2 consecutive all nighters... still have a few questions though 85 300d - PeachParts Mercedes-Benz Forum

MikeDblU · #1 04-23-2013, 08:10 AM

So I got very bored and decided to attempt to address the rather dismal accelleration of my 1985 300d. After work I ran to salvo and purchased a plethora of exhuast parts, a new air filter, and a few other odds and ends.

So I spent a night removing the entire oem exhaust (great condition, have for sale/trade/iou) and trying to figure out what an insane person would do if they were to design an exhaust system. Clearly I replaced the downpipe with a flex pips then went directly out 2.5in pipe emptying behind the front passenger side tire. Its a bit louder and those who have seen it seem confused.

Realizing that I had already gotten dirty I decided it was time to remove the egr valve which then i blocked off with a blank metal light switch plate I drilled holes into to put the bolts through. the exhaust manifold part I found a washer that would cover it, blocked the hole with a bolt and washer with loctite and reused the old vband to hold it there.

I have tried removing the alda several times but never succeeded. Well halfway through my second all nighter I decided it was happening no matter the how badly i cut and bruised my hands. Soaked it with wd4o a few times and after 2 frustrating hours I finally cut a wrench handle in half and got it off

Earlier that night I tried driving it with the alda on but all the lines to it disconnected just to test the exhaust really and it was even slower than before which is what really motivated me to finally just get it removed.

So decided to clean up, put in my new air filter and see how it runs. I was rather shocked at how much of a difference this made! It was like a different car, I even chirped my tires without even gunning it. With the added volume of the exhaust I bought a box of sound deadening mat to put down since I ripped all my carpets out for no reason like a month ago.

Now a few questions. Sorry they are a little scattered but i figured perhaps there is someone who knows the 85 300d may have multiple suggestions for my plan for the next few days

1 Nobody seems to have anything about removing the arv valve. I removed the line and capped them both but am wondering if I would benefit from just removing the entire valve or if I even can do such a thing?

2 The oil separator in the air filter housing... I know it serves a purpose but can I replace that with a catch can?

I only ask the last question because I am rather determined to make a new intake and put the filter behind the headlight on the passenger sid where the intake tube feeding the current housing is. I will make a heatshield... I dont want to do this for performance per say I just find where the current one is to be incredibly inconvenient for working on anything or even looking to see that things are in proper order.

3 Exhaust wise, when making the downpipe I could not find anyone that made something to come off the turbo and go to exhaust pipe without the use of that giant steel flange originally used... Is there perhaps a lighter weight alternative to that or something more simple,? I simply fear with having my supports too far back that could be a heavy item supported by too little.

4 Currently still have the hose off the banjo bolt to the manifold hooked up as I had nothing to plug it with. I know this seems obvious but I can put a boost gauge there correct? follow up what would i need to get the sensor in there? does anyone know the pitch and such?

Simple one, now that the alda is gone can I remove the switchover valve completely? Want to remove as many things as possible really to clean up engine bay a bit and reduce possibility of vacuum leaks.

vstech · #2 04-23-2013, 08:38 AM

You might have better luck with answers to this style of modification up in the performance forum...
shall I MOVE it for you?

LUVMBDiesels · #3 04-23-2013, 09:15 AM

To answer some of your questions.

You can run a boost gauge from the banjo bolt. I did it on my 81 300SD
You can also remove all of the switchover stuff and if I remember the "Y"fitting that feeds it can be replaced by a straight through connector or you can use a longer hose to remove the junction completely

Once you have the boost gauge installed, you can then turn up the turbo with a boost control valve. I did and I set it to about 18psi

To go further, you can get an exhaust gas temp (EGT) gauge then you can turn up the fuel via screws on the injection pump. There are lots of posts about doing this.

As for the oil separator I have heard of people cutting it out of the air cleaner housing and mounting it. Again, search for the posts describing that process.

If you can get the air cleaner from an 86 or 87 300SDL, it might work out for you - it is a decent cold air intake system...

Good Luck!

TheDon · #4 04-23-2013, 09:21 AM

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