Are vented hoods really worth it?

[Sirk]

Or are they just for looks? Would an OEM hood with washers on the back be more effective for controlling temps? Or would an OEM hood, no washers, with a Koyo copper and Altima fans be ideal?

[naed240sx]

you are gonna get a bunch of opinionated answers to your question. All of the things you mention will be effective at reducing underhood temps... but I dont think that anyone has actually done a test. Decide what is most practical for you, and then if you still dont like the amount of heat, add on something else.

[chmercer]

hood washers dosent do ****. ive had it on metal hood and fg hood, sucks. just gets leaves and crap in your engine bay.

yes vented hoods lower engine bay temps. its not just "for looks".

[hek1620]

yes but vented hoods also let a but load of rain in on ur engine. i'll keep my washers thank u much. even when i get an O.E. STYLE cf hood. plus vented hoods are just another way for people to mess with ur stuff. they could throw or spill whatever they want onto ur engine.

[InsanityInc]

SOME vented hoods work, most do not. Ask the manufacturer if the vents are functional before you buy one.
Modified by InsanityInc at 1:40 AM 9/7/2005

[97ka-t]

It dissipates enough heat for me!!

[chmercer]

check your engine bay temps, it does like nothing.

yes i guess vented hoods would let water into your engine bay, i guess that would suck if you drive a show car.

pretty much every vented hood ive seen on the internet for s chassis is functional aside from the VIS hood with a vent on top of the radiator.

[grimple1]

Well since hot air rises, any venting will reduce temps. So a vent would work, a scoop would allow cooler air in the engine bay.

The washer thing seems a little non-efficient to me. You'd have to have a lot of washers under there to make it as effective as a vent/scoop.

You could just run hoodless. That'll vent the heat out.

[HashiriyaS14]

Depends. On an S-chassis....probably does a little something.

On something with a TMIC, like an Impreza, I'd expect it to have a bit more functionality.

[InsanityInc]

Well since hot air rises, any venting will reduce temps. So a vent would work, a scoop would allow cooler air in the engine bay.

Blargh. No. Hot air doesn't rise when you're in motion. Air is flowing from the front to the back of your engine bay. Just punching a hole somewhere in your hood isn't going to let anything extra out while you're in motion. Sure, if you're really worred about underhood temperatures at idle it'll help, but I don't think anyone is.

A vented hood that really works has to be designed with knowledge of the underhood airflow, namely where the air gets turbulent enough to flow upwards and out a vent. On a 240, that's probably about 1/3 - 1/2 way back on the valve cover. The air is flowing pretty straight before it hits your engine.
Modified by InsanityInc at 4:50 PM 9/7/2005

[BaliLover]

I remember reading somewhere that the flow of air over a vent while the car is in motion creates a vacuum effect sucking the hot air out of the engine bay.

The old school cowl induction hoods for example, had no openings facing forward, but when the car was in motion air was sucked in due to pressure change. Or something like that. I'm sure someone out there can explain this effect better.

[Lil_JV]

I remember reading somewhere that the flow of air over a vent while the car is in motion creates a vacuum effect sucking the hot air out of the engine bay.

The old school cowl induction hoods for example, had no openings facing forward, but when the car was in motion air was sucked in due to pressure change. Or something like that. I'm sure someone out there can explain this effect better.

I believe this is true. No need for forward facing scoops. The cold air is sucked in.

[grimple1]

Blargh. No. Hot air doesn't rise when you're in motion. Air is flowing from the front to the back of your engine bay.

Modified by InsanityInc at 4:50 PM 9/7/2005

It's still rising, granted not in a 90 degree angle but it's always rising.


Modified by grimple1 at 7:33 AM 9/9/2005

[97ka-t]

[SloS13]

Hot air rises whether in motion or not. A hole would create a vaccum (if at the correct angle) while moving. My car runs a couple degrees cooler with the washers.

[rico05]

Just put some spacers under the hood hinges, and call it a day.

[ArticDragon192]

That's some? lol!!

[wilfonzo]

haha, thats badass

[PantherRacer]

Just put some spacers under the hood hinges, and call it a day.

The man has a point people. Why waste money on some hood that invites water into your engine bay when u can just use spacers?

[wilfonzo]

im probably going to sound like an idiot, but what are hood washers

[Kouki40]

just the latest in low budget JDM mods