At which point does the supercharger begin to kick in. Does it engage at all stages of driving, or will it set off only during certain sriving conditions?I know it runs constantly, as it is synched with the crank shaft, but when does it become part of the system to a full extent?best

 

You should feel a slight pulling sensation once you hit a certain RPM. I think it's between 4K-6K never really thought about monitoring when it actually hits.

 

While I don't know anactual RPM kick-in point I believe a belt-driven supercharger is always instantly ready to go. Since the supercharger is powered by a belt from the crankshaft it is always "on" and requires no spool-up time or 'lag' that commonly occurs with turbochargers that are driven by exhaust gases.
That is why a supercharged car is often noisy when started from cold because the environmental controls keep the engine RPMs high to warm up the engine and catalytic converter. The increased RPMs also turn the supercharger at a higher speed. The increased speed of the supercharger results in either a whine or clanking sound when the car is idling. Once warmed up the engine RPMs drop and so does the noise level of the supercharger.
The beauty of a supercharger is its instant response and the absence of the lag and its usefulness at either low or high RPMs.

 

Superchargers don't "kick in"....they are always "in". As to where you feel the car pull the hardest DUE to the effect of supercharging, it's really hard to tell since supercharged engines have a pretty flat torque curve. It's not like kicking in the four barrel on a carbureted car. My supercharged car (another car), not a MB, can bring in all it's power and boost from idle when you nail it. I don't suggest doing that, but it will. If you want more power, increase the boost, or spin the supercharger faster. That's why they sell smaller pulleys for the front of the supercharger. But again, with that, you are going to need a correspondingly larger amount of fuel to make it work right. Everything is dependent on something else.

 

Isn't Superchargers also predetermined by amount of boost? If so then it will only engage fully at a set RPM or boost level correct? So by stepping on the pedal your increasing the overall RPMS so when it hits that magic number the supercharger engages fully right? Can you safely increase the boost on the supercharger without fragg'n the internals of the Merc?

 

mello> no, not exactly. It's just a matter of semantics here. Superchargers are always "engaged". You don't hit a magic number or rpm which "engages" them, although the boost is probably only fully realized when you put the accellerator pedal to the floor or load the engine. Engage is the wrong word. And, yes, superchargers are built to provide a certain amount of boost (psi) at a certain rpm on a certain engine. This provides power over a broad rpm range, which is ideal for a street car. Yes, you can increase the boost, but you have to be very careful. Octane requirements must be raised, or timing must be backed off, fuel mixtures must coincide with the increased air coming in, and so on and so on. Also the engine must be able to take the increased pressure it was built for. It's a very effective way to increase power, but you have to know what you're doing. Increasing the boost stresses everything in the engine, crank, rods, head gaskets, etc. and this has a tendency to find the weakest link in your car, and it will! I have learned the hard way over the years supercharging many engines myself. Mercedes has built in a modest amount of boost to provide a car that runs well at all rpms and driving conditions and gets good mileage too.

I think I said that right.

 

Hmm interesting facts for sure. I am curious to know what the stock PSI is possibly around 7 ? Yeah I know about setting timing back and how much a stock crank can really handleI learned the hard way playing with NOS.

 

I've never had anybody tell me exactly what the boost is on a C230K....I would guess somewhere around 5-7 lbs, but I really have no idea. The only way to tell what you really have and when you have it is to put a boost gauge on it. Simple.

I hope nobody misunderstood me in the last post about the supercharger always being "in". I didn't mean to imply that it means that the BOOST is always in. It's not. A lot of the times on a supercharged car, the blower isn't making boost until you either push down considerably on the gas pedal or put the engine under a load. My other car, with a boost gauge in it,
doesn't make any boost at all driving around on the street normally in traffic unless I want it to. Then the needle will move up to maximum boost almost instantly at any speed I'm driving.

Nitrous has a really INSTANT effect. My last hot rod was a 700+ hp Chevy, supercharged, with a 250 shot of nitrous. The combination of the two together was something I'll never forget. This was all in a 1,500 lb. lightweight fiberglass body.
What a wake-up call THAT was. I sold it after two years of nearly killing myself in it for half what it cost me to build it, but at least I lived to tell about it.