| Author |
Message |
Philip Airey (Pma1010)
Junior Member
Username: Pma1010
Post Number: 227
Registered: 7-2002
| | Posted on Tuesday, May 06, 2003 - 10:44 am: | |
Thanks all for the responses. Helpful as always.
On the ducting, Brian Keegan pointed out that the early GT4s and GTBs had venting ducts from the extremities of the grill area into the fan motors. (This was subsequently discontinued due to the amount of debris which tended to be picked up by the fans and then thrown around in the cockpit). Either these ducts or something comparable can be used to duct ambient air to the brakes.
Looking at the car last night, a reasonably sized duct (say up to 10" x 5") can fit in the early cars just below the bumper/side lights/turn signal lenses and behind the grill. Should be close to invisible from a casual glance at the car.
While a fi-glass duct would be ideal, the immediate solution is going to be some silicon ducting which can snake inboard and, with a bit of clip/clamp fabrication, it looks like hose can be anchored to the upper steering knuckle bolt and thence duct cooler air to the caliper.
Tazio, with the Euro spoiler my expectation is for negative air pressure immediately under the front lip of the spoiler and I assume a front facing intake would get more direct effect/positive air pressure on to the rotors and calipers. I was planning on cutting and welding the backing plates as it sounds like you did but the Carbotech engineer (Larry), suggested removing all together. His view was you are trying primarily to cool the caliper.
Peter, yes that's the technique I had reinforced this weekend. Short and hard use of the brakes -- near antithesis of what I tend to do on the street (progressive and long). I haven't removed the lower fender covers. Will look at this as I route the hose.
One other somewhat related topic, in switching pad materials, it is necessary to rough up the discs with some abrasive paper (60 - 80 grit according to Larry at Carbotech).
Finally on pad choice, this also feels like religion with some. I had been using the R-4S with Motul last year and it held up. However, Carbotech (recommended to me by the BMW CCA instructor) also claims their Panther/Panther Plus lines will give similar cold braking performance to the Porterfields but they have much greater heat tolerance (1100 - 1200 degrees rather than 800 degrees). No affiliation etc, just passing along the perspective. If this doesn't do it, I'll go for an all out race pad and just expect to switch pads in and out at the track.
Philip |
Dave (Maranelloman)
Intermediate Member
Username: Maranelloman
Post Number: 1420
Registered: 1-2002
| | Posted on Monday, May 05, 2003 - 9:54 pm: | |
Phil, my $0.02 is that R4S pads make mediocre track pads. I tried them once on my M3, which weighs about as much as a 308/328, and they worked OK, but didn't last. A higher temp pad solved that even before I ducted more air to the poorly ventilated front brakes... |
peter james moran (Pjm)
New member
Username: Pjm
Post Number: 48
Registered: 3-2002
| | Posted on Monday, May 05, 2003 - 5:15 pm: | |
Did you remove the inner forward fender shields? The Motul worked great for me. My braking style also helps me, too. I brake late, hard and let off as quickly (and smoothly) as I can and no trail braking. I do plan on making fiberglass brake duct scoops this summer for my 308. If other people are interested I be willing to develop a kit. |
Lawrence Coppari (Lawrence)
Member
Username: Lawrence
Post Number: 590
Registered: 4-2002
| | Posted on Monday, May 05, 2003 - 4:46 pm: | |
I put ducts on my Porsche track car. The difference is amazing. Ducts come from the front and shove the air into the rotor directly. The kit came with disks that come to within 1/8 inch of the rotor air intake on each front wheel. Now the fronts are not as hot as the rears after a track session.
Highly recommended. If you are handy with fiberglass, you could probably fabricate your own for your car if a kit is not available. |
Tazio Nuvolari (Nuvolari)
Junior Member
Username: Nuvolari
Post Number: 198
Registered: 9-2002
| | Posted on Monday, May 05, 2003 - 3:49 pm: | |
Hi Philip,
There are a few things you can do to increase cooling efficiency and reduce brake fade. My first reccomendation is to have your brake rotors slotted. This works very well and is also pretty cheap. If you have the time, have the rotors AND pads cyrogenically treated. I have seen up to a doubling of brake life with no trade off of any kind by cryoing these components.
Secondly, get some air there. If you want to keep the car looking clean, install NACA ducts under the car. They are impossible to see once installed and do a very good job of ductiing air. Use high temperature ducting hose to bring air to the brakes and you can modify the existing backing plates to accept these hoses. Drill the backing plates with a hole saw and weld a metal tube to accept the ducting hose. If you do this job well, it will be (from the outside) near impossible to see that it was ever done and would go a long way towards cooling your brakes. Good luck with it. |
Philip Airey (Pma1010)
Junior Member
Username: Pma1010
Post Number: 226
Registered: 7-2002
| | Posted on Monday, May 05, 2003 - 2:10 pm: | |
I asked about this topic once before to no avail. I'll try once more and then fabricate something/get something made up.
I just had my first track days of the year at Road America this past weekend. New brake fluid (AP550), freshly bled, bedded pads (Porterfield R-4S). Brake fade. Part poor technique (hopefully fixed), part brake system performance. I have ordered a higher temp pad from Carbotech and I am going back to Motul 600 fluid. I also want to look at some better cooling.
I am going to remove the rotor "covers" on the front brakes and, I am interested if anyone has tried any ducting to cool the calipers and, if so, what did you do and are you pleased with the performance and aesthetic appeal of the solution?
TIA, Philip |
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