W123 40 mpg goal : The Most Aerodynamic brick - Page 2 - PeachParts Mercedes-Benz Forum

280EZRider · #16 05-26-2008, 03:09 PM

Don't forget to replace the USA bumpers w/Euros. This will reduce the weight considerably. Reworking the door handles for less exposure to oncoming air could also reduce resistence. The rear spoiler, however, is a waste of time. This is an inverted airfoil which doesn't do anything until maybe 90mph (works on formula 1 cars, but gimmickry for passenger car sales). Doing this speed is contrary to your entire goal, is it not?

t walgamuth · #17 05-26-2008, 03:15 PM

The best thing you can do is switch in a 224 rear end.

The fender skirts and belly pan should be good too. and probably blocking off part of the grill.

A six inch roof chop would help a lot too.

Maybe lowering will help too.

Tom W

TheDon · #18 05-26-2008, 03:25 PM

I'm going to need these for my mooneye look wheel covers

https://www.mooneyesusa.com/Store/product_info.php?products_id=1365&osCsid=5e85dbfc8ec126b57fcdb816ee8205b4

H-townbenzoboy · #19 05-26-2008, 04:12 PM

Take out the whole interior, carpets, back seat, center console, just leave the driver's side seat in. While you're at it, take out the dash and the spare tire. Once you end up with this result, ONLY then will you achieve the right weight for 40mpg in a W123.

JimmyL · #20 05-26-2008, 04:30 PM

You're going about this all the wrong way.
Just buy one off of ebay that already gets 45 mpg. I see them listed all the time.......

R Leo · #21 05-26-2008, 04:36 PM

Quote:

Originally Posted by techguy512

I've thought about how to do this. It's a little complicated in that you need to measure the difference between the fuel delivered to the IP and the fuel returned through the return line.

Not impossible, just complicated.

FloScan makes a diesel flow meter for marine use. I suspect it somehow measures the flow to and from the engine then subtracts the return and displays the difference.

It probably displays in gal/hr too.

R Leo · #22 05-26-2008, 04:39 PM

That's an interesting looking 5-speed in the AMG ad....FWIW, the biggest single improvement you can make to improve mileage in one of these cars is to install an 5-speed with an overdrive top gear. I went from 23 to 26-27 mpg in mine after installing the 5-speed and I haven't changed my driving style one iota.

Even with 2.88 gears it's a simple fact that they turn too damned fast at highway speed.

If I consider that I have about $750.00 in the 5-speed conversion, at 4 $4.79/gallon it will take approximately 27250 miles to recover the cost. Of course, if fuel continues to go up, the amortization is faster. I didn't take into consideration anything such as reduced engine wear, etc..

t walgamuth · #23 05-26-2008, 05:31 PM

Quote:

Originally Posted by H-townbenzoboy

Take out the whole interior, carpets, back seat, center console, just leave the driver's side seat in. While you're at it, take out the dash and the spare tire. Once you end up with this result, ONLY then will you achieve the right weight for 40mpg in a W123.

Weight reduction would help around town but on the highway it will not do anything measurable.

Tom W

#24 05-26-2008, 06:10 PM

Honestly, I think it would take some effort to get to 35 mpg, and I don't thing 40 mpg is feasible with the current engine,

GREASY_BEAST · #25 05-26-2008, 07:42 PM

Aerodynamics is key for good highway mileage. Minimizing surface imperfections such as trim and mirrors is a start, but the biggest gains will be when/if you change the overall geometry of the car. I think a boat tail, belly pans, wheel covers, and a front spoiler will make a world of difference in terms of mileage, provided they all work together to reduce turbulent separation and "suction". Improving the ease with which the car "plows" through the air or "separates" it would also likely help. I bet the W123 could benefit extensively from improved geometry of the rear of the automobile (boat tail) to clean up the way the air leaves the car.

EDIT: gains will not be as effective if engine rpm at speed isn't lowered. A 2.47 rear is an easy (and inexpensive) way to do this. ~2500rpm = 65mph.

DieselGrrl · #26 05-26-2008, 07:44 PM

The Don, take off your hood star, that will give you a 0.1% improvement.

#27 05-27-2008, 03:53 AM

Streamlining will be the key.

If you want extreme improvements you need to make extreme changes.

TheDon · #28 05-27-2008, 08:55 AM

I might not even bother with the benz. I have a friend with an old geo he might sell. I've got time and some money... maybe an electric car conversion is in order. I've been doing a lot of research on them since last fall.

myssrhl · #29 05-27-2008, 08:58 AM

Don,

Don't forget some tall / narrow tires pumped to 50psi +.

Ohhh..and the magnet on the fuel line to align the molecules of the fuel.
I actually bought one back in 1973.

Heck just blacking the trim is worth 10% on mileage.

Chad300tdt · #30 05-27-2008, 09:17 AM

Quote:

Originally Posted by TheDon

I might not even bother with the benz. I have a friend with an old geo he might sell. I've got time and some money... maybe an electric car conversion is in order. I've been doing a lot of research on them since last fall.

Have you checked out the Zap cars lately? I just went to the site and saw 2 NEW models available. One is priced at $32K and the other at $60K. They look pretty cool.

http://www.zapworld.com/

I saw a site recently where a guy built an electric car out of 2 scooters.