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I know others have made or attempted to make front brake ducting before, but it's either for Series II (DIY Brake Ducts for a Series II - RX8Club.com), or self-admittedly half-baked or early ideas and then going to the Mazdaspeed Bumper (#GRIDLIFE Street Mod Time Attack RX-8 Build - Page 16 - RX8Club.com). While using the Mazdaspeed bumper would be nice, having to find one, wrap it, etc isn't in the cards for many. This thread will catalog my design process for adding front brake ducting to a Series I.
Initial idea is to use the fog light area and dodge around the oil cooler. I know Garrett made a 3D printed mount that went in the original fog light, but that limits to 2in intake diameter. I need to get parts in hand (and 3D scan them) before I can decide the path forward.
Close up of the Fog light area, and looking online, there does seem to be enough area to the side of the oil cooler to get a good size hose through there. Some folks have also cut holes in the radiator ducting, but obviously reducing flow in front of the radiator isn't ideal when it's already marginal on cooling.
View from the front. Looks like I need to clean up a bit here, previous owner put some tape in random places, and secure the lower plastic paneling.
Side view from inside the radiator ducting. I'll probably post this photo again with doodles of ideas.
Last edited by Tacit.Blue82; 01-08-2024 at 02:35 PM.
Reason: Adding photos and comments
A couple of things (caveat: I haven't made ducts for mine).
- ducting off the radiator area invites air to not go through the radiator, which could be detrimental. We know leaving the undertray off causes cooling problems, and 2 2+inch openings could as well. Especially assuming you want all the cooling you can get on track.
- the foglight area could be enhanced with a funnel that filly fills that corner of the opening, probably doubling the effective area?
- what about taking air from behind the oil cooler? It won't be as cold as fresh air, but for brake cooling the difference between 25C and 35C to cool a 300C disc is probably minimal? You'll want to make sure it's not creating a restriction that prevents the oil cooler from being effective, but if done well, I think this could work? Anyway that area is occluded from behind by the splashguard.
- Could you duct from behind the nose, where the intake sits? It's a high pressure area, you should be able to get positive flow without a ton of work.
@Loki I numbered your questions and provided my thoughts in-line and colored red, matching the number.
Q1:ducting off the radiator area invites air to not go through the radiator, which could be detrimental. We know leaving the undertray off causes cooling problems, and 2 2+inch openings could as well. Especially assuming you want all the cooling you can get on track. A1: Agreed, and I don't think this is the direction but has definitely been done before. Q2: the foglight area could be enhanced with a funnel that filly fills that corner of the opening, probably doubling the effective area? A2: This is definitely something I was thinking about as an enhancement over just the 2in fog light opening, watch this space. Q3: what about taking air from behind the oil cooler? It won't be as cold as fresh air, but for brake cooling the difference between 25C and 35C to cool a 300C disc is probably minimal? You'll want to make sure it's not creating a restriction that prevents the oil cooler from being effective, but if done well, I think this could work? Anyway that area is occluded from behind by the splashguard. A3: Without pressure (aka the ram air from forward motion), there wouldn't be much flow. Some, likely, if the fog light is removed, but little compared to a duct. It'll diffuse off the back edge of the bumper opening and fill the area but have less direct flow.
Q4: Could you duct from behind the nose, where the intake sits? It's a high pressure area, you should be able to get positive flow without a ton of work. A4: likely could, but I've not done any work on this car yet so I'm not familiar with that area and how things are shaped. I'll definitely look into it!
Some scanning I did of the fog light area exterior:
I'll probably take the bumper off and get the backside of it as well, and then take the fog light pod out and scan it in situ again.
a naca duct behind the bumper and pointed at the ground, and in the correct orientation will work. or run a hole saw through the bumper under the oil coolers
a naca duct behind the bumper and pointed at the ground, and in the correct orientation will work. or run a hole saw through the bumper under the oil coolers
NACA could work, but you don't have as much total pressure with that than you do with the forward facing scoop. (At work, we have used NACAs on undertrays/diffusers for component cooling in the past with success but that's basically the only option for some things).
Cutting a hole in the bumper is the nuclear option, and I really don't think it looks great. Right now I'm personally looking for a no-cut solution (minus wheel liners, I'm fine cutting those right now), and hopefully others will be as well since I plan to offer them if it's something thats in-demand.
It is also debatable whether they're necessary at all for that use case, but I've read/ seen multiple accounts of increased brake pad and rotor life with ducting, even if fade wasn't a problem, as well as been recommended by an experienced driver familiar with the chassis to add front ducting. Mostly this is a design exercise and an excuse to use the scanner and 3D modeling tools.
totally understand, thats great. we endurance race an 8 and did several races with no ducting of any kind, was fine. fwiw i do now have 3" ducts going to the front, but i dont run oil coolers so i used those openings. i work occasionally with a couple of ta2 cars and we run naca ducts from under the car for the rear brakes. works pretty ok
Now with a scan of the opening next to the oil cooler, and the scan with the bumper on without a fog light, I aligned the scans and we can move forward with the actual duct design.
The Shining3D Einstar. I've really enjoyed it so far, the software is decently easy to use, it has pretty robust tracking, and re-orienting itself. I've not had to use markers on any of the scans I've done so far.
To be fair, this could definitely be done with some Cardboard Aided Design, but learning the tools as we go here.
Last edited by Tacit.Blue82; 01-10-2024 at 06:41 PM.
Initial draft of what I was thinking for the ducting shown below, haven't done any work on the mounting yet, but this looks promising! I may try to take up less of the oil cooler's frontal area since on the Series I, it's not got a lot of exposed area anyway, don't need a ton of extra area for a 2.5in diameter hose.
Rear Isometric View Front Looking Back View Top View
I don't quite like the sharp turn that it takes initially, v2 will definitely have a better transition there.
Last edited by Tacit.Blue82; 01-14-2024 at 08:19 AM.
After working on some other scan projects for friends, and needing to grab the mount points from the backside of the bumper, we're back! With the new mesh, I kind of had to start over, but I realized better some of the tools in Fusion360 (I use different CAD programs for day job work, so it's sometimes hard to do something you want to do if there's no direct way to do it). I basically decided to take cuts at a few planes and Fusion has a nice Mesh Section cut tool, as well as a satisfyingly good "fit to mesh section" tool in sketcher. Ha, take that CATIA! I went about taking some cuts and giving them an offset, so I could build a curve in 3D to follow the back edge of the opening. Whats pictured isn't perfect, but should be better once I get all of the offsets in for section cuts. These offset splines will also provide good tangency points for guide curves for the neck down to the 2.5in hose.
01-08-2024, 02:20 PM
