Real hood louvers?

[RipperXX]

Wondering if anyone has thought about doing this before? I found a site that sells them RunCool Real Heat-Escape Hood and Side Louvers thinking about adding one to my stock hood. And or maybe flipping one upside down and adding it to the passenger side pop up headlight cover.


I know a few people have put vents on there hoods but I am thinking this might look better AND might work better too? I was originally looking for one of the vents like I have seen on a few peoples cars and stumbled on this. I had no luck finding the other ones everyone else seems to use.


What do you guys think?

 

[bpestilence]

It would look stupid but it would be functional. These louvers look like they belong on a classic car more than a DSM.

Also, vents on the hood without baffling lead to one big problem: Water on the engine when it rains. You are better off just using fender louvers. FG or CF DSM fenders with louvers molded in are not very expensive, and would be just as functional. (Although, to get full function out of a louver you must also build an undertray)

 

[bullettdsm]

I did it on the NA (I like the idea a lot). But I did Home Depot special, . $25(?).

I thought I had a pic of it. But this may give you an idea (hard to see);
YouTube - 6/13/2008 current Mitsu 420a NA record 13.302

I like the idea of louvers because they generate an low pressure area to help pull the air out, while maintaining some aerodynamic form for the air to flow over.

MB

 

[bpestilence]

Well, louvers don't GENERATE a low pressure area. They take advantage of one, if you put them in the right spot.

By Bernoulli, the areas of highest flow velocity will be the lowest pressure. These occur near the aft end of the fenders and the cowl area of the hood. Putting a vent on the sloping area of the hood will actually force MORE air into the engine bay.

The ideal aero solution would be a splitter and undertray, a body tray with skirts, a diffuser, and vents on the rear of the fender. (Basically an F1 setup, not counting a wing and canards)

 

[RipperXX]

I was just looking for a simple but not hideous way to get some heat out of the engine bay, I am stationed in Lawton OK, about 40miles from TX and it gets hot out here in the summer, hell it's already been hitting the 90s! It's not uncommon to see temps around 103-105 in the summer. And it already takes forever for the engine to cool down once I park.

 

[snowborder714]

Hood vent?
18x10 Carbon Fiber Hood Vent - $119.00 : Carbontrix, Composites Design and Production

 

[RipperXX]

^ thank you! I googled everything I could think of and the louvers were all I could find.

 

[xsboost]

GOOD GOD THOSE THINGS ARE EXPENSIVE!! They look like overglorified floor vents.

 

[RipperXX]

Yea, I wasn't expecting them to cost that much either... It's making me want to wait untill I get a CF hood then do the vent to it vs doing it twice.

 

[crimsondragon]

Just invest in a good hd design. Like this:
http://imagehost.vendio.com/a/10579...932647655_extreme_gt_hood__95_99_ECLIPSE_.jpg
I have that hood right now. It's starting to get warm but temperatures are good. Stays in the middle. I recently just changed a good 75% of the cooling system though. New hoses, thicker aluminum radiator, and new thermostat w/ seal. I might change the radiator cap too. I like that hood design because aerodynamically it should generate the low pressure area right above the vents. It's placed up front too so any rain will fall right through to the ground and not on the engine.

 

[MIdsm]

The louvres the OP found would work pretty good. There are other options as well. There are speed/hot rod shops that could stamp the louvres right into the hood metal. I have seen it on an ambulance an aquaintance used as a work truck. The only issue is that the under hood bracing has to be cut out of the way ahead of time and the hood has to be painted. .

The low pressure on top of the hood usually occurs at the front edge as that's where the flow is at its fastest. The back side of the hood usually sits in a high pressure area and that's why the AC air intakes are located there and why hood scoops (high in the back) work with carbs. The louvres located at the front of the hood should point backwards so the air gets expelled toward the back as close as possible in the same direction as the air flow over the hood.

The fender vents are there to release high pressure air that accumulates in the fender wells and decrease lift at high speeds.

The following is a force distribution over a general vehicle:

http://us1.webpublications.com.au/static/images/articles/i1097/109741_3mg.jpg

This is a pressure distribution over a vehicle Red for high and Violet for low:

http://us1.webpublications.com.au/static/images/articles/i1103/110351_7mg.jpg

Both pictures thanks to autospeed.com from down under.

The question is if the vents have to look good, work good and if the cost is a factor as well. A few years ago I installed a household AC vent and installed it on my beater crx. The smooth side of the vent was installed toward the engine bay. I spent $8 on a AC vent at Menard's, a few bucks on stainless steel mesh and pop-rivets (to prevent leaves and detritus from falling on the hot manifold) from Lane Automotive and a couple hours of work. The vent has been positioned in between the radiator and the engine. There have been no engine issues due to ingestion of water.

Good luck.

 

[bullettdsm]

By Bernoulli, the areas of highest flow velocity will be the lowest pressure.

I use peices of light fabric to see where my air is going. You can be sure that my air is moving OUT of the engine bay (because the air draws the pieces out of the hood as the car moves).

Yeah, real simplistic, but it tells me where my air is going.

Btw, I do want to note for the OP, my louvers are facing the back.

MB

 

[gixxerdrew]

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[ali]

i just want to know how this one works?

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[RipperXX]

Been meaning to ask you about your hood louvers... Your hood looks flat, does it not hit the timing belt cover? Or did you lower the engine a bit? I know you did a crap load of functional mods to your 2g so thats why I ask.


I was thinking IF I had a way of getting the 1.8L 1G hood (without the bump) to clear I could use these vents and it look a lot better.

 

[gixxerdrew]

It clears because the entire hood sits like 2" higher it bulges up like crazy

 

[underradar92]

I s'pose unless the wall behind the radiators was opened up, which I've seen on some NSX's, they wanted to cool the spare tire?

 

[Bohrn]

releases underhood pressures and keeps the front end from lifting. (on the NSX)

 

[underradar92]

releases underhood pressures and keeps the front end from lifting. (on the NSX)

There isn't any "underhood air pressure" in the trunk on an NSX unless the wall behind the radiators has been cut away, as I mentioned.

 

[Bohrn]

so its completely air tight from the bottom?

If so, well, those louvres are just useless on there then.

 

[underradar92]

Yes, it's the trunk so it was designed to keep luggage and groceries dry. The front panel of the well is just behind the radiators and when people install those awesome looking extractor boot lids, that panel gets cut away.

So yeah, in this case it is unlikely that these louvers are useful.