routing brake duct hose on 74-89 911

[sjanes]

The next project on my list to hook up my brake ducts to the holes in the front valance. I currently have the brake ducts that hang under the A-arm, so I need some ideas of where to route the 2" brake hose so it doesn't get ripped off, crushed, kinked, etc. I have 225's in the front, so there doesn't appear to be enough room along the side of the tub to route it.

How are you guys that have 74-89 911's running the brake hose?

[jakermc]

Not successfully. The passenger side is OK but I continue to puncture holes in the driver's side. It appears that my Carrera sway bar mounted in the stock location is causing the problem. I am going to try and fabricate some sort of shield out of a thin sheet of aluminum and wrap that around the one spot that hits.

As a side note, its amazing what cooling does to extend the life of your brake pads. The driver's side pad wears about 40% faster due to the problem I described.

[IROC]

My set-up uses 3" hose and I can't get it to work satisfactorily. My last attempt lasted one track event. It appears that you have to either go into the trunk in front and come back out near the strut or get real creative and make something out of something like dryer ducting sheet metal that runs along the a-arm.

I'm not keen on trying to run it into the trunk and still need to cipher on the ductwork idea...

Mike

[Cory M]

I tuck it up tight under the body and under the conrtrol arm- I compress the hose under the control arm giving it an oval shape for more gound clearance. I have thru body sways. This has worked fine for me on several cars. If it does rub you can always tape it. Smart Racing Products makes a plastic duct that allows you to go thru the control arm and gives more clearance, a few guys here have made their own Home Depot versions too, I haven't seen the need, my hoses hold up fine without them.

[nostatic]

We are using 993 deflectors instead of hose. Fairly robust solution and seems to help, although I'm pretty gentle on brakes...

[jakermc]

Originally posted by nostatic
We are using 993 deflectors instead of hose. Fairly robust solution and seems to help, although I'm pretty gentle on brakes...

Try that in Texas, I dare you .....

[nostatic]

which, the deflectors or being gentle on brakes? Because its hot in Texas?

[DanS911]

Originally posted by jakermc
Try that in Texas, I dare you .....

I am using the 993 deflectors here in FLA with good success.

[jakermc]

100 degree ambient temp can be fairly common at MotorSport Ranch - Cresson during June, July, and August. I spent half my life in S. Florida and don't remember it being nearly as bad.

I think the deflectors are a great improvement and have experience with them as they are stock in my 968, but I would question their ability to cool as effectively at ducts pointed right at the rotors. A little bit of insurance never hurts (along with a light foot on the brake pedal).

[nostatic]

Forecast is 102 for this weekend at Willow Springs. The CA desert gets plenty hot. Ducts might be more efficient, but they also are less robust and more complicated. But whatever works...

[jakermc]

Originally posted by nostatic
Forecast is 102 for this weekend at Willow Springs. The CA desert gets plenty hot. Ducts might be more efficient, but they also are less robust and more complicated. But whatever works...

All true. But even if the deflector can provide enough cooling to avoid brake fade, my unscientific theory is that I will get longer pad life from using the ducts. Once I put a sleeve on the driver's side duct to protect the one spot that keeps tearing, they should be just as robust as any other solution.

[Bill Verburg]

100 degree ambients have little effect on brake temps that can go over 1000

There is no really good solution, a combination of scoops, ducts which surround the A arm, using as large a central front opening as possible, using internally smooth unconvoluted duct, using open faced wheels which pump air across the rotors, it all adds up.

Of course pads and fluid rated for the temp you are seeing are also prerequisites.

[sjanes]

Thanks for the feedback guys. FWIW, I'm not trying to fix a brake fade problem (I have S4 brakes on the front). I'm more trying to extend pad/rotor life with cooler temps. I think I'll start with a HomeDepot version of the SmartRacing manifolds and go from there.

[jakermc]

Originally posted by Bill Verburg
100 degree ambients have little effect on brake temps that can go over 1000

I was thinking about ambient conditions affecting track temperature. Hot track = less grip with the tires. When this happens you need to use more brake than on a cooler day.

It sure seems like I go through my brake pads faster on a hot day versus a colder one. Efficient cooling helps slow the process.

[Dixie]

Hot track = more grip.

[Bill Verburg]

It sure seems like I go through my brake pads faster on a hot day versus a colder one

You do, it's the last 100 degrees that the killer, not the first.

[JeremyD]

A-arm scoops??

[nostatic]

Originally posted by Capt. Carrera
Hot track = more grip.

in my experience it depends on the tire and how hot.

During the summer at Willow, I find that it doesn't take too many laps for my Toyos to go off. In general the 2nd run session of the day is fastest for a lot of people. By the 5th I'm at best running an equivalent time but working a lot more.

In spring and fall the track seems to get faster as the day goes on...but ambient temps are in the 70s or 80s.

In the winter, the engine is happy, but the tires aren't

[Chuck Moreland]

Originally posted by Capt. Carrera
Hot track = more grip.

That all depends. If you have trouble getting the tires up to temp, absolutely Hot track = more grip. But if you run at temp normally, then Hot track = greasy tires.

Run a little higher hot tire pressure and drive a little easier to bring the temps down, and/or run wider tires. And don't run full-tread depth.

[JoeMag]

Make the home depot version that goes on the a-arm, they'll work just fine. I've had mine on my car for 3 years (dedicated race car pretty low) and never had an issue. However my verion is simpler than clam shell type. Envision the plastic pipe below the a-arm bar. A-arm bar is red hot and you just push the pipe up onto the bar and melt a slot into the pipe until the top of the bar is just about above the top of the pipe. ...So essentially what you do is take the plastic pipe and cut a slot into it as would be in my melting example above. Hose clamp it on around dia of pipe (that's why bar is to just protrude over top of pipe), and rtv up the gaps around the bar. That thing is not going anywhere.

For the part of the hose that gets slightly sandwiched between tub, I wrap it with duct and aluminum tape.