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Posted by: c/s914 Dec 29 2017, 01:32 PM

So I just fibreglassed in some brake ducts into my front bumper and realized after I did a test fit that they are counter cross-eyed (wall-eyed?) as the Sherdian bumper is angled inward slightly on the sides:

But as I was getting ready to cut the ducts back out too redo them ...I had an epiphany of sorts?

Except when something is spinning around in front of us, every time we brake on a racetrack it's before a corner. So wouldn't it make sense to have the duct orientated towards the direction of the car after we release the brakes for maximum cooling? Additionally there would be less drag on the straights if the cross section of the hole is more oblong? Yeah I can sell that in the paddock, right?

Besides the car car looks wider and meaner this way too, ha!

S.Chapman

Posted by: wndsrfr Dec 29 2017, 04:53 PM

Geez your car looks so good....run it like it is & enjoy. Where did you source the headlight delete hood?

Posted by: c/s914 Dec 29 2017, 06:22 PM

Thanks, unfortunately I'm not sure who makes it as it came with the car when I bought it from New Mexico.

BTW now that I've upped my power, I find myself braking longer/harder and cooking my brakes ...funny that? Here's a pic without the ducts added:


Photo courtesy of Kevin Doubleday

Stacy

Posted by: wndsrfr Dec 29 2017, 09:44 PM

What brakes are you running? I converted to Wilwood & use Porterfield pads--they're huge 4 3/4" stocker size...Calipers only weigh like 3 1/2 pounds & replacement rotors are $35....hard to beat. I've got both the ducts and scoops mounted to the A-arms & have no trouble with fade....prolly because I'm not working the car hard enough....

Posted by: c/s914 Dec 30 2017, 09:58 AM

I'm running 911S calipers, cryogenic Frozenrotors, Tilton bar, Hawk DTC-70/60, and Castrol SRF. Incredible initial bite, awesome braking, good feel, countless seasons on the same rotors, and without any ducts no fade until I switched from a 3.2 to a 3.6L engine...

That being said I've always wondered if there was better performance to be had? Is there a thread anywhere comparing weights, a part number list, what to use for a master cylinder, etc...? Gotta say love the look of the race parts, that alone might be enough to get me to switch ;v)

Photo courtesy of Harold M.

S.Chapman

Posted by: Krieger Dec 30 2017, 11:37 AM

Some guys have better luck with Mogul brake fluid.

Posted by: ablesnead Dec 30 2017, 12:09 PM

Try Motul 660...With air ducts to your rotors consider titanium backing plates ...their resistance to heat transfer buys some time for the heat to be removed by the forced air from your ducts , before it can heat the fluid in your calipers

Posted by: c/s914 Dec 30 2017, 01:35 PM

After my first session with my new found power I noticed some extreme radiant heat when checking tire pressures, so I jacked up the car expecting a stuck caliper ...but everything rotated freely. As I had no fade I went out again after lunch but had to back off my rear brakes a notch to keep from swapping ends going into T1

The SRF held up fine, but I melted every gasket and o-ring in the calipers (which the titanium plates would have helped) and turned my front Hawks to dust. Cooling these rotors off is definitely the first thing I got to do!

BTW these would be nice if I could find them cheap enough:


S.Chapman

Posted by: ThePaintedMan Dec 30 2017, 02:13 PM

Also consider ducting directly into, or at least at the calipers. That's what I did, similar to Racer Chris.

Posted by: stownsen914 Dec 30 2017, 08:36 PM

I think S calipers are probably not enough for a 914 running wide slicks and a 3.6, even with cooling. You could look into getting some Boxster calipers, or maybe some Wilwoods. I have Wilwood Superlites on my car, and they have served me well.

To your question about the duct orientation, I'd guess that ideally they'd be pointed straight ahead, but as you noted the incident air won't be flowing straight at that location on the car, so maybe it's hard to say what would be best?

Scott

Posted by: Krieger Dec 31 2017, 11:00 AM

You could add in some plastic or fiberglass "eyebrows" on the outside of each opening pretty easily.

Posted by: c/s914 Dec 31 2017, 02:19 PM

A brake upgrade is probably in the future, but unless I get up to Mosport or something ...our little track http://www.atlanticmotorsportpark.com seems to be easier than usual on brakes?

I'm confident that providing some air to the brakes will fix my problem as I did have some cooling before when I bled the air coming in the front centre grille through cutouts in the inner fenders (...without any ventilation directly to the centre of the rotors using something like those carbon fibre pieces). But when adding the front cooler required for the larger engine I chose to exit the air out the hood as sending hot air towards the brakes didn’t make sense ...and probably more importantly I didn’t care for having those hot rotors exposed while refueling!

As for adding “eyebrows” I’d ruin all that work I did to create a 935 style opening ...I mean anybody can cut a hole in a bumper, but can they say that to get the shape right (albeit a bit crooked) for a mold they used a toilet bowl floor gasket on their Porsche

Stacy

Posted by: jmz Dec 31 2017, 04:40 PM

I have a set up 993 TT brakes (Big Reds) that I took off of my car when I switched to 15" wheels. Brakes are in great shape including the front rotors. I kept the rears.

I'm not sure but I think market value is around $2,500 or so... I'd need to double check that I guess but if you have any interest let me know.

Posted by: campbellcj Jan 2 2018, 01:51 PM

I agree you may be under-braked for that car/tire setup - I'm only running a (race) 2.7 but went with Carrera wide-A calipers and vented rotors, Pagid pads, usually Endless or Motul comparable race fluid. Then later i added the Smart Racing Products duct backing plates similar to those ones shown above, except metal, and high-temp duct hose to the front spoiler inlets. I'm usually running ~10" Hoosier radial slicks on 8's and 9's.

The main issue I have is I need to remove the front spoiler to get the car on/off my current trailer, and that has become a significantly bigger PITA with the ducts installed. Also the duct hose is too vulnerable with this routing and it's expensive stuff. But, zero fade and excellent performance once this setup was all sorted.

Posted by: c/s914 Jan 2 2018, 07:31 PM

Currently I can out brake every car in this picture going into turn 2 except for the Wolf (...doesn’t mean that at least a half dozen of these cars can also outrun me everywhere else though, ha! )

Picture thanks to Kevin Doubleday

During the odd “both feet in” situations I have been known to momentarily lock up the fronts but can quickly regain the threshold point, so they seem pretty dialed in (with no fade when I ran some air to them from the front grille) ...and except for the afor mentioned front brakes failing and a very scary right rear lockup going over the hill at T1 (Villeneuve corner, as it is where Gilles dumped his Formula Atlantic in ‘77) I’m quite happy with the balance in the rear, although someday I may try some DTC-70’s back there and keep adjusting the tilton bar up to see if I am leaving anything on the table now that I’ve gone to a non-square setup?

So if I were to upgrade i’d hate to lose the feel, that crazy hard initial bite, and maybe an unsprung weight advantage (A 911s caliper probably weighs more dry, but do the wilwoods extra fluid capacity make them weigh more? ...not to mention the larger rotors must be heavier?)

...But as I develop the car, or start going to other faster tracks I’m sure I’ll be eating my words and back on this forum looking for the best setup

Stacy
Edit: PS when I said that I now have more power with the 3.6, it’s probably not that much as my 3.0L punched to 3.2 was also race built ...but with a very narrow power band, and this new engine is stock except for headers and a chip. Additionally I put the car on a diet and I’m 200lbs lighter now too despite this heavier engine

Posted by: wndsrfr Jan 3 2018, 09:09 PM

Doubt the fluid adds any appreciable weight....certainly less than the pads themselves....
Here's a link to the rotors that I'm using....8.1 pounds but the aluminum "hat" that it bolts to is probably another 1 1/2 pounds....
http://www.wilwood.com/Rotors/RotorProd.aspx?itemno=160-0471

Posted by: stownsen914 Jan 4 2018, 07:38 AM

Wilwoods are pretty light. Choice of rotors is probably the bigger factor in weight gain as suggested. Bigger brakes will surely improve your braking experience, even if it only eliminates the overheating. Just don't go overboard. It doesn't sound like you need big reds and 13" rotors and the weight that would come with them. I recall that a common bolt on upgrade is Wilwoods in front with Carrera 3.2 rotors (I forget which rotors you said you're using, you may already have these). At the rear you could probably use a little more stopping power too if you upgrade the front, but it doesn't need to be as big as the front. You might try to find a way to use your current front caliper on the rear? You'd need to pay attention to the brake bias if you run "mismatched" brakes. Wilwoods come with different piston sizes, and * I think * the 1.375" size allows you to keep the stock brake bias using early 911 rears. Or possibly buy something like a set of older Boxster or 944 turbo brakes (all four corners) since they'd be matched.

Scott