So I know that sometimes they are actually functional and other times they are just for aesthetics. I've honestly been thinking about getting one though after the supercharger swap cause the under good temps have gone way up.

My biggest problems with the ones on the market now are price tag, material, and design. $600 for a good seems kind of steep and I'm not a big fan of carbon fiber. Also the vented ones I see have the two front vents an two side vents and the side vents one of them close to the PCM and fuse box. That issues alone worries me.

I live in Texas where it gets pretty hot during the summer so I could see here it could be beneficial. Just kinda want to get people's opinions on vented good designs and see what people run and of there are any alternatives to the expensive hoods on the market.

 

I would just paint the VIS carbon hood in the vader 2 style. I have it and the vent sit right over top the intake manifold, keeps temps in check. When running the water from rain just evaporates due to engine heat.

 

^yup thats ur best option though it is still expensive and i think only carbon fiber so u'[d have to paint it

 

Well my car is black so carbon fiber may not look too bad unpainted on a black car.

 

I too thought about this. My SSTC stock hood gets super hot. And here in Texas with summer heat I can cook a egg on that dam hood.

And I do agree the design options out there suck!

 

Ok. So I have done a quick search on google about this and I found something kind of interesting and want to gauge opinions on.

I found this on a Honda forum and it seemed to turn out rather well for the guy.


Basically the guy cut his own vents in the hood. Now obviously we don't have the same hood structure or under frame to do those type of vents, but would cutting vents and having them flat like that work? I mean does it need the lip around the vents like the VIS hood has? Or is that lip just for show?

 

My hood is functional n helps keep temps down.

 

Well I really don't want a ram air hood. I've looked at them but idk, I just can't sell myself on it.

In a perfect world I would rather have something subtle.

 

I'm guessing that lip actually does something. From this pic, it looks like they're trying to show that the airflow over the lip helps draw out the hot air, but I'm probably wrong..

 

^^i wouldnt say that. air dynamics can be a complex thing. certain designs create bubbles, vacuums, etc etc. from the look of it, that lip creates a vacuum, which in turn helps pull the hot air out. so instead of forcing air into the engine compartment and causing unnecessary drag on the front of the car, it lets the natural flow of the air over the car pull the hot air out.

 

What you have there is a heat extractor hood. The lip should (sort of) create a venturi effect where it is speeding up the air over the hood opening creating a vaccum drawing the hot air out. It will also allow your grille openings and under car air dam push more air into the engine, keeping it cooler. If you look at the Corvette C6 ALMS cars, they run hoods with big heat extractor vents in them, and they are very functional.

There is 1 vendor that used to make a functional heat extractor hood, but if I remember correctly it was really expensive and I'm not sure if they even make them anymore.

 

 

the lip on the front helps create a low pressure area in the opening helping extract the air from the engine bay... generally the carbon fiber hoods you see on the street are just for show and have little if any aero advantage...

I can see that evo style vented hood helping the supercharged guys a lot... those little buggers put off some heat and its trapped under a sealed hood...

heres some info on GurneyFlaps and how they help...
http://www.timeattackforums.com/foru...-evaluate.html

 

at the base of the windshield between the wiper arm posts roughly, the air reverses at the base of the windshield. The vents need to be in the side. You can make them yourself, just cut the hood and bond in mesh to keep small children from falling in.

makes a big difference.

if you put the vents before the rad tie bar, it doesnt work either.

this works:







this version works but not as well as the previous pictures; the vetns are too small. I found tht at 150 mph the base of the hood actually lifted at the rear hinge. This is really really hard to do by lifting it up by hand, in the garage standing still, which just illustrates how much air is jammed under hood at speed

this works but its the rear lol

 

All funtional vents.

 

i want to get a vented hood as well. but all the vented hoods for the cobalt look rice as ****

 

I'll be honest, I went ahead and cut a couple holes in the hood about a week ago. I still need to clean them up a bit more and repaint the area around them or else I would have posted updates with pics. But basically I took the hood off and flipped it over. In the center of the hood there are two small triangular shaped areas right over the supercharger. I cut about half of the bottom portion of those areas out so it's opened right above the supercharger. I was concerned about vents on the side due to water potentially getting in over the belt and electronics, more specifically the fuse box and computer.

They do have some functionality. I was seeing coolant temps running around 207* at idle then falling to about 198* during normal driving. After opening the vents I'm now seeing idle temps around 198* and cruising temps between 190*. So I'm averaging about a 7* drop in engine temp overall. I've also noticed the supercharger doesn't seem to stay as hot as it did prior to opening the vents. Also, at speeds of around 115-120mph it doesn't seem to become unstable. I haven't pushed it over that speed yet as I really have no place to get it up that fast safely.

It doesn't have a lip at the leading edge to create the low pressure zone to suck out heat, which may be why I'm not seeing as big of a drop during cruising conditions as I do at idle. Eventually I may see about molding a lip on that edge and seeing if the effects are greater then because I would assume that having a vacuum to suck out the heat while cruising should drop those temps down further then what I'm seeing at idle.

I'm going to try and get it polished up a little better this weekend sometime or maybe early next week then I'll post some pictures and what not.

(disclaimer: for those who may potentially say that by doing this I've become a "ricer", it actually has some function and in the end, I dot give a **** about your negative opinion. Function over form.)

 

There used to be a person on here who lifted the rear of his hood up a bit with a few washers and claimed a few degrees lower in his coolant temps. It was real simple, hardly noticeable, and functional, but a ton of people flamed him for it. I wish I remembered the thread name...

 

See I'm not a big fan of the good tilts. I've seen a few people do it on other cars and to me it just looks like a poor fitting hood.

 

There is someone on here with a custom cowl induction hood that looked pretty good. Theoretically they do the same thing.

 

See I'm not a huge fan of cowl hoods unless on something like mid 80s camaros. Haha

But I'm surprised I haven't gotten more **** for cutting my hood already. Haha

 

My hood works very well for this. I was actually really surprised... And i have never had a problem with rain in the engine bay at all, but my hood came with a cover for the 3 vents in case I want to put it on so that water doesn't actually get in.

 

oh god, im so glad that effin hood lift fad went away in the honda community...

 

What hood is this?

 

Looks like this...


VIS Racing Chevrolet Cobalt VIS Racing G Speed Black Carbon Fiber Hood - 05CHCOB2DGS-010C