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Anyone done hood vents?

52707 Views 89 Replies 1 Participant Last post by  Brad96
As I've gotten more and more into open tracking over the past 10 years, I've learned a bit more about aerodynamics. Heat extractor vents in the hood have all sorts of benefits - reduce pressure under the hood (thereby reducing front end lift), improve airflow through the radiator, let some air out over the car rather than passing under the turbulent, non-aerodynamic underside, etc. The hood of the V looks like it wants to jump right off the car when you're blitzing down the straightaways at high speeds, so I'm sure some vents would be effective.

So, I've been planning to vent the hood of my Subaru for a while. I've done most of my track days in the Subie and I think it would benefit from some hood vents, particular for the improved flow through the radiator. I've accumulated a variety of OEM vents off Ebay and from junkyards as I looked around for a possible solution. In the end it looks like the Subie's going to get a '10 Mustang GT500 hood vent, but that leaves me with some other vents to play with.

In all the pics below the trailing edge of the painter's tape is about where the trailing edge of the fan shrouds is. No point in having the vents any farther forward than that.

Here are some vents taken from a 80s/90s Trans Am GTA. As you can see in the linked picture, the larger ones were actually run 180deg opposite of what I'm looking for, so I guess they must've fed the air intake rather than acting as vents. Whatevah!

Another option would be to put them so they're venting out to the sides. The shape of them doesn't really work out too well - they wouldn't line up with anything quite right.

And then there are the smaller, side-facing vents. I think these would be a nice, subtle touch mounted in basically the same place they were mounted on the GTA hood. Line them up with the character lines on the hood and I think they'd look almost OEM. The down side, of course, is that they're not very big.

An older picture with vents from a 80s turbo Lebaron:

And the biggest, baddest vents of them all, the Lumina Z34 vents.

On the Z34's hood they were mounted to vent to the side, kinda like the second set of pics I posted of the Trans Am vents. I could also do that on the V's hood, and it doesn't look bad, but for whatever reason I didn't take any pictures in that orientation.

Although I don't have them with this set, as installed on the Z34 they had rain drip trays beneath them. I would have to either get the drip trays, or make my own, otherwise the engine bay would get doused in the rain. But I could just pull the drip trays off for the track.

They line up almost perfectly - if I position the side of the vents parallel to the character line in the hood, the front edge of the vents lines up pretty well with the front of the hood. It's not perfect, but since they're set back almost 2ft I don't think it would matter.

In the more expensive, blingier realm, there's these CF vents from Anvil Auto. I don't have a pair of those handy, so I can't show you how they would look on the V's hood. :) Here's a nice shot of them on a classic Camaro:

They're about 8x12". In comparison, the Z34 louvers are about 7x20".
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I did a search, but couldn't find where anyone has added extraction vents to a factory V1 hood. If anyone has already done it, I would love to see pictures.

The reason I'm interested is because I run the Big Bend Open Road Race ( almost every April, and I'm thinking about running my V next year. Especially if I add a belly pan under the engine compartment, I'm going to need to let the air escape out through the hood, both for radiator airflow and to minimize aerodynamic lift.

So, I'm thinking about TrackSpec Motorsports ( louvers. Of course, they don't offer a fitment specifically for the V1, but the C6 kit looks like it might go well with the Caddy's body lines. To get a better idea, I cut out some cardboard pieces to the dimensions from TrackSpec's website, and laid them out on my hood.

First, here's what the underside of the factory hood looks like without the insulation (in case you've never seen it):
Automotive lighting Hood Grille Motor vehicle Automotive tail & brake light

And, here's the hood with my cardboard pieces on it:
Car Automotive tail & brake light Land vehicle Automotive parking light Vehicle
Tire Wheel Vehicle Car Land vehicle
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I merged your post into an older thread with discussion of hood vents. (The old thread was in the Appearance Mods forum, which is probably why you didn't find it.)

Unfortunately, I've never gotten beyond the initial hole cutting that I did a few years ago (the pics in post #73). The hood is still sitting in my basement and I don't know when (if ever) I'll get around to finishing it.

Edit: Earlier in the thread (post #51) user crankedupforit actually beat me to the punch and had a shop install the Z34 vents into his hood. His were positioned a bit differently from what I was planning to do, but same general idea. crankedupforit passed away a while back, but the car resurfaced on this forum last year in the hands of @CtsFeVer. They may be able to give some more pics of how the vents were done on that hood.
Thanks, AAIIC. I did read your posts about the Lumina vents some time back. But, when I went to post my thoughts on Sunday, I couldn't quickly find it. I do like how they turned out on crankedupforit's hood.

The C6 layout that I showed above looks a little crowded to me. Unfortunately, there's not a lot of room under the hood to spread the 3 vents out further, without compromising their function. When I get a little free time, I'll try mocking up a pair of TrackSpec Motorsports' "Large Angular Universal Hood Louvers" to see how that simpler set up looks and fits.
Here's how the large universal vents might lay out:
Automotive parking light Automotive tail & brake light Vehicle Vehicle registration plate Automotive side marker light
Tire Car Wheel Vehicle Land vehicle

It's definitely a lot less crowded, but also less open area for moving air, and maybe doesn't match the angled lines of the stock hood as well.
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Yeah, I think if you're just doing the 2 smaller vents, I would think the 2 similarly-sized ones from your first pics would match the lines of the hood better.

Or what about doing just the big center vent?
I agree that the smaller louvers from the C6 kit better match the hood lines, because they're tapered. I was thinking that they're too small by themselves. But, comparing dimensions, they're not much smaller than the "Large Universal" louvers.

The big center louver by itself would probably be more effective at venting under-hood air at speed than the two louvers placed further back. The main reason I like the idea of having those two back there, is to give heat coming off the headers (that I don't have yet) somewhere to go, when the car is parked hot. Otherwise, the engine compartment turns into such an oven, and all the plastic bits get baked to death. It seems like having openings in the hood directly over the headers (or as close as possible) would provide the best opportunity for natural convection to do its thing and minimize under-hood temperatures after parking.

Hmmm, decisions, decisions...
I just ordered the C6 T1 louver kit. Once the actual louvers and templates come in, I can work on the layout some more. Currently, I'm just estimating with cardboard, because TrackSpec's website doesn't provide all of the dimensions. If I can't find a layout that I like, I'll consider shortening 1 or more of the louvers, or not installing all 3 pieces.
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Here's how it looks with the center vent installed:
Car Land vehicle Vehicle Automotive side marker light Grille
Automotive parking light Tire Wheel Automotive side marker light Car
Grille Automotive lighting Motor vehicle Hood Cloud
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That came out quite nice! The sides of the vent seem to line up pretty much parallel with the character lines in the hood, so it fits the lines of the car.

What's it look like from the underside?
Thanks! Despite being marketed for the C6, I think it's a close enough match to look pretty good on our V1's.

I haven't reinstalled the hood insulation yet, so here's how it looks from the underside:
Grille Automotive lighting Motor vehicle Hood Automotive design
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