Supercharging a 280 SL

[thelews]

How are the other drivetrain components affected by the substantial increase in horsepower and torque?

[ja17]

Hello John,

Naturally, the weakest link in the chain would show up quite quickly. I suspect that with 350HP,  the driveshaft flex disc and the universal slip joint in the rear diff would fail. The good news is just fitting up stock MB flex disc and diff slip joint from a 6.3 sedan would cure any issue.

Any weight savings would help take the strain of all drivetrain parts also.

[mirkwood]

it's an old thread but i think the m130 would be an excellent engine to run a supercharger on. It was done decades ago on engine used for circuit racing in Australia and it's still raced now(or recently) in historic event in New Zealand. See pictures..
The thin walls between the cylinders in the SL block would need filling in the cooling slots ,possibly a metal stitch in each groove.
 Then the block would need "o"  ringing to provide a more positive seal for each cylinder . Better pistons would be an advantage ,with a thicker,lower crown. The rods only have a oil squirter which aims from the big end at the piston. A better idea would be to drill the rods down their length with a oil feed to gudgeon pin as on the V8's and oil feed to give a more positive oil spray to the underside of the pistons.
The con  rods are pretty rough compared with earlier M180 and M127 engines which have polished rod beams so a bit of rework needs to be done in respect to polishing and shot peening to stress relieve the rods for the sake of reliability .

I have had great success from baffling radiator header tanks on mercedes to increase the length of time the water passes through the radiator without restricting the flow  and the SL could benefit from a bit of redesign in this  respect.
Supercharging increases the intake air temperature and this is historically coped with by fitting larger radiators . In the case of the Sl this would be impossible so an intercooler mounted in front of the radiator could be installed to bring the intake temperature down. 
On a lot of 1930's supercharged cars you will notice the intake manifold was finned in an attempt to get rid of this extra heat.
 A modern version of the old water injection to keep temperatures under control is available from a couple of sources which use ECU's to inject water under high pressure to each intake tract and this provides extra power . The most spectacular set up I have seen was on a mazda rotary producing over 1000 hp on pump fuel with dual turbo chargers and water injection .
This water injection would be absolutely necessary on street driven SL with modern fuels because of qulaity restrictions.  one major advantage is the possibility to run even more ignition advance than normally aspirated engines.
 I wouldn't bother running a distributor as the inaccuracy of spinning mechanical components doesn't lend itself to high performance and the Fitting of Ford EDIS components is cheap and easy. You  can then map the ignition very accurately.


 

[Raymond]

Mirkwood,
Do you have any experiences you could relate regarding the EDIS?  If so, how about starting a new R&D thread on that with whatever advantages that might have for the performance of an M130.  Supercharging is an exotic and extreme idea for most of us, but improvement in ignition efficiency or performance for a stock engine would not be.

[Benz Dr.]

I go to a local car cruise every Tuesday night. Not for the cars but rather for the social aspect. I find, for the most part, that a good number of the hot rodder types have never really grown up and most still kind of live in the '50s or '60s. Nothing wrong with a little nostalgia but some of them go to real extremes to modify their cars.   The more crazy it gets, the better they like it. And if it doesn't go, then chrome it. Most of them like the car only for how it looks and are only satisfied when it has 500 HP, tilt steering, power steering, 4 wheel disc brakes, 5 speed or modern trans, cruise control, AC, power door locks, and the list goes on and on. Why don't they just go and buy a new Mustang, Charger, or Camaro and have done with it?  

 It never fails. Some guy will open his hood and they all stand around and ooooh or aaah at what's under there, with chrome plating scoring big points. Most of them have little, if any, real knowledge about cars outside of their chosen preferences. Most don't have clue one what a real full classic car is and don't care either. Their idea of a great car show is when 5,000 cars show up for an event. None of them have ever been to a high end show. Too bad, they would like it.
 
They've sort of come to accept that at least some cars were made in other parts of the world - really neat cars. It's not until they get behind the the wheel of my car or something I might be working on that they realise that small bore, high HP engines, can really perform well in non modified, stock issue. The handling, braking, and comfort, usually surprises most of them.
By comparison, they're stuff rattles, the ride is either choppy or it wallows all over the road, and they had to do extensive modifications to improve handling and power. It only underscores just how far behind and how cheaply made the average US car was during 50 and 60s. These cars lend well to any and all sorts of mods because for the most part, the stuff is crap to begin with. Style wasn't too bad on many of them and the mechanicals were simple and durable - just what people wanted.

After the war a lot of service men brought sports cars back with them or had been introduced to some very innovative ideas. Much of that overflowed on to  hot rodders in the USA and the rest is history.

Joe is right though. Buy something already there that has all of the stuff you want. 600SL's are selling cheaply these days. Not that I'd want one, but they are powerful. Keep your vintage car in stock form unless you really don't care about stuff like that. In which case, why are you here?  

I know it all sounds snobby but it really isn't. I look at their stuff, ask questions about the build and all the usual car guy stuff. Oddly, they're the ones who show little interest in what I bring - and it's different every week. They are slowly coming around though.  
 

[W113SL]

It would really be interesting if someone with more money to burn that I would go to the expense of building a race engine that would be streetable using a M129 or M130 black.  I had an engine builder do a computer simulation evaluation based on a M 130E engine.  He speculated conservatively that he could approach one HP per liter (or near 280HP) by using larger stainless steel valves with thiner stems, by having customer made pisitons with 11.5 CR or more, by cleaning up the head for improved flow, by opening upn the intake runners , and creating an extractor exhaust syetem.  A hotter cam with more overlap ground to work in concert with the mentioned modifications would be necessary.

According to him, the biggest contributor to improving horsepower is to unrestrict flow in the head.  He is an experienced engine builder and I would have used him to do this for me, but I sold the car.

I still would like to do this just to prove it can be done, but engine longevity is affected adversely.  The driving factor is in vintage racing where you are restricted to the orginal block and transmission.

As you can see, I'm not big on engine transplants.

W113SL

[Travis71280]

It can be done and it would be interesting to see someone do it, but after factoring all the money you would have to put in the motor to make that kind of hp, you'd be better off just doing a motor transplant like an gm ls motor swap or a late model MB motor, but then again it be one of a kind 

[W113SL]

The subject here is vintage sports car racing which does not allow engine transplants at all.  The key to competitive performance is getting as much weight out of the car as possible (2350 pounds dry is possible with an early 230SL) and creating enough horsepower to have less than 10 lbs per HP.   I was able to get the weight under 2500 pounds with window glass, hardtop, passenger seat and rear bumpers.   As far as engine transplants go I believe the orginal SOHC engines, properly maintained and tuned are just fine.

W113SL

[webmig]

Hello everyone,

I know it's an old post, I know this car was not designed to be a racer, I know many things can go wrong and we all know it could work just fine so YES I decided to go for it and bought a supercharger and YES I am going to install it.

I'll take pics on the process and hopefully they will show whatever you all would like to see.

This is where I am now:

1.-   C30-74s Supercharger from Rotrex Denmark   http://www.rotrex.com
2.-   2 Pass alum high efficiency alum radiator and oil cooler, removing fan/clutch and installing 2 electric fans and shrouds.
3.-   Electronic distributor from 123 Ignition and a good handheld air-fuel ratio meter (I'll try and try to get the fuel injection pump to tune-up properly).
4.-   Bolt-on rear stabilizer bar (no drilling or soldering).
5.-   Battery relocated to trunk compartment.
6.-   AC pump and mount upgrade (old York piston type take too much space and power).
7.-   Deciding wheter staying with V-belts or upgrading to 8-rib flat  belts (I am checking on available space).
8.-   1:3.25 rear fifferential gear and pinion mounted on the original rear axle.
9.-   Engine totally rebuilt by Metric to 8:1 compression.
10.-   Getrag 5 speed manual transmission.
11.-   Performance header exhaust system by Eissenmann Deutschland   http://www.eisenmann-sportauspuff.de
12.-   Deciding on progressive suspension springs.
13.-   Scratching head, looking at my wallet and crossing fingers...

[GGR]

Wow ! That's quite a project ! It may be tricky to adjust the mechanical injection pump properly for the boost.

Keep us posted !

[pagoden]

And wow again!  That's great ... great spirit.  Sounds like a good starting plan -- they seem always to get modified you get deeper into them.  Go for it and all the best of luck.

Please inform and advise regarding the "bolt-on rear stabilizer bar"; where can I find out about such products, their specs, manufacturers and availability?  From reading your line item #4 it seems you may have already picked one out.  If so, I'm very interested in that one as well as any others you considered, as I have had no luck in this quest myself.

TIA and good wishes,
Denny

[webmig]

Denny,

It's being shipped, it will take a couple weeks.   Let me get it, unpack it and try to set it right so I can tell you about it.

The car is totally dismantled and being repainted, parts cadmium plated, etc., I will post pics in a few weeks.

Any suggestions or ideas anyone?

Miguel