32 replies to this topic

[Litre8]

Those are A9X brake ducts, 'modified' to allow use of the low-mount K-Mac front bar (you can get ones that clear the brakes ducts but didnt see any of those in 1991). Given that the car will be moving (and hopefully quickly) when the brakes are applied then the ait from the ducts will probably end up hitting towards the centre of the rotor. If you were doing a custom to the max setup then you would use ducting that terminates right at rotor centre.

[dattoman]

To do it properly (for a racecar... not really required on a streetcar) would require the air to be forced into the centre of the rotor and also onto the caliper
This is for a vented disc setup of course
For a solid disc you just direct air at the caliper (no point pumping air at the centre of a solid disc)


If it was me...I would try to adapt a backing plate with a cutout to enable some decent duct tube to be mounted to direct the air



just cause you don't think you have room for some 3" hose in there with the steering a suspension doesn't mean there aren't other ways to do it
http://fsae1000.blogspot.com/2009/01/full-brake-ducting.html
Front wheels drives have more stuff in the way and they manage to get around the driveshafts and steering on those
Sometimes you just need to be slightly more creative (snail)

However... you can overcool too... so you need to monitor disc temps to keep your pads in their optimum range
Sometimes you actually need to restrict or complately block off the ducts on cool days or when its raining

[Heath]

So on a ventilated, non-slotted rotor, would standard brake ducts (similar to Howard's) be beneficial?

[dattoman]

Brett those pics are just random google pics
Mostly Mustangs I think

Heath ...not alot... but better than nothing
If Howard was a serious racer and used the car more often I'd be designing something better for it
Fine for street since they really won't get too hot
But if your going to use that thing of yours for more than 2 or 3 laps at a time on a circuit... then you need to cool them
What calipers did you decide on to go with the HQ discs ?
Caliper choice makes alot of difference
A cast iron caliper holds alot of heat and needs to be cooled too
An alloy caliper would be better just cooling the disc (from centre) as it won't retain the heat as much
But cooling both caliper and disc is best as long as your not overcooling

Example
My car will run 3" Nyladuct tubing to the centre of the disc
But only 1.5" to breathe on the caliper itself (AP 4 pot alloy)

[Heath]

Yeah well it will mainly be a street car that does springs and hillclimbs and stuff. Is it worth having cooling ducts that I can block off or anything? Or maybe just having mediocre ducts like I'm thinking would be a good happy medium?

[dattoman]

I'm guessing its not going to weigh as much or be as fast as Howard.... so no need to go all out

[Heath]

Yes and yes, but the brakes won't be half as large as those 'standard Holden units' either LOL

[MRLXSS]

The choice of wheel would go a long way in helping cool the brakes better yeah?

I'm assuming bigger and more open is better?

[Heath]

Something with nice deep spokes to get the air really flowing.

I've always thought that the wheels in this pic would be pretty good for it




But you've also got the vehicles with a circular series of vents that go around the wheel, like a blue meanie. That kind of thing is on a lot of rally cars etc, and it looks pretty purposeful. I suspect that most wheel designs are quite reasonable for brake cooling, some (such as Dragway centrelines) are particularly bad, and some others are particularly good.

Edited by Heath, 19 November 2009 - 10:47 AM.

[MRLXSS]

Just thinking out loud here... As you mentioned about deep spokes.. I wonder if wheels were designed to swirl in so they suck the air in and blow them onto the brakes? As long as they don't create to much drag... Or wouldn't that actually do much?

[TerrA LX]

Just thinking out loud here... As you mentioned about deep spokes.. I wonder if wheels were designed to swirl in so they suck the air in and blow them onto the brakes? As long as they don't create to much drag... Or wouldn't that actually do much?

Im sure there are quite a few examples about but I would want the air pumping out out, not sucking in, don't want too much turbulence under the car at speed.

[MRLXSS]

Just thinking out loud here... As you mentioned about deep spokes.. I wonder if wheels were designed to swirl in so they suck the air in and blow them onto the brakes? As long as they don't create to much drag... Or wouldn't that actually do much?

Im sure there are quite a few examples about but I would want the air pumping out out, not sucking in, don't want too much turbulence under the car at speed.

HAHA! Good point! Vortex shoot the air out sideways/backwards!

[orangeLJ]

the VL commodore wheels they ran at bathurst? they were a "fan blade" type design?

[Heath]

^ Yeah that's the kinda thing I was talking about with the rally car wheels

[Heath]

Okay Brett those pics are kinda useless but using my elite hacking abilities I visited your cardomain website and copied the full sized images and tinkered with them in photoshop so we can see what's goin on. Looks good!

Edited by Heath, 05 December 2009 - 09:52 AM.

[Heath]

Look at the tyres Pat

[rodomo]

Lap times?