kaps

just had some questions about k&n. how much do they cost? where is the best place to get them? and lastly and most importantly, what are the gains from it, in both hp & torque, but also, non-number wise, how does it affect the car's driving? does one actually feel the effects of k&n airfilters? (p.s. need 2 K&N's for a 55 right or is it only one?)

5439cc

Kaps,
I have two K&N on my 02 CLK55 the gains are little but the sound and breathing are much improved. I purchased mine from
http://www.performaceproducts.com the cost was 38$ per. compared the the stock ///AMG filter the K&N is oiled and allows better breathing for the beast.

trock3155

Why would you need 2 filters? And in doing so would you have to do any special work for them to fit the engine?

bodyart27@aol

You do need two filters. The airbox that sits on top of your engine has two filters that lay horizontal end to end. The runners flow into the area of the airbox with the filters (separated) then converge at the back of the box right above the throttle body. Just carefully remove the airbox by tugging at the corners (held by clips - two metal prongs that grip a little rubber nub).

Be careful with the clips on the plastic runner part. There are little tabs on either side of the radiator brace. Flip the airbox over and you will see a bunch of torx (sp?) screws. Losen and the aibox opens. It's a one screwdriver (out of five) difficulty. I swap them if I dyno or go to the track.

Yes - it's good cheap horsepower. Attached is my dyno with stock rims and tires.

http://members.aol.com/clk55amg2001/dyno.jpg <---link to dyno graph)

bodyart27@aol

see the little stems with the rubber nubs that the airbox grips? See the brass discs at the front of the block (fuel pressure regulator maybe?). Go out to the far corner at a 45% angle from those discs a few inches - now do you see them? There is another set on the valve covers near the rear that are also visible in this pic. Notice the single throttle body opening in the rear center.... (big black circle back near the firewall).

bodyart27@aol

There are a bunch of torx (sp?) screws around the perimeter of the airbox. Notice the big rubber seal that goes over the throttle body bottom center. With the airbox flipped upside down, you can see where the two filters sit side by side.

bodyart27@aol

K&N on left, stock AMG filter on right

bodyart27@aol

let me try it this way...
All torque and horsepower numbers are at the wheels (not crank)... stock 17 wheels / tires.... geez, maybe 2K miles on the car? Dyno'd at Bob Norwoods in Dallas TX.

http://www.bobnorwood.com/

trock3155

wow. thanks alot for your help. Its nice to see the actual dyno gains to be had with the filter. Looks like I may have to invest in a couple.

DMXtremeZ

wow thanks for the info guys, i like the dyno graph showing the power gains

does it effect fuel economy also? any other adjustments you have to do manually, or after you install them, should everything like the air/fuel ratio settle by itself?

SaxManiac

bodyart - what does Norwood charge for a baseline pull? Couldn't find a price on their website.

Only time I've dyno'd a car was my old Supra...and I just don't trust the ricer shop with the CLK.

bodyart27@aol

You will need to call and schedule a time. There is a charge even for one pull b/c it takes a bit of effort to get the car on the rollers, strap it down, check humidity (or whatever calibration is necessary....) It's been a while but expect no more than $100 for 3-4 pulls.

We did some testing obviously with the filters, and he was easy to work with (that and I was working fast to switch out the filters). We also took the plastic runners off the air box, and also propped them on top of the radiator to straighten them out to see if there was any difference. We found that with no runners the car's hp and torque went down as we were pulling the hot air that was rising right above the block (heat = less hp!).

Hope that helps. The garage is quite interesting - Ferraris everywhere!

Ahmed

i've fixed a cone type on my 320. Can this be fixed on the 55 too?
Cause it sounds and feels great! I can imagine the effect on the 55!

bodyart27@aol

You would have to design a new airbox or investigate doing a cold air intake system. The current airbox doesn't have any sensors to be concerned with, but you would have to channel a pipe from the back of the block where the throttle body is located to the front of the car to get some cooler air.

Dinan makes a sweet Cold Air for the M5 while retaining the stock air box (I think):
http://www.dinanbmw.com/default.htm

Just having a cone air filter doesn't equate to more power, though it might sound better. The cone filter will definately flow more air, but you might be losing some hp conversely due to the heat of the air under the hood. The CLK55 is nice in that it channels air from the grill (cooler air) to the air filters.

Here is an example of a cold air intake on a nissan:
http://www.se-r.net/engine/cool_air_intake.html

Notice in this example the intake puts the filter into the fender which isolates it from engine heat and allows it to pull cooler air off the street. You might also see (VW/Audi/BMW) where the tuner just puts a shield in place to section off the cone filter from the rest of the engine bay to protect it from heat (thermal ? - crap I can't remember the term).

Also, resonance tuning / port matching / mandrel bends are important as well, (length and diameter of the tubing). All of this helps with the velocity of the air (not too turbalant) going into the engine. Too that point - check out the "velocity stacks" for the M5 on the Dinan page.

It's a fine balance, but with some good engineering, time, money, testing, and some inovative thinking - anything is possible.

Dyno, Dyno, Dyno - it's the only way to know.