Supercharging a 280 SL

[XK150Guy]

Do you guys know of anyone who has put a supercharger on a 280 SL? Thanks!

[RickM]

Would be interesting to see anyone has done this as well.

Thinking out loud....

I wonder how conducive the 280 drivetrain setup is without extensive modifications.

What comes to mind, is amount of torque in relation to the gearing. Is the trans and rear robust enough to handle the extra HP?.....not to mention many points on the engine that are typically beefed up to handle the compressed charge. Then there's the fuel delivery, injector capability, cooling capacity.

Perhaps a low compression, sealed oil, Whipple (twin-screw) type setup would add a nice kick....or maybe the "more German" approach with a Turbo    (In fact a BAE type system for the 911 SC may be the best candidate)

[Benz Dr.]

I would have to think that compression ratios would be one of your bigger challenges. Over heating would be right up there as well. Then there could be head gasket failure...

[mdsalemi]

The venerable but underpowered 190 SL had an aftermarket supercharger available, made by Judson.  I know nothing about it other than it existed and I saw a 190 SL with one on at the shop that restored my Pagoda some years back.

http://www.190slgroup.com/tech/judson/judson%20p1.htm

Read about in the 190 forum.

[XK150Guy]

As RickM and others have noted, there would be a number of considerations. However, Superchargers have been put on everthing from MG TCs to Suburbans with, in many cases, significant success and few problems. As MDsalemi says, I know that they have been put on 190SLs but I don't know what, if any, mods they made and how happy they were with the results. I don't know enough about 280 SL drive trains to know it they could take the extra grunt. I can't believe that it hasn't been tried, I guess we just have to hope that someone that HAS tried it reads these posts and will give us their comments. Thanks for your comments.Bill L. 

[hauser]

The only add-on that I'm familiar with is the Judson that Mike has mentioned.

There might be a turbo solution for our cars.  Karl Midelhauve has done some of this on other MB models.

http://www.mbgrand600.com/

[XK150Guy]

Apologies to Michael Salemi, I hadn't noticed that he had posted the web address of a guy who put an original/vintage Judson supercharger on his 190 SL...see the address above in Michael's post. In the blurb the SL guy posted he says he is extremely satisfied with the supercharger and says that it is "The best investment in this car you can make" and "There is now a significant increase in power off the line and while cruising" And he doesn't seem to have made ANY changes to his drive train! So, guys, wouldn't YOU want "...a significant increase in power off the line and while cruising" in your 280 So maybe supercharging a 280  IS a good idea. Hmmmmm.

[XK150Guy]

The big problem with turbo chargers in an aftermarket situation is that the installation is FAR more complex that for a supercharger. All of the exhaust manifold/turbo interface plumbing would have to be fabricated and that is a major engineering/fabrication challenge. RELATIVELY the supercharger is more of a "bolt on" exercise. I am part of a group that runs a world  record- setting turbocharged car at Bonneville and our turbo engineer says that, superficially, it  looks like installing a supercharger on a 280 SL wouldn't be much of a challenge but putting a turbo in there would be a problem. Bill L.

[al_lieffring]

there would have to be some sort of boost pressure enrichment at the injection pump. boost  pressure could be piped into a pressure pot built around the barometric compensator.

[Benz Dr.]

I had a Judson once for my 190SL but I never installed it. I sold the Judson years ago
In that case it was a complete kit but there were many extra parts to go with it such as a can that fed oil to the pump rotors so they wouldn't wear out. Boost pressure was kept to a modest 5 PSI or so. Claims were it increased HP by 40% which I think is a bit over stated but the 190SL engine is rather flat in the low RPM ranges and that's where a super charger really helps.

The injectionj pump boost pressure regulator would need to be something like what's used on a turbo diesel. I think the far better engine to use would be the 129 or 250SL. Better cooling and the largest rad size of the three cars. Since the engine was not built for this purpose, you can expect increased wear in the cylinders due to higher pressures. The ignition timming would also have to be retarded or ther pistons would melt down.

You would also have to change the front pulleys to run belts for the SC which could lead to all sorts of clearance problems. You could expect 200HP maybe so it would go pretty good.

This thread needs to be in R&D.

[RickM]

My forced induction experience is with Porsche 911s....they inherently have their own set of idiosyncrasies.

The bottom line with any project is, if you start with an engine that is worn and/or is not designed for the added stress you will greatly shorten the lifespan of the power plant. No one wants that.

That aside, I am not familiar with Judson. I am, however, familiar with centrifugal, Roots type SCs, Whipple type (twin screw) superchargers and turbos. I mentioned the Whipple, twin screw as a possibility as they are modern, efficient and small footprint units which inherently bring boost on in a more gradual manner.

Personally I am more familiar with turbo fabrications and therefore more comfortable with their use......and yes they're more involved.

Luckily there are many ways to skin this cat and the options available to make forced induction work to your advantage are well proven. From intercooling, piggyback computers to precision wastegates and Rising Rate FMIs you can really design a system that walks the tightrope of increased power and longevity.

[mdsalemi]

Well, I'm glad XK guy noticed the link, and went to it.  A lot of information there.

If one must absolutely, positively have <<more power>> in their Pagoda, its probably easier to do an engine swap than try to rig something up with a turbo or super charger.

With the latter, you delve into all sorts of unknown areas (which by the way, hundreds of talented engineers in this area work on full time every day on cars you might see in 3-5 years).  With the former, you take 2 proven units (engine and chassis) and your issues become more simplisitic.

There are plenty of engine swaps on record, including the Mechatronik SL which has been done exceptionally nice. http://www.mechatronik.de/en/engineering/the-m-sl.html

If one managed to actually fit some kind of --charger to the M130, and was in the middle of solving the myriad problems you would encounter (Al Lieffring brought up a couple) with 40+ year old parts, you might appreciate it when an engine swap Pagoda pays you a visit.

Also, as a reference, see this: http://www.mbcoupes.com/memberscars/T/satishtummala/page1.htm  kind of covers some of the issues in a swap.

[GGR]

As shown by Hatch & Sons, the 3.5 m116 is a reasonably straight fit. The 4.5 m117 also fits, even if there are more clearances issues. Later alloy M117 5.0 and 5.6 also fit, but the exhaust manifolds are very near from the chassis rails. The 560 SL manifolds may be the best option. The advantage of the 3.5 and 4.5 iron blocks is that they offer the possibility to fit a manual transmission, but I guess there would need some tunnel modifications for the side shift system to clear. The m116 4.2 may be the best option: reasonable displacement and light enough because it's an alloy block. There is a possibility to mate it with a Getrag 265 5 speed manual transmission with a bit of adaptation work. With a good fuel & spark management system this would be a very balanced and spirited car.

[Ulf]

I once saw a US-spec Triumph TR6 fitted with an Eaton supercharger which made it about as fast as the fuel injected Euro-spec cars. Generally, I think supercharging is a much less complicated and dangerous way of getting more power as opposed to turbocharging but even a mild form of tuning will almost certainly reduce the life span of engine, but probably in a much more entertaining way than others...

[mdsalemi]

Ulf,

Having been in an Opel Manta on the highway, at speed, when it "threw a rod" so to speak, I can tell you there is nothing entertaining about an engine "explosion".

The only good news was that I was not driving and it was not my car!

[RickM]

I think supercharging is a much less complicated and dangerous way of getting more power as opposed to turbocharging

IMHO, I'd reverse the conclusion by saying the supercharger is more "dangerous" as it (for the most part) is always robbing power from the crank. The turbo is much less parasitic as it scavenges it's drive power from the exhaust under load.

Additionally, one can very easily reduce boost by way of an adjustable wastegate, therefore, reducing stress on the engine/drivetrain.
One pretty cool tweek back in the day was an adjustable boost knob in the cockpit. One could run a relatively mild boost for everyday driving and at any time turn the boost up for a spirited run. (Some would get carried away though and grenade their BIG buck engines)

[Ulf]

@Michael - I wasn't referring to an exploding engine as fun, but rather the thrill of driving fast - even if you know, that it'll shorten the life expectancy of your engine as opposed to killing it off due to lack of maintenance
I didn't know that the Opel Manta was available in the US, my parents neighbors had one from new (in a suspicious shade of orange) that I though was a really cool, when I was 7 - especially since my own father drove a dull 4-door Opel Ascona at the time...

[mdsalemi]

Ulf, I knew you were joking.  The Manta I was in that threw a rod was in 1980.  It was not new at the time.  My boss was driving me to work, it was the 2nd version of the gas crisis and we were carpooling.  The next day we took my BMW. 

[hauser]

Mike, just a little curious.  When the break down happened did you tell your boss you would be late for work?   No better excuse for being late when the boss just happens to be with you!

[treedoc]

   I'm with GGR, any of the aluminium block V8 motors would get my vote over a blown M130 280, you need to remember the 280 is a bored out version of the 230 which in itself is a seven main bearing, bored version of the 220 thus the thickness of the cylinder walls between the cylinders is relatively thin to start with, leading to early popping of head gaskets.
    A couple of re-bores and oversize pistons plus an extra 5 to 10 psi boost pressure may require some very tight head bolts to stop head gaskets popping regularly.
    Should, heaven forbid, our 280 ever throw a rod, unlikely as we keep it down to a 4000 RPM max, then I would be tempted to install  a Euro Spec 560, plus 38 kw on the  US & Australian versions, and a diff from a 108/9 450.  The hydraulic tappets would also do wonders for engine noise control compared to the M130.
     Having had a Euro W126 560SEC as a daily driver for the past 6 years I think they have great motor, lots of grunt and very resonable fuel consumption at legal speeds.

[dixy2k]

The 280 engine is bored up too much. The walls between the cylinders are way too thin.
You would be better off supercharging a 250 or a 230.

The injection system would have to suffer some mods.

Maybe a dual carburetor would be better in this case.

Why not consider a V6 swap? The 3.5 V6 comes to my mind all the time.
The V6 is shorter than the L6 and lighter in weight.
The new weight distribution would much better since most of the weight would fall behind the front axle.

[ja17]

My two cents worth.........

 Your need for more speed may be best served by spending the money on a faster model already to go. There are plenty of very, very fast good used Mercedes roadsters, coupes and sedans out there for little money these days. Not only do they go fast, they also stop and handle so much better.  They also have more creature comforts (AC, sound systems etc) Enjoy your W113 for the great car it is. It is still plenty fast, it will increase in value and  serve you well in the years to come, just like it is.

[RickM]

My two cents worth.........

Your need for more speed may be best served by spending the money on a faster model already to go.

Ahhhwww, you're no fun..... 

[ja17]

Hello Rick,

Yes, I must admit that I have modified more than my share of all manor of Mercedes cars over the years. In the end, it is what makes you happy that works best I guess!

[ja17]

Hello,

I guess,  if I was looking into a serious mod on a W113 car engine these days I would consider one of the very light powerful Mercedes V-8 aluminum blocks as "treedoc" implies. Another even better choice would be the early 90's 300 E engine (M103). It had well over 200hp, single overhead cam engine, lighter than the original M130, very simple design to work on. They usually go for 300,000 miles or more. Would also be a much easier conversion than the V8.

Even more radical........ John Olson (SL Market News Letter) is fitting his W111 coupe with a modern SLK V6 AMG engine (SLK32 AMG).  It has 350 HP !