K&N air filter for 300SD - PeachParts Mercedes-Benz Forum

PeterT · #1 06-17-2004, 12:38 PM

As a newbie to this site and forum, I have read with interest the reports (all positive) about using K&N air filters. I went to my local Kragen and special ordered one for my 1985 300SD. It came a few days later, and I could tell without even opening the box that it was not the correct shape or size. I asked the store to double check the product number which they did and assured me that it was correct. The problem was that my car is a California car and the 1985 SD came with the now infamous trap oxidizer, and also has a different filter (smaller around and much deeper) than all other 1985 models. Bottom line is K&N does not make an air filter to fit this car. My question is whether any other states required the trap oxidizer in 1985 or is this an "only in California" problem.
Thanks in advance for any responses. Love the site!

oldnavy · #2 06-17-2004, 01:56 PM

Something you need to know from both my own experience and the experience of members on the TDI forum.

1. Does not produce any increase in power as measured on a dyno on turbocharged engines. (K&N type of filters in general)

2. From engine oil sample testing, the filter does allow way too much dirt past filter media, and it shows as high silica readings. This was my personal experience 15 years ago with a K&N on an '87 NA 4.0L Jeep Cherokee and about a year ago findings of TDI forum members with same problem that's cured when OEM filter is replaced.

3. No one reported any useful increase in MPG.

4. At $50 or more for one of these K&N filter and the only gain being the filter is reusable, it would take 7 or 8 years to pay for itself. But the problem is the likelyhood of engine damage occurring.

If you still think these are the best thing since popcorn, just remember these were first designed for race cars to protect the engines from large particale injestion. We all know that race car engines don't get driven for years before being rebuilt. Most are rebuilt in under 1000 miles. The K&N filters were not designed to protect your everyday family car from the fine dirt and dust particales that the street car is exposed to for years and tens of thousands of miles. They sell these things to street users for the simple reason there is big proffit involved and more sold more proffit.

Grdenko · #3 06-17-2004, 02:30 PM

yeah, i was gunna say, hardly all of the K&N related posts are positive, but i like mine.

it gave me 4 mpg more on the highway, but no perceptable increase in power

#4 06-17-2004, 02:31 PM

Does anyone know if you can clean oil off a K&N filter after it's been in a SD? My regular air filter gets a nice coating of oil fairly quickly. If you can get engine oil out of a K&N filter, the purchase price might be worth it.

Also, is there anyway to upgrade the oil separator? Mine doesn't seem to do the best job at keeping oil out of the filter housing.

Last year I built my own custom air intake, but the oil separator I made leaked too much. It was nice hearing the turbo, though.

Hatterasguy · #5 06-17-2004, 07:30 PM

I thought the trap-ox was supposed to be replaced under a recall?

oldnavy · #6 06-17-2004, 07:47 PM

Check out the CCV Filter I designed for VW TDI now being sold, I think we can easly made to fit a 240D, don't know about the 300's though. STANCO Machine If there were enough interest I'm sure we could get a special group buy just like they do on the TDI Forum.

vwbuge · #7 06-17-2004, 08:20 PM

Peter,
I feel your pain. After I paid $36 for a stock air filter I decided to toss the whole setup for the federal version. This may be a hard swap for you as you are in CA and I am in PA. A donor 300SD was pretty easy to find with the federal emmissions. Follow the link at the end and you will see what I did to my car. It was well worth it. Response was quicker it is a bit faster now also. I used a knockoff K&N and I have had no trouble with it. I was afraid it was going to be too loud but it is perfect. A barely audible whistle from the turbo sounds awesome. I absolutely believe the car is more responsive because of this filter. The turbo seems to wind up a bit quicker. Others on this forum will swear up and down and stomp their feet and tell you it is impossible, hogwash.
You should be able to rid yourself of that air canister and fix some kind of filter to suit you.

Oil Burner,
You can purchase a foam sleeve to fit over your K&N to absorb the oil and just pull it off to clean.

http://www.peachparts.com/shopforum/showthread.php?threadid=90424

#8 06-17-2004, 08:37 PM

The Fram 8006 (I think

) has the same diameter opening as the turbo inlet. A rubber tube connector on the turbo inlet to a few inches of PVC and snug the Fram on the end of it. All the + of a K&N for $45 less.

oldnavy · #9 06-17-2004, 08:40 PM

It's been proven too many times on a dyno that you can't increase power on a turbocharged engine by more then about 2 hp with a "high flow" filter over a standard filter.

If you really want to help your turbo spool up faster remove the muffler. On a turbo diesel a muffler removal will be the cheapest and easiest way to lower trap times and increase top end speed. All this with little, if any difference in exhuast note and the ability to hear the turbo whistling. Now that's a beautiful sound.

You should hear a 1.9L turbo diesel VW with a "mufflerectomy" it is music to a diesel lovers ears. Been there, done that with oversized injectors and stage II chip. 134 mph by GPS and not red lined. It sure will make the ricers with "fart can's" jealous.

PeterT · #10 06-17-2004, 08:44 PM

The recall work on my 1985 300SD trap oxidizer was done by the local MB dealer (free) several years ago. I'm a bit unclear as to what exactly they did (anybody know?) but the air filter housing remained unchanged. I believe this setup is fairly unique to this year in California. As a result, the standard replacement
filter is $56 at Kragen and comparably priced elsewhere. This was in part why the concept of a reusable filter seemed attractive.
Based on some of old navys' comments, the unavailability of the K&N for this year may have been a blessing in disguise.
I seem to recall paying less than $20 for a replacement air filter for my '77 300D (RIP) 285K, not so long ago.

dc88168 · #11 06-18-2004, 02:13 AM

I got the CA version air filter from Rusty's for about $33.

David
_________________
1985 300D Turbo

vwbuge · #12 06-18-2004, 10:36 AM

The original trap-ox and replacement catalyst look exactly the same. An untrained eye can only tell them apart by part number. The only thing they did was replace the turbo and the exchange the trap for the catalyst. It would be easy just to get rid of that large cannister and buy some sort of filter to replace it with. The large tube coming from my turbo has a small piece of PVC reducer to make it fit the filter opening.

vwbuge · #13 06-18-2004, 10:41 AM

This is what it used to look like.

TomJ · #14 06-18-2004, 01:15 PM

Quote:

Originally posted by vwbuge
........ I absolutely believe the car is more responsive because of this filter. The turbo seems to wind up a bit quicker. Others on this forum will swear up and down and stomp their feet and tell you it is impossible, hogwash.....

Ditto to the above. The system I had installed on mine (similar to vwbuge, but mine had a cold-air intake setup) POSITIVELY gave faster spooling (felt start at 1800rpm) and certainly more response than the stock setup (slow spool and starts at 2400rpm.) But the Triple-K turbo I used in the alt filter setup had a larger compressor than the Garrett and the Garrett seems to work better (spool at lower RPM, regardless of air intake setup) with the 123 than the Triple-K from the SD.

PeterT · #15 06-19-2004, 01:05 AM

An earlier post touted muffler removal as an effective method
of getting the turbo to kick in sooner. Just wondering if anyone has tried this on a 5 or 6 cylinder MB diesel ( in a populated area).
It seems like it would be loud enough to attract police attention, and I would think be illegal as well. My neighbors probably wouldn't care much for this mod when I start my car at 3AM to go to work.