Which way should my hood vent face? (1 Viewer)

[SmokingRocks]

OK so I have been doing some digging and couldn't find a good answer to this, so here is the conundrum:

I am building my rig to be a trail rig yet still have the capability of making a 5 hr drive if I need it to. The trails I plan on doing with this rig are 10mph max usually under 3mph, doing some good twisting which may go on for 3+ hrs.

I am thinking of doing a vent around the back of the hood, near cyl 6. I have seen people do hood vents two ways; 1) intake facing forward or 2) exhaust facing backwards. Now I have also seen the exhaust facing backwards version with an electronic radiator fan to help push out the heat.

So my question is, what is best for slow rock crawling? Pushing hot air out or pulling cool air in?

Thoughts?

 

[Corbet]

reward, that is the way the fan is blowing and generally the direction the truck is moving.

 

[SmokingRocks]

Thats what I've been leaning to do.

 

[cederholm]

Hot Rodders always have their louvers facing rearward. ...not sure if that helps you at all.

~ Carl

 

[SmokingRocks]

anyone who has vents have input?

 

[ChiTown]

The openings go rearward, the air flow over them creates a vacuum that pulls hot air out of the engine bay. If you face them forward the air will force air in the engine bay along with rain, dirt, birds, small children.

 

[Proven]

On my Tacoma I put it facing the windscreen. The venturi effect causes hot air to be pulled from the engine compartment when moving and convection allowed hot air to escape when the fan operated, or didn't. I put one on each side of the hood, they were about 4 x 4inches in size and stood up about 1 inch. It's been about 8 years since I owned that truck.

At least that's what I told myself and people agreed with me at the time.


What does yours look like?

 

[Golgo13]

The vents should be open to the rear to pull air out. Look at pictures of the FJ40's vents.
The air in the engine bay, for all intents is not moving, or moving slowly compared to the air flowing over the hood. Yes, the cooling fan moves some of it around, but it isn't like the air rushing over the hood or fenders.
Low air speed means higher pressure, high air speed is lower pressure. The air will move from areas of high pressure to areas of low pressure.

If you want to force air into the engine bay, like for an intercooler, then the vent should face forward, but then you get all sorts of stuff forced into the engine bay, as ChiTown mentioned above...

See what TreeRootCO did...
https://forum.ih8mud.com/threads/hood-louvers-retro-fzj80.238896/

 

[SmokingRocks]

Thanks,

As I said while it will be beneficial to have for highway driving I just want to make sure that I am keeping underhood temps in check on slow trails. I think I will face it rearward and maybe add a fan as well.

 

[ChiTown]

Keep in mind that there is a speed at which the vents will stop working due to their shape and size.

 

[e9999]

you can always cut the hole if you're sure where you want it, stick a temperature sensor under the hood and try it out with the scoop both ways (if it fits). Then decide.

 

[blkprj80]

You'd want the benefit of air exiting from the top of the engine bay when crawling. You'd also know when something was going south (smoke, steam, etc. rising from the vent).

At highway speeds, it might just act like a normal hood due to the cowl induction theory, but at that speed you won't care anyway.
http://www.camaro-untoldsecrets.com/articles/rpo_zl2.htm

You may also notice that your fenders have big openings from inside the hood that could maybe use a better escape path. Hmmm?

 

[SmokingRocks]

I've thought about the fenders, however not only am I running a dorkle which eliminates the fender option on one side but I wanted the most direct route to get heat out from the cyl 6 area.

 

[SUMMIT CRUISERS]

Here's my original GTP hood vent post: https://forum.ih8mud.com/threads/grand-prix-gtp-hood-vents-installed.294227/ They need to face reward and it is amazing how much air moves through them.

I installed them for problems idling during the summer in drive-thru's and slow crawling. I also installed a 12 or 14" pusher fan. The hood vents helped as did the pusher fan but the ultimate fix was thicker (15,000 cst) fluid in the fan clutch. Now the temps never move above the 45% line on the stock gauge.

 

[SmokingRocks]

Those are the ticket! I still think one in the center of the hood near the windshield would help a bunch too.

 

[ChiTown]

Remember your fresh air intake for the hvac system is right there also so you want to keep engine heat/exhaust away from that area

 

[Qball]

I've thought about the fenders, however not only am I running a dorkle which eliminates the fender option on one side but I wanted the most direct route to get heat out from the cyl 6 area.

Running a dorkel actually enables you to use the side for vents as the intake is no longer there so you won't be worried about venting hot air into intake.

Since I just got my dorkel installed I think side vents are in my near future. And also as other have said the air intake for your cabin is right there but also serves as early warning system if you have smoke.

 

[jrmudder92]

Did my rearward came out better then I thought! The only thing I would have done different is bought the large ones!