5UPRAH had an off on the track with incar video!

LordDigital

LordDigital

Member
May 21, 2005
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5uprahboy;1311600 said:
Cheers :)
From what I've been told - as long as I use decent pads, add some cooling ducting, the 324mm (12.75") will be fine - heck, the V8 supercars were using one about that size up until a few years ago lol
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I agree ,with the right cooling ducts you could use smaller rotor as long as you keep it reasonable so you car does not become "the Ultimate Proboscis Vehicle" :icon_wink like most of the group-B Supras were (as seen on the BiYo's ,Minolta's ,Fujitsu and Sard Race MA70(s))

Now seriously the proper ducting design seems easy but the brackets that are suppose to direct the airflow through the rotor veins proven to be a serious challenge on the 13" disk with 17" rims ,after fabricating for a few days I finally gave up since I never could get the angling as I wanted it to be.(I was using these as a model ) ,but you might have a better luck with the 12.75"...
 
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Shane001

Racer
Jan 1, 2008
38
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Sydney, Australia
Do ureself a favor, by some thermal paint (Brembo for example), around $AU200 and will last you forever. Paint u're rotors, then match u're pads to your rotor temps.

A quick and easy way to drop front rotor temps is to make up a makeshift splitter under the front bumper. A piece of 3-5mm alloy, the full width of the bumper, extending from around 5cm in front of the bumper to the full depth of the bumper (just be careful of tyre clearance). This will have a scooping benefit for the radiator, and will also force all air coming in the side pod holes (or whatever u wanna call em) in the bumper to pass the wheels, rather than just wash away under the car. Not sure if it's the controlled passage of air, or a vacuum created as a result, but it definitely drops u're rotor temps.

U'd be surprised once u paint them that they're probably not getting that hot anyway. U just gotta run decent pads in the right temp range and check them regularly to make sure u don't get metal on metal contact, even on a small part of the pad. This will overheat the rotors real quick and they'll crack and fail!

PS: All the above is from personal experience lol!
 
supraguru05

supraguru05

Offical SM Expert: Suspension & Vehicle Dynamic
SM Expert
Dec 16, 2005
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I still run the stock calipers with raebestos pads. ive blown a stock caliper but the seal broke not the slider and it was over winter not at a event. at the events at the end of each day all the brakes get broken down and the synthetic grease gets replaced this is important especially on the slides. im not worried about my stock brakes
 
prsrcokr

prsrcokr

Motörhead
Apr 3, 2005
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That looks like a fun track layout, Mr Kiwi ;)
Are you talking about running the splitter on an angle so it scoops air bewteen itself and the bottom of the bumper or flush against the bottom of the bumper like most splitters so it creates some front downforce.

I agree sending/ducting air to the area of the caliper/rotor would help but not nearly as much as directly into the center of the rotor, this way it's forced to flow through the rotor veins, not just against the inside face.

Do you know what that paint is rated at (Deg.?) I used some caliper paint previously (rated 6-700 F?) but it woouldn't hold up on the front calipers (rears it does ok)

I'm on the same pads as Guru, they're a custom cut for mk3's by a fellow road race guy (Geoff M.) i've got tons of brake power, just not the grip to match. In 95 deg. F. amb. temps doing 25 min. sessions (30 miles a session) I had no fade. Fighting ABS as the tires got greasy was another story :) This was stock caliper, blank rotors, dust shields still on and BG fluid (502 F rated dry BP)
 
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Shane001

Racer
Jan 1, 2008
38
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Sydney, Australia
Flush. I agree ducting direct to the center of the rotor would be better, but u try getting decent ducting there on a MkIII! Good luck lol!

And for the degree of effort, is it worth it? IMO & experience not, but it depends on your rotor/caliper/pad/wheel setup. Whereas the splitter is pretty easy and offers additional benefits in engine cooling and aero. With the splitter my rotors will be lucky to see 500degC. If I had ducting as well they'd be running too cold lol ;)

The paint I'm talking about comes in a pack with three temp ranges. Can't remember what they are now but if u have a look on the Brembo or AP Racing or probably any other major brake website involved in motorsport u'll be able to find them. I know the AP & Brembo paints are identical, just different label. U paint a small patch on the outside edge of the rotor, and the paint changes color at certain temperatures, giving u an indication of peak rotor temps.
 
prsrcokr

prsrcokr

Motörhead
Apr 3, 2005
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Ok, thought you mean caliper paint. Yeah, I've seen that stuff and it would be helpful.

Yeah ducting would be tough to setup properly but it's done on others so should be possible. I agree that depending on the temp. during your event, blocking off the ducts may be needed to keep from staying to cool. On hot events, I don't think it'll be a problem. I was hoping to take the dust shields and modify as a temple for a duct.

If you think about it Ian, the biggest sink is the disk and then the hat which sits on the hub. That Al. would transfer a whole lot more heat from the disk than the Iron stock type. Too bad they don't make the 5000's for stock rotors like the mk4 (and in the US)
 
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Shane001

Racer
Jan 1, 2008
38
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0
Sydney, Australia
IJ, it would be interesting to hear what DBA have to say about the temp differences. Have u thought of giving there tech dept a call for a chat.

As for the alloy hats, I doubt u'd really see much temp decrease due to the hats, but could be wrong...

Someone should really break this thread out to a new thread on brakes, seems we've taken over 5upraboy's thread, though I guess we're keeping it at the top of the list lol ;)
 
prsrcokr

prsrcokr

Motörhead
Apr 3, 2005
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Richmond
Those are the mk4 ones you're using (rear?) or some custom for your calipers? When I checked they weren't listed for ma/jza70.

I'd bet they do help, the rotors (and calipers) are heavy. That was going to be my reasoning for upgrading, not the braking power (although at some point it'll also be needed)

Shane, I'm trying to see how the splitter would help with brake temps. Do you have a diagram? It seems like unless there ducting or something it would only create downforce and redirect more air through the bumper opening that would have flowed under the bumper/chin.
I had an idea to add small cups to the dust shields (used on an instructor's S2000) to run ducting directly to the shields. Of course getting the sheilds off to do this isn't easy as I don't feel like removing the wheel bearings again. Was thinking cutting the sheilds in two pieces may allow them to be installed without pulling the hubs.

Sorry for the hijack 5upraH, maybe we need another thread like Shane said.
Brian
 
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5uprahboy

New Member
Aug 22, 2005
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Auckland
IJ.;1316936 said:
Shane: Nah never thought about it ;)

Brian: Yes Mk4 F&R 5000 front and 4000 rears and AP Racing 4 spot 5000 series calipers.
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Thread hijacking is fine by me - I'm very interested in braking advice :)

The rotors I've got (324x30mm 350z track rotors DBA4600 is their DBA part number) are a better fit than the MKIV ones, and 1mm larger :biglaugh:

I will try and source some rotor heat paint and see what the temps are like.
 
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5uprahboy

New Member
Aug 22, 2005
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IJ.;1317850 said:
Yep have a set of the track Rotors here for a friends car ;)

They didn't exist back when I built my "kit" so I had to use the Mk4's and turn the hubs down to suit.
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To be honest I don't have genuine DBA ones. I'm using some other knock off sort so I assume I'll have to bed them in and heat cycle them etc

but at $78 each new - I couldn't complain :)
 
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5uprahboy

New Member
Aug 22, 2005
343
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Auckland
IJ.;1317864 said:
DBA 5000's are stupid expensive even with my discounts ;)

That said they do work very well!
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The 5000's are a 2 piece? From what I remember they were 2/3's again the price of the 4000's....
 
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