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Performance Modifications

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Achim says: I remember an article of a 280 SE (108) owner who had his engine tuned by AMG in the late sixties. Instead of the original 160 hp (DIN not SAE) this engine developed 196 hp and was "fast." Probably there is still some information left at AMG how they tuned the engine. AMG was an independent company for decades that tuned Mercedes cars. Now, they are part of Daimler Chrysler.

Will, on a camshaft regrind he had done: it was not very expensive, about $200-250 I think. All they did was give me more overlap between the intake and exhaust so that the engine has more time to take in and expel gases. In addition to that I think I ported and polished the head. This also allows the gases less restriction. Since then I have found out about Teflon coating of the internal parts of the engine, which reduces friction. I also use Total Seal gapless piston rings. This system uses a 2 part piston ring so that you end up with no gap. Helps reduce loss of compression. I also no longer use factory piston rings. They seem to have a weak oil control ring which leads to excessive smoking. This has been a problem on the alloy V-8's as well. I will let you know how it runs once I get the car finished.

Anyone have any thoughts on using wastegates or other methods of open exhaust systems on a 113 (230 SL) engine? The velocity runs are high speed and I've already increased airflow going into the engine with a K&N Filtercharger (HUGE difference/easy modification), and am thinking that my next bottleneck will be getting exhaust out of the engine, a wastegate will allow me to run normal exhaust most of the time, but open the system to reduce backpressure at high speeds... I know a certain amount of backpressure is needed and I don't want to over-scavenge the system, but @ 6,k RPM's it would have to help, just not sure how much to open it up...

I've read with interest the comments of noticeably better performance from this K&N air filter. I assume it is less restrictive and allows more air to be drawn into the intake. To reap this benefit, is it necessary to make adjustments to the fuel delivery? Because without a concurrent modification to deliver more fuel, I would think a less restrictive air filter would simply result in leaner mixtures.

At the moment I have no way to determine if this modification is causing a leaner mixture, it seems as if it is simply allowing the engine to breathe better, the performance is noticeably improved, so I really don't think it's running too lean... I don't know if the engine is compensating for the increased airflow, or not ... one of my scheduled mods is to add an air/fuel mix gauge to see what is really going on, I'll report back when I'm able to test more. But, with no other mods or adjustments, the improved performance was immediate, and significant.

I have tried to incorporate every performance enhancement that I am aware of:

  • Valve Clearances
  • New Cam
  • New Timing Chain
  • Rebuilt Distributor with Pertronix unit
  • No resistance in wires
  • Ceramic Coating inside exhaust manifold and exhaust system.
  • New Injectors
  • Rebuilt Fuel Injection pump
  • New Fuel delivery system

It runs great, but I always want more. Any other thoughts?

Dan Caron: Yeah, early header pipes. Matching all the ports in the head. Hotter coil. Synthetic oil ETC.

Here is the tried-and-true list of performance options used by the hotrod community. They are all meant to increase the horsepower-to-weight ratio or reduce horsepower eating drag.

  • Reduce Driveline Friction:
    • Synthetics in engine, transmission, rear-end & wheel bearing.
    • Adjust bearings on the loose side.
    • Better Air Flow through the air pump (engine):
    • K&N Filter (direct attachment cone is the best)
    • Add an air scoop for some positive pressure at speed and utilizing cool (denser)outside air and not warm engine compartment air.
    • Modify the exhaust after the two header pipes come together to three inches with a non baffled muffler, i.e straight through.
    • Modify head with larger valves
    • New cam grind for the most desired RPM/speed
  • Better timing:
    • Electronic ignition for more precise timing
    • Advance ignition to 1 degree less than ping
  • Reduce rolling resitance:
    • Higher air pressure in tires
    • Purchase tires with the lowest rolling resistance
  • Less air drag:
    • Good wax job
    • No radio antenna
    • No right hand side mirror
    • Drive only with the hardtop on
    • Keep the windows rolled up
    • Lower the car
  • Lessen the weight:
    • Empty every non essential out of the car (carpet, radio, passenger seat, AC, trailer hitch, etc.)
    • Go on a diet

Part of this is extreme. The idea is to get one into the mind set of less weight, less resistance, and putting air through the 2.3 engine. In my racing days these principles plus true intake and exhaust headers allow me to get a 1966 1300 cc VW to run 100 mph plus a little.

You probably could turbo charge your car and reap great benefits. If you keep the turbo small enough and the boost low enough you should be able to have the best of all worlds. Having though of this myself(Having not even driven my own car yet but having read the 0 to 60 time of 11 seconds) a couple of the major hurdles would be manifolding the exaust gasses to the turbo and enrichening the fuel mixture to accout for greater air density. You might be able to solve the latter easily enough just by connecting a tube from the intake to the atmosphere port of the injection pump (it would have to have a check valve to the atmosphere so the port would see only boost and not vacuum) but you would probably be much better off adding a later fuel injection system which would be far more adaptable.

I did a lot of study on this subject while building my vintage race 230SL. First I was lucky to find a 2.8 engine out of a 300SEL 2.8 with the Euro "09" cam in it. I had the head ports matched and polished. New valve job with good quality three angle valve seats ground. I also had the intake and exhaust manifolds extrude honed to clean them up. I had the engine cleaned up by installing new pistons and had everything balanced to 1/2 gram tolerances. This helped in acceleration out of the turns. I had the injection pump rebuilt and recalibrated for racing by Hans at H&R. I used him because he has had experience building racing mechanical fuel injection pumps for Porsches. Then I installed new injectors. Has recommended the early style injectors found on 230SL and early 250SE and SL's. He thinks they flow better. Lastly I did install an abbreviated intake system using a large K&N filter. I actually removed the entire canister and attached the K&N to the intake manifold. The exhaust system was modified by using one large 3 inch pipe into a very small straight through muffler. I have since replaced this with a Borla stainless steel which seems to flow very well. I used the Crane emitter and detector style point replacement system and it has worked flawlessly. With the Euro cam and a 3.92 rear end ratio, I can rev to 7,000 RPM in first and second gears. After all of this, I think the engine barely makes an honest 200HP. I believe they were a bit overrated when new like all engines of the period. I had an engine builder evaluate this engine on a computer program and he believed it would require a much hotter cam, larger intake valves and thinner exhaust valve stems, a compression ratio of 11.5 to one to get 250HP. He though the intake manifold throttle size could be made larger and possibly get up to almost 100HP per liter. I figured this would cost an additional $4-5K. This would cost too much money and destroy the reliability of the engine which is very good at this time, so I opted for reliability and placed most emphasis on handling, braking and driving schools.
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