Now, For those of us that are pretty familar with the intake setup of the W126 and W140.

Lately I've been seeing alot of things and stuff about cold-intake systems and such and read how they supposedly increase horsepower and more recently, increases mpg ratings.
A couple of friends have suggested that I should get a cold-intakes system for my W126, except looking at the normal cold-intake system and compared to the ones that is one the W126, a cold intake looks like it wouldn't do a thing or add benefits to my engine. In fact, the way the W126 (and I believe the W140 also), is set up, it's set up to take the cool air that flows as the car is in motion (that comes in near the radiator and aux. fan) into the twin tubes, and thus into the intake, and thus seems to be a bit better than a cold air intake. Which basically puts a special filter (most cases a K&N) attach, a black heat shield, a tube (sometimes metal in some cases), and into the intake. And thus a cold-air intake? So what makes this different from a normal W126 intake? Maybe I'm missing something. Anyone care to enlighten me on the art of cold-intake? And wouldn't a metal tube absorb more heat, (like an exhaust) and heat up the air anyways?

 

On my W220 I already have cold air stock. The inlets for each cyl bank are at the grille, about as cold as one can get. All these CAI units are rarely better than stock. There is much discussion about these on the 300C forums, I had a volant CAI on my 300C and sold it, it made a nice intake roar but otherwise was of no value. I have not seen one dyno sheet or 1/4 mile data to show any performance gains and I did not realize any MPG gains on the 300C. There are several reports of K&N filters allowing too much dirt in, some seemingly substantiated with oil analysis data.

 

That's interesting! I have not noticed any noticeable difference other than a slight roar increase during acceleration, from the K&N filters that I've installed. Nor have I noticed any change in the engine oil. I am still trying to determine for myself (in light of the rhetoric and printed media), whether the K&N serves more of a benefit or not.

As for allowing more dirt, well, I'm sure that has a lot to do with how much oil is or is not on the filters. So, far I have not had to clean my filters, and I've got about 7,000 miles on them. And my understanding is that they do not need cleaning until at least 30,000 miles. I doubt that I wait that long, but we'll continue to monitor them, of course.

As for the CAI, I'm still waiting to hear real life experience of someone that has made the transition to really state the recorded difference over stock. Thus far, I've not heard or read it. Thus far, I'm just not convinced.

As for increase horsepower, I keep asking myself this question: "If a computer chip will reprogram and increase my engine horsepower (which is dramatic), how is it that a filter or gadget (turbonator or the like) gets to do it? I don't know these answers scientifically, but common-sense doesn't allow me take that plunge! Not yet, anyways.

So, for me, keeping the engine clean, keeping the oil clean, keeping the injectors clean, being mindful of the gasoline used, and the performance of preventive maintenance, that ought to do all that I need done.

But I'll still keep my ears and eyes open.

 

After looking closely, I notice a little dust like build up around the intake and it probably getting into my engine. I think I will probably take that darn K&N thing out and go back to regular filters before something ends up broke.
Hell, the money I save on filters probably won't add up to a new engine anyways.

 

I owned a Mini Cooper S once, and replaced its stock intake with a CAI, and then for giggles did dyno testing to see the improvement. From what I could tell, the CAI:
1) didn't cool air, it just took it in from a location that was less likely to be prewarmed by the engine
2) was much less restrictive in airflow than the stock setup; the stock intake was a 3-foot snorkle with a number of bends, leading to a flat (approx 6"x9" filter), the replacement was a 6" cylndrical canister leading down a 9" large bore tube to the throttle body.
3) was noisier
4) took air from a location that was likley to see high pressure at speed (windshield cowling area) instead of one that would see lower pressure (inside the nose vent).
5) increased measured bph by 5

Point being, for some car designs, the stock setup is not optimal for performance, but is perhaps more optimal for safety/noise/manufacturing cost. CAIs might not make sense for every car, particularly ones with a good design in the first place, but there's a place for them in the rest of the automotive world.

For the record, the CAI I used on my Mini was one with a reputation for modest HP improvement; many others when measured showed negligeble improvement. The K&N drop-in rectangular filters were minimal gain items on the Minis as well.

 

I had one one my 97 Grand am with the 2.4 twin cam and it made a definte difference but on my W126s i cant see how it would help same with my Audi cold air from the grill doesnt get much better.

 

Well I guess it is safe to conclude that the effectiveness of a cold air depends on the stock designs. Most cars are put together and sent out into the world. The upper end of the totem pole, the designers and engineers probably looked closer at intake and such and more detail and designed it accordingly. And thus a $30 aftermarket intake part probably won't do a darn thing to increase performance in a motor that come out the factory already tuned for high performance. Drop a cold intake in a Focus and it probably will show some increase in HP and maybe even a MPG gain. Drop it into a S55 and it's a waste of time. And don't forget many of them things like anything are fraud to begin with.

 

Blackwolf hit the nail on the head. Kinda like putting N2O in your car without all the other modifications needed to ensure your seals don't burn out.

 

It already has cold air intake