SlothGarage

I've noticed there are nearly no modifications for the C240, using basic flow physic principals, I figured out a way to give these cars a nice deep growl under load, slightly more torque, and mildly improve fuel economy.

Tools:
T25 screwdriver or bit
1-3/4" hole saw
1-1/2" hole saw
Drill
Fine grit sand paper (around 320 grit)
1 to 2 hours time

Start by removing the air box, there are quite a few guides on this, it's even in the manual under replacing air filters.


Remove the air filter covers using the T25 screwdriver or bit


Using the 1-3/4" hole saw, cut four holes along the outside (nearest to the cold air intake tube) and four 1-1/2" holes next to those closest to the inside. (note that the drivers side air filter cover needs the 4th holes cut above the clip)


Using the fine grit sand paper, clean up around the hole saw cuts to prevent any lose plastic from getting stuck in the filter.


Install some clean filters, this would be the ideal point to install some drop in dry flow filters from AEM or K&N but mine haven't arrive yet.


Reassemble just as a normal air filter change would go, again, notice here that the drivers side of the filter (left side in the photo) has the 4th set of holes relocated to the top because there is a clip in the way.


Once it's back together, install it back on your car as if you just did a normal air filter change, but due to the additional intake, the induction noise will be greatly increased under load as well as improving torque and due to the holes being along the bottom right above the engine and exhaust manifolds, it allows more warm air at cruising speeds to give you a mild increase in fuel economy on longer drives.

Here's a video of the induction sound after the mod was done.

eteller

You do realize cold air is denser and makes more hp, which is why the air box intakes route to the front of the car and the tubing is kevlar to avoid heat soak. Basically you just removed the cold air intake MB probably spent hundreds of hours designing on a CAD program, flow bench and dyno, but if you like the sound go for it.

SlothGarage

Okay, I know exactly what the ducts are for, and in city driving, you want torque, not horse power, torque is what makes you go fast, horse power is what keeps you going fast.

I wanted to increase the low end torque and by doing this you run shorter air runners or increase the volume of the intake (throttle body spacer or intake manifold spacers helps with this as well as porting and polishing the intake manifold)

This is by no means a sports car that in any way benefits from a cold air intake, it has less horse power then a Mazda Miata and is nearly three times the weight, so with odds like that I feel like gaining fuel economy with a hot air intake so the fuel burns more effeciently (better mpg) and more torque are much smarter decisions for a luxury pig of a car going around town.

I appreciate your input as there many be others out there who don't know what the intake tubes are for, but in every aspect of this mod I see it as a gain, at least personally I do, it may make less horse power now (so it will have a slower top end speed which is well over local speed limits), but more torque (so it's faster off the line), and improved mpg, I was getting 15mpg before, I'm now getting 16.5 mpg after this mod and I don't take this car on the highway and all driving habbits have remained the same. It's actually been colder recently so I feel like it will level out to around 17mpg in the summer or more with some low rolling resistance tires and lowering the car for better aero dynamics.

But again, not trying to be a dick, it's obviously just my two cents, but with the maybe 1 to 2hp gain of a proper cold air intake the car comes with, vs the amount of gas I'm saving, it's literally the difference of driving with or without a passenger, and the car does feel much faster off the line when I'm driving alone, it's all in such small variables none of this really matters in real world, it just sounds angry and I'm saving gas now.

Russell Ormerod

Nothing wrong with giving it a try as an experiment. But really cold dense air will make more power and torque. If it doesn't work then just buy another filter housing from a scrap yard.

Holmes5518

lol, I don't recommend anyone do this to their vehicles. This guy didn't outsmart German engineers.

kanadian

ive been waiting for someone to reply to this for so long... cutting holes will not do anything because your piston stroke will not change. therefore the air needs to be forced into there with some sort of mechanism like a turbo. hot air will decrease performance.