lowering underhood temps pros/cons

[Murphy]

So I have a 95 Spirit 3.0 v6 3 speed I picked up recently. For an intake I have a 3" cone filter coming right off the throttle body sitting right behind the battery, which is also pretty close to the exhaust crossover pipe. I was thinking if I lower the overall underhood temperature, it would give me colder air in the engine, and should help keep the whole intake cooler. My car already has 180* thermostat to help keep the engine cooler. This post is kinda 3.0 based, but I figured it could help out with turbo engines too since they get pretty hot.

So I was thinking I could start by removing the insulation on the hood. Easy, and I lose weight too, win/win right?

I had herd you could add some washers to the hood springs, so when the hood closes, the back sits higher and causes a cowl induction type effect. Does the cowl induction really help to lower underhood temps or is that just an intake thing? Would I benefit from this if I moved my cone filter to above the rear valve cover so I would pick up the cooler air coming in? I recall hearing something about this raising the overall air pressure in the engine, and making it harder for air to pass through the radiator causing overheating, is this true or am I thinking of something else?

would doing this cause any problems? Any other thoughts/suggestions/ideas?

[turbovanman²]

Right now, the position of your air filter is costing you power, raising or shimming up the back of the hood is an old trick from days gone by. GM and others used cowl induction at that area as is a high pressure area when driving.

Go ahead and do it, you'll allow colder air in and it should run cooler, I did this years ago on my old 78 Civic, made a huge difference but then it was 12:1 compression, Sidedraft, header,

[A.J.]

This works: http://www.turbo-mopar.com/forums/sh...ad.php?t=21046

A.J.

[GLHNSLHT2]

the problem with raising the rear of the hood is you kill the efficiency of the radiator.

[TheCanadian007]

How about taking a Charger 2.2 scoop and making a functional cowl induction hood? Pros, cons?

[GLHNSLHT2]

sure as long as you feed it into the engine. If you want to see a high efficiency attempt at lowering underhood temps, keeping radiator efficiency up, and downforce/drag good look at a factory example of the 84-86 Turbo Z/CS. That's how you do it. Or for modern day interpetation the latest model Viper. Nose sealed off to shove air through the rad, chin spoiler to keep air out from underneath the car, and big slanted back heat extracting vents well fore of the high pressure area at the base of the windshield.

[Ondonti]

Here is some interesting personal experience about lifting the back of the hood.

It certainly would not work for "cowl induction" at lower speeds. My duster has no climate control system and I had to drive it home while the windshield was icing up constantly (no wipers either).
Heat from the engine bay started coming up to my windshield and when I hit the freeway my windshield was totally free of icing.
So I found that cool that I wont ever have to worry about that problem even though I have no defroster/climate control. To be safe I would just have to warm up the engine BEFORE driving.

Just make a cold air intake. Move the battery tray forward if you need to. it doesnt require all of the bolts to be used. Ive gotten away with only 2 bolts holding the tray to the frame. Cut off parts of the tray if they get in the way etc.

[Ondonti]

Here is some interesting personal experience about lifting the back of the hood.

It certainly would not work for "cowl induction" at lower speeds. My duster has no climate control system and I had to drive it home while the windshield was icing up constantly (no wipers either).
Heat from the engine bay started coming up to my windshield and when I hit the freeway my windshield was totally free of icing.
So I found that cool that I wont ever have to worry about that problem even though I have no defroster/climate control. To be safe I would just have to warm up the engine BEFORE driving.

Just make a cold air intake. Move the battery tray forward if you need to. it doesnt require all of the bolts to be used. Ive gotten away with only 2 bolts holding the tray to the frame. Cut off parts of the tray if they get in the way etc.

I never reinstalled my Spirits CAI after I deturbo'd the car 3 years ago and then I finally installed it again 2 weeks ago. I have a smaller battery so I just cut the side off the battery tray and I had room to run a 3" 90 deg elbow from the TB beside the battery instead of my old setup where moved the tray forward and ran my CAI behind the tray. It would probably help to build some sort of wall between the rad outlet air and the filter.

[GLHNSLHT2]

I cut out the back of the power buldge on a spare hood I had and mounted it up. Then I taped yarn all around the hole. Fired up the car and the rad fan kicked on cause the car was warm. The yarn was blowing out away from the hole which was cool to see. I thought GREAT this is gonna work nicely. Took off down the road and at 25MPH all the yarn turned around and sucked down into the hole. On the freeway I thought it was going to rip off the hood and go down into the engine bay. Needless to say I put the stock hood back on.

Now the nose area on my car isn't stock. The bottom is sealed off (like the 84-86 TurboZ's) and I have a big spoiler underneath. So that all the air going into the nose HAS to go through the radiator. What tries to go under is pushed out and around the car by the big airdam on the bottom. So there's a huge negative pressure area in the engine bay pull air through the i/c, then the a/c then the radiator. So much so I'll run a 195 T-stat in 110 degree heat and not have the car get even to the middle of the gauge on the freeway.

I'm not sure what Ondonti's car looks like completely but if it's anything like the dash then I assume anything that's deemed extra weight is removed? Like splash shields and air dams?

[Ondonti]

It has an air damn that sits about 3" from the ground. No splash shields though. It never had any.

A yarn test sounds cool though. Wouldn't be able to show heat rising even if airflow isnt quite following the heat. I think I will try that on both cars in the future.

From my experience flipping the plenum backwards and running the intake on the passenger side of the car, it didnt help at the track even if I removed the filter at the end of the 90 degree bend and removed the passenger headlight (straight shot for air to go through the headlight cavity to the open 3" pipe behind it).

I think once you get up to a decent MPH heat in the engine bay is not a big deal. And heat in stop and go traffic will probably result in better gas mileage. Less pep though in stop in go I am sure.

[GLHNSLHT2]

With no splash shields in the wheel wells high pressure air is allowed to flow into the engine bay area. Also high pressure can get in depending on how people have their i/c piping setup. I've seen a lot of people get a T2 rad, take the i/c and a/c out and just run the pipes through the big gaping hole left there. Well when the air hit the rad it's not going to want to go through it when there's a nice easy hole to the left to go through. So now the rad loses efficiency. All those seals and shields are usually there for a reason. A yarn test would be interesting on your car Ondonti. I'm wondering if the air twirls there enough to grab heat out of the engine bay and defrost your window but doesn't really allow any air to escape.

[Ondonti]

Yeah I figured the lack of spash shields would do that. The fact is that the car is so much easier to work on when you can ignore those parts :P
Maybe I'll catch some video when I remember to try this test.