solid reasoning, its not always a necessity.

My personal philosophy is that when upgrading a vehicle, address everything, to maintain a nice balance.

However, there is a flaw with part of the logic of "if you upgrade one you must upgrade all 3 in order to remain safe"

If you go from stock, to 400whp, upgrading the brakes, IS NOT NEEDED AND YOU WILL BE NO SAFER THAN YOU WOULD BE ON STOCK BRAKES.

Now, I know a lot of you are now no longer reading this and are already forming your replies, and unfortunately many of you will base them on beliefs you have formed by reading what others have said on the internet, who only said what they said, because they read it on the internet. Or based on misconceptions. (some of you may have well thought out and solid arguements as well) Those of you about to say I am wrong, I assure you, are wrong. Please do me and yourselves a favor, and make sure you UNDERSTAND WHAT I AM SAYING before replying.

Here is the thing.

A WRX with @170whp (stock 2.0L typical) traveling at 10, 40, 60, 130mph, will take the exact same force to stop, as a fire breathing alcohol fueled 800whp WRX traveling 10, 40, 60, 130mph.


Take either of those cars, put a $14000 stoptech 8 piston f/6piston r setup, and do the same full boogie panic stops, and what do we get?

THE EXACT SAME STOPPING DISTANCE.

(now, lets leave heat induced fade off the table for now, as it isnt something that 90% of people that would argue that you have to upgrade the brakes would ever run into on stock brakes anyway) For the sake of this discussion, lets look at what people are really talking about. Panic stops, someone pulls in front of you OH ISHT nailing the brakes to avoid hitting them, stopping or the rate at which you can slow down enough to avoid impact (since you dont always have to stop)

Why is that?

What stops cars? What is the ultimate force that determines what point the traveling vehicle will no longer be traveling?

Friction. Not the friction between the pads and the rotors, but the friction between the tire and the road.


Now, lets take 2 cars again.

First WRX, 170whp, bone stock brakes. 225/45/17s in a dot legal R compound.

Second car, whatever WHP, and $7k in brake upgrades. Stock tires. Heck lets even say they went to stock STI 225/45/17 RE070s.

Send both cars down the same road, in the same weather conditions at the same speed. Have someone pull out in front of them.

Tell me, which one will stop short enough, or be able to slow down fast enough to avoid a wreck?

I bet more than half of nasioc would pick the car with $7k in brake upgrades. Those people would all be in an accident.



How does a car stop? Well, how does it move? What moves, that causes the big hunk of metal to move?

TIRES.

What gets a car off the line faster? Less wheelspin. WHat gets you less wheelspin? Stickier tires.

What gets you through a corner faster? More traction, what gets you more traction? Stickier tires.

Just like when you are trying to accelerate a vehicle, the amount of grip the tire has on the road, will determine how fast you can get moving forward (or backwards if you are a launch in reverse type of guy ) Its the EXACT SAME THING when trying to slow or stop.

OEM brakes have FAR more than enough power to lock up even a big wide sticky r compound tire.

People like to cite that the STI has a shorter stopping distance with its Brembos. The brembos have nothing to do with it. The RE92s have everything to do with it.



So a lot of people at this point, will argue that "well then why do they put brembos and big brakes on sports cars if they dont stop you any shorter"

The answer is intended purpose, and as much as many people dont want to believe, LOOKS/CUSTOMER PERCEPTION.

The "intended use" for the STI is hard performance driving. Track days, racing, its a car with actual motorsport use in mind. Even if they have watered it down and softened it for normal day to day use, its still a car that was built for motorsport use.

Big fixed mount calipers with lots of pistons, and large diameter rotors offer something a floating caliper with normal sized rotors dont offer. Mass. More mass=more resistance to heat induced fade. They also offer a more consistant and precise pedal, which allows finer braking control into corners.

They also offer a look. Like the new WRX, look at how many people complain that they "downgraded" the brakes. When in fact, from a stopping distance standpoint, there is no change.

Look at the competition for the STI, the EVO. What would happen to STi sales if they removed the brembos and the EVO kept them? That would sway those people who are on the fence, a little more towards the EVO.

Finally, lets look at the group-N STI rally cars. What brakes do they run?

That's right, not the Brembos. They run the older FHI 4 pot/2 pot setup in order to clear the smaller rally wheels. Yet they stop JUST FINE.



Lines, well lines are, from a stopping distance and fade standpoint, completely useless. Nail the brakes, things lock up rubber or steel lines makes no difference. Heat the brakes up, stainless lines have nothing to do with anything.

What lines DO get you, is a more consistant pedal, allowing more precise control.



Fluid, unless you are doing repeated hard braking enough to boil normal fluid, going to "upgraded" fluid, is a waste of money, and $18/bottle motul wont get you anything that $3 autozone fluid wont.




Rotors? NEVER an upgrade unless your factory rotors are damaged/very worn. Or if you go to a larger diameter rotor. Even then, that will only increase the amount of force per bit of pedal travel, to the point where they just lock up. Which would have happened on OEM sized rotors anyway. Slotted/drilled, at this point, is pointless and is for looks. Modern pads dont off gas like they used to, so having the slots/dimples/holes to vent off the gasses, well there is no need. Not only that, but 90% of drilled rotors will end up cracking. So if you want the look, GO FOR IT!, but buy a rotor that was cast with holes, not a solid that was drilled after. Break out the wallet though, and be prepared to search, not many people carry them and they arent cheap. If you do shows, do what I did, carry a set of $99 ebay cross drilled rotors with you and slap them on at the show. It takes 20 min.





"BUT MY BUDDY PUT BREMBOS ON HIS WRX WITH WTFBBQ ALLOY PADS, SUPERBUTTSEKS INCREDITAINIUM LINES AND CHUCK NORRIS BRAND FLUID AND IT STOPS WAY HARDER."


No, it doesnt. It has a lot more INITIAL BITE.
95% of people will mistake initial bite and/or decreased pedal travel, for the ability to stop shorter.

A locked tire is a locked tire. And while big brakes can lock a tire without having to push the pedal as hard, stock brakes can still lock the tires instantly if you nail the pedal. Therefor, stopping distance and rate of slowing down, is unchanged.,




So what can you do to make the car safer if you up the power?

Well, for one thing, if you are driving responsibly and within the law, why do you need to upgrade the brakes at all? Ok so obviously that is a dumb point to bring up

No but seriously, you upped the power and you want the car to be able to stop shorter


Well, as we have established, the grip of the tire on the road is the ultimate determining factor, so you want wider and or stickier tires. Preferably, both.

There is another aspect to look at too. Weight. A heavy object takes more force to accelerate or decelerate than a lighter one.

Put your car and yourself on a diet.

I think its hilarious that someone adding 50whp, and refusing to upgrade the brakes, is shunned and flamed, yet someone adding 200lbs of stereo gear/other things, no one even mentions the brakes. Rest assured that 200lbs of weight WILL increase stopping distance measureably.






Handling, thats another story altogether. A car that handles better is always safer than one that doesnt. In fact if you are so worried about safety, handling should be your first priority. Guess where the very first place you should look when it comes to handling Yup, those same black round things that will make you stop shorter.





This is a bit of a mind dump, so forgive me if it jumps around a bit or if I missed something or repeated myself.

Ill add more or edit it as needed when I get a minute.
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Old 03-22-2013, 05:22 PM   #521
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Quote:
Originally Posted by mexicanmissile View Post
2013 New Impreza sport 5 speed noises
Ok, So Id like some advise. Dealer changed factory oil at 1k miles per their recommendation to remove break in metal etc deposits they billed me and serviced the vehicle with 0w20 oil synthetic subaru oil. The car had a moderate engine clacking noise, but now after the oil change its significantly louder, to the point i can hear it under acceleration even with the radio on, and on decel its loud as heck too. This is my first Roo, and need advise. I truly love everything else about this functional and fun car, but none of my previous 16 cars have ever had these noises (not that can be heard like this) and they have all been used. Thanks.

Dafuq does this have to do with the original post?
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Old 03-22-2013, 05:42 PM   #522
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^^not to mention he quoted the entire original post... it's wrong in so many ways
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Old 03-22-2013, 06:53 PM   #523
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Quote:
Originally Posted by FCmaniac View Post
^^not to mention he quoted the entire original post... it's wrong in so many ways
Haha, right! I'm scrolling and scrolling, aaaand scrolling down expecting to read another argument for why big brakes are absolutely necessary for street cars and instead -he's got a ticking noise...?!? WTF?
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Old 03-26-2013, 06:28 AM   #524
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Excellent write up
Very informative .
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Old 04-30-2013, 01:19 AM   #525
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agreed
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