Like the title says this post refers to the effect of Radiant Heat on our CAI's.

This all started when I installed my new Scanguage II a couple of weeks ago. In an effort to try and figure out what guages would be the most useful I decided on MPG, HP, IAT, and water temp.

I have a PDM intake on my car. So it's basically an aluminum pipe that goes from the fender to the stock airbox. I had already insulated the pipe a while back with fiberglass backed reflective tape so I thought my IAT wouldn't be that much higher then ambient temps. Yea, I was wrong. On average my IAT's were around 30-40º hotter than ambient temps! Yikes that's not good.

This brings me to Radiant Energy. I found that this type of thermal radiation soaks into black objects like water into a sponge. That led me to look at radiant barriers for the big black airbox itself. The stuff I found I really like is too expensive. I found it at Pegasus Racing and it reflects 78% of radiant heat. It also happens to be similar to the material used in both the McLaren F1 and LEM (Luner Exploration Module). It is a GOLD Reflective Heat Barrier Film (http://www.pegasusautoracing.com/pro...p?Product=1838). As I said though it's expensive so I went with something less exotic...aluminum. Aluminum also makes an excellent radiant heat barrier and there are different types. Some thin fiberglass backed stuff like I used on my intake pipe and some thicker stuff with better insulation characteristics.

Two things that are key in radiant barriers are reflectivity of the barrier and an airspace between the barrier and the radiant heat source. The route I went was very cost effective for me. I spent $15 roll of foil tape from Lowe's. It was a painstaking process, but I think it came out OK especially for me. I'm not really good at stuff like that. The effects are interesting though I've only had this set-up for one day. It cut the AIT by about 20º on average. I also noticed that if the car kept moving the temps would stay lower, but as the car was stopped the temps would slowly rise as my poor barrier was overpowered by the engine heat. Before it was pretty much hot all the time. Tomorrow I'm going to test out how it does at highway speeds if it's fairly warm out.

Anyway here are a couple of pics...enjoy

 

No idea where you're gettng the most heat into the air intake from? But what you've done looks awesome and would definatelly shield the airbox to some extent from heat radiation.

To reduce IAT, you really want to place as much air betwen such tape and the object you're trying to protect from heat as once the tape reaches a specific temperature from radiation/convection, it will simply conduct the heat into the object it's attached to. By placing an air gap (ie glass fibre) in between the barrier and the part your trying to keep cool, you're slowing (eliminating conduction, reducing convection) the heat transfer rate.

At speed the air travelling through the air intake will cool the manifold down and in time reduce the IAT. Also where is your IAT sensor located? Maybe move it up and down the manifold to get an idea of where you're getting the most heat from (measure temp increase rate form cold start).

Nice work

 

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Thanks for the compliments Locco. I don't know why the IAT's were rising so much either. Your right about the air gap. The foil tape used on the pipe is that type. Fiberglass backed foil tape. The problem is the stuff is expensive. With a low investment of $15 I wanted to see what effect the plain foil tape had. It seems to have lowered IAT's about 20º relative to ambient temps. Ideally I'd like to wrap the intake pipe, airbox, and intake mainfold in gold foil. Hmm maybe one day

 

For a cheap experiment you could try wrapping/covering the intake pipe and air box with cut up strips of thick home blanket and maybe securing it with some wire or electrical tape? This would give you an idea of how far you could really push this insulation mod. If you move the insulation around and leave strategic areas uncovered it would also give you an idea of where you're getting the most heat ingress from. Just an idea

 

Sounds like a plan Locco. The problem is that I can't cover the airbox with anything too bulky. I'm happy with the improvement so far, but I'll know more when it warms up outside and I can see the differences then. I kinda know where the heat's coming from though. I did a surface check with an IR thermometer. The airbox surface temp was usually about 30-40º warmer than the intake pipe before I covered it. Now it's within a couple degrees of the intake pipe.

OH BTW the IAT sensor is located in the airbox up and to the left of the throttlebody. You can see it clearly on the close-up pic.

 

I think I might jsut have to give this a try with my Cobb. Thanks Sal.

 

Your welcome.

With a Cobb set-up you may want to try something like this:
http://store.summitracing.com/partde...0&autoview=sku

Here's a pic of the sleeve on a fellow Suby owners thread from the RS25 forum.

 

No way dude, that thing is like $45 plus tax (I live in the same town as the west coast summit warehouse) and the insulating tape is like $15.