My first and maybe only aero mod for Benzilla?

[Varn]

I am going to make some strakes in front of the front wheels of my Benz.

Here is a view of it on the road.


The main reason that I am adding it is because the front wheels are well exposed from the front.

I have thought about bringing a front skirt down across the front of the car but with the condition of our roads in winter I think it to be unwise.

I plan on constructing the strakes like I made them for my camo minivan. Use a wire frame that has cloth stretched over it to use it as a mold for building up with composite.

[MetroMPG]

I'd re-consider that air dam.

What's the lowest point underneath the car? Do you strike the road surface with it? If not, that's food for thought about how low you may be able to make an air dam. Also, using a material with some flexibility on the bottom edge means you could go lower still, have occasional contact, and not necessarily wreck it.

[arcosine]

Dave, Benzilla is on the wrong end of that semi-truck. Consider a flexible material for under body parts.

[Cobb]

If your bens is anything like my 240d Id say the best mod would be to loose the directly bolted mechanical fan that has no clutch. I then used a paper clip to keep the electric one on the whole time the key is on. Just bridge the sensor up front.

[Varn]

Good points. Metro, I will make the wheel skirts first then decide about the cover. Tony She is drafting on the VW. The trucks were running 70.

Kind of getting off the aero theme but you have a good point Cobb. What kind of mileage were you getting?
I have thought about the mechanical fan. It has at least 7 blades. I am a bit concerned about running an electric fan full time. It only has a 65 amp alternator with probably a lot of hours on it. I have an unused antenna switch which might be used to manually control the fan.

[Cobb]

Your auto antenna doesnt work either? I left mines half up and disconnected it. The coil inside the motor/mast was jammed.

I kept up with traffic and got 32 mpg. I even sent off the brain box for cruze control to get rebuilt and used it exclusively on i95. A member here may have it some where if you are interested in it.

Yeah, having no over drive the engine is turning some rpms. I didnt add an additional electrical loads, so the alt is fine.

[Gasoline Fumes]

I played around with a Dodge Dakota air dam when I played around with a 300D.


A couple more pics here:
My 1985 300D

[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.

2) Adjust your valves or have someone do it for you. Its best done every 15,000 miles Mercedes Diesel Valve Adjustment Procedure
Note dieselgiant also has a video showing the difference this can make.

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.

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).


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.

[Varn]

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

Originally Posted by ConnClark

2) Adjust your valves or have someone do it for you. Its best done every 15,000 miles Mercedes Diesel Valve Adjustment Procedure
Note dieselgiant also has a video showing the difference this can make.

Done

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.

It is 9 right now. I am going to make a manual boost controller.

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).

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.

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.

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.

[arcosine]

Dave,
What do think about this:

1979 Mercedes 240D