urfsin Posted October 15, 2009 Share Posted October 15, 2009 Ok boys and girls, I was busy this last weekend working on my homebrew ghetto fab brake ducts and I wanted to share. Before we get to the pics, I want to answer some questions... WHY? Because I have been to the track a few times and each time I have had problems with the brakes. The first time I had a street pad (I did not know any better) and I melted them. The second time, I had race pads, but I generated too much heat in my rotors they cracked. COST? Well lets see here....about $30 in parts / supplies from Home Depot. WHY HOME BREW STYLE? 1st off, I am a cheap SOB and I did not want to buy a kit. Plus, I don't event think on there is one on the market anyway. 2nd, I like to engineer my own stuff and make it a reality. On to the pics. http://farm3.static.flickr.com/2606/4013234538_00ec136c53_o.jpg Here is an overview of it. As you can see, 3" flexible dryer ducting is feeding the air to the brakes. I cut the stock dust shield back to make room for the hose to feed cool air to the rotors. http://farm3.static.flickr.com/2639/4012466609_ece55f3c66_o.jpg Here is a closer view. http://farm3.static.flickr.com/2663/4012466861_a9cf8db7fc_o.jpg This is how I attached the hose. I used the ABS sensor for the lower mounting point. I added a washer to the bolt to help clamp down on the hose wire. This point is very secure. When I cut the hole in the dust shield, I cut it in four sections and left some material in place. This formed 4 tabs. I bent the tabs back and mounted the hose to those tabs. On the uppermost tab, I drilled a hole and used a zip tie to secure the hose. http://farm3.static.flickr.com/2453/4012467041_4a2fe269c2_o.jpg Here is a close up of the intake. Now remember that I have an Outback XT, so my fog light holes are HUGE. Like 6 inches across huge. The hole that collects the air 3 1/2 inches wide. I used a piece of roof flashing for the collector and cut it to size. I used the stock holes for mounting, so if I want to put back my fog lights, no problem. http://farm4.static.flickr.com/3484/4012467199_6349ea3d12_o.jpg Here is a wider view. On the left is the brake ducting intake, on the right is the stock fog light. Slide It Sideways Link to comment Share on other sites More sharing options...
StoplightAssassin Posted October 15, 2009 Share Posted October 15, 2009 Nice work. You were having the overheating troubles on road courses or rallyx? Link to comment Share on other sites More sharing options...
urfsin Posted October 15, 2009 Author Share Posted October 15, 2009 Road course. I don't rally the Outback any more, I have a beater 2.5RS for that now. Slide It Sideways Link to comment Share on other sites More sharing options...
RochNY91TSI Posted October 15, 2009 Share Posted October 15, 2009 I like the effort! One suggestion though; you may want to lessen the bend where it goes down to the dust shield. Seems like a pretty extreme angle right now Link to comment Share on other sites More sharing options...
urfsin Posted October 15, 2009 Author Share Posted October 15, 2009 Yeah, I am in the testing phase right now. I have been driving around with this so far and I need to change the ducting route a little. Right now when the wheel is at full lock, the tire rubs and smashes the ducting. I am going to drive around a little more and see if I wear it down. I think I may have to route the ducting down lower by the A arm. We will see. Slide It Sideways Link to comment Share on other sites More sharing options...
schwinn Posted October 21, 2009 Share Posted October 21, 2009 Cracking rotors? Were they drilled or slotted? Hopefully not drilled, because that would be the problem right there. Slotted might be ok, but I'd say stick to solid-rotors instead. I don't think cooling them more heavily will help your cracking problem - the sudden temp changes are what's causing the cracking, and this ducting could make it worse. From what I can see, you need to get the air onto the center, so that the vanes can do the work, but that still may allow for too large a temp-gradient and leave you cracking rotors again. The key is, too much temp gradient = cracked rotors. A few notable threads I googled on the matter: http://forums.nasioc.com/forums/showthread.php?t=1615082 http://forum.miata.net/vb/showthread.php?t=27373 Link to comment Share on other sites More sharing options...
urfsin Posted October 22, 2009 Author Share Posted October 22, 2009 Right on, thanks for the links. Yes, the rotors that cracked were slotted and drilled. I am running just straight blanks for my track rotors now. As for air getting into the center, I tried my best to rout the hose to a spot where it could do that. The only way I could make it better would be to buy a kit from another car and make it work on this car.....but that goes against the spirit of the whole project. Slide It Sideways Link to comment Share on other sites More sharing options...
schwinn Posted October 22, 2009 Share Posted October 22, 2009 Yeah, drilled rotors are not recommended by anyone for track use. Brembo's pages usually say this, though other brands may not. Drilling is for looks, and that's about it. The only cars that use drilled rotors in RACING are those that use special ceramic rotors, etc... those holes are not "drilled" at all. Again, I don't think ducting is needed... what you need are good pads. Are your pads fading? If not, then you don't need cooling. Link to comment Share on other sites More sharing options...
urfsin Posted October 23, 2009 Author Share Posted October 23, 2009 My pads at the first event were Axis Ultimate's. They lasted all of three 20 min sessions on track. About 5 min into the fourth 20 min session we all had to pull off the track due to an "off" of another car. I noticed smoke coming out of my front wheel wells, so I got out and look at my brakes. They were toast. The funny thing was, there was only a little brake fade with those pads. They just wore down super fast. Then I decided to go with some dedicated racing pads. I did not feel like spending big bucks so I went with EBC Yellowstuff. They held up great and I had ZERO fade for the whole day. I did something like Eight 20 min sessions with out any braking problems. On my way home at the end of the day I noticed some pulsating from my rotors, almost like they were warped. Only that it was happening when I was NOT on the brakes. Also, problem only got worse when I applied the brakes. I was only about 1/2 mile from the track at this point. I pulled over and upon inspection I noticed that I had some cracking in one of my rotors. So I said enough was enough and I did the whole brake duct thing. So yeah, I think I need some cooling. Slide It Sideways Link to comment Share on other sites More sharing options...
GTS Jeff Posted October 23, 2009 Share Posted October 23, 2009 Nice. A ton of people do this sort of shiet and it always seems to be a worthwhile mod. Link to comment Share on other sites More sharing options...
Saul_Good Posted October 23, 2009 Share Posted October 23, 2009 Ursfin we need to hit the track up when i get back. Link to comment Share on other sites More sharing options...
AZP Installs Posted October 23, 2009 Share Posted October 23, 2009 If you track a lot, ducts are KEY. I have been too lazy/busy to actually make some for mine but it's in the works over the winter. -mike Link to comment Share on other sites More sharing options...
caramall2 Posted October 24, 2009 Share Posted October 24, 2009 Thanks for the pics and write up...I've wanted to do this but just haven't had the time and who knows when I'd get to it....I have the hose sitting in the garage. Would be nice to see rotor temp differences at the track. I'm sure it certainly helps. Link to comment Share on other sites More sharing options...
maxjlone Posted October 24, 2009 Share Posted October 24, 2009 Yeah, it might. If it is a problem, I will just use another small bolt, nut and washer on the top end. _________________ Are You Paying More Auto Insurance Than Your Neighbour? Click Here And Save! Link to comment Share on other sites More sharing options...
schwinn Posted October 24, 2009 Share Posted October 24, 2009 If you track a lot, ducts are KEY. I have been too lazy/busy to actually make some for mine but it's in the works over the winter. -mike Although I don't think ducts are necessary, AZP/mike is more accurate with his statement... it all depends on how much tracking you do. I figured you weren't doing that much tracking because you started off with drilled rotors and non-track pads... both imply you haven't been tracking much at all... which is why I am saying you need to get the right brakes first, THEN think about ducts and such. Link to comment Share on other sites More sharing options...
AZP Installs Posted October 24, 2009 Share Posted October 24, 2009 Although I don't think ducts are necessary, AZP/mike is more accurate with his statement... it all depends on how much tracking you do. I figured you weren't doing that much tracking because you started off with drilled rotors and non-track pads... both imply you haven't been tracking much at all... which is why I am saying you need to get the right brakes first, THEN think about ducts and such. Agreed. Upgrade to at least HP+ pads or higher and smooth rotors before getting all crazy with ducts. They will also only be effective on track since on the street the cooling effects will be negligeable compared to the total heat you will be building in normal driving. If you are in bumper to bumper traffic, you will build heat, but won't have any air flow to cool them. On the highway you won't build any heat but will have the air flow. On track you will build the heat due to braking for turns, but will immediately then have air flow from the straights. -mike Link to comment Share on other sites More sharing options...
magnetic1 Posted October 24, 2009 Share Posted October 24, 2009 If you are in bumper to bumper traffic, you will build heat, but won't have any air flow to cool them. On the highway you won't build any heat but will have the air flow. On track you will build the heat due to braking for turns, but will immediately then have air flow from the straights. -mike Agreed with Mike. And if you dont use the proper pads on the street, you could end up overcooling. I always tell people to have separate pads for street and track. Ducts on the track will also prolong pad life, but for a street car, brake ducts are a little overkill. Unless you are using some really crappy street pads or are riding the brakes, you shouldnt have them overheat. Free Sonax Cleaner Deal http://www.brakeswap.com Carbotech, Hawk, PFC, DBA Rotors, Motul, Wilwood, Castrol... Great service. No bumping required ! Link to comment Share on other sites More sharing options...
coSTIgan-GT Posted October 25, 2009 Share Posted October 25, 2009 Check Ebay. You can find used NASCAR carbon fiber brake ducts and blowers for cheap. Link to comment Share on other sites More sharing options...
SubyShop.com Posted October 27, 2009 Share Posted October 27, 2009 Have you used a pyrometer to check brake temps before and after the ducts? Curious to know what kind of temperature difference you're seeing with the ducts. I have not had any rotors crack yet even in braking zones from 130+ MPH, knock on wood. I still might look into making some ducts next season. -Franz Link to comment Share on other sites More sharing options...
GTSpeed Posted October 27, 2009 Share Posted October 27, 2009 Did this on my 1994 MX6 when I was in high school. Made a funky whisteling sound around 50 miles per hour. Link to comment Share on other sites More sharing options...
schwinn Posted October 28, 2009 Share Posted October 28, 2009 A fellow MX6-er, huh! I had a 93 MX6 until I got this LGT... what a difference! I didn't do brake ducts on that car either, of course... but pads and struts and springs - what a difference! Still kinda miss that car... Link to comment Share on other sites More sharing options...
urfsin Posted December 11, 2009 Author Share Posted December 11, 2009 It's been a few months since I put these ducts on and I am here to give y'all an update: Problem #1 When my front wheels were @ full lock Left and Right, the inside of the tire would rub and crunch the ducting. This is not a big deal on the track as you don't see full lock very often if at all, but it's an easy fix. Solution: Just re-rout the ducting to give my wheel more space, not a big deal. The only drawback is that the ducting will hang a little lower to the ground (should not be a problem on a smooth track, but could be a problem on DD aplications) Problem #2 These ducts are NOT to be used for more than a weekend of driving. They are NO BUENO for daily driver application. I wanted to test the durability of these ducts when I installed them. They had been on the car for a few months and I did not have any problems (other than the rubbing). I went on a road trip over the Thanksgiving weekend and I had intended to take the ducts off. Well I got lazy and did not do it. Needless to say, the road trip was too much for the ducting.... It ended up tearing (remember, this is just cheap dryer hose ducting) and it got caught up on the front axles, both sides. The ducting hose and wire was all wrapped around the front axles and it was a big god damn mess. I ended up busing out my dremel cutting tool and going hog wild on the axles to cut off all the wrapped up ducting and wire. It was a PITA, but there was no harm done to the axles or the CV boots. In the end, I got lucky. Solution: Don't DD with the ducting in!! It should hold up fine for the weekend at the track. It should even be fine for another week or two after that. But don't wait 2 months to take it off. Slide It Sideways Link to comment Share on other sites More sharing options...
KartRacerBoy Posted December 11, 2009 Share Posted December 11, 2009 Thanks for the report. Sucks to be ducts! Link to comment Share on other sites More sharing options...
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