More brake cooling. . . 993 air deflectors option?

Tom '74 911 · 01-05-2009, 09:45 AM

Hi -
I'm upgrading my brakes to 930 rotors and calipers and have been researching the various options for routing more air to the front rotors. One option that I came across is using 993 air deflectors with the deflection plates on the outside of the rotors - see pics of the 2 items below if my termonology isn't correct. Is the 3rd photo how the deflection plates would attach to my a-arms? Should this really be adequate?

Also, I do have an IROC front bumper w/provisions for brake cooling ducts and could easily buy or fab the required things to do it that way too. I've always wondered how much air really travels through a 2.5" or 3" ribbed hose with bends and twist in it - although I know that this really is the most used method. Sorry to beat a well beaten horse again.

Thanks,
Tom

Bill Verburg · Bill Verburg's Garage

w/ '78-89 930 size rotors you will have plenty of thermal capacity for most n/a 911s. Cooling won't be much of an issue and the 993 scoops works well, 996GT3 are even bigger but I haven't seem them used on an earlier 911.

You are right to worry about the volume of air moving through the small 2.5 -3 " ducts, it gets worse when they are bent and/or kinked.

efhughes3 · efhughes3's Garage

I believe Jack Olsen runs those on BBII.

lfot · lfot's Garage

I have the 993 deflection plates on my SC. I put them on after smoking my fronts a couple times. Never happened again after installing the deflectors, so I'm quite happy with them.

aston@ultrasw.c · aston@ultrasw.c's Garage

I run this exact set up on my 85 911. In addition I removed the rotor backing plates and I use PFC97 pads.

Since the mods I have not had any heat related issues.

Full on DE track days at 100F ambient.

lfot · lfot's Garage

Quote:

Originally Posted by aston@ultrasw.c

I run this exact set up on my 85 911. In addition I removed the rotor backing plates and I use PFC97 pads.

Since the mods I have not had any heat related issues.

Full on DE track days at 100F ambient.

Oh yeah... I should have mentioned that. You have to remove the dust shields in order for them to work properly.

JeremyD · JeremyD's Garage

I run these now on my 1987 Carrera - They seem to push a nice volume of air towards the rotors comparable to the a-arm scoops.

rfloz · 01-05-2009, 11:26 AM

I haven't had any brake fade in limited DE use at Streets of Willow (930 brakes w/ dust shields removed).

One down-side is that they hang pretty low - I have found mine cocked sideways a couple of times (probably from street use, driveways, traffic humps, etc.)

Still, the price is right and installation is a lot easier than ducting.

Tom '74 911 · 01-05-2009, 11:49 AM

Thanks so much for all the input - I appreciate the first hand experiences. Sounds like the 993 scoops are a good way to go.

Tom

vash · vash's Garage

i am stunned they work so well. i zipped tied mine one for ease. someone here welded on tabs and installed them "more properly".

KTL · 01-05-2009, 02:13 PM

Wow. I feel like a celebrity- that's my car in picture #3.

Like Bill said, with your hefty 32mm thk 930 rotor up front, you won't have much of an issue with brake fade, even without the scoops. But the scoops and blockoff plates (by the way, the plates go on the inside of the rotor like a one-piece washer under all the rotor bolt heads) are very cheap relative to brake pads and rotors. Any cooling you can get in there is going to extend the life of your pads and rotors even more. I say even more because when you do a brake upgrade, you'll find that your pads last much longer than the original pads do.

I used the scoops with my 993 brakes (JeremyD has these) and never had any sort of fade whatsoever. I've also had my share of off-course farming and soil testing, so I know for certain that the way mine are installed stay put- i've never had one come off yet.

Tom '74 911 · 01-05-2009, 02:16 PM

Kevin -
Thanks for loaning me your photo!
Tom

Jack Olsen · 01-05-2009, 02:48 PM

It depends on your car's weight and the amount of braking you're doing. I've never had a cooling problem, running 964/993 deflectors and ATE Super Blue/Gold fluid.

It's a total non-issue in street driving, but I assume you upgraded to 930 brakes because you track the car.

Tom '74 911 · 01-05-2009, 02:58 PM

Quote:

Originally Posted by Jack Olsen

It depends on your car's weight and the amount of braking you're doing. I've never had a cooling problem, running 964/993 deflectors and ATE Super Blue/Gold fluid.

It's a total non-issue in street driving, but I assume you upgraded to 930 brakes because you track the car.

Yup. I'm sure my driving technique could be vastly improved, but as I get faster and more aggressive (a very slow process for me) I am finding that I need to bleed my stock brakes at the track - at the very least between days, more would even be better if it's really hot. I could run more cooling to my existing set-up, but I have the pieces and parts for a full 930 upgrade that I bought last year. They also fit into my long term master plan for more power down the road too.

Tom

ninesixfour · 01-25-2009, 03:46 AM

I may try these 964/993 ducts. I have the brake cool kit now with the scoops that mount under the control arms then have a hose that attaches to a manifold on the rotor. Does anyone think the 964/993 ducts will work better?

efhughes3 · efhughes3's Garage

I'm making the same switch. I got the diverters, and when you set them in place, and look at the ducts, it sure SEEMS that they can deliver more air.

911pcars · 01-25-2009, 03:29 PM

Not sure I've seen a thread that addresses the following situation:

Granted, the 930 brake system is swell, and so are big reds. However, there is a massive unsprung weight penalty using the huge 32mm wide rotors at each corner. Bill, can you give us the comparable weights?

There must be a brake and air induction system combination that provides minimum unsprung weight offset by an adequate brake cooling scheme. This may be a YMMV situation depending on a lot of factors, but it might be something to consider for the more pragmatic among us.

Sherwood

Noel · 01-25-2009, 05:12 PM

With 930 rotors you should have no issues. However I tried the 993 diverteds on my SC about 5 years ago and I found the under A arm scoops worked better, which is what I still have on my car.

911st · 01-25-2009, 06:53 PM

Anyone have a picture of a 964 or 999 with the deflectors installed please?

Thx

ninesixfour · 01-25-2009, 07:05 PM

Quote:

Originally Posted by Noel

With 930 rotors you should have no issues. However I tried the 993 diverteds on my SC about 5 years ago and I found the under A arm scoops worked better, which is what I still have on my car.

That is not what I wanted to hear. I even have an IROC bumper I could run ducts from but the hose is so long and not straight it seems like not enough air will make it to the rotor.