Greg Fishman

I understand your point but the duct is basically just help by a thin wire and is easy to tear. The zip tie might not break but my guess is the duct would.

kary993

John, by chance have you used the 993 rotor shield to do what you are talking about? The reason I ask is the placement of the cover in relation to the shock tower, hub and associated assembly does not really suit itself well to creating a mount for the hose that would be anything other than viewed as some sort of mess when completed. The cover of course only goes around about 2/3 rds of the way to make room for the caliper, the caliper is forward on the rotor while the strut is rearward, and the sheild is behind the mounting for the hub on the opposite side of the rear hole where you want the hose to blow the air. So it makes it difficult if not impossible to create some sort of mount that will not affect other parts of the suspension. I always try and make these things rather simple to avoid creating additional problems with loose parts causing other failures, but then that's just me

Anyway, if you have donw this with a 993 can you post a picture of what you did?

Flying Finn

Kary,

FYI, here's a shot of how I've attached mine. This is right after install but after lot of track days in more than two years time (damn time flies) they're still there in place so even though the attachement is definitely not "high-tech", it's working.
I think the key is that the piece from the last zip-tie that goes into the calibe opening is "too long" for that space, in other words, I've "stuffed" it in there so it's naturally pushing it's end into that opening and zip-tie keeps the pressure since it can't move away from the caliber.

RedlineMan

Kary;

I have no direct experience with the 993 setup. However, I usually can come up with something that does what you want without fouling everything else in the area.

I ALWAYS think the same way as you, bro! That's the difference between done and done BETTER. Spend more time thinking than building. For me, there is no other way.

TheOtherEric

My setup (explained above) is just like Finn's except as I mentioned I also have it zip-tied to the brake line. Although I was initially reluctant about tying it to the brake line, I eventually concluded that the benefit outweighed the risk. I just can't see a scenario where this could be a problem. Hence, I concluded that the added security of having the end positively positioned (by tying to the brake line) was reasonable.

kary993

Your implementation though is going into the oval area below the caliper, correct? I agree with previous posters that this is not really very efficeint for cooling as you are merely blowing air on the inside surface fo the caliper, which is not going to be as efficient as blowing into the center of the rotor forcing air through the internals of the rotor.

It is a difficult problem to get the hose to the center of the rotor and have it mounted in a way that is simple and will work, that is for sure.

I agree with John, though, thinking is the key and this weekend I am going to spend some time working our various proposed solutions so see what might work. I might just end up where many of you ended up

As a side note, I have noticed that the outer surface of the rotor is cracked far more than the inner surface from an initial inspection. Is that normal? Is there more air traveling over the inner rotor due to the scoop on the a-arm versus all the way inside the wheel for the outer surface?

TheOtherEric

LOL, sorry Kary we have a little misunderstanding. The big oval hole that I (and probably everyone else) are using for our cooling duct is both under the caliper AND blowing the air into the center of the rotor so that it is forced thru the internals of the rotor. It's one and the same.

I don't really know which way is most efficient, but I DO know that I'm blowing air into the center of the rotor so that it gets blown thru the inside of the rotor.

Flying Finn

Ditto that.

Way I have my duct set up is blowing to that hole and as Eric said, it blows it inside.

I've measured rotor and caliber temperatures right after the cool down lap and they are always same or little less than rear brakes which leads me to believe cooling if quite effective since I assume rear brakes don't get nearly as hot as fronts too.

I'm thinking of blocking the ducts for one session, opening them up for next and comparing the temps.

BTW, my cooling ducts don't start from the Turbo S fog light ducts. I used to have it that way but after I installed extra euxilary oil cooler I wanted more air to the coolers so now I'm getting the air from the fog light opening which won't "suck" as much air.

Still cooling has not been a problem (I was suspecting it might be) and for the record, I don't think I brake early, now lighty.

Below is a photo shoing where the air gets in, you can see the area is quite a bit smaller than if I'd use openings that are meant for the ducts.

kary993

There was some earlier discussion about tucking the hose into a hole in the hub area just below the middel of the caliper. That was the confusion, at least on my part.

So since you are directing the air into the center "round" hole ( not oval) how close is the hose to the hole? The reason I ask is the speed sensor gear is in there and will get tangled with it if it is too far in there.

TheOtherEric

My duct stops probably 0.5" to 1" short of the actual rotor. I don't see too much reason to put it really close to it.

Sorry if I confused you by calling the hole "oval". The hose doesn't fit in there without a little effort, so I just assumed it was kind of oval shaped.

kary993

Just wanted to update some folks here on my brake ducting project. I followed Fin's basic model for installation and it worked out well. I modified the design a bit at the rotor though. I ended up follow some others recommendations from the race forum to put some aluminum bands at the end of the hose near the rotor and leave a long tab from the fabricated hose ring on the hose to attach to something on the strut. I ended up attaching it to the metal tab that the brake line is bolted to by drilling a small hole and riveting the support to it. This makes sure that when the shock moves the hose is with the rotor and does not mismatch on the location. I then fashioned the metal bracket to the angle and position that would blow the air into the center of the rotor. I also riveted the metal bands (1 inside and 1 outside) on the end of the hose to secure the hose better. I put the hose about 1 inch away from the entrance of the rotor center.

It worked very well this past event and I also did not get any rubbing on the hose up front when turned in, though I really never turned the wheel past one complete turn in the pits. Brake rotor temps, while I did not measure them, were much better. Normally I see some smoke coming from the rotors when coming in without a cool down lap and this time it was not an issue. I will be putting on new rotors for the coming year and will see if the cracking is minimized since I generally run the same schedule each year.

One thing I did notice, since I am now directing the air from the front scoops (where the foglights were) entirely to the brake duct hose and no longer allowing that air to funnel to the oil coolers (on both sides, I have tow coolers), my oil temps were slightly higher that before. About 8:30 to 9 after 25 minutes of running. I normally see about 7:30 to 8:30 at most. This was at an elevation of 3000 feet, temperature in low to mid 90's and on a track that does not have any time to really cool. I am not sure if it is because the reduced air flow from the attached hose, or the fact that the brake duct hose goes by the oil coolers thus reducing some of the air's ability to enter the coolers. I may consider finding or fashionined a dual intake for the brake duct that will send air to the brake duct hose and into the oil cooler area on both sides. As it is now the air flow is probably not enough just coming in through the lower front opening. I will do some more testing in the coming months to determine what I need to do here. Oil temps are fine though if I left it that way.


Just thought I would share this experience for those that are interested!

Greg Fishman

Kary,
Start the brake cooling hose at the "dam" that keeps the air from flowing past the oil cooler instead of running them all the way to the front.

kary993

I see what you are saying, sort of. Great idea. Let's see if I understand. Are you saying I would run the hose low to the front lower opening rather than to the ducts I have in place of the fog light opening? Or are you saying I should cut the hose back to the point where I am entering the wheel well wall to allow the are to go through the cooler and also enter into the hose to the brake rotors?

Greg Fishman

The second is what I am referring to. My shop built a new wall out of thin alumium to hold the brake cooling duct and dam up the area between the cooler and the chassis.

kary993

I am feeling some fabrication coming on here Gre, do you possibly have any pics of your fabrication? I know it is inside and not all that visible but just maybe you have some pics? Maybe........?