300sd wastegate membrane and K&N - PeachParts Mercedes-Benz Forum

GregZ · #1 02-15-2008, 10:19 AM

Hi All,

Now that my turbocharger is in the smallest pieces possible, I noticed that both the wastegate membrane and the blow-off membrane are ripped (shut). Any idea where to get these (I checked fastlane with not much luck)?

Also, I read some old posts about a general discouragement for using K&N (or similar) high performance air filters and oil separators. I am not sure I am convinced. Could somone reiterate quickly for me why not use a seemingly superior product (anybody with first hand experience)?

Thanks,

Greg

babymog · #2 02-15-2008, 10:54 AM

No first-hand experience.

K&N is a good filter system, but is it as good as the OEM paper? I have not seen any data comparing the two, I even have filtration efficiency graphs on my furnace filters, but was not able to get them from K&N when I requested them.

Any filter will restrict flow, the more you filter, the more you restrict. If you filter less, you restrict less. Whether the K&N does it more efficiently and removes as much of all sizes of particles is the important thing. Sure you can get more airflow by reducing or eliminating your filtration.

Oil on the K&N has been said to be a problem with MAF sensors. Some oil vapor is said to get on the platinum wire over time and cause it to be inaccurate, even fail. Not a problem in your '87 and older Benzes, no MAF sensor.

Last, it is not really shown to benefit the '87 300Dt, as you are already airflow-rich, the engine has to limit airflow (boost) at the top-end, where airflow restrictions affect power. Since your car needs the wastegate to limit airflow/boost, it indicates that increasing available air will not benefit your car with more power.

So in summary: No benefit, and possibly less filtration/more engine wear, and personally I feel it is much easier to lift out a dry paper filter every couple of years than to wash and oil a foam filter. Been there / done that on engines with oil-bath and foam filters, have changed them out to paper filters whenever possible.

Another item: If you're looking for the famous "cold air intake" look in your car, note that the OE air filter system sucks air in from outside of the engine bay, where it should be higher pressure and cooler than in the engine compartment where most ebay-style "cold air intakes" suck their air, look kind of cool but do the opposite of what you want. You might be considering the replacement filter that goes in the stock filter box, I'd stick with a good paper filter.

toomany MBZ · #3 02-15-2008, 07:40 PM

I've seen somewhere on this forum, I think, someone had done a test with filters, and the K&N didn't do so well, but there you have it. I use paper filters, after buying a K&N, new in box, if you're interested, PM me. This is for a 617 diesel.

#4 02-15-2008, 10:40 PM

Read through this and you will see why K&N is cr@p.
http://home.stny.rr.com/jbplock/ISO5011/SPICER.htm

Quote:

Compared to the AC, the K&N “plugged up” nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt.

Knightrider966 · #5 02-15-2008, 10:51 PM

The stock K&N airfilter is not going to give you any more horsepower! If you install the filter in an oil bath assembly and a foam pre-filter, you will trap more dirt this way. I use one here in the desert because of our desert dust storms, but not just like it is out of the box!

babymog · #6 02-15-2008, 10:53 PM

Interesting that heavy off-road equipment typically uses a cyclone and paper element. If only there were the space under the hood for a cyclone-style filter on the 123!

whunter · #7 02-16-2008, 01:58 PM

K&N filter topic links thread
http://www.peachparts.com/shopforum/showthread.php?p=1354738

K&N adds ZERO performance to a MB diesel, it passes more trash into the engine = increased wear/damage/cuts engine life.

Have a great day.