need OPINIONS on cutting a vent into my hood.

[almostquick]

http://www.240sx.org/links/installs/hood/hood.htm

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so, yay, or nah? what do you think, I'm open to sugestions and I'm a cheap ass so keep that in mind also, I dont want to buy $100 hood vents, or $300-$400 hoods.

 

[halik008]

http://www.240sx.org/links/installs/hood/hood.htm

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so, yay, or nah? what do you think, I'm open to sugestions and I'm a cheap ass so keep that in mind also, I dont want to buy $100 hood vents, or $300-$400 hoods.

i'd say got for it BUT:

1.get an old hood to try it on 1st....if you never done something like this before it's always better to try it on useless hood then fuk up ## own

2. cutting the semi-circle shape will be a major PITA....can't use angle grinder since the wheel is too large and would leave grind marks on either side of the cut....so use dremel tho it will take forever the results will be much nicer

3. move the vent much farther to the center....it's too close to hoods edge and looks funky

halik

 

[ndilo21]

I think it would look good if you put a nice black mesh behind it. Here are the links to the two greyforest hood mod threads, if you don't have them already. They might help you out a bit.

http://www.dsmtuners.com/forums/showthread.php?t=67265
http://www.dsmtuners.com/forums/showthread.php?t=92011

 

[weith1111]

Eh, I like the 1g hood without holes, and if you have to cut the framed parts of the hood, I'd say forget it. Have you done any of the other mods to reduce underhood temps:

1. have an exhaust manifold heat shield since 80% of people don't
2. removed the plates behind the passenger headlight
3. shim the rear of the hood or remove the foam trim
4. make a cai since you have a FMIC
5. heatwrap the turbo, manifold, DP

The 1g has such nice lines...

 

[ndilo21]

i'd say got for it BUT:

3. move the vent much farther to the center....it's too close to hoods edge and looks funky

halik

I agree, I would move it back a little further. If he goes back any further there may be an issue with the hump on the hood though, I can't really tell from the pics.

 

[almostquick]

it can't go farther up on the hood because of the hump, where it is now, is as far as it can go. as far as the other things to counter the underhood temps, yes I have done them all except put on a heat sheild, but I do have my exhaust wrapped. It looks good on the 240, thought I would give it a shot on a 1G. and the grey forrest hood mod is too much of a pain in the ass, I would have to stencil those little holes out since I have a 1G, not a 2G.

 

[ndilo21]

it can't go farther up on the hood because of the hump, where it is now, is as far as it can go. as far as the other things to counter the underhood temps, yes I have done them all except put on a heat sheild, but I do have my exhaust wrapped. It looks good on the 240, thought I would give it a shot on a 1G. and the grey forrest hood mod is too much of a pain in the ass, I would have to stencil those little holes out since I have a 1G, not a 2G.

I like your idea, just thought the greyforest threads might have some helpful pointers in them.

 

[weith1111]

Heat shield will arguably make the biggest difference in keeping the temps down

I'd wager to say more than a hood vent even.

 

[almostquick]

thanks, and thanks for the links also, it gives me some idea's about how to go about cutting the hood. I think I'm gonna go through with it, if I screw it up, hell I'll just buy a fiberglass one.

 

[mavisky]

Simply cutting a hole there won't be as effective as if you rolled the front lip up just a little bit. That'll create a pressure difference to help pull air through there. Are you overheating alot right now?

 

[EclipseTrbo420A]

Simply cutting a hole there won't be as effective as if you rolled the front lip up just a little bit. That'll create a pressure difference to help pull air through there. Are you overheating alot right now?

Smart suggestion. I also cut a vent in my hood ( carbon fiber ) , but same idea non the less. I would suggest using door stripping from auto zone to line the edges of the cuts you make. Its thin , black and looks decent. good luck and check my gallery to see a pic of mine.

I look up the thread I made.

 

[almostquick]

Simply cutting a hole there won't be as effective as if you rolled the front lip up just a little bit. That'll create a pressure difference to help pull air through there. Are you overheating alot right now?

go to the link, I'm doing the exact same thing that he is, but mine is curved. Only the front part of that template will be cut, the back part of it will be rolled down into the engine bay. no I am not overheating right now.

 

[super97gst]

i dont know what you intent to cut this big vent out with but i would suggest not using something like a dremmel or die grinder. i would suggest using a roto-zip. i used my roto-zip on my hood on my 2g when i did the greyforest hood mod. it worked great. just make sure you use carbide tungsten bits. i broke like 6 bits before i went to the carbide ones. they would just snap off as soon as the bit hit the metal. good luck on this, it appears that its gonna be a job.

 

[knighteclipse1]

Well, since you asked for opinions....here's my .02 worth....nay, I believe you get what you pay for.

 

[redeclipse7782]

Well, since you asked for opinions....here's my .02 worth....nay, I believe you get what you pay for.

I agree and eclipsetrbo420a i think you ruined a perfectly good carbon fiber hood, you should have bought an invader carbon fiber hood if you wanted a hole in it. I also have a fiberglass hood for sale that is vented, check my gallery for pics.

 

[Defiant]

http://www.240sx.org/links/installs/hood/hood.htm

so, yay, or nah? what do you think, I'm open to sugestions and I'm a cheap ass so keep that in mind also, I dont want to buy $100 hood vents, or $300-$400 hoods.

I'd like to see a tuft-test on that vent to find out how much air is being forced into the engine compartment by that, and how badly it's blocking flow through the radiator.

 

[greytalon26]

Wouldn't a better idea be to get a hood that forces air out of the engine bay like the one on this 1gb:

 

[xveganxcowboyx]

^^^ At that point you might as well just raise the rear of the hood with a few washers. Easier, cheaper and looks better.

 

[mavisky]

^^^ At that point you might as well just raise the rear of the hood with a few washers. Easier, cheaper and looks better.

That forces air under the hood, not out of it. Same as a cowl induction hood. It's all based off of air pressure principles. It's a commong mis-conception that lifting the rear of the hood lets hot air out, in fact it forces cold air in. This is good except that the air then usually exits below the car causing more turbulence and lift.

 

[mavisky]

Wouldn't a better idea be to get a hood that forces air out of the engine bay like the one on this 1gb:

That vent is simply a molded and painted carbon fiber vent from carbontrix.com, I myself intend to get one of these vents.

 

[xveganxcowboyx]

That forces air under the hood, not out of it. Same as a cowl induction hood. It's all based off of air pressure principles. It's a commong mis-conception that lifting the rear of the hood lets hot air out, in fact it forces cold air in. This is good except that the air then usually exits below the car causing more turbulence and lift.

Thanks for the correction. I understand cowl induction, but for some reason I thought raising the hood would be different. Now that I think about it I'm not sure why.... Stupid air vacuums making everything more complicated. Why can't air just flow straight!

 

[mavisky]

Thanks for the correction. I understand cowl induction, but for some reason I thought raising the hood would be different. Now that I think about it I'm not sure why.... Stupid air vacuums making everything more complicated. Why can't air just flow straight!

It does, but only on flat straight surfaces.

 

[TURFNNSURF]

Just my .02 as well since I tried a 1G hood mod in the shape of EVO styling. I was fighting high coolant temp problems this past summer and thought modifying an old junkyard hood might help cool things down. Here is what I did:

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Here are my results: There was NO decrease in the coolant temps with the new holes cut into the hood. From what I could see with a piece of tape and some yarn, air was being pushed into the engine compartment and creating back pressure thus lowering the amount of air coming in through the radiator. The only time this mod helped cool the engine bay down was when the car was shut down, radiant heat could escape faster through the vents and cool down time was shortened.

The final result, even though I liked the vents, I'm glad I cut up a junk hood. Right now I have my stock hood back on. My high coolant temps during the summer I'll live with until i break down and remove the AC. It's the price I'll pay for having a FMIC and wanting a weekend race car.

 

[speedy13]

damm that sucks,I liked it better on the 1g and the 2g,but form follows function, so i guess i wont.I love that carbon fiber vent,i always wondered were to get one,thanks mavisky,maybe next year i'll buy one.

 

[mavisky]

Just my .02 as well since I tried a 1G hood mod in the shape of EVO styling. I was fighting high coolant temp problems this past summer and thought modifying an old junkyard hood might help cool things down. Here is what I did:

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Here are my results: There was NO decrease in the coolant temps with the new holes cut into the hood. From what I could see with a piece of tape and some yarn, air was being pushed into the engine compartment and creating back pressure thus lowering the amount of air coming in through the radiator. The only time this mod helped cool the engine bay down was when the car was shut down, radiant heat could escape faster through the vents and cool down time was shortened.

The final result, even though I liked the vents, I'm glad I cut up a junk hood. Right now I have my stock hood back on. My high coolant temps during the summer I'll live with until i break down and remove the AC. It's the price I'll pay for having a FMIC and wanting a weekend race car.

I agree that cutting straight vents into hoods like this will never help in getting more cool air to the radiator. Properly designed hood vents though such as the carbontrix vent and others can be beneficial although don't expect drastic changes. Making a block off plate around the radiator opening and upgrading the radiator itself are much more effective plans. In fact the little rubber piping that is around the vents in the greyforest hood mod may actually be enough for those small openings to help get air out of the hood. A perfectly flat plane with a hole in it will always draw air into that area as you found out though.