Anyone using K&N air filter for the 450SL?

[speedy72t]

OK last post for the night. Anyone using one of these? It's still really earling in getting this car running right but when I did the tune up the other day the absolutely hauled ass without the filter cover on. It really ran completely different. Shifted much closer to redline and pulled much harder. so that got me to thinking that at least using a K&N might add a few of those ponies back without leaving the air cleaner completely out of the car.

[fasted]

I run K&N filters on all my vehicles. I started running these filters when they first came out and I still raced motorcross and have continued to use them for the last 25 years.

I find that in some cases I have had to recalibrate the fuel injection or carburation to compensate for the improved airflow, but overall the benefits have been substantial due to increased economy and performance.

To be honest, I really didn't notice a huge difference with my 1980 450SL though. I think the snorkel from the filter housing restricts the flow so much a K&N may only be of marginal benefit.

There are some threads on this forum about modifying the intake to provide cold air flow from the radiator valance, but this is difficult on the later cars due to the orientation of the intake snorkel.

IMHO, if nothing else, the savings from never having to buy a filter again make it worthwhile.

Ed

[230/8]

I have the K&N filter sitting on a shelf and have not used it yet. Why you ask?. Good question. I installed it in my 72 350SL and noticed that it is very slightly shorter than the original paper element. It fits, but there is not the same real solid tight seal around the filter housing lid like with the original paper element. I think it would be best to add a thin strip of foam weather seal to the sealing surface of the lid, hardware stores have this self-stick foam for sealing doors and windows. Only about 1/8 inch thick of foam would be needed to get a nice tight seal between the filter and lid. Why have I not done it yet? Lazy and other projects and my paper filter is brand new. I happen to have the K&N left over from a Mustang project. Yes, it is the same part number for both applications. I'll get around to installing the filter in the SL, some day. They work great. I've used them for years on my US cars, the only thing is the recharge oil kit is expensive, but you only need it every 10-20K miles.

230/8

[ericdee]

I use a Edelbrock Air Cleaner.

[speedy72t]

OK lets see a picture of that edelbrock on the Benz instead of a small block chevy!

I used to use K&N all the time but I stopped using them on the modern cars. There is plenty of solid evidence that the oil from the K&N can and will damage mass airflow sensors. The MAF on my Audi started acting up a few weeks after I installed a K&N so I pulled it and won't use them again. And frankly there is little need to do so with most modern cars as airflow is taken into account in a way that it wasn't on the old cars.

[ericdee]

These are old cars... No MAF sensors here.

[Greg in Oz]

I would be inclined to suggest that the air filter intake pipe, the throttle body, and in the case of K-Jet engines the air flow flap would create more obstruction to air flow than the filter element. MB tend to use pretty generous filter elements for the size of their engines. I found that modifying my air filter intake pipe (larger diameter and supplying it with cold air) yielded worthwhile performance benefits still with the original air filter element. Some 500 and 560 models uses two rather than a single intake pipe to the air filter (still with the standard filter element) which would reinforce the argument that the intake pipe is a significant obstruction. See my threads regarding the intake modification at:
Improvements to M116 in early 107 (true cold air intake)
Modification for early 107 (D-Jetronic M116 or 117)
Modification for D-Jet M116 and M117

[speedy72t]

Thanks for the post. I was thinking that I would prefer to do some sort of cold air intake with the original housing and this give me a place to start. I may still do the K&N in there but that probably isn't needed. I'm quite sure there will be gains in this area though. With the air cleaner completely removed The car definately pulled harder and was shifting 500 rpm higher. right now full throttle shifts are well belowe redline.
That's the least of my concernes right now though. First I want to make sure everything is tight with no vacuum leaks and do a full fluid flush on the trans before I start hammering full throttle shift adjustments.

I'm still betting that my best power increase investment would be nice new injectors. Cleaning is good but there is no way that 30 year old injectors are going to be completely up to par. Of course neither is the fuel distributor but no way am I spending $1500 on a new distributor for this old rat.