Seriously considering encapsulating the bay on a W123. But where the hell am I going to fasten this thing?

It would have to be strong material to span such distances w/o fasteners and the whole point would be negated by adding weight.

Anybody have the chassis manual and some diagrams / numbers?

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oops. I actually have the chassis manual. It does not provide much dimensional data.

Use the factory skid plate option and go from there.

good call. If I can find a cheap one, it'll make a perfect mounting base.

If i can't, maybe I can use the mounting bolts for the plate and span the area with some bent conduit.

Good brainstorm, thanks again!

aluminum sheet is awesome for this kind of mod!!! easy to work with cutting bending shaping and east to drill and fasten! just like most race car's

Why don't you grab some of those plastic panels off of some newer mercedes or other car? Like from 1989 to 1999. Got to be a few of those kicking around in junkyards now.

The only thing that would worry me about a big aluminum sheet is the potential for damage to the rest of the car if god forbid it were to come loose. I say use aluminum to make a frame of some kind and use plastic, either used modified OEM, or some new thick grade styrene for the overall covering.

(11-10-2009 05:01 PM)willbhere4u Wrote:  aluminum sheet is awesome for this kind of mod!!! easy to work with cutting bending shaping and east to drill and fasten! just like most race car's

I can usually get scrap stainless. Its a bitc%h to work with, but durable...

....and shiny.. oooh.

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(11-10-2009 10:29 PM)dropnosky Wrote:  Why don't you grab some of those plastic panels off of some newer mercedes or other car? Like from 1989 to 1999. Got to be a few of those kicking around in junkyards now.

The only thing that would worry me about a big aluminum sheet is the potential for damage to the rest of the car if god forbid it were to come loose. I say use aluminum to make a frame of some kind and use plastic, either used modified OEM, or some new thick grade styrene for the overall covering.

Those panels are mostly flat and way too weak to span the distance on the w123. The 123 has a really low sitting oil pan and I think it might require 2 pieces of fabbed metal on each side... one crazy-bent, large ass piece of metal would flop around like a sail without some reinforcement.

I'll take pics 2morrow w/ dimensions (i've heard that before)

There would probably be some increase in fuel economy, right? maybe not much considering the overall shape of the vehicle, but it would be interesting to see if there was any difference.

I forget the number, but there is a pretty big improvement in fuel economy for properly designed underbody panels (10% is what I want to say). One thing you should keep in mind is that there are cooling aspects that need to be accounted for. Have a look at Dave M's pictures of the W124 Panels. The W124 has a completely sealed engine compartment... there are side panels, underbody panels, and seals against the hood. Since this isn't the case in the W123 you may not need to worry about it as much.

All the panels on the W124 are plastic, and the panels on my CDI are also plastic. Keep in mind you're going to have to take these things on/off whenever you work underneath it!

What if you combined it with some kind of fairing up front as well, like the AMG models? The sheet could come directly back from the bottom of a fairing instead of the curved body panel under the bumper.

what you need is a lovuer press just like thay do on hoods! it will help cooling and let water and fluids drain out

(11-11-2009 11:49 AM)willbhere4u Wrote:  what you need is a lovuer press just like thay do on hoods! it will help cooling and let water and fluids drain out

They use heat actuated louvers that vent into the front wheel wells (same basic operation as a thermostat wax pill).


If you leave the transmission tunnel open it should flow out enough air to keep everything ventilated.

The main frame rails are vertical in the drawing, the lower radiator support is on top.

The lower oil pan sits 7" below the main frame rails.

I might be able to span the holes on the frame rails with one bar and send one piece of flat stock from that bar to the crossmember under the engine. This should make a good backbone.

all my pics were too large... sorry, too lazy.

This might make your fuel economy worse. Take a plastic food container (like a yogurt container) and hold it open end facing forward out the window of your car while you are driving. Now cut a hole on the bottom of it and hold it out the window again. See? Without the hole it acts like a big scoop. The yogurt container is your engine bay, the open end is where your radiator goes.

That's why I recommend the louvers

wouldn't that only hold true though if it were a completely sealed bay?

If you were able to close EVERY little source of air leakage, I could see that might be a problem, but it seems to be a standard feature on newer cars, so the gain of streamlining it definitely makes sense. You would just have to allow a provision for air to escape.

It seems likely that this mod would be for underneath only, so air could still escape outside the wheel well areas.

and around the transmission tunnel