Eurocharged Rick

If it does, i just figured out something very significant for our cars....i was reading some info in a thread on the E55 forum and i think i figured out why our cars are so sluggish below 3000rpms...


anyone know?

ScottW911

I was counting on you to know the answer to that question. When I searched recent threads about the same question I found the answer here: https://mbworld.org/forums/showthrea...ghlight=bypass

Thing is, you answered the question in that thread. Are you doubting yourself now?

m444

no bypass?

Vadim @ FD

There is no bypass valve on C32.

Your C32 should not be sluggish under 3000 rpm. If it is, than you might have something wrong. Get a hold of OBDII scanner and look at data stream and error codes.

Zeppelin

No bypass. The clutch on the supercharger disengages taking care of need for a bypass.

Eurocharged Rick

Yes...that is why i am asking the question...and i am trying to figure out why it seems that the car is bleeding boost below 3000rpms...

why would the E55 have it and ours does not? is it not the same setup with just a smaller supercharger?

the E55 has a clutch for the supercharger and a bypass valve, fyi...

ScottW911

Doesn't the S/C kick in at 2900 rpm or is it 44% load or a combination of both? If it is just a straight 2900 rpm, than isn't that why it would feel like it's bleeding below 3000 rpm? Having driven turbo charged cars since the early designs of 1978, I am used to the old turbo lag, but I've never figured out why there would be a supercharger lag. Any technicians out there able to explain?

Bif powell

I have been asking myself this same question ever since I saw the first mention of the 2900+ s/c kick-in. Can we change this threshold

Eurocharged Rick

i agree with you on getting an OBDII scanner, i need to get one to see what is going on...but i know the vehicle is fine, just had it checked out by the dealer

Eurocharged Rick

it would be nice if we could get a tuner to figure out a way to lock-in the supercharger sooner...

Zeppelin

It locks in instantaneously. Were just dealing with a 3.2L motor that no amount of forced induction is going to give it torque in the 1500-2000rpm range.

C32AMG/02

All positive displacement blowers producing over 5lbs of boost must have a means of dumping boost. C32s make 300 ft-lb at 2300rpms; torque peak is 332ft.lbs at 4400rpms with 14.5psi of change pressure / boost. without a bypass valve, 14psi of boost can damage head gaskets, rings seals or other pats of your engine.

Even with a magnetic compressor clutch, at light throttle, deceleration, transmission shifting, damaging boost surge can happing causing damage to your engine. There must be some means of controlling over boosting.



Boost surge is when changed air is being forced into a closed throttle, until the pressure is higher than the amount of boost being created by the supercharger.

I can’t find any mention of a by pass valve in EPC and WIS programs, AMGs are consider euros in the USA and as such not be supported by theses USA programs.




According to MB a compressor squeaks is caused by “friction vibration on compressor coupling” meaning when the compressor clutch is engaging. Remedy “it is not allowed to replace the compressor when theses complains occur, this motor specific noise is state or the at, at best, replacement of these parts leads to a temporary solution of the problem and customer dissatisfaction will increase”

I wonder how many supercharger unrelated noises are being diagnosed as “compressor squeaks”, by MB techs, only time will tell.

Vadim @ FD

Incorrect. Our engines are still running fine.

There is no overboosting on a C32. Boost is a function of pulleys ratio and VE of the engine.

The throttle on C32 is before the kompressor.

Because bypass valve does not exist on C32 and appears you are not familiar with WIS either.

C32AMG/02, save yourself some time and just please use search function. There are numerous pages on C32 tech and R&D on this forum going back to 2003.

ScottW911

Now that I believe we have established that the C32 does not have a bypass valve, we are still unsure about the whole 2900 rpm/44% load question. Vadim? I'm still curious.

Vadim @ FD

[QUOTE]we are still unsure about the whole 2900 rpm/44% load question [QUOTE]

It is correct. However, in most driving conditions you are rarely below 44% load.

Can it be changed? My guess yes. The problem is who is going to spend R&D time to locate the maps in the software and test them.

ScottW911

I can understand that. I guess I am curious if S/C engagement is at 2900 rpm or 44% load? Combination?

Fifth Ring

Better yet, have an override switch to turn the sucker on nonstop when you need it.

Vadim, do you need to hack the software or can you just create a "short circuit" on the solenoid that switches the clutch?

Downside, of course, would be that the engine could not protect itself if, for example, your intercooler pump died and intake air was too hot.

Vadim @ FD

If kompressor clutch is rigged to be on all the time transmission will not shift. This was the very first thing I tried when I got my C32 back in 2002.

Fifth Ring

Thanks. Amazing how complex electronics have become. I suspect this is to protect the transmission from shifting during high boost (which must mean that the clutch opens up during upshifts).