Intake air temps comparison 128i-N52's

[CACTUS1549]

Does anyone know how the stock air box temps usually correlate with the ambient external temps in comparison? I installed an Injen CAI before getting my p3Cars gauge so I have no idea how hot the stock box was running in contrast. I usually got intake temps of 10 over ambient at coolest with the Injen, then I installed AFE scoops and got 7 over ambient at coolest. Recently, however the two rubber weatherstrips on the top of the heatshield have come off and now I'm lucky if I can get below 10 over ambient at coolest. I almost never see my 7 degree difference anymore.

Two questions...
1. How does the stock air box usually compare?
2. Can I get a cover for the top to fit over the heatshield and extend over the filter like this:

[TheSt|G]

Stock airbox is very well insulated to the engine bay. I wouldn't be surprised at all if it had lower temps than what you were getting. Aftermarket air boxes tend to focus on sound and power gains before the engine warms up and heat soaks them.

[chris82]

Put your stock box on and tell us!

[631twentyeighteye]

My dyno runs proved that the injen gets incredibly heat soaked even after just 1 pull.

[TheSt|G]

Originally Posted by 631twentyeighteye

My dyno runs proved that the injen gets incredibly heat soaked even after just 1 pull.

Exactly.

Most people don't seem to realize that the stock intake and exhaust components on a BMW, even the cheapest one they make, are very well engineered from the factory.

[CACTUS1549]

I think I may run to the local hardware store and get a 1/8" thick sheet of plastic and cut it to fit over the heatshield. Maybe I'll buy some rubber damming as well to seal it tight. I was also thinking of getting some standard temperature wrap insulation to wrap the elbow pipe behind the filter, since I have the SS pipe, it would only seem logical that it is highly affected by ambient temps. I'll let you guys know how it goes, and how pretty it turns out to be.

On a lighter note I did however get a consistent 4 degrees over ambient the other day. I think what has been bothering me is recently we've had like 95 degree days in NC, so it naturally has been running hotter. Past few days have been cool and cloudy.

Originally Posted by Chrisar82

Put your stock box on and tell us!

When I do my CAI cleaning and MAF sensor cleaning I will goof around and pop the stock box back on for a baseline judgement on temps.