New Racing Brake kit

[CL65 Captain]

Since we have some well informed racers posting on this thread, I need an honest opinion... do these wind deflectors for brakes work? How much can you possibly cool a thick steel rotor by blowing a little extra air on it? Seems like wishful thinking to me...

Dali deflector and 2" ducting hose going to the rear of the front rotors - 158F average drop before and after.

2" ducting on the rear - 87F average drop.

Dave, try this at home. Stick a pot in the oven for 500F for 20 minutes. Take it out and sit it on the stove top. Now wait 5 minutes and go stick your finger on it and see if you get burned. Now repeat, but this time get a big fan blowing on it and then stick your finger on it and see if you get burned.

Let us know how it turns out.

I think my ducting helps more than he Dali defectors as they go right to the center or the rotor, but for $45 the Dalis sure don't hurt.

 

[TURBO2GO]

Dali deflector and 2" ducting hose going to the rear of the front rotors - 158F average drop before and after.

2" ducting on the rear - 87F average drop.

You actually measured? So you are thinking it is worth spending $100 on?

 

[CL65 Captain]

You actually measured? So you are thinking it is worth spending $100 on?

yes. How much do you pay for new rotors when they crack from heat? How much do you pay for pads?

Not only do I get less fade now, but my rotors are lasting longer.

 

[docjohn]

Before you go cooling your front rotors with tubes and duct work just make sure you know the optimal temp range of your pads,and what your rotor temps are at the tracks you visit.If you are using track pads you may not even be getting your rotors up to the optimal temps.

 

[CL65 Captain]

Before you go cooling your front rotors with tubes and duct work just make sure you know the optimal temp range of your pads,and what your rotor temps are at the tracks you visit.If you are using track pads you may not even be getting your rotors up to the optimal temps.

Ya, if you brake like a pussy.

 

[TURBO2GO]

What gadget do I have to buy to get rotor temps? On the last checkered lap we are running slow and I avoid using brakes at all. By the time I pit it's probably cooled off already. This is a very small investment if it extends rotor life. Besides.... I like buying gizmos.

 

[docjohn]

Pussy or not, some track pads like 400-600 deg ,and if you are at a pussy track that means double pussy which means all you are doing is glazing and eating your cold rotor.Turbo ,any racing shop or catalogue like longacre have infrared or metal probe temp gauges.

 

[john@johnhudakracing]

if you are at a pussy track that means double pussy

I don't know about the rest of you, but I need to go to that track!!

 

[CL65 Captain]

What gadget do I have to buy to get rotor temps? On the last checkered lap we are running slow and I avoid using brakes at all. By the time I pit it's probably cooled off already. This is a very small investment if it extends rotor life. Besides.... I like buying gizmos.

Rotor paint. IR thermometers are OK if you pit in w/o a cool down lap and have your pit crew take immediate temp readings while you sit in the car. No pit crew? Me neither... Use rotor temp paint. :wink:

IR temp gaget is cool to have and can help with before/after comparisons, etc but isn't going to tell you what peak temp that rotors are getting to.

 

[CL65 Captain]

I don't know about the rest of you, but I need to go to that track!!

Meet you there John.

Is there a track in Minneapolis (Twin Cities) perhaps?

 

[john@johnhudakracing]

Meet you there John.
Is there a track in Minneapolis (Twin Cities) perhaps?

Umm. That would make me go faster.

I wouldn't even need brakes at that track. I'll just go ahead and leave them at home!

 

[Dhalsim]

Great thread... learning a lot and thanks to all contributors.

+1 :smile:

 

[stuntman]

Temp paint is very helpful, so are temperature strips on the caliper (aftermarket, the strips wont stick to the stock caliper).

Once my street car is finished, I am going to be measuring the effectiveness of aftermarket deflectors like STMPO vs. stock vs. 2" ducting. -To answer exactly the unaswered question you just asked. I have some resources/methodology that should proove accurate and give a pretty definitive answer.

Many pads see 800-1200*F under load, when a rotor comes in off the track at 400-600*F, it has cooled down significantly from the last time you used the brakes. Your rotor temps also drop hundreds of degrees within a few seconds after you release the brakes.

 

[TURBO2GO]

So you really want to know what is going on with your rotors before going and changing parts. I have a question on the paint. I read the description but it doesn't say. Will the color change record your highest temp and stay that color lomg enough for you to find out after you are off the track?

I saw these DBA rotors at the Tire Rack a while ago and they listed an NSX application. The DBA site still shows the NSX app but Tire rack no longer does.

This is from the tire rack:

"Thermo-Graphic markings are placed on the outer edge of each DBA series disc rotors and are used to monitor the core temperatures achieved during braking application. The markings change color as the rotor heats up to alert the driver to rotor temperatures that exceed optimum levels".

If you see this link its detailed as to how you can see the temps.

It still does not say how long these color markings will change. You want to know the peak temps, right? Or is that not correct? How do you get the peak short of pitting in right after braking? Billy you are saying these cool very fast, right? Seems like you need the equivalent of a peak hold gauge for your rotors.

 

[CL65 Captain]

They change color and stay that color.... which indicates the peak temp.

Just like my bright red painted calipers turn maroon after a day at the track and stay that color until I repaint them. :frown:

 

[WingZ]

So you really want to know what is going on with your rotors before going and changing parts. I have a question on the paint. I read the description but it doesn't say. Will the color change record your highest temp and stay that color lomg enough for you to find out after you are off the track?

I saw these DBA rotors at the Tire Rack a while ago and they listed an NSX application. The DBA site still shows the NSX app but Tire rack no longer does.

This is from the tire rack:

"Thermo-Graphic markings are placed on the outer edge of each DBA series disc rotors and are used to monitor the core temperatures achieved during braking application. The markings change color as the rotor heats up to alert the driver to rotor temperatures that exceed optimum levels".

If you see this link its detailed as to how you can see the temps.

It still does not say how long these color markings will change. You want to know the peak temps, right? Or is that not correct? How do you get the peak short of pitting in right after braking? Billy you are saying these cool very fast, right? Seems like you need the equivalent of a peak hold gauge for your rotors.

That pic is of the 5000 series that has the aluminum hats which they don't do for the NSX.:frown:

 

[Yokohama_91]

Thanks very much for the update and your comments.

Like you, I had to do a lot of grinding on the OEM calipers to make sure the RB 324mm rotors would not touch the calipers either cold or when hot.
But as you, I have been very happy with the upgrade in performance.

Have ONE question though. I choose the 1997+ 303mm rotors in the rear in combination with the RB 324mm rotors in the front. You did the 330mm rotors in the rear. Do you feel the bigger rotors in the rear are really necessary?

I choose the 330mm rear rotors as it seemed the suggested upgrade from the NA2 brakes, which I had run for a couple of years.

This seemed the right way to go as I had heard a lot of problems from my friends with brake balance when fitting Brembo or AP Racing kits, the problem being that with equal sized rotors the fronts would lock [trigger the ABS] first necessitating the need for a balance valve, but having the bigger rotors with more torque at the rear, would offset this and give better stability under extreme breaking, this seemed logical to me as there is more weight on the rear wheels.

I discovered after fitting that one of my friends has a Brembo kit with the same rotor sizes as mine F324/R330 and no balance valve.

Anyway the brake balance seems perfect especially while turning in slow corners.

Simon

 

[TURBO2GO]

Billy I am just curious have you ever seen or heard of a hat shearing off the rotor in any other application? either with RB's or anyone else? I am asking because I am just wondering how common this is and if your situation was unusual.

 

[docjohn]

I've had hats crack around the periphery of some not all of the mounting screws.These were the comptech hats for the 12.4 kit.Two sets did this back in my 12-14 track events/year days.

 

[TURBO2GO]

I've had hats crack around the periphery of some not all of the mounting screws.These were the comptech hats for the 12.4 kit.Two sets did this back in my 12-14 track events/year days.

Is this an issue with 2 piece rotors in general? Or is it poor build or materials quality? Wasn't the Comptech kit Brembo?

And while we are on the subject, can someone tell me why Porsche, Ferrari and Lamborghini continue to use cross-drilled rotors? Is this just a bling thing? I can't imagine that they expect their car owners to be racing in the rain that much. Shouldn't cross-drilling have dissapeared long ago?

 

[MvM]

Is this an issue with 2 piece rotors in general? Or is it poor build or materials quality? Wasn't the Comptech kit Brembo?

And while we are on the subject, can someone tell me why Porsche, Ferrari and Lamborghini continue to use cross-drilled rotors? Is this just a bling thing? I can't imagine that they expect their car owners to be racing in the rain that much. Shouldn't cross-drilling have dissapeared long ago?

One of my NSX friends had a BRAND-NEW NSX OEM Rotor breaking, shearing the hat completely off. And as you know, those rotors are one-piece rotors.

Have seen other one-piece rotors that have failed in a similar way. It is (luckily) not a very common thing but it is possible.

As far as your cross-drilled rotors is concerned, I don't know the answer. Don't know about Ferrari and Lamo, but the Porsche rotors AFAIK have their holes cast in, so their rotors are not strictly speaking cross-DRILLED. More like cross-holed :biggrin:

 

[Prospeed]

Having it casted into the rotor helps prevent stress cracks at each hole on the rotor. Porsches get away with it however I've seen a few Porsche rotors with stress crack on them anyways and that is with spirited driving... no tracking... so I tend to stay away from any cross drilled rotor or cross holed hehe. Slotted would be the most I would do.

 

[TURBO2GO]

I've seen a few Porsche rotors with stress crack on them anyways and that is with spirited driving... no tracking...

Yes, I have heard of the same, which makes me wonder why they continue to put them on everything. Even a base Boxster comes with cross-drilled rotors.

I'm sorry I just can't say cross-holed, it sounds too sexual. :biggrin:

 

[FastraxTurbo]

Billy, you had mentioned that the tabs on the RB rotor failed. Have you also seen premature wear, or short service life of these rotors? This may be due to the composition of the rotors, as I have seen many types of materials used and the RB rotors have a very high ferrous, or iron content. I dont know metallurgy, but excessive iron, and/or the casting process may make the rotors more brittle, or soft.

 

[docjohn]

Is this an issue with 2 piece rotors in general? Or is it poor build or materials quality? Wasn't the Comptech kit Brembo?

And while we are on the subject, can someone tell me why Porsche, Ferrari and Lamborghini continue to use cross-drilled rotors? Is this just a bling thing? I can't imagine that they expect their car owners to be racing in the rain that much. Shouldn't cross-drilling have dissapeared long ago?

I have no idea why the aluminum hats failed in this way,but Just eyeing them they are at thier thinnest just over the mounting screw and that is where they failed,These are made by comptech ,the rotors are brembo.Now on thier full size kit which did not fit over the stock 16 inch wheels the hats were more beefy above the mounting screws or bobbins.