26 gal. auxillary tank from the time of the 70s oil embargo - PeachParts Mercedes-Benz Forum

veg_burner · #1 01-10-2006, 02:35 AM

has anyone had experience installing one of these?
got one for my 300D vegmobile off ebay...

nazrat · #2 01-10-2006, 11:52 AM

No, but post a picture. I've never seen one and I'm sure that others haven't either.

-Tad

whunter · #3 01-10-2006, 02:35 PM

Bad idea...
The rear suspension will NOT carry the total load, your headlights will point at tree tops, and your MPG will drop due to the extra weight load.

I installed many of those in the 1970's, and took most of them back out when the vehicle owner filled it up before a family trip, and had the rear end squat down, headlights pointing at tree tops, broke springs or had massive MPG loss.

Calculate how much extra weight you would add behind the rear wheels with an additional 26 gallons of diesel.

Mitch H · #4 01-10-2006, 06:23 PM

Quote:

Originally Posted by whunter

Calculate how much extra weight you would add behind the rear wheels with an additional 26 gallons of diesel.

About 200 lb with tank. What's the trunk capacity of the average non-sls 300D or SD?

#5 01-10-2006, 09:19 PM

Just a FIY,

My 300sd hauled about 65-70 gallons (not sure..I know it was 10 more gal than 55) ALL IN THE TRUNK.

Of course it was not terribly fast, and it was a littly saggy...but it can be done.

I would hesitate doing this for long trips but if you are just kicking around town picking up oil here and there and the tank is usually empty when on road trips...I'd go for it.

Just remember...an extra 200-300lbs makes a lot of difference in your MPG. Not to mention the extra load on the rear suspension.

A 560SEL would be a good candidate..with the hydraulic rear suspension. Or a diesel wagon with the same stuff!

Lycoming-8 · #6 01-10-2006, 09:35 PM

Routinely carried 4 full 5-gal cans of diesel in the trunk of the 220D during the fuel crisis times of the '70s. At some point I switched to a poly tank mounted just behind the rear seat, which had a capacity of about 12 gallons. The move was made to allow the use of the trunk for luggage as well as fuel, due to family size increase. Found that a maximum of 8-gals was the appropriate quantity when stowing a reasonable amount of luggage back there. Any more would cause the rear end to hunker down pretty badly, and we were concerned about the half shaft u-joints' lifespan. All in all this was a pretty good compromise and still got 30+ mpg and all the range you would want at the then accepted 55 + 5 mph.

veg_burner · #7 01-10-2006, 09:38 PM

Quote:

Originally Posted by whunter

Bad idea...
The rear suspension will NOT carry the total load, your headlights will point at tree tops, and your MPG will drop due to the extra weight load.

I installed many of those in the 1970's, and took most of them back out when the vehicle owner filled it up before a family trip, and had the rear end squat down, headlights pointing at tree tops, broke springs or had massive MPG loss.

Calculate how much extra weight you would add behind the rear wheels with an additional 26 gallons of diesel.

if it's 200 lbs. it would be about as much as a hefty male riding in the backseat? or is the weight distribution different, as far as worrying about breaking springs. not too worried about mpg as i'm driving for free, and i would only really be using the aux tank on a long trip. at this point i've paid for it & all so i guess it'll be an experiment... supposed to arrive this week; i'll be sure to post pics after it does.

veg_burner · #8 01-10-2006, 09:42 PM

Quote:

Originally Posted by Lycoming-8

At some point I switched to a poly tank mounted just behind the rear seat, which had a capacity of about 12 gallons.

where exactly was it mounted? & was it custom made or?

Lycoming-8 · #9 01-10-2006, 10:01 PM

veg_burner,

The poly tank was mounted in the trunk right up against the rear seat bulkhead. It had a semi-trapezoidal shape, larger at the bottom than the top, when viewed from the side. There was a filler port in the right top surface, and a drain port and valve in the right bottom side. The drain port was plumbed to the main tank via a small ball valve and flexible tubing clamped at both ends. It was apparently a commercial item, designed and built specifically for the MB 220D trunk space; but I have no idea of the manufacturer as it was bought slightly used.

Have since seen an aluminum unit of about the same size and shape, but fit into the W-123 trunk space. Don't know if these two tanks could be considered as interchangeable since I'm not sure of the differences in the two forward trunk space dimensions (W123 / W115).

Mitch H · #10 01-10-2006, 10:36 PM

Quote:

Originally Posted by Brandon314159

Just remember...an extra 200-300lbs makes a lot of difference in your MPG.

Then why does it seem like the 116 and 126 300SD get the same mpg as the 123 turbo?

dunl · #11 01-11-2006, 12:37 AM

So where do you store an extra tank for WVO if you are running dual?

I always thought it went into the trunk?

pawoSD · #12 01-11-2006, 12:52 AM

I did 70-80 mph all the way to washington (730miles) with well over 700lbs of cargo (more like 1000...there was 300lbs of two people too) in my car, and I still got 21.6 mpg. We had tons of firewood, supplies, about 10 gallons of drinking water, and all kinds of stuff in the back seat too (trunk was filled to the top, every nook and cranny) By the time we were heading back we'd shed about 400-500lbs at least, and I was back up into the 24-26 mpg's. Car had no problem. Yes brakes needed more push (I could FEEL the weight of the car) and acceleration was slower....overall though, no biggie, especially with that big of a load.

sailor15015 · #13 01-11-2006, 01:00 AM

Quote:

Originally Posted by veg_burner

if it's 200 lbs. it would be about as much as a hefty male riding in the backseat? or is the weight distribution different, as far as worrying about breaking springs. not too worried about mpg as i'm driving for free, and i would only really be using the aux tank on a long trip. at this point i've paid for it & all so i guess it'll be an experiment... supposed to arrive this week; i'll be sure to post pics after it does.

Correct me if I'm wrong but a hefty male sitting in the back seat is at the minimum sitting over the rear axis, if not between the front and rear somewhat. Whunter's nice diagrams show what'll happen. The difference between someone in the back seat and a tank in the trunk is that the tank will be out beyond the rear axis, using leverage to point the front up, where the man in the back seat will be more evenly distributed between the front and rear axis. Also something I didn't think of when I had my dad build me a honkin' big 23 gallon tank is that you're probably heating that with engine coolant (I do) and that's a heck of a lot of oil to warm. Now I use a small ten gallon plastic tank. I can go for almost a week, it sits up next to the seat so the only noticable ride height difference is when the main and veg tanks are full. If I need more, say for a road trip or something, I still have usable trunk space to store more or other stuff. That 23 gallon tank killed my trunk space.

pawoSD · #14 01-11-2006, 01:03 AM

I've hauled an extra 22 gallons in cans in my trunk, and I didn't even notice it was there barely...car didn't go down more than 1.5" or so....and virtually no difference on acceleration......

26 is probably not that big of a deal....if it was 40 or 50 gallons, THEN it would be, as you'd be up in the 400lbs category....

sailor15015 · #15 01-11-2006, 01:32 AM

Maybe there's some suspension differences between the D and SD?? Both of my D's would weigh down very noticable with a full diesel tank and 10-15 gallons of veg. I'm going to install some heavy-duty Bilsteins in the rear and comforts up front. I read somewhere that that was a good combo.