Chuck84TA

Ok, so how about this setup for the front brakes

Front Rotor:
http://m.napaonline.com/parts/PartsD...27L_0129747922


Front pads:

http://www.stillen.com/product/brake...4hd-28027.html

Worth it for a summer semi-daily and occasional track driver ?

Chuck84TA

Rear would be pretty much stock replacement .... Trying to save money somewhere

87350IROC

iTrader: (2)

I would skip the drilled and slotted rotors and just get the blanks.

ibmtech

iTrader: (1)

I think it all depends of what you want. Are you doing alot of agressive driving? Single piston brakes aren't the best design but do an effective job for normal daily driving. I have always thought if you are building the car to perform faster or better, you need to protect your investment to help it stop better as stock isn't ideal.

SlickTrackGod

I would put the Stillen pads on the rear also otherwise you will be locking the rears.

I know that doesn;t make sense to you- your first thought is why would the OEM pads in the rear be more powerful? They are not, they are not as agilie and go from not working-to-locking up quicker with less sweet spot. The Stillen pads can be pressed harder without locking up as soon.

chazman

iTrader: (4)

Based on this thread, I think I'll give the Stillen pads a try.

Thirdgen89GTA

iTrader: (5)

Fixed.

InfernalVortex

iTrader: (4)

Ive had a VERY hard time finding ANY modern race car with drilled rotors. MANY have slotted rotors, though. So how come all modern race cars use slotted rotors instead of drilled if slotted is so much better? NASCAR, F1, ALMS, Daytona prototypes, they all use slotted rotors these days as far as I can tell.

SlickTrackGod

Yes, I would agree. So what is your point in quoting me?

How come race cars use slotted rotors, then you say slotted is better than drilled? Yes for racing temps, Are you asking a question or trying to state a fact?

Most use dimpled rotors actually, are you asking because you are using your car for race only?

SlickTrackGod

Did you just quote me and try to debate something about race cars use slotted rotors and not drilled- but not actuallly read what I wrote in the post you quoted me? If you read what you quoted me you'll find I answered this already

I think if you are trying to debate that if its good for racing then its best for street use, then yo are wrong in your debate. I listed where a larger rotor diameter with drilled holes would be better at cooiling that a rotor of slightly smaller diameter WITH THE SAME MASS. THe larger diameter rotor has more surface area exposed to the atmosphere. I was very detailed and specific. I personally do not think you have bothered to read enough of this thread- because if you did then you would not be so confusing in your post. If what is good for racing is best then for street use, then why not run around town with full race temp brake pads I ask you?

SlickTrackGod

Now I agree its hard to find a race car with them, but I can find many many very high dollar exotics that can run all day at road race track temps with drilled rotors- Like the Ferrari 599 Fiorano shown here than I instruct in. I can dig up several more if you'd like, but yes its more rare. Most cars run dimpled rotors because the holes tend to weaken pure iron rotors at extreme temps. Dimples are patterened like holes, but do not breach the vented cavity and thus just carry away heat gases in the little dimples rather than slots that chew up pads.

I will throw in pics of our Lambos and our Ferrari F430 and 430 Scud that run drilled rotors also from the factory. The Scud and the Fiorano are pretty much factory race cars (Fiorano in case you do not know is the name of Ferrari's private test circuit. Both the 599 Fiorano and the Scuderia where developed on that full road race circuit- both have drilled rotors. SO I ask, with all the money Ferrai has in technology, why would they conclude in using drilled vented rotors? because the off gas the best into the vented portion of the rotor and guide the heat away from the pad friction surface best. It boils down to rotor quality and material- most iron rotors will crack under extreme heat with drilled voids.

SlickTrackGod

Also I present to you the 2012 Corvette ZR1 that has successfully set a record on Nurburgring on yes- drilled rotors

TTOP350

iTrader: (8)

They are carbon rotors and pads on the ZR1. I'm guessing the rotors don't work like cast rotors. (obviously better)

Chuck84TA

Thanks all for the info!

I can honestly say that I learned more about brakes and the right choices to make!

Thanks Slick Track for all of your efforts to teach and explain!

So the conclusion I can draw from this is that:

The stock 4 wheel disc brakes with a stock or mildly modified L69 V-8 (for summer street driving and 2 or 3 "novice to intermediate" HPDE's per year) will be fine with the Stillen drilled rear rotors, NAPA premium front flat rotors, and Stillen pads all around. Estimated cost: $400 plus or minus.

If I were to go with a motor with 300+ hp and 300+ torque then..well that changes things..

This

My plan at this point is to try to keep my existing stock rear end. At some point when I do get a new rear axle, I will look into a overall brake upgrade.

SlickTrackGod

Yes to everythinhg. you'll be happy with that bang for the buck- I promise that. As long as your factory combo valve is functioning the stock configuration works fine. If you stab the brakes hard in the wet and one or the other axle (meaning fronts, or rears, or both) are not locking the brakes then the combo valve is going bad and not sending good pressure. I had this happen on my car back in about 2002. The front brakes would not lock for anything and kept feeling like they were getting worse over a few months time. My car was an original J50 rear drum, but I switched to the 1LE rear disc combo valve (J65) even though I did not have the 1LE brakes, I had 4 wheel 10.5 delco Moraine brakes with the exact setup you speak of. I actually put stillen drilled rotors on the front but took them back off after a year because they were in fact starting to crack from some heavier track use I had done with the car. I never had any issues with the driled stillen rear rotors and actually noticed a slightly better rear brake inital bite when I went back to the solid front rotors. THe car was slightly more stable stabbing the brakes just prior to corner entry and allowed me to set the chassis better with the brake pedal upon entry. It was a nice setup, but I just did not like how the delco morraine calipers do not retain the pads well and allow them to rattle at 5mph in grocery store parkinglots etc. I eventually built my radical Wilwood packages simply because of that noise and figured I would go all out and reduce my unsprung weight for handling purposes on an already light weight chassis car so it rode and handled beautfully.

Nothing wrong with that package you are doing other than brake pad rattle- it's and inherit defect in Gm design of the calipers

SlickTrackGod

That is correct. The carbon rotors will not crack. Because of this, these rotors are being used with full void drills again into the vented cavities to off gas the heat into the vent where it is best disapated for cooling. It also better allows the pad to remain in contact with the rotor for a more consistant pedal feel as heat changes in the friction area. These brakes are used in the most extreme cases all with drilled holes in them because of material advances.

That tells you drilled rotors are best for cooling brakes. Problerm until now has been that when iron rotors got too hot they would crack between the holes under extreme road racing heat. Around town? they are the vest at the lower temps for maintaining a more constant heat temp and pedal feel.

Problem people face in modifying things is they take a stock size rotor and lessen the mass. Better to go a larger rotor and lessen the mass down to OEM with holes, rather than OEM with less mass. I used to fall into this mistake when I was uneducated on how things work- we all learn. But as stated, with my experience, the backs can work grat with drilled holes because they are sufficiant mass even with drills in them, not the fronts at OEM sizes.

InfernalVortex

iTrader: (4)

You seem to support the idea of drilled rotors, and then recommend against slotted rotors, yet every mainstream racing circuit in the world is dominated by slotted rotors. Seems like the actual competititve engineers in the world have all switched over to slots, and drilled rotors are just around for aesthetic reasons.

Not trying to argue, just trying to provide a counterpoint and see how you felt about it. You say slotted is better for track use and not street use and that sounds plausible enough for me.

SlickTrackGod

Here's the skinny on brake technology that most people have no idea of. This will explain alot to you so you ave a far better understanding of how things work and what you personally need.

Street type brake rotors normally do not exceed about 400* temperature on the rotor surface. Under this heat condition, brake pads will work in an "abrasive friction" mannor which means they grab the rotor alot like sand paper on wood. Drilled rotors healp keep street pads working under these temps when pressed a little hotter to lets say 600* so they can cool the gases off the pads and bring them back to the adhesive friction range. Using slotted rotors just gives several knife edge passes on each rotation to scrap away more friction material and wear out an abrasive friction pad much quicker than needed.

Racing rotors should not breach aout 1100*. Why? because when they do the iron will change properties into what is called cementite and become very brittle. When an OEM rotor is drilled (reduced mass so they run hotter on the dynamic friction surface when friction area is reduced, they are very suseptical to hot spotting a part of the rotor when a person stops at a light on the street after making a very hard stop coming off a freeway from 100+ mph in spirited street driving. That very hot pad sitting on a now heated rotor to about 600*, then sitting still on a hot pad of about 1200* sitting on one section of the rottor since it is not spinning and bleeding off heat evenly- it will hotspot the rotor- now if there are drilles in the rotor surface and that metal becomes brittle from breaching 1150*, the rotor develops cracks between the holes. THis is a common practice with OEM drilled replacement rotors and novice drivers pressing the car hard then sitting still on them. You have to remember the rotor spins, the pad does not have changing friction area like the rotor so the pad can get much hotter. the heat generally bleeds from the pad to the rotor to take away heat and keep the friction area at or under the 400* abrasive mark.

Now- race pads do something entirely different. They develop friction stopping power with "Adherent friction" rather than "abrasive friction". What this means is at higher temperatures, the pad will transfer a thin layer of brake pad material onto the rotors surface when the pad chemical bond gets hot enough and releases material. This broken bond of material causes friction which slows the rotor. Slots in the rotor surface keeps the pad clean of gases so that this bond breaking continues more efficiantly. THe slots also carry away the hot gases and try to help cool the rotor and keep it under the 1100* range so as not to mess up the rotor properties into cementite. Drilled holes on the rotor surface with these alot hotter heat ranges make a rotor much more boarderline to fail since the holes make the already heated structure weaker with voids. Even though the drilles work more efficiantly, often the 1100* temps are breached (ever see rotors glow on a race car-yep that would be what's happening) then the drilled rotors could come apart much easier that a solid rotor with slots or dimples without structural voids.

Now to Carbon rotors- they can manage alot higher heat and not turn into cementite or become brittle. THe carbon material used in these brake rotors are of the highest quality used in any carbon products and the materail is baked in an oven at about 1000* for several weeks to form it and cure it. After it is machined into shape it can withstand an extrodinary amount of heat. Now to brake pad choice, that is reliant on what heat range they will run at. As in F1 cars, the heat range wil start at 600* and when the brake pedal is predssed it will do nothing for a half a second- but in that half a second of force the temp will increase to 1000* starting point to where the F1 used brake compound will bite and start pulling the car down from about 200-0mph in about 4 seconds building incredible heat in the process. These rotors can withstand drilled voids to aid in cooling and not worry about the limitations of iron rotors.

SO why do we not use "aherent friction" on street cars? because it does not work until it reaches a few hundred degrees- so on a cold morning you would have no brakes at all pulling out of a steep driveway on the way to work- nothing until they go a little heat into them to start the bond breaking process. So- you want to run a material that is full abrasive, or at least partial abrasive like the Stillen Metal Matrix pads that have a proprietory compound develops of some ceramic, some metalic, and a few other guarded unknown materials in unknown quanties that work great in the 0* to about 700* range which is more than adequate for street and light track use.

As for rotors- it boils down to operating temp. If the rotrs are large enough and the driving style is appropriate heat range and dicipline to keep a rotor from ever getting hotspotted or breaching fade temp of the pad and cystalizing, then a drilled rotor is very good for keeping a rotor in more of a consistant range of temp. If an Adherent temp pad is used(for racing purposes only) on an iron rotor? it has been proven that a slotted rotor will clean the pad and help carry away the hot gasses safer on an iron rotor that is always closer to the edge of cementite transformantion.

Several companies make a brake rotor with heat indicators like Brembo and DBA- in my opinion these are silly becuase you have to stop th car to look at them- and thus hot spot a rotor with a sopped brake pad siting on one spot of the rotor crystalizing it and thus ruining it. You can check a regular street rotor by using an iffared heat gun pointed on it when you stop on normal driving, or you had beeter spend alot of money on telemetry to gain heat temps while in motion, but long and short of it is if a rotor is constantly developing a warpped feeling then you have hotspotted the rotor and need to either one or both- 1) change your stopping habits and learn to cool the brakes first by driving around slow before stopping, or two you need to increase the size (mass) of the rotor materail to allow for a more consistant lower rotor temp.

Have a good day all- that was a novel

Dean

SlickTrackGod

In conclusion, I want to say again-

Take two rotors for example of the same mass:

example 1 is a solid 12.6" diameter rotor

example 2 is a drilled 12.9" diameter rotor

lets say if machined correctly that both have the same exact pad surface area on the rotr surface because the larger one has driled surface voids-

Conclusion- the larger drilled rotor of the same mass will run ALOT more consistant in temp and run cooler than the smaller non drilled rotor of the same mass. This will keep an abrasive friction pad inside its normal operating temp better suited for street use rather than a smaller rotor with a race pad that does not work cold.

Stillen pads are a hybrid abrasive/adherent friction pad so the rear drilled OEm rotors will allow for lighter weight and better cooling to keep the rear system more consistant in street and light track temp range. The fronts I would not risk with reducing oem mass with a 10.5" rotor on a 3500lb car. The back drilled rotors also allow for a better initial bite when the pad is hot under autox conditions and will keep the car from yawing as much under corner braking entry without grabbing either to put you into a tailspin- it works benefit both ways. They are great pads and a perfect temp range with that combination of rotors. Just do not sit on them or any other pad after a high speed freeway offramp stop- stop early and keep inching forward until the light changes

chazman

iTrader: (4)

Or step on the clutch and take your foot off the brakes.

Great thread! Very informative.

Chuck84TA

Wow, good stuff!

87350IROC

iTrader: (2)

The transfer layer actually occurs even with semi-metallic pads. As was pointed out, the transfer only occurs at high temperature. That is why you must bed in new rotors with a series of high speed stops. What you are doing is getting the brakes up to a temperature such that the pad will transfer material to the rotor. Now you have pad material on pad material friction stopping the car. The pad on pad coefficient of friction is much high than the pad on iron coefficient of friction. This is also why pads wear much slower than rotors. If you were scraping metal of the rotor when the brakes are engaged, you would be wearing the rotor as well.

Now there were mixed results when the society of automotive engineers tested the effects of holes on the rotor surface. They tested several different cars and found that during braking there is no difference in heat rejection on a blank vs drilled rotor. They did find that the drilled rotors did cool slightly faster on two of the three cars tested, IIRC. But remember they also have a smaller thermal capacity. So the balance point of which "performs" better really depends on the percentage of time you will be on the brakes vs off. Again this only generally applies to track usage as you typically will not overheat a rotor on the street. However the OEM rotor is small enough that it does get into heat capacity trouble quite easily. SAE also found that the drilled rotors had pad wear that was 25%-50% higher than a blank rotor when the brakes were up to temp. At ambient temperature the difference is negligible. Again in most cases on the street the rotor temps are close enough to ambient, however our OEM stuff is quite small and I find they are always "at temp". They didn't test slotted rotors, but I suspect the wear rates would be similar to drilled rotors. I also suspect the wear rates are highly dependent on how the holes'/slots' edges were treated, square, deburred, chamfered, etc..?

Slick, not sure if you have ever played with the rotor paint, but all of it that I have tried (including DBA) is one time use. Once the paint hits its critical temperature it turns white and stays white "forever". So it actually is somewhat useful. IR guns are nice, but by the time you pull into the pits, you have already lost quite a bit of temperature. Check out this picture, you can actually see the temperature gradient on the rotors. The rotor area just leaving the pad is noticeably hotter than the part of the rotor entering the pad. Very cool picture.



For me, I tend to go overkill on brakes for my own car. That is one area where I am happy to be overkill, it gives me confidence. For me the biggest issue with the drilled rotors is the stress cracks. If you are willing to be diligent with inspections, I see no issue with running them. I just prefer slotted rotors as I don't mind the extra pad wear over blanks and it gives me a warm fuzzy feeling barreling down the straights at 140+.

John

Nelz

I think those NAPA high performance rotors were for the 1LE "high performance" brakes, not the stock 10.5" delco morraine brakes featured in pre 1988 vehicles. But, call them and double check!

87350IROC knows a lot about brakes, but if you just want to try slotted, I used these guys (yes, I know we're going to disagree on this as you do have a valid point on thermal mass. Some guys just want to try it, so why spend more. Everything now-a-days, including OEM stuff is off shored and repackaged with an American label. It still says made in anywhere else but the USA though except Edelbrock stuff.)

http://www.ebay.com/itm/Except-model...-/261064227266

Brake labs, I think they're from Cali.
http://www.brakelabs.com/

For less than $200, you get 4 slotted only rotors, and cheapo pads that you can use to bed the rotors in before you install the pads of your choice. (BEDDING IN THE ROTOR CORRECTLY IS CRITICAL TO THE LIFE OF THE ROTOR!)

The fact is, IF you could find a company that makes curved vane rotors for our cars, that were blanks, that would have been optimal. Except, I haven't been able to find it. I remember seeing and reading about them in old magazine articles, but they were CRAZY expensive, and at that price point, you should just upgrade to LS1 brakes or something with a BIGGER rotor to give you more leverage to stop the car. LS1 Brakes MINIMUM!

The slots do cut down on thermal mass. But they do improve initial brake bite, and as the pad wears, the debris particles are cleared away from the face of the pad and rotor. The slots also help reduce brake dust buildup.

Nelz

Or here:

http://www.ebay.com/itm/2-Front-2-Re...item4167cff3f3

For $150, they will ship you 4 rotors and NO pads. All slotted. If there is enough meat on your old pads, you can use your old pads to bed the rotors.

From pg. 140 of Brake Systems by Mike Mavrigian and Larry Carley

"When bedding in new rotors, use only pads that have already been bedded." use the brakes gently at first from initially low speeds, and progressively increase to normal racing speeds, but continue to use gentle braking pressure when applying the brakes. Do this for about 8-10 miles or so. After this, apply the brakes hard for 3 or 3 applications. During this final braking, you want to raise rotor temperature to at least 600 degrees F and possibly up to about 800-1000 degrees. You will need to apply temperature indicating paint for this procedure. New rotors are referred to as "green" rotors, and require a slow break in period. Don't go out and hammer new rotors on the first few laps. Allow them to build heat slowly, eventually up to race temps, then allow them to cool completely."

So basically, if you have some meat on your old pads, put on a N95 dust mask, sand the pad a little bit to get off any old glaze (you really don't want to inhale brake dust. I don't care what they say, I still think it can be cancerous.) and install them and bed in your new rotors as described above.

Then install your "new" pads.

I've been blogging about this slowly at www.[URL]http://www.gmbrakes.org[/URL].

But if you want more braking, unfortunately, you'll have to go the LS1 route or bigger.

Everything has it's limits, the stock brakes, just don't have as high a limit. That doesn't mean that you can't make it better, but don't expect a miracle. That's like expecting 400HP from a 305! (It can be done, but it's REALLY HARD!!!!!! Much easier with bigger cubes, like a 350 or 383. Just like with brakes. Easier to stop short with larger rotors.)

TVP122

iTrader: (5)

my best advice ......

don't take parts advice from a garage queen owner !
I want to hear it from the guys that have smashed cars with roll cages , greasy hands that don't come clean , and scraped knuckles from dragging the ground

and back to the question .. rotors ....

MASS ? have you ever weighed them ? the FACT IS , better rotors have BETTER METAL !!! pure and simple ! metallurgy ... look it up .... LIGHTER ONES CAN BE BETTER !!!! they even cryo freeze rotors for better wear !! drilling and slotting is for OUT GASSING (as posted) ..

keep in mind ... the CHEAPOS ARE WORSE THAN THE GM ROTORS YOU ALREADY HAVE !!!! that you can probably TURN for half the price !!! i.e. REMOVE MASS and they are still better then HEAVIER cheaper rotors !!!!

but then again I'm a newbie ... what do I know

bottom line ....... like others have posted and got no reply .....
are you going to the track or the grocery store ?
did you warp what you got ?
or just wear it out ?

when choosing parts .... what I found to be the trick is ....
rockauto.com .....
find your part .. .in this case, a rotor ...
scroll down , you'll see GRADES OF PARTS ....
starts at CHEAPO ..
then stuff with a warranty and a brand name ...
then the PRO LINE ...
then the COMPETITION stuff ....

pick a good brand name and go from there ....

my pick for my daily driver? a station wagon HHR, that I warped the stockers on raybestos under the pro line .... with hawk street pads .... skip the drilled unless your going to track the car .... mine were about $120 bucks worth, with shipping ... my trailer hitch cost more than that !!! and since your going in deep ... get SKF bearings !!!

SlickTrackGod

Nelz, I do not agree with that bedding process at all for a street car- that is strictly for an adherent friction pad and a race car rotor that will take several cool down laps. They are heat cycling a race rotor and trying to bring it into"condition" as quick as possible for race use and a car that really has limited track use- but its is in now way the best situation for conditioning a rotor for longevity for a car that is driven daily adn the rotor replace maybe every 10 years. A race car rotor can be changed every few thousand miles so there is a major difference in rotor lifetime and quick conditioning needs for race readiness.. They are subjecting those rotors to thermal shock (like pouring hot liquid over ice- you hear than crackling sound). You always want to try and introduce heat slowly and let it cool slowly. then repeat a few times more this process the bring the rotor into real world heat AND pressure cycles that can not be duplicated in an oven no matter what people will claim. It removes all internal stress of the iron rotor and conditions the iron to accept heat evenly and avoids crytalizing hotspots. This is an overlooked important step that makes a rotor "seasoned" not to be mistaken with "conditioning" a rotor which is prepping it with pad material.

It is not about miles per say, its more about how long it take to bring the rotor temps up a little about 300-400*, then how long to lower them naturally without stopping on them until they are down to about 200* lets say. Then
let then sit until you can touch them and no heat is present at all- then do it again a little more, etc. I like to do this for about 5 times before I do any hard stops.

Yes the above needs to be done with old brake pads (important noteld pads that are smooth without worn ridges on them!) Why used pads? Because they are heat cylced already and the pad compound is already cured. It will help transfer heat more evenly then a new non-cured pad. Once the rotor is "seasoned" (the iron has been though several heat cycles to help relieve any internal stresses, it now can be used a little harder with several low speed hard stops to bring it up to about 600* and put some pressure/heat into the rotor as well as give it some pad material transfer to condition it- then of course you let it cool again without stopping immediately on them. At that point I then put on the new pads and still drive the car slow for about a 100 miles to bed them against the rotor surface and to cure the new pad pompound. Generally I figure I do about 3-5 heat cycles on the pads minumum in that 100 miles, not just one trip- again its about heat cycles. and slowy building braking pressure until you can get the new pads bedded and up to heat enough to transfer material for an adherent friction if thet type of hybrid pad is used.

Johnny Blaze

iTrader: (15)

I wish I could get 10 years out of a set of rotors on the street.

I average 2 years on rotors, which is about 20,000 miles.

87350IROC

iTrader: (2)

And you are talking about who?


Better metal?

Maybe, but not in terms of performance.

All rotors short of carbon ceramic, useless titanium, and the very rare steel are made from various grades of gray cast iron. It is not glamorous stuff. Gray cast iron is used because it has good thermal conductivity, good wear resistance, its cheap, decent high temp properties, good vibration damping, good heat capacity, and good corrosion resistance. It is the ideal material for the job.

There are several grades of gray cast iron ranging from G1800-G4000. They all have basically the same density, heat capacity, and thermal conductivity. As a results from a thermal point of view, they all perform equally. Basically the only advantage of the higher end material is it has significantly better wear resistance.

In reality all the materials are so similar that the performance of the rotor comes down to the design of the cooling system, the vane design. It is true a lighter rotor can perform better if it has more and better vane design. However, this thread is talking about OEM replacement rotors. No such improved design exists for the 10.5" rotor; at least I have not seen it.

John

87350IROC

iTrader: (2)

These are 10.5" rotors? You are at minimum thickness at 20k miles? If so you have a compatibility issue or the pads never transferred material onto the rotors. What pads? Were they bedded in? My OEM rotors showed almost no wear at 65k miles when I removed them.

How long do you pads last?

Johnny Blaze

iTrader: (15)

Actually, I'm speaking of the rotors on my Grand Cherokee.

Haven't driven the camaro in years. And more like 40k miles in two years.

Nelz

The only reason my car is in the garage so often is because I break it from racing so often Usually from Auto-X or track days.

The 2000-2008 rotors aren't as good as you think they are.

However, the NEW FNC treated rotors from GM are GREAT!

http://media.gm.com/media/us/en/gm/n.../1130_fnc.html

The new FNC treated rotors heat treat the same el cheapo brakes from who knows where. Kinda like taking a cheap off shored brake rotor and cryo-freezing them to get the molecules to line up.

If you can get FNC treated AC Delco blanks, you're doing good! But I'm not sure if they make them for third gens yet. The dealership or any parts store will probably try to sell you all their old stock first.

Eagle223usa

They don't seem to make a set for an '89...

87350IROC

iTrader: (2)

I will eat my hat if GM ever offers thirdgen rotors that are FNC treated.