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Originally Posted by ConnClark
A few things,
First get your engine up to snuff.
here is a good link Mercedes Diesel Maintenance tips
My 85 300SD has basically the same engine. To get good mileage on an OM617 the engine needs to breath. If they don't breath well you make soot from your fuel instead of power.
1) The first thing you should do is check the simple things. check your air filter and possibly replace your fuel filter. |
Done
Quote:
Originally Posted by ConnClark
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Done
Quote:
Originally Posted by ConnClark
3)The next item is to check your max boost pressure to make sure its in spec (11-12.5 psi). If not you need to adjust your waste gate which is kind of a pain but well worth it.
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It is 9 right now. I am going to make a manual boost controller.
Quote:
Originally Posted by ConnClark
4) 85's have an Air Recirculation Valve (ARV) on the turbo. Plugging the ARV vacuum line on the compressor housing of the turbo will get you a little better mileage in town as well as a slight boost in power at lower rpms ( higher rpms will remain uneffected).
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Done, The boost would stay at 1-2 then jump up to 6 as the vacuum solenoid kicked in. I just blocked off the Vacuum line to it for now. Also I blocked the EGR it was leaking bad. These really helped the mid range and low end. I figure that If I can push the throttle rack down less to get the same speed I am gaining FE.
Quote:
Originally Posted by ConnClark
5) With the 85 300D there is no direct mechanical linkage to the fan. It uses a viscous fluid coupling that only firms up when it gets hot. If it is working right most of the time it free wheels. Changing to an electrical fan would be less efficient. To keep the fan free wheeling as much as possible do a citrus flush.
Now back to aero
I would also say forget the airdam. I never met a w123 4 door owner that benefited from one as far as mileage (handling is a bit different story though).
If you want to do wheel strakes I would suggest making them out of broom bristles. You can trim them to fit. They won't break if you climb over a curb inadvertently. They are also cheap.
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Oh they can't look like broom bristles or coroplast. Not allowed.
About half of the front tire is exposed to the front. Aero wise that can not be good.
As far as front spoilers I personally have not had much luck with mileage improvements.
I bought a new roll of 9 gauge wire to start work on this project. I will weld up the strake forms and go from there.