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Discussion Starter #1
hey guys, i was reading around some other threads and found that some have removed their hood insulation in order to cool temps a lil bit... has anyone removed their hood insulation on their ss? i think im going to, any negative thoughts on this?
 

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I would think the more practical way to cool things would be to change the thermostats for the radiator inlet and the electric fans. Everything else is just window dressing.

I don't know the temps for the fans, but I would guess they come on at 180 deg F or so.

The cooling system factory thermostat is probably about 195 deg F. You can't go too cold. Keeping things pretty hot helps fuel economy. Also, if you run a 'stat too cold the ECM may never run in closed loop, it will always think the car is still warming up. Aftermarket thermostats often come in 160 and 180. 160 will most likely be too cold.
 

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Discussion Starter #3
thats good thinkin ctrlz...however, that would take some work and i dont want to start messing with that stuff...

ive heard removing the hood insulation along with wrapping i/c and intake and exhaust piping are both very easy and inexpensive ways for cooling... i also hear that by removing the hood insulation, it makes the blow off sound from the intake louder, which would be nice

ill let u kno what i think
 

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Wouldn't you be concerned that, sans insulation, the additional heat could affect the paint over time? I'm not sure if it would get hot enough for that to matter or not.
 

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Discussion Starter #7
m4gunner is right, theres no way the paint would be affected

the insulation under the hood is mainly sound insulation to keep the engine noise down and therefore have a quieter cabbin. it plays only a very small role in insulating engine heat...


well guys i removed it yesterday and theres not that big of a difference, little louder blow off sound (i have the opti-flow intake)
 

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I don't know if it is true, but a long time ago I was told it's part of a fire-retardant system. In case of engine fire, the insulation prevents spread & smothers the fire. Now that I am older & have taken a few Fluid & Thermo Dynamics classes, I don't really think it would be all that effective.

Just throwing it out there.
 

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If your car is black, the insulation might actually keep the engine bay cooler on a sunny day. :cheesy:


(I mean that as a joke... but really the outside of the hood on a black car would be hotter than the engine heat will ever make it, as far as the concern about heat and paint goes.)
 

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Discussion Starter #12
thats very true voodoo, the hood will get no hotter from the engine heat than it would on a very sunny day when u can barely even touch it

gunner- it only took me 2 minutes to take it off so id say its worth it, no time at all. the insulation rips pretty easy so what i did was make a small rip by each of the screws and then stretched it around the plastic rivets, leaving the rivets in the hood. this way, if i want to put it back on, i can just restretch the insulation back around the plastic rivets and itll be fine
 

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SeanArc said:
m4gunner is right, theres no way the paint would be affected

the insulation under the hood is mainly sound insulation to keep the engine noise down and therefore have a quieter cabbin. it plays only a very small role in insulating engine heat...


well guys i removed it yesterday and theres not that big of a difference, little louder blow off sound (i have the opti-flow intake)
Doesnt that contradict the whole reasoning for taking it off?

if it doesnt have any great insulatory properties as you state then how will removing it make the engine bay significantly cooler without it?
 

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Discussion Starter #15
i was taking it off mainly for the sound reasons, for a little more blow off sound...

i was just saying that people in the other forums were taking it off for cooling reasons which is contradictory
 

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Are these readily available as part replacements for our cars?
For it to work, the new lower temp thermostat would work effectively only if the electric fan cuts in earlier. Im not sure whether that is controlled by the ECU thru a sensor. Most other cars have a mechancal/eclectrical fan switch which can be changed out to a different value.

ctrlz said:
I would think the more practical way to cool things would be to change the thermostats for the radiator inlet and the electric fans. Everything else is just window dressing.

I don't know the temps for the fans, but I would guess they come on at 180 deg F or so.

The cooling system factory thermostat is probably about 195 deg F. You can't go too cold. Keeping things pretty hot helps fuel economy. Also, if you run a 'stat too cold the ECM may never run in closed loop, it will always think the car is still warming up. Aftermarket thermostats often come in 160 and 180. 160 will most likely be too cold.
 

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SeanArc said:
i was taking it off mainly for the sound reasons, for a little more blow off sound...

i was just saying that people in the other forums were taking it off for cooling reasons which is contradictory

Are you serious? You want to take it off for more sound?????

I don't think that will much much of a difference in sound.
 

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EarthDweller said:
Are these readily available as part replacements for our cars?
For it to work, the new lower temp thermostat would work effectively only if the electric fan cuts in earlier. Im not sure whether that is controlled by the ECU thru a sensor. Most other cars have a mechancal/eclectrical fan switch which can be changed out to a different value.
You are correct.

You would probably need to find a different relay/thermostat and wire it onto the stock Saab fan. There probably needs to be a bypass mode for the A/C (fan is always on for A/C), but that's probably obvious in the wiring. I doubt there is ECM control.

Unless the diameter is something unique, you can probably find cooler radiator thermostats easily. Remember, going cooler means less effective cabin heating in the winter.
 

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The main purpose of a hood insulator pad is for sound deadening, so yes, removing it should increase engine noise. It may or may not affect temperature appreciably. Many cars don't come with insulators, so I wouldn't worry about it affecting the paint. It won't get much hotter than it would on a hot summer day with the sun beating down on it!:cool:
 
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