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Widgmaster

Supporting VIP
1,235
974
Aug 24, 2018
Sarnia, ON_Canada
I have been thinking about putting hood vents on my 2001 Mitsubishi Eclipse to get rid of engine bay heat . I found the 2001 Subaru Impresa looks the best ..I would paint them the same color as the body.. What do you think ...This is a picture I mocked to show what it would look like.
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It looks pretty good but you have to be careful with hood vents. You could cause issues with heat release if you put the vents in the wrong place. It's not always obvious where hood vents are beneficial.
 
What exactly are you trying to gain from doing this? Do you have issues with overheating now? Is the car modified or mostly stock?
 
It looks pretty good but you have to be careful with hood vents. You could cause issues with heat release if you put the vents in the wrong place. It's not always obvious where hood vents are beneficial.
Sorry, quick question what do you mean by “heat release”? I always thought that we needed to keep engine bay temps as cool as possible. Not saying you are wrong, just curios. Thanks.
 
I have been thinking about putting hood vents on my 2001 Mitsubishi Eclipse to get rid of engine bay heat . I found the 2001 Subaru Impresa looks the best ..I would paint them the same color as the body.. What do you think ...This is a picture I mocked to show what it would look like.
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By the way, to me it looks good but make sure you measure three times so you dont mess up your hood. If you are stock I would leave it alone bit thats just me, good luck. Looks good to me.
 
I would love to find a beat up evoIII hood

Id steal the vent off it and do a little custom project with a spare 2g hood. same location as evoIII
 
Sorry, quick question what do you mean by “heat release”? I always thought that we needed to keep engine bay temps as cool as possible. Not saying you are wrong, just curios. Thanks.
Well, I'm not an authority on this subject but here it goes: Under and above the hood you have different pressure zones. If you're not careful, you could put a vent or inlet in the wrong pressure zone. For example, lets say you want to vent hot air out of the engine bay but you put your vent in a spot on the hood that actually has pressure going INTO the vent. Now you have air going into the engine bay possibly causing turbulence and PREVENTING the release of hot air from other areas designed to release the air. I'm just saying it's not always obvious where to place these openings and you could hurt the car's performance if you're not careful.
 
Sorry, quick question what do you mean by “heat release”? I always thought that we needed to keep engine bay temps as cool as possible. Not saying you are wrong, just curios. Thanks.
This is like an oxymoron. I don't get your question.

By releasing heat you are keeping the bay temp cooler.
 
From the angle of your mock up picture it looks like they'd be more of an air scoop pressurizing your underhood & decreasing the the pressure drop accross the raditor core making it harder for your raditor to cool the engine. I'd suggest rotating them 90 degrees & moving them further back from the nose onto a more flat area of the hood. So nay for me.
 
+1 vents look too far forward. I think a lot of the air in the engine bay is designed to go back toward the cowl (please correct me if I'm wrong, I'm by no means an expert). If I were you, I'd move the vents closer to the cowl and spread further apart from each other (maybe if you spread them further to the sides, rain wouldn't land directly on the engine).

Also, do the mods on your car justify this? It's okay if you just want it for looks. Just weigh your options because it won't be great to drive in rain.
 
I think a lot of the air in the engine bay is designed to go back toward the cowl (please correct me if I'm wrong, I'm by no means an expert)
Interface between hood & windshield is a high pressure zone (like the front edge) & openings (or lifting the back of the hood-hinge spacers) causes air to be forced into the engine bay. This would increase the engine bay pressure on the back side of the radiator reducing effieniency. Also reduces front end downforce which gets worse as speed increases.
 
Wow... I love this site . I am a member of another Mitsubishi web site and never get any response to questions or advise. My Mit is totally stock other than a cold air intake. I dont care about speed ( I just got my license back ) I am going for the look... sort of like the Mit from 2Fast 2Furious … the car looked great but we all know they did not go as fast as the movie makes out. I do plan on putting a rain catch underneath the vent just like the Subaru Impreza... Thank you all for the replys… You guys made my day .After I post this I will be buying a paid membership. This site rocks … Thank you once again .
 
Thank you for all your input .. This information was very helpful and now I have made my decision . I really like the look of the vents in my pic but being aware that they may cause me problems like you have mention I will take your advice and install them as dummy`s . I will drill just for the bolt or even better cut the bolt off and use double sided tape and fasten them that way.. Once again thank you to all who replied …
 
You might have longevity issues with the double-sided tape. But hey, whatever works man.
I've seen some pretty crazy stuff held on by double-sided tape. Some over-fenders on modern cars are held on purely by double-sided tape (I've seen some with 1 or 2 bolts accompanying and some without any, just tape).

I will take your advice and install them as dummy`s .
As long as you like the look! Just be careful about what others might think about the dummy vents.
 
Hey just saw this thread... the Impreza vents you are after are much smaller than you have posted on your hood there. They are in reality only like 4" long by 2" wide. I was a long time Subaru guy- before betraying my cult.

My advice for these vents when you decide to do this is to put them in the exact configuration as on the Impreza hood (ie closer to the fenders). They should in the configuration I described work better at pulling heat and angling it off the side air streams rather than disrupting the air stream going over your windshield.

It would work best if you had the V6 since I would imagine it has a similar surface area to the boxer in the engine bay but ya know most of us aren't engineers so who cares. :p

Also also if you go to Pick n pull you can snag them for nuggets (like $20). Just don't let a subie guy catch you throwing them in your eclipse, he might flip out
 
I have been thinking about putting hood vents on my 2001 Mitsubishi Eclipse to get rid of engine bay heat . I found the 2001 Subaru Impresa looks the best ..I would paint them the same color as the body.. What do you think ...This is a picture I mocked to show what it would look like.
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looks good.
 
You want to install the vents at an area in the hood where there is the greatest differentiation between underhood and overhood pressures, as this will promote the best movement of air flow through/out of the vent. The best way to do it would be to get yourself a Magnehelic gauge and do some on-road testing. This autospeed article is a great guide:

http://www.autospeed.com/cms/article.html?&title=Undertrays-Spoiler-Bonnet-Vents-Part-3&A=113178

Just note it's written by an Australian author - "bonnet" = hood. ;)

Short of that, if you want to hack up your hood without measuring a best guess would be that the best placement would be at the leading edge of the hood. As shown in the autospeed article, this is typically the highest-pressure area under the hood (with air coming in from the nose) and lowest pressure area above the hood. It also promotes airflow through the radiator, and helps to evacuate the radiator heat out of the engine bay, which is by far the biggest cause of underhood heat.

Also of note, I believe your impreza vents area poor choice, as they are far too restrictive. Something like this would be far more effective:

http://farnorthracing.com/hood.html
 
Thank you so much for the informative article . Original the air intake on this car was just below the hood at the leading edge . By adding a cold air intake I moved the air intake from this position to the fender well just behind the left signal light . At the moment there are plastic pieces simulating more vents below this light. I plan to purchase a 5pc Grillcraft Grill ( https://www.carid.com/grillcraft/mx...mpn-mit3309s.html?singleid=354347&url=1299882 ) which will open up this area to more air flow for cool air. My reason for the hood vents is more for looks than any thing else. Personal I think they look sharp. After all the information I have been given by DSM Member my plan is to install these vents as non-operational …
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From the angle of your mock up picture it looks like they'd be more of an air scoop pressurizing your underhood & decreasing the the pressure drop accross the raditor core making it harder for your raditor to cool the engine. I'd suggest rotating them 90 degrees & moving them further back from the nose onto a more flat area of the hood. So nay for me.
Farther back I would agree also.
 
The plot thickens... I just received my hood vents from Rallytech and I see I will have a problem installing my vents. These vents are meant for a 2001 Subaru Impreza . The mounting surface of these vents are not flat as you can see in my pictures . I mounted the vent to a piece of 18 gauge metal and you can see there is a very significant gape under the vent. I have prepared the vent to correct this problem .I am going to use a bumper repair kit and see if I can mold this thing into shape. Never done this kind of work before so wish me luck . Also I have added a picture of a vent install gone wrong ..
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