Upgraded Brakes

[HeDog]

Today I finally finished upgrading my brakes, painted my calipers & re-undercoated the wheel wells. It took me over a week to do everything, and I hope I never have to do it again. It was a real Biotch to paint the calipers while they were still attached.

Next the compression test & then turbo!

I took a few shots in case anyone's interested.

 

[wret]

You know, I was questioning my dedication to performance the other day as I repainted my calipers (kind of an anual spring ritual). Then I as I passed a nice GS-T yesterday with rusted grey lumps grabbing it's rotors, I felt a little better. Lookin' good is important too.

 

[HeDog]

I'll agree with that.

 

[MNGSX]

I know the feeling...

I just did mine...

Upgraded ALL the bushings, both sway bars, bead blasted and repainted all suspension arms, undercoated the wheel wells, blasted, painted and undercoated the gas tank skid plate, painted the shaft on the cv shafts, and polishing out or touching up every blemish in the paint.

After all this... I don't feel like such a dork for driving a POS in the winter from now on instead of the GSX....

 

[igs]

it looks like the rotors are on backwards

 

[slow guy]

i dont see anything wrong

 

[PaulPDX]

it looks like the rotors are on backwards

Maybe something else is backwards.

Slotting can go either direction. Some manufacturers like them with the direction of rotation... others don't. No one can say for sure which way is best.

 

[AWDspoOLiN]

Its a pretty popular misconception that the slots or drills determine disc rotation. The direction of rotation is determined by the geometry of the vanes of an internally vented disc. However, there are vane types that are non-directional.

 

[Todd TCE]

 

[spyderman]

You need to check your "non-directional" theory. They most certainly are directional. There are lefts and rights if you bought them from a reputable supplier. Slots and/or drill pattern should go from center slanting back when looking at the upper half of the rotor. This is most critical for the slotted type as the slots are intended to dissipate water from the rotor while the drilling is intended to remove gassing from the brake resin during heavy brakeing.

 

[PaulPDX]

Uh.. ok, so Todd doesn't know his stuff then. Both drilling and slotter are for the purpose of dissipating gas, not water. The tremedous amount of pressure calipers place on rotors makes water a non-issue.

I could be wrong but drilling was originally meant for dissipating gas and save weight at the expensive of strength. Slotting is perferred on the track because it dissipates gass while allowing enough matterial on the rotor for it to remain strong despite rapid heat cycling.

Some true competition carbon fiber rotors don't even have slotting or drilling since the material itself dissipates heat well and is light.

Slotting doesn't have to go any particular direction... the cooling vanes do.

"The Power of Knowledge is the Power of Choice" Exactly... the choice of information you choose to believe and spread.

 

[spyderman]

Uh.. ok, so Todd doesn't know his stuff then. Both drilling and slotter are for the purpose of dissipating gas, not water. The tremedous amount of pressure calipers place on rotors makes water a non-issue.

I could be wrong but drilling was originally meant for dissipating gas and save weight at the expensive of strength. Slotting is perferred on the track because it dissipates gass while allowing enough matterial on the rotor for it to remain strong despite rapid heat cycling.

Some true competition carbon fiber rotors don't even have slotting or drilling since the material itself dissipates heat well and is light.

Slotting doesn't have to go any particular direction... the cooling vanes do.

"The Power of Knowledge is the Power of Choice" Exactly... the choice of information you choose to believe and spread.

I guess you need to take your issues up with TRW who designs the rotors then. This is where my information came from. And remember, these rotors are sold for more than just track use where water may not be an issue. Water is an issue on the street and in rally racing.

 

[AWDspoOLiN]

You need to check your "non-directional" theory. They most certainly are directional. There are lefts and rights if you bought them from a reputable supplier. Slots and/or drill pattern should go from center slanting back when looking at the upper half of the rotor. This is most critical for the slotted type as the slots are intended to dissipate water from the rotor while the drilling is intended to remove gassing from the brake resin during heavy brakeing.

What is there to check? Three vane types exist as far as I know. Curved vanes, Pillar vanes, and straight vanes. The first being directional and the other two being non-directional. A curved vane disc must be installed in such a way that the vanes run back from inside to out in the direction of rotation. Placing the disc in this way creates a pump that allows the disc to dissipate heat better. Maybe the misunderstanding is when I use the term "vanes". I'm most definitely not referring to the slots and/or drills but am referring to the "vanes" in an internally vented disc. As far as your comment about the slots and/or drills having to slant back when looking at the upper half of the rotor, take that issue up with the rotor suppliers as I have seen rotors that are intended to be installed with the outer edge of the slots coming into contact with the brake pad first. No, these weren't some of the cheapo suppliers that I don't even bother with in the first place. Help me out here Todd of TCE. Am I all wrong with this one?

 

[igs]

About the water issue, this is from Porsche's web site:

"Wet-weather performance is considerably enhanced with the aid of cross-drilled discs. By enabling rapid dispersal of the water vapor generated under braking, the distinctive drill-hole pattern ensures greater consistency in the wet."

 

[igs]

I could be wrong

Yes you are wrong, once again. No big surprise.

 

[PaulPDX]

Gee... someone is holding a bi*** grudge. No surprise there either.

How much pressure is put on the rotor surface by the caliper and brake pads? Yeah the holes and slots help rid the rotors of water, but their function has more to do with heat dissipation and evaculating gases created by friction of the pads and the rotor surface. Think of it as a squeege with a lot of pressure behind it. During the first revolution or so with pressure being applied there may be a micro thin layer of water remaining still, most of the water is brushed aside by the pad and flung outwards because of the rotation of the rotor.

Heat and gas build up between the pad and rotor is the number one factor in influencing brake performance. Even if the slots were going the "wrong" way, they would still serve to help evacuate water and gas. It is the direction of the cooling vanes (if they are directional) that dictates which way the rotors have to be installed.

 

[spyderman]

OK, now that we have established that the cross drilling and slotting DOES improve wet weather performance (as quoted by someone from the Porsche site of which I was told earlier the holes and slots had nothing to do with water), and we have established that the rotors, at least some of them, are in fact directional, and the fact that TRW specifically labels there rotors left and right, what part of the FACTS don't you understand? The vanes are for cooling the rotors and nothing more. The holes and slots are for disipating gas and water. The holes are drilled in the spiral pattern to stay center between the directional vanes. The slots are located central to the holes. This make the entire assembly directional.

 

[ECTurboDSM]

I also read in Sport Compact Car that newer brake pad materials are not creating the amounts of excess gasses that performance pads of the past did. That's another reason you see race cars going back to solid rotors.

 

[Todd TCE]

The only aspect of directional VANES are the manner in which the castings are made.

VANES are not 'slots' or 'holes'.

"Wet-weather performance is considerably enhanced with the aid of cross-drilled discs. By enabling rapid dispersal of the water vapor generated under braking, the distinctive drill-hole pattern ensures greater consistency in the wet."

Yea, so what? There is no statement made here to the manner in which the pattern is drilled. You can say the same for any drilled rotor.

Most drilling patterns are intended to accomodate the inner venting properties of the rotor only. Meaning you can't drill one type of pattern on all rotors based on the webs inside.

All this being said, debated, whatever; if the car above has universal web design to its venting properties you can mount them any way you like. You'll never know the difference. Me? I like the old racer trick of the tic-tac-toe pattern. Quick, easy and as effective.

If you're happy, that's all the matters. Move on.

* I might also add that the value of gas slots had diminished so much over the past ten years or so that they are way more cosmetic than functional. Still they do as intended- vent the boundary layer. But then all good 'real' pads are also now of block design for the same purpose, thus negating the value of the rotor slots.

 

[igs]

"Wet-weather performance is considerably enhanced with the aid of cross-drilled discs. By enabling rapid dispersal of the water vapor generated under braking, the distinctive drill-hole pattern ensures greater consistency in the wet."

Yea, so what? There is no statement made here to the manner in which the pattern is drilled. You can say the same for any drilled rotor.

You did not read the first sentence:

About the water issue, this is from Porsche's web site:

 

[igs]

* I might also add that the value of gas slots had diminished so much over the past ten years or so that they are way more cosmetic than functional.

They are much more functional than you think. The following is from a company that makes real brakes:

"Disc grooves and sometimes cross drilling are frequently used on racing brake discs to clean the surface of the pad and allow gases produced to escape.
In doing so the friction characteristics are modified, different groove and & drilling patterns affect the friction characteristics in different ways, some affect overall friction and others the bite or release characteristics and therefore the best solution is not necessarily the same for each application."

"Latest design gives improved bite and debris clearance and reduces distortion / vibration"

 

[PaulPDX]

And just because Porsche says it on their website it's the law? A lot of things said in marketing are half truths. No offense to Porschephiles but most of Porsche customers could care less how their car works. Most of them buy it for the status symbol. If there are any techno-babble they can spew out to help sell cars, they will.

8 years in advertising and working multimillion dollar accounts for 3 fortune 500 corporations, I would know.

If water on rotors are such a big deal with disk brakes, there should be massive multicar pile ups on all of the highways and streets across the country whenever the planet's atmosphere decided to shed a little moisture. Yet, there aren't. Water is an issue but not to the degree some of you like to think it is. Heat fade is the main cause of degradation in braking performance. That's why in a lot of automotive journal tests they run repeated tests of braking from 60 to 0 as a part of the vehicle review.

Pad compunds have gotten good enough where heat and gas isn't as big of a deal as it used to be. Cross drilling these days are mostly done for looks... and if they can put a "yes it really does something" spin on things other than just saying "it looks cool" to move cars off of a dealer's lot... hey, what the hell, why not. Customers at dealers look at a particular car because they already think the car looks good... obviously. They don't need the salesman to tell them what they already know... and a smart salesman and smart marketing firms know that.

 

[Todd TCE]

You guys are spending waaay too much time on this.

Yes, I did read the first sentence.
"Wet-weather performance is considerably enhanced with the aid of cross-drilled discs.
It make no reference to any specific pattern of the holes at all.You could rightly say the same thing of taking a 1" hole saw and punching four holes in a rotor.

The gas slot reference is very well founded and I agree completely with what was stated there. However the need for this is very diminished from ten years ago. And I might add that ANY change to the surface results in faster pad wear, faster rotor wear and more dust. It should be obvious, but somehow folks don't understand that.

As for who said the last quote I suspect this is (or if not you need to look at this one too!) the latest from Alcon and their new 'hook' style slot. When does it end?? Straight, angle, six, four, hooks, curves, and my favorite; the atomic look! (whatever it's called it looks cool) You like slots? Check out this one; http://www.reddotracing.co.uk/eng/RedDot Home Page.htm Go to 'discs' and check out that fourty slot rotor, yea baby! You might also note the shot of the asymetrical drilled rotor on the home page.

Or then again this one;http://www.wilwood.com/products/rotors/gt48fcr/index.asp

Or you may want to reference my tic-tac-toe pattern (the back side is opposite) I use for simplicity. While not one to think of it, that was Carroll Smith, it's simple and effective.

As for marketing, very good thinking. If one can come up with the right buzz words, bling and some great wording on it then it must be true! The shear and utter rotor abortion performed with 40 slots and then putting a buch of buzz next to it saying its track worthy supports this pretty clearly. Not on my car thank you.

My point being; buy what you like but don't loose any sleep over the way your gas slots or holes on a non directional rotor point. There are many more important things in life.

 

[spyderman]

You know this whole thing started about 7000 threads ago when someone commented on the photo and said "looks like the rotor is on backwards". I recently put cross-drilled and slotted rotors on my car. I contacted TRW for an explaination of the slots as I already new why the holes were there. I was told by their design engineer that the slots were for moisture and debris as someone else also stated in one of these threads. The rotors have directional vanes and the holes and slots are drilled/machined accordingly. They are then sold for specific right/left application. Maybe they do have more form than function but that was not the original issue. It has been stated many, many times by know-it-all PaulPDX that some of the vanes are directional and some are not and those that are directional need to be on the correct side in order to properly cool the rotor. Being that the drill pattern of the rotor in question appears to coincide with the directional vane pattern, then the answer is YES, the rotor is on backwards. And it is so wonderful that you work in advertising, I work for one of the top engineering and construction firms in the world and we just don't sit around thinking of ways to piss away our R&D budget just to make things look cool. Enough already!

 

[Todd TCE]

It appears that the rotor in questin is NOT directional vaned.

If it's directional then the pattern may well be considered backwards, but VERY FEW of the aftermarket rotors are directional. Frankly I know of none for this car. Show me who makes them. ? I don't believe there are any TRW parts that are DV for the Eclipse.

I'm not looking for an arguement in it, just trying to help clear up what's what. A rotor with gas slots is not necessarily directional vaned. Nor is a hole pattern required to match the casting webs inside it. Most do, and the pattern is as above. In looking and thinking about it you can drill a swept pattern the other way also on a DV rotor. Now what do you do??

All that I'd be concerned about is IF the rotor pictured is DV then get it on properly, regardless of holes and gas slots. You'd be surprised how many folks call and ask if I marked the right when I shipped them out. The OD of the rotor does not 'bite' into the air....