posted on January 10, 2013 00:00
Project S2000 - Testing Track Upgrades and Custom Brake Ducts
By Khiem Dinh
Khiem Dinh is an engineer for Honeywell Turbo Technologies at the time of this writing. All statements and opinions expressed by Khiem Dinh are solely those of Khiem Dinh and not reflective of Honeywell Turbo Technologies.
All of the stars aligned a few weeks ago and I took Project S2000 to the track. Centerforce clutch and AP1 flywheel – installed and broken-in, Hasport engine mounts – installed and broken-in, custom brake ducts – prototyped and test-fitted, K.R.O.P.S holding track day at Willow Springs – scheduled, other MotoIQ project cars going – check. Custom brake ducts? Let's start with those.
I've been meaning to design some new brake ducts for a long time to replace my ghetto-ducts. I had two requirements: be easy to install quickly and be effective. Though I had no numbers to back up the effectiveness of my ghetto-ducts, I did track the car with and without the ducts on separate occasions. During a track day at Chuckwalla in hot 95F air temps with the ducts, the brakes seemed to remain relatively cool and no roasted pad smell. The track day last January at Streets of Willows in 45F air temps with no brake ducts resulted in some pad smell when braking down the main straight. So even though it was about 50F degrees cooler, it seemed the brakes were getting hotter without the ducts attached.
|While the ghetto ducts were cheap and seemingly effective, they were a bit of a pain to install. I zip-tied them on in three locations: front undertray, Whiteline subframe brace, and the bottom of the shock.
To meet the functional requirement of being effective at cooling the brakes, I decided to go with an enclosed tube design as the 2" tubing I used for the ghetto-ducts seemed to work just fine. To meet the requirement of being quick and easy to install, I borrowed the control arm mounting concept used on my old 2005 Evo and also used across Porsche’s entire vehicle lineup.
My old Evo and many Porsches use an air deflector mounted to the control arm to guide air towards the brake rotors. These guides poke down into the airstream beneath the car to grab air. The Viper and Corvette also have brake cooling schemes which duct air from the front bumper towards the back side of the wheels, though they don’t go all the way to the rotor.
|The Evo utilizes these little air guides attached to the front control arms.
|The Porsche GT3RS uses these rear brake ducts attached to the rear control arms. These rear ducts differ from the front ducts as the rears are fully enclosed ducts as opposed to just air guides. Photo from suncoastparts.com
Thursday, January 10, 2013 6:45 AM
Awesome well thought out mods, thumbs up!
Thursday, January 10, 2013 8:08 AM
Whoa Whoa Whoa. I get the whole CAD then solidoworks part but where did you send your designs to have them made in PC-ABS? How were they made? (3D printed, vacuum molded, spun, etc.)
That is such an awesome part of this site, I can't remember the last time I was reading about a "mild" project car where the owner just happened to throw in some fully custom parts that he whipped together.
Thursday, January 10, 2013 8:14 AM
Thursday, January 10, 2013 8:31 AM
The ducts look 3d printed - that they're made out of ABS is a clue too. I'm now pondering using my printer for similar on the RX-7, or at least doing that to make molds from for carbon. I'm preeeeeetty sure our brake temps are too high for ABS.
Thursday, January 10, 2013 9:39 AM
Any reason why the S2k would be abusing the rear brakes so much mroe than the 370Z?
@Kenku: The ducts won't see actual brake temperature. You could probably use ABS without issue...
Thursday, January 10, 2013 10:30 AM
@Protodad, I used a company named GROWit (growit3d.com). For this particular part, it's a 3D printer. There are various options for materials (ABS, ABS-M30, ABS-PC, etc) and they have material data sheets online for all of those. The price difference between those materials is pretty minor, so I went with the ABS-PC as I felt it best met my needs. FYI, it's pretty expensive.... but that's the cost of doing R&D. You trade cost for time and conveinence.
@kenku, these sit far enough way from the brake components themselves where I don't think it's an issue. And while in motion, there is always cool ambient air going through them. You could always wrap the outside portion of the duct near the brakes to reflect radiant heat. I always do a good cool down after coming off the track too (in addition to the cool down lap).
@HudsonMC, I imagine the stock front and rear brake temperatures on the S2k would show the same bias as the 370Z. Actually, follow the link to the Fluke Thermal Imager article and you can see the front StopTechs brakes heat up at the same rate as the rears. But the StopTechs cool down much faster. The stock front brakes should heat up faster than the rears because they have less thermal mass than the StopTechs. Therefore, I imagine the stock front brakes will be hotter than the stock rears like how they are on the 370Z.
Thursday, January 10, 2013 12:40 PM
Nice job on the ducts, those a sweet!
Thursday, January 10, 2013 12:46 PM
Thursday, January 10, 2013 3:01 PM
Another way to make a duct would be carve it all out of pink HD foam, cover it with fiberglass or carbon, vacuum bag or just wrap it tight and melt out the foam with acetone. Can do some pretty crazy shapes for cheap
Thursday, January 10, 2013 3:15 PM
I really enjoy your articles Khiem! When its not supplied by the aftermarket; make your own. I wouldn't be surprised if you get hit up to make more.
Thursday, January 10, 2013 4:27 PM
using a fdm abs print is handy. just watch for dimensional restraints. 12"x12"x12" volume is typical. theres also a balance of actual material used and support material necessary. for this particular application a fine resolution isnt necessary. other formats of 3d print can provide higher res or different materials but vary in cost dramatically.
Thursday, January 10, 2013 5:02 PM
@spdracerut: For the application I'm thinking of... in an ideal world, I want to seal off the whole center of the rotor, ala "real" race stuff - I suspect an EProd 1st gen RX-7 is a lot harder on the brakes than the S2000. Probably roughly similar weight, similar horsepower... but full blown slicks and only a 9.8" front rotor.
What I'm tempted to do is make a female mold out of FDM'd plastic, coat the inside with mold release, and fill it with expanding foam. Then the carbon-over-lost-foam trick. Nice thing about having your own FDM printer though, is the ability to play around a bit.
Thursday, January 10, 2013 5:46 PM
If you do a version 2, consider adding screw bosses or something similar to the body of the duct so a stiffer (aluminum, etc) mounting tab can be used instead of the ribbed ABS piece. This will also give some flexibility in mounting options, so different mounting configs could be used with the same base duct design. Single piece designs may be simple and elegant, but can often artificially lead you down a single path during the design and prototyping process.
There are some soluble rapid proto resins that are made for composite fabrication (as opposed to the lost foam trick), but they're pricey. Consider making a pair of molds in the traditional manner for hollow parts (and joining the duct halves together), which is the usual way to make a non-structural irregularly shaped tube. You'll have an outside seam (where the halves join) on the finished part, but that's a minor cosmetic issue. Actually, if you're clever you can easily turn a section of the seam into part of the mounting scheme similar to your prototype..
Great project, and make sure to post updates as things progress!
Thursday, January 10, 2013 8:27 PM
@Fabrik8, I was going for ease of getting a part as this was just a proof-of-concept, hence the 1-piece. If I do a second iteration, it will be with the intention to sell and it will be 2-piece with an aluminum mounting bracket and the duct attached to it with a mechanical fastener.
The downside to this concept of hanging low is that it can get ripped off if the car goes off-roading. So a 2-piece design will allow for just replacing the duct part as the mounting bracket should be undamaged in an off-roading incident.
I have some more custom stuff in mind.... and I bought a spare hood to chop up ;)
Thursday, January 10, 2013 8:30 PM
@SC, at my day job, we have a 3D printer. Our old machine had a relatively small build envelope. To build big stuff, we'd print in multiple pieces and glue them together. It was all just for visualization and packaging tests, so appearance didn't matter.
Thursday, January 10, 2013 9:08 PM
Nice thing is that there's getting to be some commercialized versions of the reprap coming out in a form that's like, a fully troubleshot kit for a grand and change. My dad and I got one of those; going to have to use it to make a copy of itself. Amongst other things, you can directly make patterns for investment castings - PLA, one of the major printable plastics, burns out pretty nicely.
Thursday, January 10, 2013 9:27 PM
There are some resins made specifically for investment casting too. =)
Thursday, January 10, 2013 10:03 PM
Probably, but even in my incredibly halfassed setup to see if it would work, PLA burned out perfectly. Or at least well enough to have thirty thou thick fins on an impeller. Really need to get a setup to melt aluminum built.
Friday, January 11, 2013 7:45 AM
3D printers really are getting cheap enough these days that they might become a staple part of any gearheads garage.
Need to fab a part, print it out.
Broke a random plastic tab, print a new one.
I can't count the number of times I would have killed to have access to that level of rapid prototyping while trying to make repairs.
Friday, January 11, 2013 8:22 AM
It's a different skill set from a lot of more traditional fabrication methods though; it's a lot different thinking out the whole part you need at once rather than forming it progressively from bits of whatever. The suckers take time too, at least on any of the cheap options. On the other hand, having more tools is always a nice thing. I may have to see how well mold release works on some printed plastic, come to think of it.
Friday, January 11, 2013 9:42 AM
Most mold release will likely work fine on printed plastic (I've done it before with a few types of mold release) but you have to have the normal attention to detail beforehand that would need on any mold. It looks like you're using fused deposition prototyping, which tends to have a fairly rough surface finish that will need fairing and sealing before mold release. The higher the exposed surface area (from a rough surface), the less likely the part will release cleanly. You'll have to figure out what type of products will work with that type of plastic to fill in the surface texture, etc. (body filler, Duratec primer, high build primer, whatever works), or it may just be a matter of doing some sanding and then passing a torch over the surface for a rudimentary flame polish.
Sunday, January 13, 2013 11:19 PM
Nice, I like what you did with the ducks(quack, quack). The big old heavy GT-R's need some brake cooling. With the front mount caliper, axle running though the center of the rotor, its tough to get air in.
Monday, January 14, 2013 12:27 PM
So, the cover photo is a screen capture from a GoPro video. Where's some on-track vids?! ;-p
Monday, January 14, 2013 9:00 PM
@Rockwood, page 6 foo!
Wednesday, January 23, 2013 9:04 PM
Great job on brake ducts, I want a pair! But really you are doing such a great job with the whole project. I really like the cause and effect. You have a problem or see room for improvement and find and implement a solution. Then you test and document change. I do not see that done anywhere but here. There is so much bolting on crap cuz it looks good or an Asian chick with a mini skirt is selling it to you. Kudos to the whole project!
Sunday, January 27, 2013 5:45 PM
I called Fluke a while ago and they did confirm the Raytec MT-6 is the same as the Fluke, at a bit lower price.
Ducts are pretty awesome. I'd totally buy a set if they were for sale! I doubt the 3D printing is cheap, though. Any interest in sharing the CAD file?
Wednesday, January 30, 2013 8:43 PM
Khiem, Buddy Ole Pal, as I think about this installment something was bothering me. But what was it??? You started in part 1 working in your driveway. You were the friend of the shade tree weekend warrior. What you did any guy could do with simple tools. Your installments have been a road map for many, I know they were for me. Now you have left us to that league of pro racers who transform their cars with custom made parts using tech not available to the average guy. In short I liked the old ghetto ducts better because I could have these and they worked. I do not have much interest in looking at mods that I can never have. Sorry you left us.
Wednesday, January 30, 2013 10:04 PM
@uberthin, the 3D printing was cost a pretty penny. If everyone knew how much, they'd say I was crazy. But that's the cost of doing development work :) And I need to make changes to the design to eliminate the clearance issues and improve fitment.
@DaGou, Phase I was the trackable, reliable, street build. Phase 2 is the weekend/track car build along with some of my own design/development work :) I got some more cool custom stuff in the works. Well, in my head at least. I haven't found time to do the actual work yet.
Wednesday, January 30, 2013 10:04 PM
Oh yeah, the intent of the custom stuff is to possibly make it for sale if I can get the capital.
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