Lining intake boxes with heat resistant material

Genxer said:

Ford Performance chose an open design as well as Roush. Is their hood seal better than others? I don't know. Anyone see different temps with those designs?

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Exactly. Because people like Hot Air Intakes and will buy them. So they make money by offering and selling those "cool" parts (pun intended).

My friends Roush Stage 3 has much higher IATs from their "Phase 2" Hot Air Intake, when driving it, despite it making more power on the Dyno over the original closed airbox. I wish he dynoed the car with the hood closed with both intakes, but he didn't. That would better simulate how each intake really takes in air, however no one does it and an open element will almost always make more power with the hood open on a Dyno over a closed box. But hey, it looks cooler and all people care about is looking cool and making more power on a Dyno, even if they're slower on the road.. but you can't measure that so it's not a concern, nor does it sell parts one way or the other.


0.02

bjstang said:

I can make the intake air temperatures hotter by using the lava mat in the wrong places. The long explanation is here if you're interested, post #103. http://www.mustang6g.com/forums/showthread.php?t=74739&page=7

Bill

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I dunno.. my JLT air box is half wrapped (POST #20 in this tread). intake tube fully wrapped. Seen nothing but cooler iAT's. Mine also seals right to the hood.. not sure how much that helps with the wrap.
:cheers:

I've had reflective heat shield underneath my boss manifold for about a year now. Haven't dynoed it or tested temps. Works fine.

after I put this on I used Aluminum foil tape, it's been on ever since last August of 2016, no issues as of yet.

I did the insulation thing using foam with aluminum top cover tape, bought at Lowes or Home Dept. (don't remember which store)

By observations of IATs compared to ambient over time (a few highway trips) I found a 1.5 degree reduction before vs. after insulation. I say 1.5 because sometimes it was 1 and about the other half of the time it was a 2 degree reduction.

I spoke to Steeda (the manufacturer of mine) at a HPDE event I participated in that they sponsored. When they noticed it, they said they measured a 1.25 degree reduction in their testing of the same approach. I conclude there is a benefit, albeit small.

Heat soaking by sitting during idle seemed to occur more slowly and recovery was noticeably faster although I didn't take any data points here because it would nearly impossible to try to duplicate the conditions before and after.

So for what its worth, quite a bit of work for a small gain BUT every little bit helps, right?

Forgot to add, I dropped 6 - 7 degrees IAT as compared to the OEM setup before the insulation was added. Now that's a significant improvement. (which took less time than insulating)

All you need to do is compare your IATs at idle with hood down and hood up. Then feel where the hot air is coming from.

You want the MAF/temp. sensor on the inside of the heat shield to keep the radiator heat away from it. Most heat shields that seal against the hood block the driver side heat extractor causing it to sit in a high temp area. No manufactures CAI makes the sheild protect the MAF like this and it wouldn't take much. I would guess it would make a big difference in idle IATs.

I added these and dropped another 1 degree IAT.
Only the driver side is functional, the passenger side is blocked off.

Wally-Bob said:

I did the insulation thing using foam with aluminum top cover tape, bought at Lowes or Home Dept. (don't remember which store)

By observations of IATs compared to ambient over time (a few highway trips) I found a 1.5 degree reduction before vs. after insulation. I say 1.5 because sometimes it was 1 and about the other half of the time it was a 2 degree reduction.

I spoke to Steeda (the manufacturer of mine) at a HPDE event I participated in that they sponsored. When they noticed it, they said they measured a 1.25 degree reduction in their testing of the same approach. I conclude there is a benefit, albeit small.

Heat soaking by sitting during idle seemed to occur more slowly and recovery was noticeably faster although I didn't take any data points here because it would nearly impossible to try to duplicate the conditions before and after.

So for what its worth, quite a bit of work for a small gain BUT every little bit helps, right?

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That reflective wrap would work a lot better on the outside of the box.

BmacIL said:

That reflective wrap would work a lot better on the outside of the box.

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I slightly agree with you.
In short, I chose reliability over absolute maximum performance.
Here's why:

Something black will absorb radiant heat (infrared rays, AKA radiant heat waves) very efficiently. Something black will also radiate via infrared very efficiently. A reason your car radiator is painted black instead of silver.

Conversely, something silver does not absorb radiant heat very well nor does it radiate infrared heat well. All good in theory until a slight coating of dust covers the silver and it begins to absorb and radiate a lot better.

Now moving our attention to heat conduction, heat transported thru the material by molecular motion. Here is where the R value comes into play, the value of thermal conduction thru materials. The aluminum (silver metal) of the wrap/tape conducts very well whereas the foam insulation of the wrap/tape conducts very poorly. The plastic air box conducts heat somewhere between the two. So again, it doesn't make any difference which is first or last, the R value is the sum of the materials of the composite.

The insulation used in your house has the silver side facing towards the inside wall and works for either keeping heat in or out. The R value is the same in both directions which is why there is only one value stated. In terms of radiant heat it doesn't make any difference whether the silver side is first or last. A good thermos is silver on the inside and the outside is usually anything but silver. They work equally well for keeping things hot or cold. (Ice cubes are not considered for discussion here since melting changes the physics of the total quantity of heat transferred.)

Now here's why I slightly agree that the silver should be on the outside.

The overwhelming source of heat is hot air coming from the radiator which considerably over powers the radiant heat coming from the radiator and block. The headers (silver) are nearly completely obscured from the air box's vantage point. My point here is that the outside surface temperature of the air box as I have it would be just ever so slightly higher than if it were silver because it is constantly being washed with a massive flow of hot air. As I have built it, yes there is slightly more heat making its way into the air box.

I chose to construct it with the silver wrap/tape insulation on the inside for longevity. Keeping it out of the hot air blasts washing over it should equate to a longer time before the adhesive fails. Inside when it does fail, it will just separate from the box but mostly stay in place as it slowly delaminates. Conversely, on the outside of the box, the air rushing past will cause flaps to wag like flags and accelerate the delamination.

markmurfie said:

All you need to do is compare your IATs at idle with hood down and hood up. Then feel where the hot air is coming from.

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Unidirectional. But mostly from the rad

markmurfie said:

You want the MAF/temp. sensor on the inside of the heat shield to keep the radiator heat away from it.

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Did that, remarkable difference in IAT's.

markmurfie said:

Most heat shields that seal against the hood block the driver side heat extractor causing it to sit in a high temp area.

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So does the stock airbox.. sits pretty close to the hood. Less then a inch clearance. But allows excessive high pressure to bleed out.
Otherwise it just 'dams up' in the box.

markmurfie said:

No manufactures CAI makes the sheild protect the MAF like this and it wouldn't take much. I would guess it would make a big difference in idle IATs.

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You are correct Sir.

Wally-Bob said:

I slightly agree with you.
In short, I chose reliability over absolute maximum performance.
Here's why:

Something black will absorb radiant heat (infrared rays, AKA radiant heat waves) very efficiently. Something black will also radiate via infrared very efficiently. A reason your car radiator is painted black instead of silver.

Conversely, something silver does not absorb radiant heat very well nor does it radiate infrared heat well. All good in theory until a slight coating of dust covers the silver and it begins to absorb and radiate a lot better.

Now moving our attention to heat conduction, heat transported thru the material by molecular motion. Here is where the R value comes into play, the value of thermal conduction thru materials. The aluminum (silver metal) of the wrap/tape conducts very well whereas the foam insulation of the wrap/tape conducts very poorly. The plastic air box conducts heat somewhere between the two. So again, it doesn't make any difference which is first or last, the R value is the sum of the materials of the composite.

The insulation used in your house has the silver side facing towards the inside wall and works for either keeping heat in or out. The R value is the same in both directions which is why there is only one value stated. In terms of radiant heat it doesn't make any difference whether the silver side is first or last. A good thermos is silver on the inside and the outside is usually anything but silver. They work equally well for keeping things hot or cold. (Ice cubes are not considered for discussion here since melting changes the physics of the total quantity of heat transferred.)

Now here's why I slightly agree that the silver should be on the outside.

The overwhelming source of heat is hot air coming from the radiator which considerably over powers the radiant heat coming from the radiator and block. The headers (silver) are nearly completely obscured from the air box's vantage point. My point here is that the outside surface temperature of the air box as I have it would be just ever so slightly higher than if it were silver because it is constantly being washed with a massive flow of hot air. As I have built it, yes there is slightly more heat making its way into the air box.

I chose to construct it with the silver wrap/tape insulation on the inside for longevity. Keeping it out of the hot air blasts washing over it should equate to a longer time before the adhesive fails. Inside when it does fail, it will just separate from the box but mostly stay in place as it slowly delaminates. Conversely, on the outside of the box, the air rushing past will cause flaps to wag like flags and accelerate the delamination.

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A few more tidbits to add for what it’s worth;

My IAT always reads 2 °F higher than the ambient temperature reading. This is measured BEFORE starting the engine and after allowing more than 24 hours to elapse since last engine run. This seems to be consistent with most reporting the same observation.

I have the 50th Anniversary Trim package so as such my grill is different than most. About half of my honeycombs on the extreme driver’s side of the grill are open as stock. I can see the silver insulation inside the air box by looking thru the grill. I have contemplated opening the balance of the honeycombs AND adding an air dam to prevent air from washing over the front of the radiator, (not passing thru when slow or stopped and fans off) thus heating up and entering the air box.

I currently read at steady state (given sufficient time to dissipate heat soak) 2 – 3 degrees above ambient reading. I say 2 – 3 because half the time it’s 2 and the other half it’s 3. So I conclude that means a 2 ½ degree difference. Now with a 2 degree difference between the sensor readings when all is cold suggests that my CAI set up (some open honeycombs stock, functional hood scoop and CAI w/insulation) keeps all but the last ½ degree of heat from being ingested.

It is important to add that this ½ degree of heating is only achieved at highway speeds, 70+. At prolonged periods of 30 or 40 mph I do not achieve ½ °F rise, rather 2 – 4 degrees higher typically. I attribute this to the hood scoop providing the ram air boost at higher speeds thus drawing less thru the grill. There is something to be said for more air flow due to more throttle at slow vs. fast mph, thus more air to heat with the same rate of heat transfer thru the insulation.

I did insulate the bottom of the Voodoo IM, but keep in mind this advantage will not affect the IAT since it is down stream of the sensor.

So in closing, I’m fairly satisfied that I’m near the maximum of what can be achieved with the current set up. Like with everything else Hot Rod, lots of time and $$$ could be spent chasing the last few small benefits of improving the system which in the end may be hard to measure. That $$$ is better spent elsewhere where benefits are more easily achieved.

Stock air box

Opening the grill up and insulating just the lower part of the stock air box helped I should have taken a pic with the box out but the complete lower box is insulated may not be pretty but it really helped