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I have a 240D that is getting an honest 35mpg but I'm hungry for more (i bought it for the sole purpose of fuel economy.. although i dig driving the bling bling pimpin gold mercedes).

I have dumped some extra pounds, such as the spare tire, jack, and hitch. I need some help brainstorming.

First there si the Ethos fuel addative which is basically a misture of esters which apparently is used by diesel truckers to improve fuel economy- more than compensating for the cost of the addative.

Another is propane injection. I am hoping for some DIY plans to do this because otherwise it is way too pricey. I think that it would be a good addition to my biodiesel conversion becasue cold starts wouldn't be much of a problem with propane injection. Propane injection apparently improves mileage more than compensating for the cost of the propane.

I don't see much in the way of aerodynamics. Not much to do about that sort of thing.

Wheels and tires are something to consider. It would cost a lot to drop weight by buying super light wheels. Good tire selection might help.

Temperature control in a diesel is something that i don't understand in the least bit. For many vehicles, the colder the better. For diesels, i am not all too sure. But good ways to drop temp is (1) Redline water wetter for Diesels (2) maybe a flex fan or something in the fan department? (3) underdrive pulleys or something of the sort (4) insulating various places, cold air induction, etc... not too sure.

Any ideas? I think that cooling off the engine is a good idea in particular if i do the propane injection because then the combustion won't be as incomplete. What do you think?
 

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1982 300D Turbo
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Diesels are set to run at a given temp. If you lower that temp then parts will wear out a lot quicker and is harder on the engine. I really suggest you dont do that, thats number one.

Heres a link to propane injection, but if it was my car i wouldnt put propane injection on it.http://www.mrsharkey.com/lpg.htm

About your wheels and tires the newer style alloy wheels(bundts) are lighter and there everywhere. Easy to get a hold of so you could get a set of those and a set of 195 70 r14 tires and keep them inflated well and that would be another gain.

Make sure your brakes arent lugging wich would slow the car down with no brakes applied

Also make sure your wheel bearings are good and do not need repacking.

Check your air filter to make sure its clean and rotate it every so often. Dont add on a cold air induction, because it would actually be getting hotter air due to the air being sucked from the engine compartment instead of the ram air set up from the front on top of the right headlight assembly.

These are just the basics and i hope everything goes well[:eek:)]
 

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1984 300D Turbo
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I'm very interested in this topic too. I also bought a 1984 300D turbo as a commuter car to save gas (fuel[:I]). The fact that my $1000 go to work car turns so many heads is a bonus. I just ran my first tank of gas and only averaged 26 mpg. I was really hoping for more since most of the miles I travel are freeway.

I just today changed my air filter, the old one was really bad. And looked like someone had done the rotate routine on it [:D] It was like brown and black striped instead of white.

I'm also wondering about the transmission thing. Like a few others were posting my car shift threw all 4 gears and I don't know why it doesn't start out in second like it should. I have the hard 1st to 2nd shift but all the other gears shift fine. 3rd to 4th is the best, if not for the tech you wouldn't even know it shifted. If the car is supposed to start in 1st and not 2nd why would it have the kick down switch? My car will downshift sometimes when I accelerate or go up a hill without putting the peddle to the floor to hit the switch.

How do I check to see if my wheel bearings are o.k? My car seems a little strange also when I let my foot off the gas peddle (diesel peddle that is) the car slows faster than I am used to. But the car will coast fine if not in gear. It's like it is engine breaking or something.

Oh and I don't use the AC at all. I really wanted to try it but there is no fuse in the fuse box for the AC and I think maybe there is a reason for it not being there. Maybe if it gets too hot I will get desperate and try it but for now where are my MPG???

Thanks,

Mike
 

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W-1-2-3 Go!
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A light foot might also help [8)]

35mpg is very respectable for a 20+ year old car! Let alone one that has no problems at all and runs like a top!

You might also want to purge the fuel system if you haven't done so. It cleans the injection system and lets your car run smoother, meaning it's not wasting fuel just so it can run "better". While you're at it, the fuel filters might also need changing, as well as the fuel tank strainer. You might also be interested in cleaning the fuel tank of algae if any is present. Gives you more gallons of fuel too if you're able to remove alot of gunk.

Goodluck!
 

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1982 300D Turbo
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Mike! your im in san diego too, good to know. Just for your info all 300d turbos start out in first. You can feel it. when you slow down it goes from 4th gear to 3rd gear to 2nd gear and stays in that gear, UNTIL, you apply your foot to the throttle again from a dead stop, then it goes into first for takeoff then 2nd and so on. when your sitting still at a stoplight it is in second gear, but as soon as that pedal moves an inch it pulls the cable to the tranny wich shifts it into first, this happens even before the rpms start to rise at all. Try it out. Let off the brake and press the throttle very little, you would think its freeplay but its actually pulling a cable that is connected to the tranny, so push the petal a little and u will feel a tiny clunk, as it goes into first gear for takeoff. they make it like this so its smoother when slowing down and when in traffic because first gear is so low. Other gassers like the 300e and such all start off in second gear no matter what unless full throttle is aplied and the kickdown switch is pressed on the floor due to full throttle. Hope ive helped. [;)]
 

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mikec92117 - 4/21/2005 1:14 AM

I'm very interested in this topic too. I also bought a 1984 300D turbo as a commuter car to save gas (fuel[:I]). The fact that my $1000 go to work car turns so many heads is a bonus. I just ran my first tank of gas and only averaged 26 mpg. I was really hoping for more since most of the miles I travel are freeway.

I just today changed my air filter, the old one was really bad. And looked like someone had done the rotate routine on it [:D] It was like brown and black striped instead of white.

I'm also wondering about the transmission thing. Like a few others were posting my car shift threw all 4 gears and I don't know why it doesn't start out in second like it should. I have the hard 1st to 2nd shift but all the other gears shift fine. 3rd to 4th is the best, if not for the tech you wouldn't even know it shifted. If the car is supposed to start in 1st and not 2nd why would it have the kick down switch? My car will downshift sometimes when I accelerate or go up a hill without putting the peddle to the floor to hit the switch.

How do I check to see if my wheel bearings are o.k? My car seems a little strange also when I let my foot off the gas peddle (diesel peddle that is) the car slows faster than I am used to. But the car will coast fine if not in gear. It's like it is engine breaking or something.

Oh and I don't use the AC at all. I really wanted to try it but there is no fuse in the fuse box for the AC and I think maybe there is a reason for it not being there. Maybe if it gets too hot I will get desperate and try it but for now where are my MPG???

Thanks,

Mike
Hi Mike

It seems we posted at the same time. [:D]

Your transmission sounds like it's been adjusted to a spirited driving kinda manner. There is a bowden cable atop your valve cover. On it is a white nut. You can turn it so that the tension on the cable increases or decreases. When tension increases, the transmission will shift later and will readily respond to your mashing of the pedal, which I think is how your car is set up now. Retard the tension and your car will shift earlier. It would also be responsible for that firm 1-2 shift.

The kickdown switch is for downshifting at full power. Notice that when you try downshifting manually and flooring it, the car isn't as "angry" as when you use the kickdown switch.

Hey Marsh, that idea on the downshift to 1st from second when you lightly step on the pedal made me rethink my car's transmission shifting properties. I'll try it out tomorrow and see what happens. I'm pretty sure I feel 3 shifts. But it's always been weird because when I put it in L the car pulls instantly whereas from a stop it doesn't pull as quickly. So I guess you're right.

I feel 3 shifts but that's from 2 to 1, then back to 2, and on to 3. When I hit highway speeds I'm at 4th. Correct? This is exactly how my car feels like!!! So my car starts from 2nd! [8)]

Ok back to topic... [:D]
 

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1982 300D Turbo
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No, put it this way, every single 300d turbo goes through gear 1, then gear 2, then gear 3, then gear 4, every single time when starting off PERIOD!
 

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1980 300D 4 spd.
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stabmaster - 4/22/2005 1:29 AM

I have dumped some extra pounds, such as the spare tire, jack, and hitch. I need some help brainstorming.


What do you think?
I'm sure you don't plan on getting a flat tire, but
I think you should carry your spare and jack.

Using this sort of logic, since you probably won't have an accident, you should replace your front seats w/ aluminum lawn chairs. It will be much lighter.[xx(]
 
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Also check the fuel lines for leaks.
The braided ones are notorious for
leaking.
In my td wagon there is an overflow
tank for the fuel that has a few
braided lines running to it and they
are leaking.
I don't know if the sedans and coupes
have the same set up but it's worth
looking into.

Louis.
 

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1980 300D 4 spd.
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But I have been considering the propane idea for some time.

I installed a propane system on my boat, the whole thing cast about $400. (due to ABYC standards that MUST be adhered to)

heres the link on a quick overview of install...

http://www.westmarine.com/webapp/wcs/stores/servlet/WestAdvisorDisplayView?storeId=10001&langId=-1&catalogId=10001&advisor=propaneinstal.htm

I try to use boat parts on all my vehicals whenever possible because they are engineered to a higher standard than auto parts. OTOH they cost 3 times as much. [B)]
 

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1982 240D M/T White
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Other fuel mileage items.

1) Check air pressure every week

2) Throw out excess weight !

3) Consider low rolling resistance tires next time

4) Synthetic transmission fluid (Mobil 1 ATF for autos) & synthetic differential fluid (Mobil 1 75W90 for me) & synthetic Power steering fluid (Valvoline for me)
No brainer on all of these !

5) Consider synthetic engine oil (Rotella 5W40 for me)
Debateable on this

6) K&N air filter IF you live in a low dust area (like New Orleans)

7) Slow down & drive smoothly

8) Make sure car is aligned and front suspension (ball joints etc.) is in good shape

9) Clean & Wax car (1% or 2% at speed)

10) Use belts with small notchs on inner face (Gates for example) About 1/4 of 1%

11) Add cetane booster (also good for lubing fuel system. I use PS Car is also quieter !

12) Clean fuel filter

13) Use LED lights for running lights ( (Dash & a/c controls, etc. I will post more on this later)

14) Lose weight ! Also prolongs life of front seat (I live in New Orleans and the food is *TOO* good :) & :-(

Alan
 

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1980 250GD Cabrio
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There is a reasonably priced propane injection kit on the market (www.welshtec.com). Although it is marketed as an emissions reducer, it should also improve power and economy since it burns more of the fuel.

Duel-fuel diesels are not new and everyone I have asked says that there should be only positive effects if the propane is used in moderation.

As far as the obsession of recent posters with straightpipes, why bother responding to them. He has clearly decided to do this anyway. Maybe he can also put hydraulic suspension in his lowrider and hang some dingleberries around the windshield.
 
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