Reduce weight of W113

[e230sl]

Hi folks,

I am new here: 1965 model (me), studied aviation engineering (Technical University of Berlin), had two W113 in the past. Berliner living in Riga and Florida. Driving Mercedes since I am 18.

I am moving to Florida and will get me a 230SL.

I have a rather crazy project in mind that in rough terms would equate to an e-conversion WITHOUT dropping the ICE functionality. Think "plug in on steroids". So the car could still run on gas - but also electric. But with smth like 120kw electric power. Not 40kw like an average plug in.

Here my questions:
Has this be done? Electric conversions are pretty common. But leaving the ICE components (and functionality) intact?

Second:
A very rough calculation makes me believe that at a 30 to 40 miles range and with Tesla battery technology I could get away with adding between 150kg and 200kg (300 to 400 pounds). I might be over-optimistic or dead wrong: but seemingly the newest motor and battery technology is very lightweight.

The idea would be to try offsetting as much weight by replacing other parts. Examples:
Removing the spare tire (spare tires are for the hysteric).
Removing the metal tank - instead a 40l plastic tank in the trunk  (I need the space where the trunk was for the conversion).
Replacing the 12V battery with LiIo.
Maybe throwing out the seats - making lightweight, construction foam filled ones that look and feel similar but weigh nothing?
Replacing the both hatches with carbon fiber?

Just a few ideas over the top of my head.

Yes:
It so doesn't make sense.

Yes:
I am aware I could throw out the engine. But I wanna keep it.

Yes:
The energy savings are in no relations to the investment.

I know all of that. This isn't born out of any "need" - it's more a "could be done: so let's do it".

Yes l: it will be freaky expensive.

Are there folks who have tried to make the W113 lighter? How much weight can you safe WITHOUT going to extremes like removing the paint or interior (carpets, etc)? I want the soft top to remain as well. Obviously wouldn't use the hard top - as it adds weight. The A/C could be thrown out, or being  replaced with a very lightweight one. But then this car will be only driven open - just need to be able to close the top in case of sudden rain. So A/C isn't really needed.

Also: want to keep the original engine - not a lightweight modern replacement.

[doitwright]

The search function will reveal any discussions previously had on electric conversions.

No AC? In Florida? Hmm.

[e230sl]

Hi. I don't see me driving it closed. And A/C doesn't make much sense once you drive open. Just an idea where weight could be saved. Maybe a 3rd party A/C is lighter? Simply fishing for areas which could serve as battlefield to reduce weight. WITHOUT impacting the beauty. I could throw out the passenger seat. Or leave away the wheel caps. But that would look odd.

[Cees Klumper]

I lived in Florida for 10 years and would not want to drive open in the dead of summer (but that's me).
The fuel tank I think is pretty light. Hood and trunklid are already aluminum so relatively light. Seats are probably heavy so that would help. Lightest wheels and tires would be good.

[cabrioletturbo]

I am thinking you would probably want to move to Florida first, to see what you are up against with the open top and no A/C.
Secondly, the car itself was already built with many weight efficiencies in place already (you mentioned hood/trunk, smaller gas tank, etc.). You may want to consider removing glass and some chrome as they add significant weight to the total. Also the total weight may force you to go with bigger brakes, stronger suspension, different tires/rim sizes, etc, etc... That way your project becomes a full build, from which you may not be able to go back to the original setup. While you mentioned you might want to preserve the original setup?

Honestly, for the sake of originality, I would have probably consider an American car, since the starting price and cost of modifying would probably be miniscule in comparison with a pagoda. Then you would not need to revert back. Alternatively, you may consider finding just a rolling shell and go with a full hybrid transplant off another vehicle.

I guess the question is: what is more important to you? The pagoda or the challenge of e-ing the pagoda? Or e-ing a vehicle, which might not be a pagoda?

[scoot]

Steel wheels = 23 pounds
Bundt wheels = 13 pounds
Aluminum steelies = 11 pounds

[Pawel66]

I am thinking you would probably want to move to Florida first, to see what you are up against with the open top and no A/C.

I tried that in Greece (warm climate in a cabrio) for about 15 minutes, then went back to the rental office, took Hyundai Herz with AC and was very happy.

[MikeSimon]

Hood and trunklid are already aluminum so relatively light. 

I though the doors were too??

Be aware that one of the biggest issues with electric powertrains are common parasitic losses that reduce the range. Besides A/C, the other side of the spectrum, i.e.: the "heater" is a major culprit. There is a reason that most E-cars are run and tested in southern California - no heat required. Making heat from electricity is one of the most inefficient ways to do it.
When we worked on a CO2 A/C system years ago, we tested a Chevy Volt and a Nissan Leaf and the rated operating range went from like 100 miles down to 45 when heat was used.
In most E-cars the massive battery requires cooling and that can be used to make heat to an extend. But if you want to add an E-drive battery to your SL, you are faced with a major weight gain.

[etlans]

The fuel tank is not that heavy actually. The fuel tanks are never really heavy because there is no point in making them heavy. I do not really think that there is any point in reducing the weight of this kind of car. I mean, seriously, why do you actually need it?! I understand that you would like to always drive with the open-top, however, trust me, you still need an a/c. If you really want to lose some weight, I can recommend you a certain calculator that helps you to find out which are the heaviest parts, that can be deleted.

[MikeSimon]

Well...he is German...Like I am. We grow up without having A/C. Not in the house and not in the car. We can do without. I do not have A/C in my SL and would not want to have it. I also own a 1990 Corvette Coupé that is being operated only in the summer. I never had the A/C on in that car. If it is too hot, I drive it with the top panel off - like I do 85% percent of the time anyway. The A/C probably doesn't work anymore as the refrigerant has slowly leaked out over 30 years. The need for A/C in a convertible has always eluded me. But that's just me.

[Rolf-Dieter ✝︎]

I do have to agree. with Mike. On the other hand I fear that in about 10 years classic car drivers will be forced to convert to electric power our cars with fuel powered engines Will be banned from the roads (unless the become garage queens and or being towed to car shows). Anyway that’s what I think.

I drive mine for the past 2 years with the removable hardtop in place, I feel that without the hardtop I]my car is just another convertible. The hardtop does give the car the Pagoda look.

Dieter

[stickandrudderman]

A carbon fibre hard top with perspex windows would offer a massive weight saving but not as much as simply removing it!

[Benz Dr.]

I do have to agree with Mike. On the other hand, I fear that in about 10 years classic car drivers will be forced to convert to electric power our cars with fuel-powered engines will be banned from the roads (unless they become garage queens and or being towed to car shows). Anyway, that’s what I think.

I drove mine for the past 2 years with the removable hardtop in place. I feel that without the hardtop my car is just another convertible. The hardtop does give the car the Pagoda look.

Dieter

Do you really think that will happen? There will be gas-powered cars around for a very long time yet. Lots of places where electric cars are completely impractical.

[mdsalemi]

Well...he is German...Like I am. We grow up without having A/C. Not in the house and not in the car. We can do without. ...The need for A/C in a convertible has always eluded me.

Most of us of a certain age grew up without air conditioning--yes here in the USA. We suffered and we didn't like it. Nothing to do with our heritage. Houses built in the USA in most places didn't have centralized a/c until the 1980s. While some are bothered by cool air and some with warm, give me a/c anytime.

Aside from the mountains, Germany doesn't have nearly the climate range that we have in the USA. In parts of the southwest it's over 100 F regularly in the summer, but bone-dry. It's doesn't take a manly-man or anyone of a specific nationality to endure it; it takes a fool. The smart ones stay inside. In the SE USA we have the same--but with the added delight of high humidity. A/C is needed to keep an inside healthy and mold free. And then there's all the rest of the USA.

Cold spells in the winter, and heat waves in the summer anywhere routinely kill people...cooling centers open, and warming centers too. Stories like this from 2019 are becoming more routine:

https://www.dw.com/en/germany-swelters-in-record-breaking-europe-heat-wave/a-49734445

I'll keep my central climate control in my house and in my car, thank you.

[MikeSimon]

You guys may argue all you want, but....The human body does adjust to conditions. I grew up in Germany, lived there for 36 years and did not miss A/C. Every time I came to the U.S. on business or vacation, I had a cold for the first couple of days I was exposed to A/C. I was freezing all the time.
After I moved to the U.S. I slowly adjusted to A/C and now, after more than 30 years, when I go back to Germany and step off the airplane in the summer, I start sweating.

[mdsalemi]

...The human body does adjust to conditions. ...I had a cold for the first couple of days I was exposed to A/C.

OK, now that's a bit of nonsense, just like the doting mother putting a heavy jacket on the child going out on a brisk autumn day and saying "put the jacket on, you'll catch a cold".

Come on. A cold is a virus and has absolutely NOTHING to do with air conditioner or temperature. Nothing. Zero. It's a virus and spreads the way viruses do. People get colds more in "the winter" because they spend more time indoors, and it's the indoor proximity to other people that causes a cold. Not the temperature.

Yes, of course bodies adapt. People live at 12,000 feet altitude, but I cannot breath at 12,000 feet. Indigenous peoples live in the arctic and have adapted to cold, and other peoples live in the tropics and have adapted to heat.

Because you say you "don't need a/c" because you are of German heritage and grew up without it, may make you more resilient. I doubt your body is as comfortable at 95 degrees as it is at 75. Maybe your mind is...

[Mike Hughes]

When my dad was an active duty U.S. Army officer our family lived in Germany from 1960-63.  In July of '62 my grandmother, who lived in NYC, came to visit us in Munich.  The main topic that local news had been reporting on was a heat wave, and sharp rise in hospitalizations and deaths from heat exhaustion.  When my grandmother stepped off the plane she was so cold that my mom had to take her straight to Lodenfrey to buy a loden coat on the way home, because she did not think to pack a winter coat for a summertime trip. The heat wave continued during her visit, with daytime temperatures in the upper 70's in Munich and she wore that coat every day.

[dirkbalter]

Mike,
Funny you say that. I was born in August of 62 and my mother to this day is talking about how hot the summer was when I was born.
However, I think it was significantly warmer than upper 70th.   

[MikeSimon]

It may a be a "bit of nonsense" when you look at the science, but the fact is, I had a cold after being exposed to the "frigid" temperatures of A/C...Maybe I am a medical abnormality. Some have been saying that. 

[66andBlue]

...Maybe I am a medical abnormality. Some have been saying that. 

Mike,
do not despair, here is your chance to monetize your abnormality, become a posterchild - or influencer in current jargon - for the personalized medicine advocates. 🤑

[Shvegel]

Top down convertibles in south Florida are made for the evenings.  Oddly some of my favorite driving experiences involve rocketing down I-95 between Fort Lauderdale and Miami at 3 AM with the band Nirvana blasting on the stereo and virtually all of I-95 to myself.  During the day with the Sun out in the ever present traffic would be among the worst.

Other than the places mentioned the only places I see where you could save considerable weight would be the axles and suspension.  I would take a look at a BMW E39 Estate rear suspension as it is very modular and see if it might work in terms of width and mounting points etc.  Much weight could also be saved in the front but that might involve many custom parts.

[Merc_Girl]

I tried that in Greece (warm climate in a cabrio) for about 15 minutes, then went back to the rental office, took Hyundai Herz with AC and was very happy.

I have a Z4 and drive with roof down and A/C
I consider it my contribution to climate cooling 🤣