Reid Fleming

iTrader: (2)

For those wanting a fix for bad rear brakes, an upgrade to the stock system, and not wanting to spend big bucks to do it, read on......Like many on TGO I've been pouring over the various options for better brakes. My car is an '89 GTA. So I have the 10.5" Delco Morraine up front and the 11.6" PBR out back. I've had the car since new.

I replaced the pads on all corners with Hawk HPS back in 2007. They were the most popular pad here and they were alright. I didn't particularly want a heavy dusting pad, because the GTA wheels are hard enough to keep clean with regular pads. So I never bothered looking at anything beyond their HPS line.

So fast forward to 2013 and it's time to do the brakes again. I debated a few options.

1) HPS on all corners again? Or possibly HPS on the rear and Hawk ceramic on the front. The idea being to reduce brake dust up front and cripple the fronts a bit with ceramic in order to better the balance between front and rear. A surprising amount of cars here have near non-existent rear brakes. My rears weren't doing much.

2) 1LE or 12" C4 or LS1 fronts

3) Flynbye "GTA 12.2" Wilwood" package.
https://www.thirdgen.org/forums/brak...heels-get.html

4) Some sort of maximum performance stock sized setup.

I wasn't too thrilled with the HPS on all four corners setup that I did in 2007. One thing I noticed was that everybody who had done Hawk brakes and only Hawk brakes liked them and recommended them. But everybody who has had multiple brands of brakes on their cars rarely recommends Hawk as the best pad.

The 1LE/12" C4/LS1 options were possible. But $900'ish and that's without even touching the back brakes. I couldn't do the Flynbye "GTA Wilwood" package because I'm a street driving guy. It's too much money for me. If I lived in Germany and drove at 150 mph routinely or was a race track guy doing 100+ mph laps, I could see spending the money for the Wilwood setup.

This leaves me with maximizing the stock setup. One thing I didn't like about C4 or LS1 brakes is that you lose the option of using your spare tire. I blew a tire 50 miles north of Spokane Washington at 4AM one time. Thank goodness my factory CO2 tire inflator worked for me. All the better reason to keep the stock setup.

Being as I have GTA wheels, the brakes have always been invisible. So no need for red calipers or drilled rotors just for the sake of drilled rotors.

I had planned on getting slotted rotors instead of drilled, because then there would be little chance of cracking them. And a performance increase over solid rotors. Then adding some good pads to it. But once I read the thread below, all the information clicked. The link below is serious "sticky thread" material if you ask me. You don't want slotted for a street car.
https://www.thirdgen.org/forums/brak...rformance.html
(^^^ This thread is a gold mine of information)

Here is the new setup.

• NAPA premium solid rotors for the front. ($30 each)
• Stillen cross drilled rotors for the back. ($230/pair)
• Stillen front brake pads (D-154HD) and Stillen rear brake pads (D-413HD) $62 and $72 respectively.
• Goodridge stainless steel brake lines $130
• Grainger spring for brake proportioning valve $7 (part # 1NCR5)
  https://www.thirdgen.org/forums/brak...e-upgrade.html

It does seem strange at first that I would spend $60 for NAPA solid front rotors and $230 for cross drilled Stillen rear rotors. But it works very well. The front brake rotors are too small to want to drill holes in them (and thus make them even smaller than 10.5"). The larger rears can afford the cross drilled size reduction while at the same time benefit from a quicker grab on the pads from the cross drilling. And there is very little chance of ever cracking a cross drilled rear rotor...... Meanwhile the front rotors are solid, so little to no chance of cracking them. The solid front/drilled rear helps fix the problem of no back brakes in our cars. Of the 2 options for the new spring in the proportioning valve, I went with the 30 lb/inch spring. I went with this one because it's easier to screw in than the 37 lb/inch spring. And I didn't want to risk getting too much rear brake bias with the 37 lb/inch spring.

Let me tell you, the solid front/cross drilled rear/30 lb Grainger spring gives you the PERFECT balance between front and rear braking. The Stillen Metal Matrix brake pads are EXCELLENT pads. They don't seem to dust any more than stock pads from what I've seen so far. They have a wide scope between gentle, medium, semi hard, very hard stopping feel. They work right away even when cold. And they were cheaper than the Hawk HPS! Dean was right when he said that the Metal Matrix pads are the ultimate pad for a street car.

Everything in, it was $560 for all corners with high quality components. No modifying anything. The spare tire still fits. But most importantly, the car stops better than it ever has.

87350IROC

iTrader: (2)

While I have no doubt that your new setup works better, but I think your reasoning is off.

Drilling or slotting a rotor does not change the coefficient of friction between pad and rotor at NORMAL temperatures. That effect is incredibly minor even at very high temperature.

It seems quite obvious to this casual observer that that vast majority of your improvements came from fixing the brake bias. This should result in a much improved pedal as has been documented here many time.

The difference in coefficient of friction between the Stillen and Hawks pads is unknown since Stillen will not provide this information. I seriously doubt its a major difference.

The difference with the metal lines is quite minor in comparison.

And the performance difference between ANY iron rotor and another is ZERO at street temperatures.

John

Reid Fleming

iTrader: (2)

I'd say the improvement is somewhere in the middle of what you said (brake bias vs pads). When I did the HPS on all corners in 2007, the car had 50,000 kms on it. I only drove it sparingly during the summer months in Canada from 1989-2007. Rotors were in good shape..... Now, I just passed the 100,000 km mark on the odometer. I've been driving year round in Texas from 2007 to now. The new rotors were mostly due to age rather than mileage.

As far as I know, the stainless steel brake lines are more for feel rather than stopping distance. But with the new setup, it will throw you into the seat belt when you want to.

87350IROC

iTrader: (2)

Right, once you fix the bias, you are using all your stopping torque that your tires will handle. Beyond that it is all about heat control and driver feel. Heat control is of course not much of a issue on the street.

100% OEM brakes with the fixed bias should throw you into the belts as well. In fact even before I fixed the bias in my car, I could lock up all four wheels if I pressed hard enough. Not enjoyable, but it was possible.

By the way, I totally agree with changing rotors due to age and/or corrosion, I do that sometimes as well. I just want to make sure we keep this factual so some kid doesn't come on here and think their brakes are going to be so much better with a rotor swap.

John

jerm5801

1

TallTim

iTrader: (2)

Reid so do your rears lock with the fronts? I'm still pondering why my 1NCR5 did not help.

novaderrik

how do you figure that the LS1 front brakes cost $1000?
i've got about $400 into mine, with every part sourced from NAPA.. it isn't on the car yet due to the never ending MN winter, but will probably be put on in the next few weeks..
of course, i made my own hubs out of some new rotors, made my own mounting brackets, and modified my own spindles. but it was easy work and honestly i don't have very much time into it at all.

InfernalVortex

iTrader: (4)

I think I had only about $200 into my LS1 brake swap...

If I had to do it again I would get some 17 inch wheels and go for C5 Z06 rotors just for the peace of mind of retaining the factory steering stops. But the LS1 setup can be super duper cheap.

SlickTrackGod

Dean here,

Reid, glad to hear you are please with everything. People will comment on things always when they actually have no real world idea because they have never tried it.

You can raise the rear bias all you want- does it help increase rear brake pressure? Yes, but that is NOT all you are after and I will explain to the skeptics WHY.

What you are after in this setup is a quicker rear pad INITIAL bite, not just more rear brake. That initial rear bite is what give the car a stable feel. If you try and do this ONLY by raising rear bias, you will have to raise it too much in order just to get that initial rear bite, but then build to TOO MUCH REAR BRAKE and slide the rear tires...a very bad thing. This setup that Reid hjust did will give the rear pads a quicker initial bit using rear drilled rotors only(not fronts) because the rear pads go directly onto the rotors without float. You don;t believe it? because you've never tried it.

I am glad you are please Reid. When I try and give advice, I triy to always do so with peoples hard work and pocketbooks in mind. This stup IS in fact a great bang for the buck, and YES stillen Metal Matrix pads are the best thing since sliced bread. They have alot deeper pedal feel without locking and grabbing. A much better sweetspot in brake pedal feel from driver input. Some of you should stop debating something you've never tired and actually learn for peoples real world experience like this post shows.

By having the rear brakes come on quicker, yet having the fronts momentarily come on stronger after initial set is what keeps a car at max potential short stopping distance becasue the tail end of the car will not yaw and stand on it's nose, nor will it skid the rears either. Initial bite, but then bias bleed is what you are after here...and this setup works miricles in that department.

Congrats Reid, and happy motoring

Dean

87350IROC

iTrader: (2)

Dean,

I think my life experiences are just as useful to the discussion as yours. Lets agree to disagree.

The increase in initial bite for drilled or slotted rotors is only effective at elevated temperatures where the pad material is less stiff and can grab the edges. Even at elevated temperatures, I am highly skeptical you could drive two cars back to back and reliably tell me which one is has drilled rotors and which one doesn't.

With that said I would disagree that $230 rear rotors are a good value.

As I have ALWAYS pointed out when talking about brake kits, pedal feel is very very important and personal. You can tell people what makes a pedal feel better, but I would never do so. It depends on the driver. This is why I always share the chart below that has relative pedal effort and travel with different kits.

Good day,

John

right click - view image for larger

SlickTrackGod

john, in all due respect, I 100% disagree. The pads will float at speed due to aerodynamics. The pads make a quicker initial bit on a rotor with drilled holes in it when drilled properly accross the spectrum f the pad surface. I have tested this first hand. Does not matter the pad temp. Only having drilled rears will make a car feel different noticibly than with the same car and non drilled rear rotors. Front seem to make absolutely no difference, but rears definately are noticible due to the design of the stock combo vvalve metering section. They come on quicker then the combo intended in stock form.

I've also had drilled fronts and plain rears, slotted fronts, slotted rears, slotted fronts plain rears, drilled fronts slotted rears. slotted fronts and plain rears. I was screwing around one week testing this years ago playing with braking bias and testing intial bite. I also rean alot of different tests with pads as well using different firctions on many different occations. I had that car for years and let me tell you this combo worked. Its why I recommended it. Try it if you believe and trust me, don't if you don't. Its just free advice. Slotted rotors do not seem to do anything except make whirling noises and wear pads quicker.

SlickTrackGod

What do bigger brakes do? they make for better heat distribution. They generally have more leverage on the rotor, but charts show they have less piston surface force generally.

You want more prake pressure? just push the pedal harder with ANY setup- but, that is not what we are after. We are after a more usablebrake pedal range. A pedal when we press harder it still does not lock yet slowes the rotor quicker. So lets explain a little further.

Take the stock front brake iron caliper 10.5 setup with a stock pad. Lets just say we are dealing with only the fornt brake (forget you even have rears for now) You press the pedal with 100lbs force and they will lock the brakes on the fronts with stoick pads. HOS may take 120lbs force on the brake pedal, meaning you can press them harder and they will put more pressure but allow for higher force movement before they grab. Both can have the same coieffcient of pad stopping power, but one can be used deaper than the other in force before they grab. others lock sooner. Its like tire rubber compound in a corner. Some tires are more forgiving and tell you when they are going to slip, others slip without notice. These Stillen pads give you alot of predicability and a deeper pedal pressure without locking while pulling the car down faster. The same pressure on a stock pad would be less coeffient but also lock sooner.

Now also combine this with the better initial contact of the rears and you can stand on the pedal in an emergency with far more confidence it will not yaw the attitude of the car and pull it down more straight. The Stillen pads have a better linear grab feel than the HPS pads do. The HPS pads have a lag, then build, then grab feel to them the timing of the fronts and rear working in sequence do not work the same on the drilled rear rotor setup as the Stillen setup does.

I think Reids post here and overall pleasure with the outcome shows a little credit to what I am saying. He is also now understanding more as to what is happening and I will eagerly await more imput from him seeing if what I say is actually what he is experiencing....I am that confident in my prediction-why? -I have used this setup.

87350IROC

iTrader: (2)

Ok, so lets think about whats going on with the rear circuit. Dean, I know you know this.

Fluid delivery. Same as front other than the prop valve. Now a properly functioning prop valve delivers the same pressure to the rear brakes as front until it hits the knee point. We all know the knee point on the OEM prop valve is WAY to low. And most of us serious about brakes have gone to an adjustable prop valve. With that fixed, I don't see how fluid delivery could affect a change in bite with drilled vs non-drilled.

Pad knockback. Here is where it gets interesting. Those with the 10 bolt have the worst deal. The axles have quite a measurable about of movement in and out of the housing. This of course causes the rotor to get pushed in and out which then pushes in the pad. Once you stop turning, now you have a small gap between the pad and rotor. The pedal is now worse because you have to make up the gap. 9-bolt guys have a better deal as the axles are bolted in and have less axial play. Now at first glance it seems as though this plays no part with the drilled rear rotor discussion.

But I wonder. Consider a certain scenario. Consider an existing vehicle with 10 bolt and worn down pads. Owner installs fresh pads and rotor (of any type). Now correct me if I am wrong, but IIRC, at least for the 10.5" rear setup, a caliper with brand new pads fits very tightly over the rotor. Perhaps so tightly that pad knockback is mitigated, at least until the components are worn. This would perhaps give the illusion that the new rotors were the solution.

Or another scenario. IIRC, the OEM 10.5" rear calipers using a ratcheting system that works with the e-brake. Now I don't recall the details, but perhaps when the new pads and/or rotors were installed you were just over one of ratchet points. Now the pad and piston has no where to go when presented with the side forces that would normally cause pad knockback.

I am not saying these are what happened, just ideas. I can't otherwise explain why you would get this sensation in the rear, but not the front. Interesting for sure.

87350IROC

iTrader: (2)

I generally agree. For a street driver that is not concerned with heat management, brake components are all about pedal feel. This is what I have been pushed here for a while. That is why I built the chart. Based on what you say, I gather you like a longer pedal. That is fine. Personally I like a shorter pedal than OEM. So I like the bigger rotor smaller piston setups. It is up to the driver to determine what they want.

I don't understand how you can say a pad that requires more pedal pressure to lock up the wheels can still have a higher coeffieicent of friction than the pad that requires less pedal effort. All other components being equal.

So again, assuming all other components equal:
- same pedal
- same booster
- same master
- same lines
- same calipers
- same rotors
- same wheels/tires

The torque the system will need to generate to lock up the tire will depend on:

- pedal
- booster
- master
- caliper piston size
- rotor diameter
- tire diameter
- tire compound
- road surface

But we are assuming all of those are the same, only a pad change.

So the torque need to be generated by the brake system is the same. And since the rotors are the same, the frictional force needs to be the same between the pad and rotors. Since the rotors are the same, the only difference is the pad friction.

Frictional_force = Caliper_force * pad2rotor_coeff_friction

If the coefficient of friction is lower, the caliper force, and therefor pad pressure needs to be higher. And vice versa.

John

paul_huryk

I never liked the front 10.5" brakes regardless of how good the components were, and every 3rd gen I have had came with them. Reason being really long stopping distances, increasing with moderate use. Sure the pedal feels nice, but 130ft from 60 to 0 is **** poor, even for 1992 when the last of these cars rolled off the line. By going to a basic LS1 or Basic Baer kit you will drop the car to 115 to 105ft with repeatability and even better stopping as the car is going faster. I'm all for stock, bu in this case it would be pouring good money after bad to expect aftermarket BBK performance out of stock appearing brakes.

I'm going to point this out one more time for those 16" wheel fans - in another 3 to 5 years, the 245-50-16 and 255-50-16 sizes will be gone, except for maybe an all season and low wear track pattern. While millions of f-bodies from 1995 to 2002 had the 245-50-16 size, manufacturers are killing less popular sizes, period - fact of life. I say this because once you move up to 17" and larger, you can fit so many more brake options and still get a large selection of tires at reasonable prices (275-40-17 and 275-35-18 as examples). Spare situation is not uncommon with older cars and upgraded brakes. All the big brake pro touring guys must have some sort of idea what to do in such situations...

novaderrik

those guys keep their AAA up to date and call a town truck when the tire looks like it's starting to get low on air..

SlickTrackGod

You are confusing pedal travel distance with pedal sweetspot. We are not talking about piston volume and MC volume, we are talking more pedal usefulness with the:
MC being the same
Caliper psiton volumes the same
a different pad material choice

Pad material choice regardless of coefficient is responsible for friction characteristics also. This is what you are missing. Pads can have the same toque coeifficient but one can have a smooth release and a grabby initial bite, the other can have a smooth bite and a grabby release, etc, etc.

Let me give you a better example so you understand better again using a tire analogy. Tires can have the same lateral grip, but based on rubber compound one can hold heat bettter and be much more consistant in lateral max grip in a range of temperature, the other can be very unpredictable and only hit the max grip in a very specific temp range. The second may wear longer, but is much more touchy when it comes to grip/slip borderline- more unforgiving and dangerous wen put on edge.....so now the same applies with a brake pad material, one can be a bit more grabby on edge of lock and just lockup abruptly, whereas the oother can be pressed a little harder with forgiving results.

You can now understand how the second would give you a longer pedal travel of sweet spot braking, rather than a narrower margin on working pressure- regardless of torque coifficient.

SlickTrackGod

You've got to be shittin me. I just typed a novel on your first quote and just lost it- for some reason the computer login timeout on me. Long and shjort of it the pad runout does not come into play.


the stock GM combo valve has 3 sections to it- one of them being a metering section that makes sure the rear brakes come in contact first before any front pressure is applied. We are helping this situation because unlike most other types of vehicle, the 3rd gen with a Tqarm rear suspension combined with a strut front is unique in dynamic form. It does the opposite 99% of other cars whereas you need an inital bit and bleedoff. Most cars need to bleedoff an intitail bite but buld on pressure as the front larger caliper piston volume build on torque. I going to stop there before I loose this again- I had way more info the first time that I lost.

87350IROC

iTrader: (2)

At the moment for me, its a can of tire sealant and 200mile AAA. Another solution would be to use a CTS-V spare which will basically cover any big brake kit.

87350IROC

iTrader: (2)

I don't know what pedal sweet spot means. Can you put that in technical terms?

Yes, the phenomenon of grab and release is well understood. I stick by my statement that drilled or slotted rotors do no affect grab or release at street temperatures. As you point out, that is a pad characteristic. I have never argued otherwise. We are talking about how the drilled rotors changes these affects. You were arguing that they do change the pad initial bite and I was arguing that they don't at street temperatures. We are in total agreement that the pad bite will change the way the pedal feels.

John

Reid Fleming

iTrader: (2)

This thread has really taken off.

The car has a very level stance when braking. Now my adjustable front Konis in the past (with old brakes) would make a difference in this regard. Full soft = more up/down on braking and taking off. More **** (stiffer) = less movement on braking and taking off. But I've had the fronts on full soft for a couple weeks now (family visiting, so why not soften it up)

Making a sudden stomp on the brakes now results in alllllmost locking up the fronts. Purposely stomping on the brakes will make you lose your lunch. The fronts will lock up with enough force. I've been having trouble finding a place to try and lock the backs up. (I live in central Houston, so there is always somebody behind me. But getting hard on the brakes while on off ramps and feeder roads with light traffic results in the car being level when getting on the brakes. I'll see if I can lock up the rears over the next couple days. I'd like to try stomping on them while turning and seeing how the car controls itself.


You remind me of those car shows on TV where they make 150 extra HP for $500. "We're going to use these aluminum custom ported heads that we had just sitting here in the shop. We bought these Pro Magnum roller rockers at a swap meet for $20. And this Dana 60 that we have over here collecting dust should fit in nicely."............. The C4 12" brakes, the 1LE, and the LS1 front brake setups from flynbye are all in the $900'ish price range. From Bigbrakeupgrade.com it's $767 for a full LS1 front setup (with pads and hoses) plus a $100 core charge for spindles. Believe me, I did consider going for the LS1 front from Bigbrakeupgrade. But that's still almost double for the fronts compared to what I paid for front and rear.

Is this a reason why GM went from 10.5" on all four corners (1988) to 10.5" and 11.6" in the rear? (1989) The larger size in the back seems to both make sense (crummy rear brakes, so make them bigger) while at the same time not make sense (bigger brakes for the back when the fronts do more work?)...........I will admit that just about everybody I've told about my new brakes scratches their head when I tell them I went NAPA solid up front and expensive drilled in the rear.

87350IROC and SlickTrackGod, I have respect for both of you in this debate. I honestly can't find fault with either perspective. It reminds me of the old Herb Adams vs Dick Guldstrand handling contest. Both guys know their stuff.

John, I agree with you that simply swapping out rear rotors alone for pricy Stillen rear rotors on an otherwise stock setup wouldn't do much. But my point of the thread was that this combination of all the parts mentioned makes for a system where everything matches in harmony and the value to price is great.

87350IROC

iTrader: (2)

Yup. If you are happy that is all that matters. I have said my piece. Sorry for distracting the thread.

chazman

iTrader: (4)

Exactly. Great thread!

Reid Fleming

iTrader: (2)

For a non apples to apples comparison, I'll compare my wife's 2002 Blazer (10.8" front, 11.6" rear) brakes. The Blazer has a short pedal. Very short. It's deceiving, because it makes the brakes seem better than they are. My wife complains that I stop too quickly if I'm driving her around in it. But I'm not the kind of person to wait and then stop quickly. I like smooth slow stops for 99% of the time. The Blazer gives an immediate 80% braking when stepping on the pedal about an inch. But once you go past that, you have very little room before the ABS kicks in. The GTA has what I would call a medium pedal. So you have a wider scope between soft braking, medium soft, medium, harder, hard, and HANG ON stopping. This makes it very fun to vary the pedal when slowing down.

Now just about every car with old worn out brakes will have a longer pedal than it will with brand new brakes. So most people would say they prefer a shorter brake pedal. But I think unless you've compared multiple brake systems on the same vehicle, it's hard to honestly say if a person likes a short vs long brake pedal.

Unfortunately, I agree that 245/50/16 tires are getting harder to find in performance tires. I've had 3 different tires on the car. The Gatorbacks for 19 years (remember, it was a summertime only weekend car for a long time). I put GS-D3 tires on before I drove from British Columbia to Texas. Murphey's Law would dictate that I would blow up one of the GS-D3's on my drive across the country. This was when I blew the tire in Washington state. So in the end I wound up buying 5 GS-D3 tires. Not cheap. But I loved those GS-D3 tires. Fast forward about 4 years. I got a non-repairable flat in one of the Goodyears. And that that time, I couldn't get new GS-D3 tires anywhere in the country. They were backordered for months. Hence why I went with a Michelin Pilot Sport A/S. Later on I replaced the other 3 Goodyears with the same Michelins. (This solved the terrible alignment issue that I had with the taller narroer Michelins despite them being the same 245/50 size tires). The car required a 45° turn of the steering wheel to drive straight with one Michelin on the car. With all four tires being Michelin, it's back to straight as an arrow. I'm still not particularly enthused about having all season tires on the car. But the Pilot Sport A/S are the closest I could get in rain performance that match the GS-D3 (we get violent flooding weather in Houston. I sure don't want to put the car off the road because I have high performance summer tires......Those GS-D3 were great in the dry and in the wet. I miss them)

Getting back to brakes though. Doing the rear rotors cross drilled and the fronts solid, this would seem to me that the rears would grab better during the initial bite due to the cross drilled being a rougher surface than a similar solid rotor, regardless of temperature. Am I wrong here?

I'm going to go out on a limb here. I haven't tried it. But had I gone for the GTA Wilwood package of 12.2" super jumbo, multi piston, big caliper brakes for the front and left the back stock, I'm sure the car would stop faster. But I have to wonder if the car would feel as balanced as it does right now with my combination.

I'm sure at some point in time, somebody here will put big enough wheels in their car to shoehorn in some 15.5" ZR1 brakes. Or if you want even more, go for the 15.75" Lamborghini Aventador brakes.



But for now, I'm sticking with what I have.

87350IROC

iTrader: (2)

I would argue that the drilled holes do not make any difference until the pads are hot enough so soften to the point where they grab the hole edges. This is based on my intuition and later confirmed by me reading an SAE test. I will see if I can find the link, its been a while. Dean, would agree with your assessment. I guess we can agree to disagree.

Your car will only stop as fast as your tires will let it. OEM brakes will lock up any tires out there. Hence you will not reduce 60-0 distances on a single stop with any brakes. Instead, depending on your selections, aftermarket brakes can buy you:

- better thermal management (think road course)
- different pedal effort and travel (see the chart I shared above)
- longer component life (pads, rotors)
- easier pad changes

Also, see from the chart above, all of the aftermarket 4-6 piston calipers have SMALLER piston area than the stock calipers. This is good for people like me who like a shorter pedal. The larger rotor keeps the pedal pressure manageable.

Like this???

SlickTrackGod

A quick search on the internet on brake pad initial bite offered up this website from a so called "brake Pro" company. A quick read shows it backs my statements. Drilled rotors?as well as slotted rotors(but we were not talking slotted here because they are terrilbe pad wear for street use) both render a better initial bite of the brake pad.

Thank you.
http://www.zeckhausen.com/How_to_sel...ake_rotors.htm

Reid, Athe senerio you talk about worn brakes make a longer pedal- this would be the wrong term, the pedal active use range is not longer, it is "deeper" The travel use range is the same, it just comes on deeper in the travel range.

John, I explained "sweet spot" a few times, but I will try once more for you.

A sweetspot is the useable range a pad will render use of the brake pedal. Youc an have the same car with everything the same. ie- te MC bore, the rotors, the calipers etc- the ONLY thing we will do different is change brake pads for different tests of each. Lets say for the stock brake pads the brake pads will touch the rotor surface and start friction at 1" travel. THis will happen with any brake pad- they will all touch at the same time. yet with a stock one touching at 1" travel, it may not start to work effectively until 1 1/4" travel, and will lock the brakes at 3" travel. Another brake pad like Stillens pads will touch the rotor at 1" also, but will become effective at 1 1/8" (works an 1/8" shallower- but smooth and light grab and not as abrupt as the stock pad. It will also allow you to press the pedal to 3 1/4" rather than 3" uuntil it locks. TYou can apply more force without it just finally ultimately just grabbing the rotor. It will remain smooth deeper into pressure and more predictable without being grabby on lock or still grabby unponb truying to release. You get a pedal sweetspot of 2 1/8" useful travel with the stillen pad with smooth bite and release, whereas you get a 1 3/4" trave use out of the stock pad with a poor initial bite and a grabby release.

The Stillen pad in this example makes for the driver to easier control the car at speed.

As a not also- the stillen pads are a hybrid of Friction and Adherent brake compound mix. So the drills do work with or without temperature in them with these pads becasue the pads do gas a little when they get hotter. not enough to need them on the fronts though on a mid weight car. I run them on Vetruck and just recently went to a front blank- Ive run cross drilled rotrs on it for years- and for the forst time the Stillen pads have a delayed response on the front where I have to lay on them a little. I just through a blank on their recently because I really want to finally get my Z06 brakes on there this year. I have a poor intitial bite up front on the truck right now with the Stillen pads cld because its such a heavy vehicle. When the front pads are hot it is not so previlant.. The truck has never donw this with the front drilled rotors on those same pads. I have had over 10 sets of Stillen pads on the front of this truck so I know this first hand like I know what my forehead looks like.

SlickTrackGod

I can not prove this theory on any calcualtion or document- it is just plain simple experience.

Why else would a brake pad used on both a plain rotor cold, and a drilled rotor cold have different time reaction for working effectiveness? The Stillen pad on the front of my truck will not work immediately with the plain smooth rotor, yet it grabs immediately with the drilled rotor.

My theory? the rotor as it is spinning and the face is rotationally inserting into the pads, air is being drawn into the friction area from teh areodynamic spinning surface of the rotor. The drilled holes on the rotor face ggive this air drawn into that friction area room to ewscape and thus letting the pads have better contact on initial bite and friction. Once friction is establishedm the air path is diverted around the pad rather than between the pad and rotor. Spin a rotor on a lath and put your finger right next to the surface as it spins- you will obvviously feel airr movement rapidly right nest to the rotor surface as it spins rapidly in the atmospheric pressure we live in of 1atm.

At this point of friction heat and then into friction/adherent heat, the drilled voids do then give an area of ridges for the pad to bite to more so than a plain rotor surface. Drilled rotors com in alot of different varieties. Most drilled rotors are not calculated and CNC drilled with proper even spacing and pad useage. This is why I do like Stillen rotors, they are engineered and CNC's properly with nice effective drill patterns. into the curved vane discs. Alot of companies out there are putting dual hole in some vanes and no hole is other vanes of the rotor- they are not engineered for proper even usage of flow and pad cross. and thus they tend to show pad grooves over time of usage.

Why do I know so much about cars and products? because I study things long and hard befor I buy anything. I have learned from trial and error in my early years and look at anything that goes wrong to find out why it goes wrong and how can I fix it wso it last longer or works better. I analyze everything. I will sit on a workstool and stare at things for an hour sometime just brainstorming. I grew up going to racing events and have been a fan of Vintage racing for many years now where I simply walk through the pits and stare at old vintage prototype cars for ideas and brainstorm...its what I do, it brings me pleasure to exercise my brain on such things. I encoursage any of you to do this with any part on your car. Under stand what forces push or pull it, how air effects it, heat, cold, wet, etc. what if I took it off, what if I moved it, what if I turned it or positioned it different- amazing how you will learn and better your car modifications.

SlickTrackGod

The few Lambos I drive do have nice brake systems (I have not driven an Aventador, but do drive 4 differnt Lambo Gallardo's including a new 2013 560LP2. The 560LP4's I drive have nice setups and a very forgiving active handling system when you unload the car hard into a corner, and what is amazing about the Lambo brakes is they run hot all day long without problems. The cars suck in handling though, the steering wheel is a handlful expecially on the 4wd Galardos (2wd are still bad also) where you are contantly wandering and trying to find your footprint. it it were not for the good brakes on the car you would never be able to use any power inthem of keep them for a diasterous corner entrance. I would consider them exceptional on a car that handle porr- so overal the Lambo is just a sos-so car that is a handful to drive. The Ferrari brakes are a dream mainly because the cars are so smooth compared to Lambos. I have had the privilage to blast both a 599 Fiorano around autox course at full speed (in other words at my own discreation) as well as a 2011 F430 Scuderia with full carbon rae brakes as well- the same as the Fiorano. The Scud is lighter, but the 599 will brake much better because of the heacy V12 powerplant over the front wheels which pull it down beyond belief. I take that 599 over a Scud or a Lambo any day of the week- most people would look at the cars an thin I am nuts for saying that- just get in the seat and Ill show you why.

All of the above cars I drive in fact have drilled rotors on them from the factory. If I were to drive my Vetruck out there as hard as I do these exotics, my truck would overheat in about 20 laps. I am driving as well as pasenger instructing in these cars for 500-600 laps on a given weekend event and it is amazing how well they manage heat and then come to an abrupt stop and sit on hot rotors for a few minutes- then repeat the process again and again. The Lambo brakes (iron rotors) will crackle when sitting there hot, but they never seem to develop pad buildup or hotspots- truely amazing cars and brake systems that you can beat the snot out of. The carbon brakes never give a peep- you would never knwo they are hot coming to an abrupt stop after a few hotlaps on course.

Reid Fleming

iTrader: (2)

There's gotta be at least some braking distance improvement with better brakes. Or else why would bicycles come with disc brakes these days rather than the "eraser" on a wire brakes that came on bicycles when we were kids. I can't see anybody ever having thermal issues on a bicycle.

Your chart is an impressive and what I would imagine, a time intensive effort to come up with all the measurements and comparisons. A question though, how did you come up with the % of pedal travel and % of pedal effort on the chart?

87350IROC

iTrader: (2)

The bike analogy is interesting. As my buddy is biker, road and mountain.

The road bike has a nice version of the old school eraser setup. Likely due to weight and requirements. I have not ridden his road bike yet.

The mountain bike on the other hand has hydraulic discs with fixed calipers. Very cool stuff.

My bike on the other hand is an old school Schwinn with the eraser brakes.

IMO the feel of the eraser brakes is awful and requires alot of lever (pedal) effort and travel. The mountain bike on the other hand is wildly impressive, the brakes grab with little effort and little travel.

I don't know about your bike, but I cannot lock up the front wheel with the eraser brakes. The rear, no problem. I live on a 15 degree hill. Going down that hill on my bike is scary while it is no issue for his mountain bike.

IMO discs on bikes offer much better braking than the eraser. Likely leading to reducing stopping distances and much lower hand fatigue. This is important for a mountain biker would is on his brake constantly on a downhill course. Not as important for the road guys.

I stand by my statement that the OEM thirdgen brakes are good enough (with proper f/r bias adjustment) to lock up all four wheels. This tells me that the brakes are producing more torque than the wheels can handle. Yes, certainly a huge brake setup can deliver more torque than the OEM setup, but you cannot take advantage of it.

Instead you have better (depending on the driver) pedal feel and thermal management, along with easier pad changes and longer component life.

Now if we are talking multiple stops in succession, then sure, the aftermarket brakes will show a clear advantage. The OEM front brakes will quickly overheat, which will cause the pad to lose coefficient of friction and at some point, the tires will out grip the brakes. How fast the OEM brakes overheat is dependent on the pad compound. You can probably make the OEM brakes last a lap or two of a road course with full racing pads like the Wilwood A / B.

I will also continue to push pedal feel. Regardless of being able to use the torque or not, aftermarket brakes made my car so much more fun to drive. Love the pedal feel of the Wilwoods. Car is now a lot more fun to drive fast.

87350IROC

iTrader: (2)

I like this stuff. The data is interesting to me and helped guide me. Hopefully it will help others as well. Unless you have serious hard requirements (road course duty) then pedal feel is the most important aspect of selecting a brake kit, IMO.

The calculations are based merely on the torque equation, Torque = force * lever_arm.

Force is derived from the piston area and lever_arm is derived from the rotor diameter. Simple as that.

The calculations assume all the systems on the chart are using:

- same pad compound
- same booster
- same master
- same pedal
- same lines
- all calipers have the same amount of flex

John

Imadude_134

iTrader: (9)

For what its worth, I have a little bit of input (no data tho)...

On my wife's 01 Accord sedan, i changed out the brakes on all 4 corners from blanks (brand unsure) with ceramic pads (autozone) to D&S rotors (brembo) with ceramic pad (autozone)...

Stoping distance was greatly reduced and pedel feel was much nicer. Under normal braking, they act just like the blanks, but if I need to emergency brake, they definatly have a noticable effect...


On my 91 RS (disc/drum), I changed out the fronts to D&S rotors (unknown brand from ebay) from blanks (unknown brand) with semi metalic autozone pads. Again, no data to back it up, and under normal driving no major noticable difference, but under hard/emergency braking, there is definatly an improvement.

Sorry if it isn;t relavant to the discussion, but i am liking the back and forth.


One question tho, how are the C6 brakes "better" than the C5s, when both are 12.8x1.5 rotor and 2 piston calipers, yet the C6 has smaller pistons than the C5? Wouldnt the larger piston in the C5 grab with more force (larger area)?

87350IROC

iTrader: (2)

If I infer correctly, you are saying that that your Accord before the drilled rotors could not lock up the tires (engage ABS)??? If you can engage ABS, you are getting all the braking the tires can handle. The new brakes may have felt better but they did not reducing stopping distance.

Same for the Camaro.


Regarding C5 vs C6. Which is better depends on the driver. Both are more than adequate of overwhelming the tires. The C5 will have a longer softer pedal and the C6 will have a shorter firmer pedal. All other factors being equivalent. So which is better for you?

John

Imadude_134

iTrader: (9)

Re the abs... only once has it kicked in, but stopping distance is shorter and bite is harder. I lock up the camaros rear tires all the time cuz the rear drums are horribly out of wack, but have let to lock the fronts

87350IROC

iTrader: (2)

Then you aren't using all the performance that is available. The ONLY WAY one brake setup will stop a car in a shorter distance than another is if one of the setups fails to use all the grip the tires offer. There has not been a car built in the last 25 years who's brakes cannot overwhelm its tire grip.

It is easy to mistake better feel for better performance.

novaderrik

since this was directed at me: i have a thread here where i show all the parts i bought from the local NAPA for the LS1 brakes.

https://www.thirdgen.org/forums/brak...ap-bought.html

i'd have to check if i posted all the part numbers on this site or on another site- and if they aren't posted here, i'll get on that... the total cost is in the area of $400 for the parts and a couple of hours of time spent modifying the spindles and making the caliper mounting brackets.. i did "cheat" and use the lathe and bridgeport mill here at work to make things a little easier and faster, but it could have been done at home with basic tools for not too much more effort.. i did the 12" C4 front brakes on my Nova 10 years ago with nothing but an angle grinder, cheap POS drill press, a couple of drill bits, and used the bench grinder to turn the drum brake hubs down to fit inside the rotors... i had about $400 into that swap..

Reid Fleming

iTrader: (2)

I walk past the motorcycle parking area every day when I go into work. Looking at all the various motorcycles, they ALL use cross drilled rotors. Doesn't matter if they're 1100 cc Ninjas or plain jane 400 cc Hondas....Since the rotors are completely surrounded by air and motorcycles themselves are ultra light weight, I have to wonder why they all go for cross drilled. It would seem that a faster initial bite would be the only difference. So Dean's theory above may have merit.

Nice work!

As for me, I had some "fun" testing out the new brakes. Merging onto the highway after work, I did my usual routine. Accelerate so that I'm about 10 mph faster than the average traffic speed and then merge into an open spot....Then if possible, move across a few lanes towards the faster left lanes, either maintaining speed or else gently raising speed. Yesterday while doing this, I noticed the car in front of me (which was going slower than me) veer off to the right to an exit lane. Why did he veer? Blown semi truck tire on the road? Nope. A full size metal ladder was laying on the lane in front of me. And it was completely sideways too. Thus taking up the entire lane.

I don't drive a lowered car because I dread running over somebody's shoe or some chunk of semi tire. But a sideways ladder? Thankfully the new brakes as well as suspension mods made it easy to zig zag my way around it while still leaving enough room behind me that traffic wouldn't bunch up and crowd my rear area.

Chuck84TA

I just noticed this thread and I wanted to add my experience to this as much as I can. I did this to my stock 4-wheel disc brake setup (10.5)

I took Dean's advice and purchased:
NAPA premium front rotors
Stillen rear drilled rotors
Stillen Metal Matrix pads
Goodridge Brake lines.

I felt an immediate difference in pedal feel immediately... it just felt more responsive and it didn't take as much brake effort to slow down.

The question that I cannot honestly answer though is by how much of an improvement over stock this is. In other words, I have no idea how to quantify the actual data other than feel.

Perhaps this can be tested. I plan to be at the Third Gen Ranch Fest this Memorial Day Weekend, perhaps a side to side comparison with a 10.5 inch brake stock setup could bring some quantifiable, objective answer?


FWIW
Chuck

87350IROC

iTrader: (2)

I forgot to respond. Here we go.

Motorcycles are about 1/10 the weight of our cars. Obviously they have different braking needs than our cars. Also due to the high center of gravity they probably can't use as much braking as a car, or the rider would fly over the handle bars.

Motorcycle rotors are solid, (not vented). So any cooling comes from the rotor surfaces. In this case the holes do add noticeable surface area to the rotor. Additionally motorcycles are very weight sensitive. The holes on bike rotors significantly reduce the mass of the rotor.

87350IROC

iTrader: (2)

Unfortunately as you pointed out, you have changed many things. I think even Dean would agree that 90% of your improvement came from pads and lines. You will never know since you made so many changes at once.

Doing a repeatable test is basically impossible with our resources. You would need two identical cars with only the rear rotor difference.

SlickTrackGod

All I can say is you guys are experiencing exactly what I experience the first time I ever used Stillen pads. I love them. I will agree it IS in fact mostly pad feel that is making the improvement, The rear drilled rotor thing was a little something extra I stubled accross with my car that I just loved the feel of. That alone is in fact noticible, but I still will give the pads the 90% credit and agree with John's statement. I have driven many many third gens, alot of them on tracks, I know the cars, I knew my car like the back of my hand. I could tell every little querk about it. When I chnaged to the massive Wilwood setup I custom built- I always said I did it only because of brake pad duability/ or lack of with the Iron Caliper stck setup. The brakes would not fade when I ran this configuration, but the probelms I had with it were the bend over tabs of the D154 pads getting too hot and unfolding a little in a few weeks time and then RATTLING TO ALL HELL at slow speed parkinglot manuvers. It was just downright annoying I went to the Wilwood build.

With that said, The car did not stop any better with the massive wilwoods becasue I could not get Stillen pads for it. I opted for the next best thing which was the Porterfield R4-S compound after many many tries of other brands. The brakes worked better on high speed road course use and controlled the heat way better, but I never faded the stock setup on the street ever- and I do drive llike what most people would consider a nut- I do use my stuff and I use it hard. That rear drilled setup just gave a great feel to keep the rearend taunt and under me - it just gave a tad bit more in setting the rear down rather than the common rear jacking effect these cars are prone for...like i said, I could definately feel the difference better drilled rears and non drilled rears.

You ahve to remeber though, that car was rediculously built more so that most anything you will see- so it was sensitive to any change because it lacked any weak links in the chassis and suspension. I would feel the slightest changes where most average or stock cars would not be able to tell- and example is I could tell if the 3rd points of the strut tower brace were removed by the way the car braked into a hard corner. Not the entiore STB removed, just the two diagonal 3rd links to the firewall removed- it was quite noticible. I do not thnk hadly anyone else here could feel that difference in their car? You would have had to drive it to understand, it was an awesome testing platform and its why I learned so much about these cars.

Reid Fleming

iTrader: (2)

Looking at the chart that John posted above, it looks like my 10.5" front/11.6" rear setup gives the same rear braking as a 10.5"/10.5" set up, but I only have to use 61% as much pedal to do it. This suggests that I'm going to be getting more rear braking happening at all times. The other factor is that I did the spring mod in the brake proportion valve. I'm not sure if the spring works in your 1984 model.

On the other hand, your car is probably a couple hundred pounds lighter than my car. So who's to say which car would stop better.

Have you spent much time getting the brakes hot and really giving them a workout on the highway?

Chuck84TA

I had several things done to the car along with the brakes... New konis, springs, etc...I never really gave it much thought to give these brakes a run for the money...

Until today......

I had them out for a "work out" of sorts. They do seem to work well when they are "hot". Whereas before there was noticeable lag in braking distance and effectiveness.

Something else that I realized today... Before the modification, I found myself using the tranny to assist in slowing down by down shifting, especially in hilly areas. There is no need for that anymore. The car decelerates at a rate that is quite noticeable WITH BRAKES ONLY.

I am now convinced..after that realization that this is a worthwhile investment in upgrading your brakes. Especially considering the alternative which runs easily into the thousands.

Would I compare this to a Wildwood or Baer setup... Obviously not..but I know the money spent was worth it.

My final verdict:
The Stillen rotor/pad Napa premium rotor / stillen pad and Goodridge brake line mod is a great bang for the buck. Period.

Chuck84TA

Thanks Dean!!'

SlickTrackGod

I got a good laugh on that one

You are quite welcome. Stillen pads are .......awesome. I am glad a few of you are finally witnessing what I did when I used them years ago. I have felt I have been preaching to the chior about these. Nice to see others getting the same results.

chazman

iTrader: (4)

What if you're running a disc/drum combo. With the Stillen pads up front, what do you do with the rear drums.

Reid Fleming

iTrader: (2)

Sounds like a happy response.

In the category of "It's a small world," I was talking to my Dad about the brake components I'd bought (before they went on), I mentioned Stillen.

Him: Stillen? That name sounds familiar.
Me: That's Steve Millen's company.
Him: Steve Millen? I met him many moons ago at Seattle International Raceway back when he was piloting Nissans.
Me: Go figure.

njmick24

iTrader: (3)

Great thread, with good info, and intelligent input.