Road Racing - help me settle this debate

Hey guys i need your honest opinion here. I have a buddie at work who has done a small amout of road racing and we were talking about it one day and he made the comment that a BONE stock miata with nothing more than a professional driver would wipe my ass at VIR. I told him no way in hell. I know the driver would be a huge advantage but down the straight aways i would be able to pull far enough away that the miata would never be able to pull back around me.

Now you can see my mods in my sig and i have sub frame connectors and slotted rotors and hawk pads. I have never driven a car on a road course but i have owned a couple of racing go carts and i am a better than average driver. My car has goodyear DS3's also. What do you guys think? Thanks for your oponion. :chug: BTW my car makes around 430 rwhp 396 rwtq.

im nobody that does road courses...

but your car would murder it so bad on the straights even with a professional drivier wouldnt be able to make up that time.. just my opinion though! doesnt mean jack shit!

thats what i cant seem to make him understand. I could pull over for lunch while i wait for it to catch up,lol.

thats what i cant seem to make him understand. I could pull over for lunch while i wait for it to catch up,lol.

most people dont understand how fast a H/C ls1 is in a straight line.. its not that they are stupid, just ignorant..

although, again.. i could be wrong, but i dont think i am..

i have never raced a miata.. but i do not think it would be pretty AT ALL..

VIR is a very technical course. While it has some decent straight sections, they have very demanding corners on each end. Personally, I think a seasoned driver behind the wheel of a spec Miata would be a handful for a street car.

The second or third time I went to a road course, I had a H/C TA with 315 street tires. I was schooled badly by a mini-Cooper.

I know it doesn't make sense. But on a road course, there is more time spent braking and turning that there is just accelerating.

In this particular case, I bet it would be closer than you might first think.

It depends on the coarse. The small, lighter cars (Miata, Minis, S2000s) are a problem on a tight coarse. Higher speed coarses with sweeping turns are what our cars like and have the advantage there. Still, a great driver in a "slow" car can surprise you.

On Power Tour last year, they had a very small autocross and a 3 cylinder Geo Metro easily beat my time, and most everyone elses.

I know the Miata with the right setup and a skilled driver would be a handfull but im talking about a bone stock one. My car has better brakes, better suspension, better tires and more power so i dont think just a driver would be enough to put the miata in front.

how tight are the turns we are talking? i just assumed this would be on a coarse with like someone said, long sweeping turns and good straights..

I know the Miata with the right setup and a skilled driver would be a handfull but im talking about a bone stock one. My car has better brakes, better suspension, better tires and more power so i dont think just a driver would be enough to put the miata in front.

how are your brakes better? unless you have a $5K porsche brake kit, just having a larger diameter rotor isnt enough. the miata weighs 1000lbs less then your car does. it can do alot on just street pads.

ive had track days with both miata type cars and some muskrats and vettes. if VIR is as technical as they say it is, then youre NOT going to just rape him. i dont care if its stock and you have your mods. keep in mind all your mods are for power and drag racing. i see nothing for handling, ie: shocks/springs/sways. not to mention a 12 bolt will probably hurt your handling more then help it. its heavier, and who knows what kind of diff you have. if its more drag racing oriented, then thats even worse.

all your HP and torque wont help a damn if you cant put the power to the ground or make it stick around a turn. while you will have to pedal out of a corner, the miata can just floor it and go.

if it was a track like NJMP lightning, which is a fast, open, flowing track, then yes he'll be left behind. but for all you know, it could be neck and neck at VIR.

I am pretty sure it would be alot closer than i would like just because of alot of the things you mentioned. I have been wanting to give road racing a try and since VIR is like 30 min from the house, this seems like a good time to do it.

My car has better brakes, better suspension, better tires and more power so i dont think just a driver would be enough to put the miata in front.

Don't foget your car has more weight ...

Roadcourses are more about weight than HP

http://www.virnow.com/images/stories/maps/full_course_topographic.jpghere is the layout of the track. 3.27 miles long with a 3000 ft front straightaway and a 4000 ft back straightaway. I just dont think there is no way in hell a stock miata can stay far enough ahead of me in the turns that i couldnt make up on the straights.

Anything could happen. If I were you I would get 10-15 laps in before actually running against the miata. I ran my LS1 rx7 on street tires at CMP (2.5 miles) first time last weekend and was beating time trial Miatas on slicks by 3-4 seconds. Your car is faster around that course than a Miata, it's just a matter of driving it well enough to get it there. Also, if you end up doing this get racing braking fluid and race pads, otherwise you will not beating any Miatas after your stock brakes fade after 1 lap (ask me how I know.)

I have slotted rotors and hawk pads on my car now and i wouldnt get on any track for a race without a little practice. I also have high temp brake fluid for my car.

slotted rotors dont do anything for better braking, and what hawk pads. HPS will overheat in several laps. so will HP+. HP+ is a minor stopgap between street and track pads. theyd make a good pad for a short, tight course that doesnt have alot of 100+ braking zones.

if you actually want better brakes, get blanks and a dedicated race pad.

Aren't drilled/slotted rotors actually worse for road course?

I can understand it cooling faster but there is less friction therefore not as much stopping power.....?

well i can tell you my car stops 10 times better than it did stock so i know they are better than what i had.

Echo what brake set up are you running?

Aren't drilled/slotted rotors actually worse for road course?

I can understand it cooling faster but there is less friction therefore not as much stopping power.....?

Drilled are ALWAYS worse, and slotted make pretty much no difference.

Aren't drilled/slotted rotors actually worse for road course?

I can understand it cooling faster but there is less friction therefore not as much stopping power.....?

im going to be beating a dead horse, but read the stickies in the handling/braking section. all ill say now is drilled/slotted do absolutely NOTHING for braking power. they dont cool faster, they dont grab better, nothing at all. if you want better brakes, get blanks and good pads. holes/slots are for looks only.

right on tireracks website, there is a disclaimer saying drilled rotors should NEVER be used on a track.

Echo what brake set up are you running?

if your car seems to stop better, it was probably because your old brakes/rotors needed to be replaced, and the new full thickness pad and rotor simply brought back stock braking power.

i have C5 brakes up front, brembo blanks and hawk HP+ for track use. my local track is a very tight course, with only one straight that might get to 100ish, so the HP+ are adequate for that. if you do go to VIR, invest in blanks and a dedicated race pad, like hawk blue or black, or get carbotechs.

read up on FRRAX.com for more info.

http://www.virnow.com/images/stories/maps/full_course_topographic.jpghere is the layout of the track. 3.27 miles long with a 3000 ft front straightaway and a 4000 ft back straightaway. I just dont think there is no way in hell a stock miata can stay far enough ahead of me in the turns that i couldnt make up on the straights.

It would be an interesting experiment. And you peaked my curiosity ...

So, I did a Google search on "Miata at VIR" and "Camaro at VIR", picked a couple random in-car vids and timed a random flying lap from each video.

The Miata ran about a 2:27 in traffic and the Camaro ran a 2:19 with clear track.

I don't know the prep level of either car nor do I know the experience level of either driver. But both drivers appeared to be hiiting the same marks.

I have slotted rotors and hawk pads on my car now and i wouldnt get on any track for a race without a little practice. I also have high temp brake fluid for my car.

definatly not enough brakes for a road course, i had the same as you, after about 3 laps on autobahns south course mine were completely faded, i now run carbotechs

thanks for the advice on the brakes and your opinions . I have already started checking into what i need to do so i can put my car on the track. It has sparked my interest as well and i hope to find out how i do on a road course.

if the miata has race rubber and you have street tires you may be in trouble. Im no miata fan but have been on track with the race versions and they move out. The newer miatas are faster now too aren't they? Watch the mx5 miata cup race from VIR if you want to see their potential.

well still a new one says 167 hp-pretty weak but i bet it beats a sn95 mustang on most courses.

Do not get mad if he passes you.There are a lot of turns and elevation changes that are gonna slow you down more than the miata.Good luck,Get rid of those brakes.Think of drilled and or slotted rotors as cheese graders for brakes

Just looking at the PICTURE posted above of VIR, it looks like the straights are long enough that you can make up for sluggish handling with a lot more power.

Even on tighter tracks, I haven't lost to Miatas any time recently. I can't remember how I compared in my first year, when my car was stock, and I was a newbie ... times were probably pretty close.

However, on a POWER track, and especially the fact that you have 315 tires (on all 4 corners?) then you'll have a decent amount of grip (and GY DS3's are relatively sticky for street rubber).

However, a little "anecdote" to show you how an under-powered car CAN keep up with an over-powered car:

Last Friday I ran a lapping day at Mosport International Raceway (track map: http://www.mosport.com/trackmap.htm). I was running my '93 Z28, with full coil-over suspension, double adjustable Konis, big bars, race pads, Hoosier tires, etc., etc. It's a bone-stock LT1, but running headers, so making what, ~300 HP maybe??

There was a guy there with a Ford GT (the exotic "supercar" thing) with engine work done. He said the car was making around ~780 HP!!

If you look at the track map and see Corner 5C, that's the start of the back straight, which ends at Corner 8. I was on the GT's tail at the start of the straight, and he disappeared like I was standing still ... it was unbelievable!! :D (keep in mind, he has 480 HP MORE than I have!!!). But for several laps in a row, I would catch up to him entering into Corner 5A :nod: ... and NO, I'm not kidding. His car was only running street tires, but they are super wide, and I think they were the GY "Supercar" tires (which are quite sticky actually ... and have very stiff sidewalls).

My point is, Mosport is a power track, and yet through the 7 remaining corners of the track, I was able to make up so much time, I could catch a car with 780 HP, with my 300 HP car :cool:. I could NOT get PAST him, but I could CATCH him. Realistically though, our lap times were probably almost identical.

So, could a STOCK Miata, driven by a PROFESSIONAL beat your Camaro, driven by YOU, with the setup it has?? It all depends, but quite possibly! Perhaps if you were both on the track at the same time, you might be able to block him and not let him by, but run independently, and he may be able to post faster lap times than you. Not saying it WOULD happen, but it COULD ;).

Now, if you actually get some experience out there, slap stickier tires on your car, and run a little more aggressive pad (Hawk Blues, or HT10's at least ... in the FRONT ONLY) then I think a stock Miata would be f'd :cheers:.

FWIW, I've been running slotted rotors for a couple years with no problems. They have been Powerslot rotors, and I've run both Hawk Blues and HT14's with them. The rotors have held up fine, and the braking has been excellent :nod:.

If you have really good aftermarket brakes and really good race pads you will beat him bad on that particular track layout because of the long straights. On a tight track you would be in big trouble. Also remember with the brakes you have now you will be carrying a lot of speed into the corners so you will lose your braking ability after a few hot laps. Fast heavy cars just destroy brakes...it is almost impossible to get enough brake under a heavy car which has a lot of power. Your fluid will boil no matter how good it is. Been their done that with a 2900 lb z06 with a lot better brakes than you have now. I hate Miata's cause they beat vettes at autocrosses all the time. Chuck

I hate Miata's cause they beat vettes at autocrosses all the time. Chuck
Auto-X is a whole different ball game ;). That's all about LIGHT and NIMBLE! Miatas seem to excel at auto-x.

definatly not enough brakes for a road course, i had the same as you, after about 3 laps on autobahns south course mine were completely faded, i now run carbotechs

Agree 100%


OP, I went to VIR first time on same exact brakes you have now (same Hawk pads)... horrible brake failure. I was getting to 150 mph twice a lap and when I got to know the track brakes faded after 1 FULL LAP, this is also on RX7 4 piston brakes. You have to get race pads or you won't be able to use the brakes, which are as important as the motor and tires on the racetrack.

If you want an idea of how much power and braking make a difference, check out these vids.

http://www.youtube.com/watch?v=RdWhAtK7J7Q&feature=related
http://www.youtube.com/watch?v=LXMpvPmlXzs&feature=related
http://www.youtube.com/watch?v=kcwy29SojKk&feature=related

Almost the same cars, with the same suspensions, on similar tires. But, he has 50+ more hp. However, I have better brakes (except where I get too confident and stuff it up the inside like a n00b). You can see that he sometimes puts 10 carlengths on me during the 1/3 mile straight. But, I'm back in his trunk after only 2 turns.

All those things that make small 1/10th second differences on the street and autox (pads, tires, suspension, hp/tq, etc.) get magnified. If you mess up an apex while following a guy, he's gonna put 5 cars on you in the next 10 seconds.

BTW, you'd be surprised at how fast a good driver can make a car go. We have 2 guys that I know of that have showed up at my local track (No Problem Raceway) in GT3 Cup cars. One of them, who is REALLY good, runs 1:16s consistently. Then, we had a guy show up and he ran back-to-back 12 second laps! Same car, but 4 seconds faster. And, it's not like cutting 4 seconds off a Ford Festiva - these are the "fast" seconds. The ones that would cost me $100k to cut off.

A pro driver in a stock Miata will make some of those corners look like straightaways. He'll toss it and make it stick, when you would swear it's gonna fly off the concrete.

That said, if all the chips are down, I'm betting on your car.

thanks for the videos and i am looking forward to giving the road course a try. And i think it will be fun to say the least. Oh and your car sounds great.

Agree 100%


OP, I went to VIR first time on same exact brakes you have now (same Hawk pads)... horrible brake failure. I was getting to 150 mph twice a lap and when I got to know the track brakes faded after 1 FULL LAP, this is also on RX7 4 piston brakes. You have to get race pads or you won't be able to use the brakes, which are as important as the motor and tires on the racetrack.


thanks for the info. I will look into a better pad before i go out.

Not trying to be a dick, but all you road race gurus seem to swear that slotted and drilled rotors are the worst thing you can add to a brake setup. So why is it that in all the multitude of race cars I've seen in my lifetime in all different types of oval and road course racing, every f**kin' one had some sort of slot or cross-drilling in the rotors? Again, I'm not trying to piss people off, but I would like to know why I shouldn't use them (which I do, and with no problems so far) if all these multi million dollar race teams do?

Not trying to be a dick, but all you road race gurus seem to swear that slotted and drilled rotors are the worst thing you can add to a brake setup. So why is it that in all the multitude of race cars I've seen in my lifetime in all different types of oval and road course racing, every f**kin' one had some sort of slot or cross-drilling in the rotors? Again, I'm not trying to piss people off, but I would like to know why I shouldn't use them (which I do, and with no problems so far) if all these multi million dollar race teams do?

Cause they only need to last a few hundred miles and then the multi-million dollar teams discard them and install muilt-thousand dollar replacements.

apples and oranges

Not trying to be a dick, but all you road race gurus seem to swear that slotted and drilled rotors are the worst thing you can add to a brake setup. So why is it that in all the multitude of race cars I've seen in my lifetime in all different types of oval and road course racing, every f**kin' one had some sort of slot or cross-drilling in the rotors? Again, I'm not trying to piss people off, but I would like to know why I shouldn't use them (which I do, and with no problems so far) if all these multi million dollar race teams do?

If you buy cross-drilled rotors and push them, they WILL crack. DO NOT get cross-drilled. If you want slotted rotors, fine. AVOID cross-drilling.

http://www.google.com/search?q=cross+drilled+rotor+cracked

Not trying to be a dick, but all you road race gurus seem to swear that slotted and drilled rotors are the worst thing you can add to a brake setup. So why is it that in all the multitude of race cars I've seen in my lifetime in all different types of oval and road course racing, every f**kin' one had some sort of slot or cross-drilling in the rotors? Again, I'm not trying to piss people off, but I would like to know why I shouldn't use them (which I do, and with no problems so far) if all these multi million dollar race teams do?

every one? no. not at all. look through the suspension and brake section. someone posted up a half dozen pics of pure, all-out race cars. not one of them had holes or slots. this includes NASCAR, ALMS, GP, SCCA, etc. etc. etc.

I'm sure some of them don't use them, everyone has there own preferrances. I'm just saying all that I have seen in the 15+ years I have been working around race cars (not just a random fan with a pit pass) all have used them. My point was that alot of people act like they provide a disadvantage in braking performance, that is what I wanted to find out. If they don't stop as well as blanks, why are they used by anybody? Even alot of high end street cars come stock with drilled and/or slotted rotors. I seriously want to know if someone could give me facts (or a link if its easier) because I'm in the market for a new setup and I don't want junk on my car! As far as cracks, do they completely break apart, or are they just fine cracks like all rotors tend to get with age?

The drilling causes damage to the structural integrity (so to speak) of the rotor and will make them crack much easier.

I just got back from VIR yesterday. I have been there over 10 times. I am not the fastest driver and I have never . . . and I mean never, ever, not even close, been even threatened by a miata, stock, raced prepped or whatever. Don't see why you should. It blows me away when I see them run off track cause I don't see how they get enough speed to do it. You should upgrade your fluid and pads and you will be fine.

As for the drilled/slotted debate, if you look at what people who pay for their own stuff bring to the track, it is mostly stock rotors. Some run the slotted as it does help in braking, but it also eats thru pads quickly. That being said, I run the drilled/slotted when I am on the street, but at the track, I switch to stock rotors I buy from people switching to d/s.

BTW - VIR is an awesome track, you should start running there whenever possible. Good Luck.

I'm sure some of them don't use them, everyone has there own preferrances. I'm just saying all that I have seen in the 15+ years I have been working around race cars (not just a random fan with a pit pass) all have used them. My point was that alot of people act like they provide a disadvantage in braking performance, that is what I wanted to find out. If they don't stop as well as blanks, why are they used by anybody? Even alot of high end street cars come stock with drilled and/or slotted rotors. I seriously want to know if someone could give me facts (or a link if its easier) because I'm in the market for a new setup and I don't want junk on my car! As far as cracks, do they completely break apart, or are they just fine cracks like all rotors tend to get with age?

I actually ran OCAutosports cross-drilled and slotted rotors (with Hawk HP+ pads) at a track day @ Pueblo Motorsports Park a few weeks ago. It was very hot that day and I was really pushing the car. Overall I probably did about 40 laps over the course of an 8 hour day and I did not have any problems with my brake setup (no fading), other than turning the paint on my front 4-piston Brembo (stock) calipers from silver to gold by the end of the day. I actually put on these rotors for the car show circuit, and never intended to use them on the track, but I got lazy, didn't want to change them out, and used them anyway with great results. Now, those results might be different if I press my luck and try to use these rotors on multiple track days. It would only be a matter of time until they just can't take any more heat cycles and finally crack, I won't kid myself into thinking that won't happen. I will be changing back to stock Brembo rotors with new HP+ pads for any future track days.

After that longwinded paragraph, I want to answer your question about why all of the high-dollar exotics run cross-drilled rotors and don't seem to have problems. Most likely, those rotors are so expensive that they were actually cast with the holes in them. They did not start out as blanks and then had the holes drilled, which significantly weakens the area around the holes, hence the heat cracking that extends from the drill holes radially. Those expensive rotors, with the holes cast in them from the start, can reduce rotating mass at the wheels, which can have a big impact on how much horsepower is getting put to the ground, handling, braking, etc. All the things that exotics must do well.

It was touched on before, but I believe that a lot of racecars run the drilled and slotted (or slotted only) because each individual rotor will only last for a certain amount of laps (or 1 race - depending on the length) and will be thrown away before any of those cracking problems would typically ever occur. And they probably get those rotors from a very high quality source to ensure that the metal is up to the task of absorbing massive amounts of heat (through friction) time after time.

I hope this helps. Just so you know, I am no expert on street cars or racecars, I have just done a lot of reading and researching on the subject and I am a Civil Engineer so I have at least a rudimentary knowledge of physics, heat transfer, mechanics of materials, etc. which all play into high performance braking.

Well, the drilling has ZERO benefit, so why even take the risk?

Most every road race car will use slotted rotors. VERY few today use a drilled rotor.

Slotting helps clear dust away and can lessen the grooving and scoring that happens when dirt and dust get embedded in a pad, I have see the improvement directly. The other thing is race cars generally build much more brake temperature than street cars do. And big cars like IndyCars, ALMS, Grand-Am cars don't have power brakes. The slotting helps to get rid of the gas layer that can build @ 1000 degrees and act as a buffer between the pad and rotor. Slotting helps get the gases out. If you have power brakes, you have a much easier time getting through that gas.

The toughest rotors I've found for stock sized LS1 brakes are the Racing Brake stuff. I picked them up because they are the most durable and run the coolest for track use. In fact the Racing Brake fronts use convergent, and directional vanes on the front... the only LS1 rotor that does. They are also made of a metal composition that is a lot tougher than street rotors. And fwiw, they also cost more because it requires more tooling because they are making two different rotors, one for each side where others cheap out and make one rotor that works for both sides (like GM). That's fine for street use, even some fairly hard street use--but not ideal when you are really pounding on the brakes like at a track day.

Well, the drilling has ZERO benefit, so why even take the risk?

Well...if you had read the post above yours :confused:, you would have seen that the reason drilled rotors exist, and especially on expensive exotic cars, is two-fold. One, they look cool, and two (the bigger reason) they actually make the rotor lighter, therefore reducing unsprung (or rotational mass). Even to shave 1 pound total off of the 4 rotors is something that exotic car manufacturers like to do. That may seem trivial to a layperson, but even small amounts of weight being removed from the wheel, caliper, caliper bolts, rotors, etc. have a relatively big increase in performance over say...changing the front seats to lighter racing seats and saving 80 lbs from the sprung weight of the car.

I believe that this is the same reason that the highest dollar brakes out there utilize ceramic rotors because they are much lighter (see above about lowering rotating mass) and have a superior ability to dissipate high amounts of heat.

By the way, I do agree with you as far as not taking that risk in track applications, but street cars (albeit highend ones) were also brought into the mix, and d/s rotors can perform great on the street.

Also something I just thought of, is I have seen an awful lot of late model Porsches that have those drilled-only rotors and I am betting that those are the types that are cast with the holes in them. I don't know about everybody's experience, but every time I have ever been to a track day I have seen some type of Porsche. And I think that a majority of guys that own Porsches like to track them, and I have never heard of their rotors cracking, warping, or breaking while on the track, so apparently Porsche has the whole drilled thing figured out.

not to mention, many of the very high end exotics now have carbon fiber rotors. holes or no holes, you cant compare CF to a regular iron rotor.

I have a prepped Autocross car. 1994 Formula. It's taken a LOT to get it to run with a stock Miata on a tight course. On an open course with some breathing room I suck them in but they can sometimes still have an advantage in certain locations and will make up the room. I will tell you however that TIRES make a huge difference and without knowing all the details of both cars its hard to judge. Miata's are pretty damn sweet when it comes to a road racing car. They are cheap to mod and race unlike my F-body which is costing a mint. BTW: A Z06 would certainly have NO issues with a stock Miata in any circumstances.

A couple of things.

First of all, NO ONE drills holes to "lighten" a brake rotor. You want the biggest, heaviest rotor that will stop the car. All that mass absorbs heat, which yields better braking. However, once you have a rotor that's big enough, you want all that mass as close to the hub as possible. My point here is that, why drill holes, which remove mass near the hub but leave it out near the wheel, when you could make the rotor smaller in diameter, have the same braking performance, but reduce moments of interia?

Second, yes, drilled crack a little worse than cast holes. But, all holes crack. Why? Because that are of the rotor will cool faster than the undrilled parts next to it. As it cools, it shrinks. As it shrinks, it pulls away from the surrounding metal. If that force is stronger than the forces holding the metal together, a crack will form.

Lastly, some real-world experience. I have 14" Baer 2-piece rotors, with stock-style Corvette calipers. When I bought the brakes, they came with slotted and drilled rotors. They were fine for braking. However, after only 3 race (20 minutes apiece) the cracks at the holes had grown from imperceptable to connecting holes and extending to the edge of the rotor.

Now, I have baer blanks. They've lasted 6 races, and look brand new. Braking performance is roughly the same. But, at $200 per rotor, it's a helluva lot cheaper!

http://www.virnow.com/images/stories/maps/full_course_topographic.jpghere is the layout of the track. 3.27 miles long with a 3000 ft front straightaway and a 4000 ft back straightaway. I just dont think there is no way in hell a stock miata can stay far enough ahead of me in the turns that i couldnt make up on the straights.


fortunately this track favors HP...BUT, the corners are slow and difficult. For a first timer like I believe you would (I may be wrong..) be, I bet a "Pro" Miata driver could easily keep pace with you and with real race experience get by you no problem...not to say you may not be able to catch up with him on the straights, but it all depends on how quickly you learn and catch on. The race track is no place to be a hero when you are beginner, that gets you into trouble.

Now, what kind of "Pro" are we talking here? Does he have a full paid ride with sponsors and a team that covers ALL of his expenses and he makes $$ off it, or is he a "Pro" driver who has a couple/few sponsors who help out on tires or brake pads or race entries and a team of him and a couple friends and is still out $$ at the end of weekend?

Because there are 2 different level of "Pro" drivers out there, those who can afford to be called a "Pro", and those who are that talented of drivers.. ;)

oh, and depending on driving styles/braking habits and setups....more specifically stock rotors, inadequate cooling, stock calipers, and race pads; slotted rotors can help resurface the pads helping to prevent the over-heating and thus creating pad glazing during a session.

Ask how I know this... :o

A couple of things.

First of all, NO ONE drills holes to "lighten" a brake rotor. You want the biggest, heaviest rotor that will stop the car. All that mass absorbs heat, which yields better braking. However, once you have a rotor that's big enough, you want all that mass as close to the hub as possible. My point here is that, why drill holes, which remove mass near the hub but leave it out near the wheel, when you could make the rotor smaller in diameter, have the same braking performance, but reduce moments of interia?

Second, yes, drilled crack a little worse than cast holes. But, all holes crack. Why? Because that are of the rotor will cool faster than the undrilled parts next to it. As it cools, it shrinks. As it shrinks, it pulls away from the surrounding metal. If that force is stronger than the forces holding the metal together, a crack will form.

Lastly, some real-world experience. I have 14" Baer 2-piece rotors, with stock-style Corvette calipers. When I bought the brakes, they came with slotted and drilled rotors. They were fine for braking. However, after only 3 race (20 minutes apiece) the cracks at the holes had grown from imperceptable to connecting holes and extending to the edge of the rotor.

Now, I have baer blanks. They've lasted 6 races, and look brand new. Braking performance is roughly the same. But, at $200 per rotor, it's a helluva lot cheaper!

I disagree, car manufacturers do market the drilled rotors as more performance with less weight. Also the mass of a rotor has nothing to do with the heat dissipating abilities of said rotor. The surface contact of the brake pad on the rotor surface is what determines the loss of forward momentum via friction heat losses. Why would highly paid, extremely intelligent design engineers use the very light ceramic or even carbon fiber rotors (look it up to believe it, I did) on a supercar or racecar? Obviously by your logic they wouldn't work for crap because that aren't the "biggest, heaviest rotors" you could fit under the wheels...which is not true at all. I dare you to go out and find a couple of 100 lb rotors and bolt those up to your car (it must work better because it has so much mass...:bang:) and see if your braking performance increases or decreases. Good braking also has to do with how much weight (mass x gravity) you are stopping, and in the case of rotational mass, every little bit saved really helps.

As for your argument about the area of the rotor near the holes cracking because it cools faster, I agree with you that it does cool faster by a small amount, but I don't think that is enough to make a rotor (with pre-cast holes) break. Again, by your logic, why wouldn't the extreme outside edge of all rotors crack and "pull away" from the other metal because that particular area cools slightly faster than the rest of the rotor. It doesn't happen...

The cracking around the holes of all rotors that have been drilled after the fact is from the stresses put on the metal through the drilling process, which are then exacerbated during the repeated heating and cooling process when used on the track.

Wow, lots of good info here! Thanks for the insight guys! Hopefully it will help me out pretty soon. I'm also heading to VIR to turn some laps. I'm gonna have an instructor with me though. I'm pretty confident in my driving, but it never hurts to have a pro show you the ropes!

I disagree, car manufacturers do market the drilled rotors as more performance with less weight.

People who are trying to sell a product will "market" them in whatever way they think will sell the most product. Just because they say something doesn't mean that it's true.

Also the mass of a rotor has nothing to do with the heat dissipating abilities of said rotor.

Of course it does. What takes longer to heat up if you use a cigarette lighter - a paperclip or a steel I-beam? A lighter rotor will heat up faster, and therefore heat up more. Therefore, it will hit a higher heat point, which is likely to exceed the rating of the pads used.

Now, it is true that a lighter rotor will also cool faster. But, if you've already glazed your pads because you exceeded their heat range, then what's the point?

The surface contact of the brake pad on the rotor surface is what determines the loss of forward momentum via friction heat losses. Why would highly paid, extremely intelligent design engineers use the very light ceramic or even carbon fiber rotors (look it up to believe it, I did) on a supercar or racecar?

You can't compare "why/how" a ceramic/CF rotor works to "why/how" a ferrous-metal rotor works. An iron rotor with regular pads works by combining 2 methods to stop the car - converting momentum to heat and friction. That's why you get brake dust, you have to replace race pads every few races, and have to get new rotors. But, ceramic/CF rotors don't use the "friction" part of that. Movit brakes has a ceramic rotor/pad combo that has been on their dyno for years now, and has logged a few hundred thousand miles of simulated racetrack driving. They are still on the original pad and rotor. They simply don't wear out.

Obviously by your logic they wouldn't work for crap because that aren't the "biggest, heaviest rotors" you could fit under the wheels...which is not true at all. I dare you to go out and find a couple of 100 lb rotors and bolt those up to your car (it must work better because it has so much mass...:bang:) and see if your braking performance increases or decreases.

Sure, let's take it to extremes - that's a valid arguement.

Notice I said "biggest, heaviest that will stop the car"? Once your brakes will stop the car like you want, then there is no reason to get bigger/heavier brakes. That limit is usually found by when your tires lockup. Once you ahve locked up the tires, there is no reason to have better brakes. If there is no reason to have better brakes, then there is no reason to have heavier brakes.


As for your argument about the area of the rotor near the holes cracking because it cools faster, I agree with you that it does cool faster by a small amount, but I don't think that is enough to make a rotor (with pre-cast holes) break. Again, by your logic, why wouldn't the extreme outside edge of all rotors crack and "pull away" from the other metal because that particular area cools slightly faster than the rest of the rotor. It doesn't happen...

Ummm - because it's a circle. As the outside of the rotor cools, it tries to get smaller. This means that it actually draws CLOSER to the metal on the inside of the rotor.

The cracking around the holes of all rotors that have been drilled after the fact is from the stresses put on the metal through the drilling process, which are then exacerbated during the repeated heating and cooling process when used on the track.

Cast holes still crack. Perhaps not as rapidly, but they still crack. Check out the following:

Some drilled holes in rotors are not really drilled at all. They are cast holes. This is done to help minimize the effects a hole has in creating a stress riser in the surface of the brake rotor. A drilled hole goes directly through and interrupts the grain structure of the metal. Where a cast hole has the grain structure formed around it in an uninterrupted flow. All holes in a brake rotor will eventually show signs of stress cracking. A drilled hole will crack much sooner than a cast one. Admittedly, a “drilled” rotor will cool better than a smooth rotor, and has slightly better “bite”. However, the person who blindly goes ahead and drills his stock rotors is asking for trouble, especially in high heat or severe brake conditions. It’s not unusual for these rotors to eventually crack completely across the surface, causing a dangerous situation. Therefore, it is not recommended to drill unless it is for an under-stressed condition or, for a street car just for looks. The best solution for people who want maximum life and safety out of their rotors, is to have standard or slotted rotors deep cryogenically treated.

So, unless you have the funds to buy new rotors after every or every other race, then you should get slotted or blank rotors.

Of course, if you have the money to buy new rotors and pads after every race ($200/rotor, $300 for front pads = $700/race), then you should probably spend $9k on a set of ceramic brakes. It'll be worth it in terms of performancea AND economics.

People who are trying to sell a product will "market" them in whatever way they think will sell the most product. Just because they say something doesn't mean that it's true.

I agree with that, but the point I am trying to make is that obviously a lot of car designers/mechanical engineers feel like there is some merit in cross-drilled rotors. Case in point, have you seen the new McLaren MP4-12C? That car (and all McLarens) are the hardest of the hardcore, and the brand new design has cross-drilled rotors. I think that the McLaren Engineers must be on to something. I mean, they only built the BEST sports car in the world with the McLaren F1 (over 10 years ago).

Of course it does. What takes longer to heat up if you use a cigarette lighter - a paperclip or a steel I-beam? A lighter rotor will heat up faster, and therefore heat up more. Therefore, it will hit a higher heat point, which is likely to exceed the rating of the pads used.

Good point, but all of the relatively cheap rotors that we are discussing are made from the same material, cast iron, which is going to absorb a set amount of heat at a set rate. I am not a Chemistry genius, but just because a lighter rotor might heat up faster, absolutely does not mean it will heat up more, there are many other factors that would determine the maximum amount of heat that a rotor could absorb and store.

I think the differences in mass of a cross-drilled rotor to a blank rotor are fairly small (although, like I said before, even shaving 1/4 lb to 1/2 lb off of a rotor is pretty big for performance gains and track times on a roadcourse...you should know that being a track guy) and I also think the amount of heat (friction) absorbed would be almost indistinguishable between the two types of rotors. What I am saying is, for my money, I would rather have more efficient rotors that are somewhat lighter than a regular blank, because you are fighting the weight of the rotor 100% of the time due to physics, but you are only using the brakes a smaller percentage of the time.

Now, it is true that a lighter rotor will also cool faster. But, if you've already glazed your pads because you exceeded their heat range, then what's the point?

Then you need better pads...:cheers:

You can't compare "why/how" a ceramic/CF rotor works to "why/how" a ferrous-metal rotor works. An iron rotor with regular pads works by combining 2 methods to stop the car - converting momentum to heat and friction. That's why you get brake dust, you have to replace race pads every few races, and have to get new rotors. But, ceramic/CF rotors don't use the "friction" part of that. Movit brakes has a ceramic rotor/pad combo that has been on their dyno for years now, and has logged a few hundred thousand miles of simulated racetrack driving. They are still on the original pad and rotor. They simply don't wear out.

Obviously you know more about that than I do, so I won't argue the info.

Sure, let's take it to extremes - that's a valid arguement.

I only took it to extremes because of your comment, see below...

Notice I said "biggest, heaviest that will stop the car"? Once your brakes will stop the car like you want, then there is no reason to get bigger/heavier brakes. That limit is usually found by when your tires lockup. Once you ahve locked up the tires, there is no reason to have better brakes. If there is no reason to have better brakes, then there is no reason to have heavier brakes.

That is pretty sound logic, again I can't argue about this point.

Ummm - because it's a circle. As the outside of the rotor cools, it tries to get smaller. This means that it actually draws CLOSER to the metal on the inside of the rotor.

Well, you have an inconsistency in your statements then. I agree that the metal contracts as it cools, so it would also stand to reason that the metal at the edge of the drill holes would contract into the rest of the rotor, not pull away from it like you said before.

So, unless you have the funds to buy new rotors after every or every other race, then you should get slotted or blank rotors.

Of course, if you have the money to buy new rotors and pads after every race ($200/rotor, $300 for front pads = $700/race), then you should probably spend $9k on a set of ceramic brakes. It'll be worth it in terms of performancea AND economics.

Very true.


By the way, I appreciate a good-natured argument. This stuff fascinates me and I always appreciate the chance to learn more about it.

Originally Posted by 00 Trans Ram
People who are trying to sell a product will "market" them in whatever way they think will sell the most product. Just because they say something doesn't mean that it's true.

I agree with that, but the point I am trying to make is that obviously a lot of car designers/mechanical engineers feel like there is some merit in cross-drilled rotors. Case in point, have you seen the new McLaren MP4-12C? That car (and all McLarens) are the hardest of the hardcore, and the brand new design has cross-drilled rotors. I think that the McLaren Engineers must be on to something. I mean, they only built the BEST sports car in the world with the McLaren F1 (over 10 years ago).



And I think the point YOU are missing is that while they may in fact perform better, you are assuming ...

... they are made from the same material as teh $100 rotors available from rotorsRus.com
... owners routinely run them on the track and then drive them to work the next day
... because a wing on a McClaren "works", a wing on a Civic must work also because its a wing
... the rotors will last 60K miles, not just a 1 hour race.

w00t!

Yeah - it's tough to know what's good and what's bad, when a lot of marketing says something is good, and only users are saying it's bad.

Silverbeast,

In stead of coming here & yappin' about it, why not go out & see? Stock Miata's can be rented & I'm sure that there will be pro's @ the track who will put seat time in one for the test. In a 10 lap race (time trial), I'd give it to the pro in the stock Miata. You didn't mention how many laps & also didn't mention that you'd be in here learning how to set up your car before the race. Sounds like your friend offered the statement as "stock Miata" against "your car as it sat in the parking lot on that day." In any event, an inexperienced road course driver over 10 laps against a pro in a lesser car = Pro FTW.

One lap, you might have a chance.

http://www.virnow.com/images/stories/maps/full_course_topographic.jpghere is the layout of the track. 3.27 miles long with a 3000 ft front straightaway and a 4000 ft back straightaway. I just dont think there is no way in hell a stock miata can stay far enough ahead of me in the turns that i couldnt make up on the straights.

Our track here is similar. They use the 1/4 as the straight. ~1/2 mile. I used to have a supercharged miata, with a whopping 130 gteched hp! I could get upto 160kph (Canadian) at the end of the straight. With a srt4/audiS4/subaru 265 I can get up to 200kph at the end of the straight. Buddy who is an awesome driver in a 190 hp M3 can lap as fast as 911 turbo's. Sorry, but the mustangs (saleens, rousch's) are all able to be passed with good drivers with average cars (haven't seen any firebirds/camaro's out there). Trouble is, miatas are freaking gutless. I could do magic on slow corners, but that track is not a low hp track. It wouldn't be close, like I bet 2-3 car lengths or more per lap.

C5/6 vs a miata. 10 seconds or more.

Which is why I am looking for a LSx powered bmw.

I bet a rookie could keep Shumacher (SP?) in a stock miata at bay on that track. However, based on our track, your stock brakes would be done after 3 laps (ask me how I know), so the miata would eventually win, depending on length of laps. Rookies tend to use way more brakes than normal, as they (used to be me too) over brake, and have less body control (adversly affecting braking/speeds/etc) using the tires/engine to brake. I went through 2 sets in the audi in 3 track events. 3800lbs and 340hp is not a good road racing receipie.

In my almost stock 09 subaru 265, I double lapped a girl in a 20 minute session in a mazda speed miata, and a guy in a gutless one (199x). My laps times are about 90 seconds. Faster guys are 85, super fast are 80 seconds. 20 seconds a lap is huge.

Summary, I would be a ton of money on you, but there is no way to find out, but race him. Take a class, practice being smooth, your car will appreciate it. Don't try to beat everything in site. Steady, consistent movements, not herky jerky will get you around fast.

Silverbeast,

In stead of coming here & yappin' about it, why not go out & see?


Well that would quantifiable data to make a point which seldom works on internet forums.

I mean come on ... who ever heard of backing up opinions with data any way.

Just going to add some fuel to the fire.....

A few companies that have made cars that use DRILLED rotors...

BMW (M3 M5)
Porsche
Maclaren (F1)
Lambo

Funny how these high end car makers are all running them. im nots argueing that drilling dosen't reduce the strength of a rotor, it has to! I have also seen alot of high end racing cars running drilled rotors. i always remeber seeing Nissans BTCC (British Touring Car Championship) they had 18inch fornt rotors (drilled) with 2 sets of 4pot calipers (water cooled). oh and they ran iron rotors not carbon. this was in the 90's and carbon wasn't that conmon even in race cars.

Cheers

Chris.

uncle

Where you have super expensive and well build, and HUGE rotors on cars that weigh less it's not an issue. We don't have 15" brakes, we have heavy but still fast cars, and the rear brakes don't do much of the work.

You apparently can't see the forest through the trees. Ok some fancy street cars have them, then why do the racing version of those cars (say a Porsche 997) NOT have drilled rotors? Riddle me that Batman.

At that, I will, on one of those rare occassions agree with Mitch and say Uncle.

Our track here is similar. They use the 1/4 as the straight. ~1/2 mile. I used to have a supercharged miata, with a whopping 130 gteched hp! I could get upto 160kph (Canadian) at the end of the straight. With a srt4/audiS4/subaru 265 I can get up to 200kph at the end of the straight.


I'd get your gtech checked, or your boost. Additionally, all wheel drive vehicles & traction control, for that matter, are for drivers whom require training wheels.

Miata + Pro (a real liscenced pro, not a trackday wanna be) > F-body + driver w/ no track experience, in a 10 lap race, all day long.


Drilled rotors SUCK!

Braking 101 from Baer
http://www.baer.com/technical/braking-101/index.php

Braking 202 Baer
http://www.baer.com/technical/braking-202/index.php

Braking FAQ (with benefits and disadvantages of cross-drilled/zinc washing/slotted rotors)
http://www.baer.com/technical/faq/index.php

Click and read people, I've posted this before somewhere. They even say cross drilling isn't necessary, but it is done today for added weight savings. Every ounce counts today on our fat cars.

Wilwood FAQ for a second opinion.
http://www.wilwood.com/Start/Centers/Information/pages/faqs.asp

They even say cross drilling isn't necessary, but it is done today for added weight savings. Every ounce counts today on our fat cars.

for the minuscule amount of weight you might save by drilling, you might as well take the floormats out and save even more weight.

for the minuscule amount of weight you might save by drilling, you might as well take the floormats out and save even more weight.

I understand that, Baer understands that, why they and wilwood call it an aesthetic upgrade. It's the manufacturer's that apparently don't get it.

It's the manufacturer's that apparently don't get it.

I just spit soda all over my keyboard.

Thanks :(

for the minuscule amount of weight you might save by drilling, you might as well take the floormats out and save even more weight.


He's talking about unsprung weight, of which effects handling. Not the same as removing weight from inside the car.

The problem w/ cross-drilling is that the negative effect it has on the rotor isn't worth the unsprung weight savings.

i know what unsprung weight is. and my point still stands. the handfull of ounces saved by drilling wont matter a damn in the long run.

i know what unsprung weight is.


Ok, wasn't sure by the post.

You know - I think that I'm going to change my arguement.

I think that everyone else should race on cross-drilled rotors. They obviously provide a sizeable racing advantage for me. When you run these rotors, I think that you will not be able to outbrake me, thereby providing me with a sizeable advantage under braking.

You know - I think that I'm going to change my arguement.

I think that everyone else should race on cross-drilled rotors. They obviously provide a sizeable racing advantage for me. When you run these rotors, I think that you will not be able to outbrake me, thereby providing me with a sizeable advantage under braking.


ill buy that. then if you beat me at a race ill take your car off your hands for $1K

hehehe

Where you have super expensive and well build, and HUGE rotors on cars that weigh less it's not an issue. We don't have 15" brakes, we have heavy but still fast cars, and the rear brakes don't do much of the work.

You apparently can't see the forest through the trees. Ok some fancy street cars have them, then why do the racing version of those cars (say a Porsche 997) NOT have drilled rotors? Riddle me that Batman.

At that, I will, on one of those rare occassions agree with Mitch and say Uncle.

I wasn't trying to be an arse, just stating what i have seen and asking why they use them. I have to agree there cant be that much advantage in putting holes in the rotors and it has to make them weaker.

Like i said not trying to be smart or anything.

Cheers

Chris.

Our track here is similar. They use the 1/4 as the straight. ~1/2 mile. I used to have a supercharged miata, with a whopping 130 gteched hp! I could get upto 160kph (Canadian) at the end of the straight. With a srt4/audiS4/subaru 265 I can get up to 200kph at the end of the straight.

In my almost stock 09 subaru 265, I double lapped a girl in a 20 minute session in a mazda speed miata, and a guy in a gutless one (199x). My laps times are about 90 seconds. Faster guys are 85, super fast are 80 seconds. 20 seconds a lap is huge.
You must be referring to Shannonville?? ;) Which configuration are you running in ~90 seconds? Pro Track? My best time has been about ~74.5 seconds on the Pro configuration (there are 4 different configurations at Shannonville). My (radar confirmed) top speed down the straightaway was just a hair over ~180 km/h (~110 - 115 mph). The C5's were about the same.

Compared to the Miatas at that track? Well, I don't see them much ;). Even on STREET tires, with STOCK suspension, I ran 80 seconds flat in my '02 Z28 :cool:.

I'm still leaning on the side of the F-body over the Miata at VIR :cool:.

You must be referring to Shannonville?? ;) Which configuration are you running in ~90 seconds? Pro Track? My best time has been about ~74.5 seconds on the Pro configuration (there are 4 different configurations at Shannonville). My (radar confirmed) top speed down the straightaway was just a hair over ~180 km/h (~110 - 115 mph). The C5's were about the same.

Compared to the Miatas at that track? Well, I don't see them much ;). Even on STREET tires, with STOCK suspension, I ran 80 seconds flat in my '02 Z28 :cool:.

I'm still leaning on the side of the F-body over the Miata at VIR :cool:.

A long time ago, I attended the Bridgestone racing school at Shannonville.
It was a great track, I really like the layout.