[Neil_p]

I’ve been looking into getting an Injen intake for my 328i, but I’ve been told by some people that this will cause a loss in performance since it’ll suck in the hot air from the engine bay, which I don’t understand since it comes with the heat shield cover for it. Is this performance loss true or has anyone experienced it? Any information would be greatly appreciated!

[AlmondJayRoM3]

Yes, heat soak is a thing. Metal pipes in the engine bay get hot. A little cover is still not going to prevent hot air from getting sucked in compared to the stock system that pipes in colder air from the bumper or fender well This probably is particularly noticeable in stop and go traffic during the summer. Just monitor air intake temperatures and you will see what I mean. They stay more or less consistent with the stock exhaust moving at most 5-10 degrees. With a similar setup in my mazdaspeed3, Temps would quickly jump 20-25 degrees F and slowly creep up from there if idling. Don’t get me wrong, on the dyno the COBB conical oil based filter breathed better and resulted in more top end hp but that’s to be expected. I could literally see daylight through the cotton element. I understood that more dirt was going to get through it. On my F80, I left the intake stock for a few reasons. The first one being the lack of filtration. Second the car is my daily and I don’t need to extract every last bit hp. It’s only flash tuned with stock downpipes.

In the end that was my experience and on a different car. Only way to find out is to try it and see for yourself.

[njdangelo]

I have an open air intake for my 340i that I purchased from a fellow forum member. He installed a stick on heat dissipating material to the metal shield and it works fantastic. While it doesn't utilize the same piping from the front grill it does sit in the same location and does continue to get the "cold air". I have monitored intake temps and only saw 4-5 degree increase. It's generally excepted that 10degrees of intake temperature equals 1% horsepower reduction (or gain if you are cooling the air) so the open air filter has not had any negative performance effects in my day to day driving. It should be noted that I haven't taken it on a track and I do not sit in stop and go traffic so your experience may differ from mine.
Like the previous poster I used to own a Mazdaspeed vehicle as well although I had the speed6. When I added the intake to that I definitely noticed heat soak but the filter was in a different location and TBH the intercooler placement on that car was probably the main culprit... directly on top of the engine. Still an incredible machine though

[tardboi]

I have the CTS intake and didn't notice any loss of performance. With how much air is moving thru those pipes, I doubt it's heating more than a few degrees - except in stop and go, but then it will cool down as soon as thinga get moving again.

[Billfitz]

Whether or not you'll suffer a loss in performance is debatable, but what's not debatable is that the stock intake is a cold air intake. If the reason why you want a new intake is to have a cold air intake save your money, you already have one.

[omie]

I have mine installed for about a year and a half now, works like a charm. Didn't notice anything, except the blow off sound of turbo, and more growling sound when hitting the gas. Injen is very nicely covered on each side, so it is also an cold air intake, as the air duct directly points towards the filter within the box. I've had many different ones on different cars, and I must say, this one is a perfect and easy fit which is fully covered on all sides.

Only at the very beginning I had some stutter with rpm, because the air levels were different of course. Within a couple of days that was gone, as the ECU adjusted the levels and made the engine work like charm.

I would recommend getting it, not for the extra power (which is nothing), but for the sound