My C55 dyno results - stock filters vs. K&N's
This past weekend I had my C55 dyno tested and was most displeased to open up the air boxes and find clogged FRAM filters in there.
1st pull through the FRAMs yielded 298.85 rwhp and 309.96 rwtq.
2nd pull after removing the panel filters and simply putting a K&N universal cone filter over the MAF sensor to prevent any debris from entering the engine, yielded 309.59 rwhp and 323.56 rwtq. I'm pleased with these numbers!
These are SAE corrected numbers. The un-corrected numbers were higher.
We also tested another C55 with stock replacement K&N panel filters and the car increased 8 rwhp over the stock filters.
This is definitely worth the $100 spent for two K&N's, and knowing I won't have to buy other air filters for the car ever again.
Just FYI...
This past weekend I had my C55 dyno tested and was most displeased to open up the air boxes and find clogged FRAM filters in there.
1st pull through the FRAMs yielded 298.85 rwhp and 309.96 rwtq.
2nd pull after removing the panel filters and simply putting a K&N universal cone filter over the MAF sensor to prevent any debris from entering the engine, yielded 309.59 rwhp and 323.56 rwtq. I'm pleased with these numbers!
These are SAE corrected numbers. The un-corrected numbers were higher.
We also tested another C55 with stock replacement K&N panel filters and the car increased 8 rwhp over the stock filters.
This is definitely worth the $100 spent for two K&N's, and knowing I won't have to buy other air filters for the car ever again.
Just FYI...

I have been preaching K/N's for almost 2 decades now, THEY are REALLY tuff to beat for the money per their return on HP.
See yeah

PS: There have been K/N's in EVERY car I have EVER owned.
However, the one flaw to this test, that I see, and I am sure the doubters will too- is the fact you said the stock filter was clogged in your car. Also, nothing was ever said about the condition of the stock filters in the other car you tested also.

Again- just something the naysayers (*sp?) will point out.
So you put a cone filter over the maf, and leave the panels empty? I have yet to inspect my engine compartment (and it feels great, coming from always working on my cars) so I have no idea about the layout.
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The cone filter test was just to see how restrictive the stockers were. Per the throttle body design and placement of the MAF sensor on the C55 it would be difficult to use a single permanent cone style filter on it. You would not be able to use the engine top cover if you did. Also it would defeat the fresh/cold air inlets from the front of the car which would likely cause a HP loss under normal driving conditions.
My filters were somewhat clogged, however my biggest concern was the fact they were FRAM, which is one of the lesser filtering mediums on the market. They may be the most popular due to their marketing campaigns, but they are not the best in micron-level filtering, whether it be oil or air filters. As for a stock paper replacement I would always use WIX or a Purolator PureONE version, however there is a great advantage to using a K&N that can be washed in the kitchen sink anytime it gets dirty. K&N also makes a good oil filter element for our cars which I'm going to use as well.
At the end of the day, there are many dyno proven tests to show considerable performance gains when using a K&N (or the likes) in place of a stock paper element. My Z28 was no different in that it picked up 17 rwhp by using a MTI air lid and K&N panel filter.
The advantage I currently have is that my friend owns a shop w/ a dyno, and also drives a C55 for now, so we're both gauging the results of any changes we make, and can do so on a regular basis. For example, he learned this week that by replacing his AMG wheels w/ heavier 19" look-alikes, the car lost 14 rwhp. That's valuable information!
Stay tuned for more results...
J
The Best of Mercedes & AMG
Not sure what we can do in terms of compensation, but you would receive the love and adoration of thousands of curious benz owners for years to come!
As for all the other testing that's been recommended, I think there are certainly some good ideas being suggested. However, since this is not my "race car", and I'm only trying to pick up a few small gains here and there, I don't anticipate I'll be doing all of these additional tests.
I believe we have clearly shown that with the K&N panel filter replacements we can gain 8+ rwhp. The number may vary 1 or 2 rwhp in either direction depending on all things being equal, but that's a good gain for a small investment. If you use other similar products, ie Green Filters, etc, you'll probably see about the same gains. However, by what I've seen, the Greens are not as durable in quality so I chose to stick by the brand I've always used in my performance apps.
I just wanted to share my results with everyone since we actually have data to back up the claims. I'll do this for any mod I make in order to help others decide if it's worthwhile for them too.

I took fresh OEM MB FILTERS, GREENS AND K&N and took them to the track granted never dynoed all of them individually but it really don't matter cause on the track in the real world the better filters shined via better quarter times...I ran each filters minimum 3 times and gave the best of all their individual runs...it proved that on my C32 they worked better while running...if the OEMs gained better at a dyno on a track is where it will really be tested for overall performance...I say don't even think about trying to run or dyno without air filters anything gets thru you can ruin the engine...people who say to test it that way should consider doing it themselves taking the risk instead. Great number though! I had dynoed when stock with fresh green filters 299 rwhp 290 rwtq and with dirty K&Ns on a warmer day by like 10 degress 286 rwhp...but on the track the fresh K&Ns yeilded better times on first track meet but greens slightly better on 2nd. Jacek ran slightly better time on OEM filters on one of his multiple runs...but I still feel that aftermarket filters are superior but not by huge amount. I can't vouch for a C55 though since its NA but I feel the aftermarket filters will shine in all cars compared to OEM.
P.S. We ran several times first to practice the launches...
Last edited by c32used; Jan 30, 2008 at 12:06 PM.
I think I also have a pair of Porterfield R4 race pads for the front axle if anyone tracks their cars. Plenty of pad left, used only 1 event $100.
Cars that run boost generate so much heat that 20,000+ CFM fans are required. Regardless of the airbox, a dyno shop should have a fan capable of proper airflow. Without it, the car will run hot and the dyno numbers come in low.













