I was an early user of the Ntech duct kit, and early this year I tore off the fiberglass duct, as it rubbed the shock while turning. Also, it's forward facing connection to the flex hose is a poor design. The hose needs to make a 90 degree bend immediately, meaning that when turned, it must bend to about 135 degrees! I'm working on a better solution.

Here is a pic showing the scuff marks and the angle:

 

Try routing straight like I did to eliminate the bend. It should work for you if you don't run alot of negative camber. I run -3.0 in camber and with a 3" hose it will rub when turning the steering to full lock. A 2" hose did the trick for me with the camber I like to run.

As for my homemade kit I haven't had any problems other than the 3" hose rubbing on full steering lock (2" hose fixed that). I have run 4 track events and other than my brakes not overheating drastically I haven't had any warped rotors or any other problems.

 

Rednezz, what kind of camber plates are those?

 

I am running the 350Evo camber control arms in the front and the SPC toe bolts in the rear.

 

rednezz,
Your design definitely looks more effective than the Stillen kit, which appears to be pointing at the inner caliper half...which really isn't very effective at all! I haven't had the need for ducting on my personal car, and we don't make duct kits through StopTech. Therefore, I haven't experimented or thought too much about how to get it done. Let me know what you find through experimentation. When I get back from vacation I'll have to talk to my Engineering Mgr. and see what he recommends. He surely will be able to give a few pointers. Thanks.

 

any thoughts from your engineering folks?

ahm

 

Well, I'm an engineer. Unfortunately I'm the wrong type and I'm just getting into tracking cars. I can point out some observations, however.

1. I don't know the sensitivity to differential cooling between sides, but I can see that it may be a problem.

2. If you wanted to evenly cool both sides, I would think your worst bet would be to aim the duct outlet at the edge of the disc. If I understand correctly, most discs have their vanes designed to pump air from the center outwards. So you'd be trying to blow cool air into an area that was blowing hot air back at the duct. I'm not sure how practical it is to get cool air to the center of the disc, but I would try to take advantage of this action. If, on the other hand, I'm an idiot and the vanes pump to the inside, then aiming at the edge could be the best thing to do. You want to provide a larger amount of cooler air wherever the disc pumps from.

3. I have the Brembos with ATE Super Blue and Hawk HP+ and have had them fade in all 3 track days I've run, so this seems like a good thing to pursue.



uwaeve

 

here's a thought...

instead of one 2.5 inch hose, aimed at one side of the rotor, why not use two smaller diameter hoses (say 1") and split them at the wheel so each blows on each side of the rotor. You'd have to fab a bracket to accomplish this... but it solves both problems I think... and I agree with they guy who mentioned the fact the vented rotors are designed to allow hot air to escape out of the rotor, not to allow cool air in

Main issue with this would be clearance with the wheel, I know... but again... just a thought

 

how can you blow on each side of the rotor without your wheel spokes getting in the way? 1 inch is too narrow IMHO. you'll need way more airflow than that to cool off something that gets as hot as rotors do.

always vent toward the center of the rotor from the inside,

 

Like I said... it was just a thought... I think when you're talking street wheels, it probably can't be done... with a real wide race wheel, maybe

I personally think you'd be better off cooling the caliper, but then you're talking even less clearance

To be completely frank with everyone... I think brake ducts on street driven and HPDE driven cars is a band-aid fix for possible poor braking technique or inadequate brake size (althought I certainly won't fault anyone for doing brake ducts while saving up for a StopTech BBK)

 

just another observation to add to the mix...

through repeated track use (and probably abuse), my once beautiful gold brembo calipers have changed color to a crimson. this change due to the heating (burning basically) of the caliper paint.

strangely enough, the discoloration is happening only on the OUTER half of the caliper and not the inner half. by means of my brilliant deduction, it would seem (at least based on this single data point of evidence), that the inner half is already cooling better than the outer half.

while adding cooling cannot be a bad thing, it seems like the bigger problem is on the outer (and therefore unreachable by cooling) half. it also seems like this helps dispell the rumors of problems with uneven cooling in to out.

then again, i'm just guessing...

sean

 

Sounds like you've visited our favorite Miata/High Speed Go Kart Track in Loudon?

 

A 2 piece rotor like those from Stoptech does pump air out between the 2 pieces of the rotor. In order to cool both the inner and outer sides of the 2 piece rotor you want to get air from the duct into the center opening of the rotor. Because of the suspension it is difficult to get the duct to point directly to the center of the rotor. What I did was use a 3" duct and cocked it at an angle to get part of the airflow stream from the duct into the center of the rotor. I tested this by blowing compressed air with smoke from a smoke machine into the opening of the ducts in the front of the car. I then turned the rotor to make sure I was getting the part of the air stream into the rotor opening. In the picture I circled the rotor opening and drew in the air flow to show how the duct needs to be cocked.

 

FYI

I was looking over some old web sites I frequented and OG-Racing sells the brake duct tubing for $0.25 an inch or $3.00 a foot.

http://www.ogracing.com/eshop/home.asp?categ=21

Also who made the brake ducts that are in Chebosto's pictures. Thanks.

 

What he said! I'd like to buy a set. I'm not happy with the set I have.

 

how much of an effect do you think routing a 3" brake duct hose from the grille to the inside of the wheel area would do? (I'd point the hose at the interior of the rotor, but from farther away than the previous pics...it'd be more to increase general flow of cool air into the area and would probably not cause any disproportionate cooling between the rotor sides) From how it looks, there's not much air flow directed into the area, so just by adding a duct, the air flow would increase considerably.
-it'd also be much less time invovled.

*Where'd you get the air flow for the rear rotors?


what do you guys think?

 

Technosquare Custom Job,

if u supply the old cust cover from the front suspension, they can make it for you--

just call them, ask for Richey. ask for the 350z Race Car (grand am car) brake ducts..

 

Thanks Cheston for the connection. I wonder if my backing plates could be used as I had to cut them up to fit my Stoptechs. Then again, new ones shouldn't be too expensive.

 

If you wanted to just get more air into the wheel area I wouldn't even put any duct. I would just cut a hole through the same places I ran my duct. In the grill and the splash guard. That would allow alot more air to flow to the wheel area.

 

oh...I didn't realize you had to cut the splash gaurd...my Z is leased and I'm trying to find a non-permanent solution. I was thinking of piping air from the front grille (which would divert some of the air intended for the radiator) to the wheel area.