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Downforce radiator duct? {new style}

I'm looking. Since DF site is down its not easy to find. This attaches directly to the radiator fan and curves upward out the hood vent.
You can contact Downforce directly but they seem to be very busy. I just ordered a engine cover from them recently.
This one? I think it's called the DF-R hood duct. They have one for the RHD as well.


  • DF-R Hood Duct.jpg
    DF-R Hood Duct.jpg
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I have this and it is VERY effective, I mean it funnels all the air right through the radiator and hood vent. When the fans kick on, it's incredible the heat that comes out of the hood vent.

The nut and rod that hold it on mine came loose. I used some JB weld on them and now it's rock solid.
I've always wondered which one helps produce more downforce (no pun intended!)

The DF duct looks very efficient but it also looks more restrictive if wind was flowing thru it.

Compare that to the factory NSX-R unit which has more surface area.

Yeah I dont know I am with you on this one Ryu, I wonder that as well. The factory one is very flat, the downforce one has a very nice curve to it guiding air up easier. It also seals much better against the hood. There may have been other non-performance considerations given to the OEM unit. Not everything OEM does is for pure performance, they have many other things to consider.

Anyway the DF one seems to work well. I think you can still get these from Downforce. Just contact Thomas. I'd get the FRP. You really have to like CF to get one you can barely see. And this weighs nothing anyway.
David does REALLY like carbon ;) you should see his interior, carbon headliner and all!
David does REALLY like carbon ;) you should see his interior, carbon headliner and all!

LOL... is he the type that will dump his girlfriend if she confuses Carbon Kevlar with Carbon Fiber? :biggrin:
how many people are actually running a vrh tank in the front?
I want a duct that will fit in front of a VRH tank. Any of you guys running a VRH with either this or a NSX-R unit?

There is no way a duct and a VRH tank will both fit there. I can tell you that for sure. Maybe one or the other but not both.

The best place for a VRH tank is hidden in the rear 1/4 panel down low and by the bumper. But you need a special sized tank for that. Ravi's done that before. I seperated my tank and compressor. Tank is going on the right side of trunk where the CD player used to be. I don't like the left mount side as you lose your ability to store a spare tire in there. My compressor is on a custom mount welded metal bracket I had fabricated at a shop, inside the right rear 1/4. It is sheilded from the elements, and I took some care to make sure it is stable, secure, vibration free, and fully waterproofed. It is a hot item. I don't like it in the trunk where you can burn your hand or targa top on it. Right now where it sits it is well ventilated.
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I need to do some volume calculations but i'm hoping to get by with a 1-3 gallon tank. Even two 1-gallons strategically placed should work. I'm building a custom VRH setup of my own anyway for the front only so I won't need a 5 gallon massive tank.

Ideally i'd like to put a tank next to my Oddysey battery on the battery tray. Still lots of room under there once the massive OEM batt is removed.

I am not an engineer, but here are my "thoughts".

The DF donut is as efficient as the OEM radiator shield allows it. And the OEM radiator shield does not cover the entire radiator - both sides of the shield remain open for air flow which means the two sides of the radiator are still pushing air albeit into the front spare cabin. I "therefore suspect" the Type-R is more efficient in capturing more air out of the radiator.

Having said this, I think a small size VHR and a Type-R (LHD version) or Dali typr radiator duct can work. I say this because I trimmed and slightly modified the Dali duct to meet my needs for a dual Spal fan encased in a radiator shroud. I had to trim the side edges as well as the bottom front lip of the duct.


From the pictures, you can see that there is about 3" gap from the back of the radiator duct to the spare tire bracket. By securing the duct to the spare tire bracket and then cutting the bottom curve of the duct to accommodate a VRH you might be able to pull this of. But do recognize that the VRH will be exposed to all the heat coming through the radiator; it gets hot in there!

I have actually been contemplating of securing the duct to the spare tire bracket to give me more of an upward tilting angle for the front (you have the tire bracket bolt as well as the rubber piece hole to use) which also makes removing the duct much easier than the two bracket it now has. HTH
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Regan, you might be able to fit a tank behind the DF duct. I'm running a regular battery, and Mike said that my tank was just barely unable to fit. I ended up relocating the battery.
Downforce has one too. But isn't this for RHD only?
I have this one from Dali. I have it setup very nicely and solid.
I'm not comitted to changing just yet but I'm more of an impulse buyer. If I found one priced right I may get a bit weak in the knees and push the "Pay now" key.:redface:
Regan, you might be able to fit a tank behind the DF duct. I'm running a regular battery, and Mike said that my tank was just barely unable to fit. I ended up relocating the battery.
Ah, that's right! I remember your setup with the meth tank right?

btw.. I saw Mike at Nisei and told him he needs to rush your car done already. I'm short SGV buddies haha
Lol.. Yeah, hopefully soon. Just a few little things, ...... but then there's SEMA. :p

I got rid of the tank in front (for intercooler, actually), and had Mike fab me a tank to replace the washer reservoir. This opened up space for me to add the duct and the VRH.
Guys I just installed my downforce duct and I think there is room for the VRH tank behind it. I will verify when I get one because I am hell bent on putting mine up there as RYU knows!

For now I did a (IMO) very nice DIY install around the lovefab suspension brace. I took some measurements and then used a table saw to rip the top and bottom cuts across with a jig of course. Then I used a hole saw to cut the ends so it molded around the bar and less air escapes. Then I took the rubber molding DavidF was nice enough to send me and used a heat gun to mold it around the curves. Finally I sprayed it with water to get the molding to cool and retain its shape. I didn't get a threaded rod with mine in the package so I will have to double check. I took some industrial size tie wraps for now and clamped it around the radiator outlet pretty snugly.
Any of you guys have instructions on how to install this? I put on the duct but can't figure out how the Nut + Rod + Spacer works at all.

Other users like Raw and Nero had to fab up something that attached to the spare tire bracket.