jus wondering has anyone taken a thermal reading of stock calipers with racing pads and stock disc on a ek after a session wanted to know brake temps

 

I know they sell stickers that change color based on the highest temp they see, haven't done an testing on it myself though.

 

any specific temp your looking for? caliper? rotor? also, what set up? stock sized ek brakes? what weight car? what tires?

 

Like lo-buck eluded to its going to range a lot depending on a lot of factors.

I'd say from ~700F on up to ~1500F is seen on most RR hondas

 

Yup

 

This might be useless to you but...I have a 93 accord lx and installed rear disc brakes from the junk yard. One had a seized caliper. That rotor was hovering around 300-400F after a quick drive around the block. All of the other healthy rotors are around 275-300F. I never measured the calipers though. I used an OEM brand laser thermometer from Autozone.

 

Anything over 1100F on GOOD discs will get them pissed, on the crappy honda discs, I'd say if you see 800-900 then you need to use a lesser friction pad or get more cooling.

On the OE pin sliding calipers, when they go over 250F the rubber pin guides get too soft and it starts to move and flex like wet well cooked noodles. And at 300F the piston seals start to crumble.

Hope this helps.

 

Are you sure about those numbers? 300*F seems awfully low for the piston seals to be going bad. Unless you mean the dust boots.

 

Remember these are street calipers not race calipers, and even on race calipers if its getting over 450F its TOO hot and needs to be looked at. Heck in Bahrain the F1 teams are tossing the calipers when they reach 300C which is about 550F because of the thermal cycles on the aluminum.

Dust boots will catch fire by the radiating temps from the backing plate and disc.

 

Normal brake rotor temps on the track will be closer to around 500-600F on moderately powered Hondas.

Lacking any tools to measure the temp, you can always look at the color of your rotors to get a ball park. http://www.muggyweld.com/color.html

 

Why would racing pads for stock calipers have such high operating temps if the failure temp was comparatively low? A quick look just at Carbotech shows the XP8's operating temp of 200-1350*F, and I've faded them in the past without caliper failure. I'm assuming that means I was seeing a higher temp at the rotor than 300*. Or am I thinking about this incorrectly?

 

There's a lot more to brake fade than just pad fade. Normally pads these days dont fade anymore. Its actually the discs that start fading. When you have a disc that is grooved like a bad Elvis record, that means that those grooves turned liquid at one point during the braking event. And over course there's no friction on liquid, hence the feel of a fading pad. You could also be overheating the fluid.

 

In case anyone was curious, the carbon discs used in F1 get to temps of about 2200F when they're glowing red. Where did you get the 300C number from?

 

Just for comparison's sake, the rotors were still in great shape, and the fluid was fine (definitely not fluid overheating, as the pedal felt fine, the car just wouldn't stop).

The liquid thing on the rotors, I've never heard of that. You're saying that the surface metal is melting, or what?

 

I'm curious...I've had over 550* on my rotors after a cool down lap. Caliper temps would be lower as they are not in direct contact with the rotors. My caliers are still in good shape.

You are right though, there's more than one factor that leads to fade.

 

http://www.raceshopper.com/temperature_paint.shtml

Looks like they expect rotor temps of 750 - 1250 F (well, higher too, but probably don't have a paint that high) and caliper temps of 240 - 500 F (although maybe the high end of that is indeed telling you that the caliper is toast).

I keep talking about getting that stuff and just figuring it out (no more speculation), maybe this discussion will motivate me.

 

You mean these?








Yes at 300c they were replacing them in Bahrain.

The temps at the disc are always going to be higher, that's where the friction occurs. The calipers have many layers of insulation to the friction surface. Pad material, backing plate, piston heat caps and heat insolator gaskets all reduce heat transfer to the caliper. If the caliper was going much over 550, there would be no brake fluid that wouldnt boil in there.

 

I was at Miller Motorsports park a few years ago work for a Koni St team.

A rep/eng/track side support from Brembo was there helping a GS car that used there brakes. We were pitted right next to each other, when we came in to change shock settings and check tire pressures. The Brembo rep walked by the car and hit the front brakes with a IR pyrometer. He was stunned when ~1,400degree F popped up on his gun.

Never had ANY brake issues with calipers, pads, rotors ect..

We used calipers for 2 race weekends and then swapped them out for new ones. (the races were ~2.5 hours plus another 1 to 1.5 hours of practice and qualifying.

There is only 'so' much you can do when you are limited to stock brakes, and you are working with a DWB fwd honda. There just isn't ANY room up there.

 

It indeed happens often, because the ductile iron in the discs has a faily low melting point, so at the time and point of a hard stop it can in fact get a very fine layer of liquid. But if your discs are fine then its the pad that sucks and the advertise MOTs are bogus.

 

I dont know why on earth would a Brembo rep use an IR gun as its very inconsistent due to the different emissivity from the different metals and colors. He should've used the heat probe that touches the disc directly like all other brake guys use. But as an example, the Daytona Prototypes, see about ~1100F front and ~900R on the discs when they pull in the pits.

 

He had that too.

As i stated he was just walking by and hit it.

The temp paint, temp indicators, and heat probes had all been used on the car. We knew what the temps would get up too, and were not concerned with things at that time. But are readings from the above mentioned methods have shown the right around the same temps.


And yes that is exactly WHY he was shocked at the temps we were seeing.

It was a 2950lbs ~230whp car with stock ~11" front brakes, stock ABS system Acura TSX.

 

Do you have a photo or a link to what the rotors would look like after such an event? I assume it looks like a polished effect?