w202 c230 kompressor, supercharger delete - PeachParts Mercedes-Benz Forum

alphanumeric · #1 08-12-2011, 06:20 PM

I finally disconnected the electro magnetic plug for the super charger the other day. the car has roughly 150k miles and the super charger is starting to get really loud. between 1-2k rpm's, it sounds like their are rocks in the super charger!

the purpose of this post is to gain some in site on some of my ideas.

I am expecting an increase in MPG. I assume this super charger takes 30hp to make 50hp, with rough calculation.

this car is a daily driver and I disconnected the super charger expecting increased reliability.

so far the check engine light has come on. I dont mind this, but, that means I wont know if the check engine light would come on for anything else.

with the super charger bypassed. their seems to be a huge restriction on air intake. I want to add a cone filter right on the MAS sensor housing. would be nice to figure out a cold ram air system too.

thoughts or comments welcome =)

TimFreeh · #2 08-13-2011, 08:57 AM

Quote:

Originally Posted by alphanumeric

....I am expecting an increase in MPG. I assume this super charger takes 30hp to make 50hp, with rough calculation.....

I'd be interested in the calculations that used to come up with this estimate, I'd be surprised if the parasitic loses associated with the supercharger were more than 2-3 HP, if even that.

Did you mean that disconnecting the supercharger will result in a 30-50 HP overall drop in power output?

My daily driver is also a C230 Kompressor with 161K miles and my supercharger is also making noises, however it seems to be an intermittent problem. At cold startup when the ECU uses the supercharger to provide aux air to warm up the O2 sensor the noise is pretty loud. It does sound like a bunch of rocks rattling around in a coffee can!! But at higher RPM ranges I can't seem to hear it at all, very strange.

I've done some searching and it appears the Eaton M62 supercharger has a problem with the "snout" bearing that supports the input pulley, most of the time the failure of this bearing is the problem. The bearing is apparently replaceable and available, do a search for the details if you want to explore the option of fixing the supercharger.

alphanumeric · #3 08-13-2011, 05:22 PM

A mechanically driven supercharger has to take its drive power from the engine. Taking a single-stage single-speed supercharged engine, such as the Rolls Royce Merlin, for instance, the supercharger uses up about 150 hp (110 kW). Without a supercharger, the engine would produce 750 hp (560 kW); with a supercharger, it produces 1,000 hp (750 kW), a total increase of 400 hp (750 hp — 150 + 400), or a net gain of 250 hp (190 kW).

that info is from WIKI. I have heard those monster dragsters use super chargers that take 200, and even heard 700HP to run the super charger!

a friend of mine works at stillin nissan, and has an extra m62 on hand, and said that super charger takes maybe 30hp to spin.

Thanks for the push on fixing my super charger.. but I always did hate that thing. I wanted a 10lb boost pulley but did not like the 700$ price tag. for every other super charged vehicle , a pulley only cost 200$. even the BMW mini cooper which uses the same S\C.

with all the cost running up on the super charger to make me happy.. I would just toss in a turbo charger.. BUT this is my daily drive as mentioned and would like a simple, dependable, stylish cruiser.

also, to boot, I am currently building a w201, m104, 5spd, turbo, mega squirt car for my speed addiction. =)

alphanumeric · #4 08-13-2011, 05:27 PM

you could be right about the s\c not taking that much power. I just ran some math. for a non supercharged m111, it makes 150hp. then add 5lbs of boost (which I think is 7HP per 1lbs of boost) 5lbsx7hp=35hp+150hp=185hp.

but between compression ratios, IF there are any, between the N|A and supercharged m111, and crank and wheel horse power measurements, who knows..

TimFreeh · #5 08-13-2011, 07:48 PM

Quote:

Originally Posted by alphanumeric

you could be right about the s\c not taking that much power. I just ran some math. for a non supercharged m111, it makes 150hp. then add 5lbs of boost (which I think is 7HP per 1lbs of boost) 5lbsx7hp=35hp+150hp=185hp.

but between compression ratios, IF there are any, between the N|A and supercharged m111, and crank and wheel horse power measurements, who knows..

I think the compression ratio of the supercharged M111 is slightly lower IIRC, maybe like 8.5 to 1?

The other thing to keep in mind is that for most of its life the supercharger is just basically rotating without putting out boost. Mercedes uses a bypass switchover valve which short-circuits the input/output lines on the blower. It basically allows the blower to free-wheel when boost is not needed.

Here's a quote from a Ford web-site that describes the function better than I can......

"The bypass is especially important. We tend to forget that in normal driving the engine is very
seldom in full-power, wide-open throttle (WOT). In a supercharged engine, this is the only time the
blower is actually being used. The rest of the time, at part-throttle cruise, idle, or deceleration, even
a supercharged engine has vacuum in the intake manifold. This vacuum is used to open the
bypass valve to open a passage between the throttle and the manifold (bypassing the
supercharger). This equalizes vacuum in the entire system so that pumping losses in the blower are
minimized. Factory tests have shown that an Eaton M90, with this valve, produces only a 1/3-hp
parasitic loss while cruising at 60 mph. As a result, the V-6 factory applications with this blower
average about 30 miles per gallon"

Even at "full-boost" on an M111 I don't think the blower would use anywhere near 20-30 HP. Compressing 6-7 psi into a 2.3 liter engine just isn't all that much work IMHO.

I'm be watching your thread to see if anybody else has tried to delete the supercharger but I think I'm going to fix mine when it finally dies.

engatwork · #6 08-13-2011, 08:08 PM

Top fuel dragster specs from wiki.

Quote:

SuperchargersThe supercharger is a 14-71 type Roots blower. It has twisted lobes and is driven by a toothed belt. The supercharger is slightly offset to the rear to provide an even distribution of air. Absolute manifold pressure is usually 3.8-4.5 bar (56-66 PSI), but up to 5.0 bar (74 PSI) is possible. The manifold is fitted with a 200 psi burst plate. Air is fed to the compressor from throttle butterflies with a maximum area of 65 sq. in. At maximum pressure, it takes approximately 900 horsepower (670 kW) to drive the supercharger.

alphanumeric · #7 08-13-2011, 08:09 PM

interesting facts. I have always been confused about how the bypass valve works and when its on and off.

the reason I shut off my super charger permanently, was so the super charger does not fail completely. I think when these things go out, they seize up and maybe it will cost more to fix.

when I picked up my car in 2004, it had 54k miles on it.. and I THINK it made the noisy super charger rattle back then too. I remember everybody at work telling me my new car sounded like **** when I would pull up..

now after many many many 6k rpm revs, the super charger is louder then ever now.. especially since I only drive city now.. I hear the rattle in the ranges of 1-2k rpm in all shifts, 1s, 2nd, 3rd, 4th in the city!. when I was driving down the street going say 35-40mph, I can hear it really good when I pass parked cars. it goes away when I left off gas. but once I press on the gas, I hear it immediately. In the city, my rpm range is always 1000-2000rpm casually driving and maintaining speed, and that rattle is constantly making nasty noise.

it definitely takes a trained ear to hear all the little noises different engines make.. to most people.. it all sounds normal. and sounds the same.

alphanumeric · #8 08-13-2011, 08:13 PM

okay , I will just install a toggle switch on my shift lever so I can turn on\off the super charger at my own desire, not the stupid computer.. and i'll change my name to mad max while im at it =D

TimFreeh · #9 08-15-2011, 08:46 AM

Quote:

Originally Posted by alphanumeric

..... I hear the rattle in the ranges of 1-2k rpm in all shifts, 1s, 2nd, 3rd, 4th in the city!. when I was driving down the street going say 35-40mph, I can hear it really good when I pass parked cars. it goes away when I left off gas. but once I press on the gas, I hear it immediately. In the city, my rpm range is always 1000-2000rpm casually driving and maintaining speed, and that rattle is constantly making nasty noise..

That's kind of strange because during normal operation I don't think the ECU engages the supercharger at all until the engine reaches 2050 RPM. As we've noted before the ECU will use the supercharger as an air-pump in warm-up mode but I don't think the supercharger is normally engaged in the 1-2K RPM range.

Are you sure the rattle you are hearing is coming from the supercharger? Did the noise disappear when you disconnected the belt?

ForcedInduction · #10 08-15-2011, 11:13 AM

Quote:

Originally Posted by alphanumeric

I am expecting an increase in MPG.

Not really. The smaller engine will be working harder for longer to get up to speed.

Quote:

would be nice to figure out a cold ram air system too.

Like stock.

Quote:

The other thing to keep in mind is that for most of its life the supercharger is just basically rotating without putting out boost. Mercedes uses a bypass switchover valve which short-circuits the input/output lines on the blower. It basically allows the blower to free-wheel when boost is not needed.

No, it uses a clutch, identical to an A/C compressor. When unplugged it does not move at all.

alphanumeric · #11 08-15-2011, 01:13 PM

the NOISE did go away after I disconnected the electro magnetic clutch wire thats in front of the valve cover near the super charger.

TRY this c230k owners. start your car up on a cold morning, set your parking brake to max, put car in reverse or drive, open the hood and walk over to the super charger and watch and listen to how ugly it sounds.

come to think of it. I have no idea why the supercharger would be engaged at normal driving (cruising at 35mph) RPM in the range of 1-2k. the S|C should be turned off. all I know is, the noise is gone!

TimFreeh · #12 08-15-2011, 02:11 PM

Quote:

Originally Posted by alphanumeric

the NOISE did go away after I disconnected the electro magnetic clutch wire thats in front of the valve cover near the super charger.

TRY this c230k owners. start your car up on a cold morning, set your parking brake to max, put car in reverse or drive, open the hood and walk over to the super charger and watch and listen to how ugly it sounds.

come to think of it. I have no idea why the supercharger would be engaged at normal driving (cruising at 35mph) RPM in the range of 1-2k. the S|C should be turned off. all I know is, the noise is gone!

You don't have to put the car in reverse or drive for a cold start demonstration of the supercharger acting as an air pump - the car will do it with the transmission in park or neutral.

Cold starts are not the only time the ECU operates the supercharger in this way, I've also noticed it can happen at idle with a fully warm engine. It seems to happen most often if I coast to a stop at a traffic light. I'm betting the ECU realizes that the 02 sensor is cold since no fuel has been used in the coast down and it uses the aux air trick in an attempt to keep the O2 sensor warm.

As I said before if you lightly accelerate to 35 mph and keep the engine revs below approximately 2K the supercharger should never engage - you may have a problem with the clutch assembly.

alphanumeric · #13 08-15-2011, 03:30 PM

could be the clutch!

the whole starting the car, apply parking brake, select drive, open hood and listen to the super charger was to hear the noise coming from the s\c. I do under stand that the super charger is on during warm up.. but once you put it in drive.. the noise becomes noticeable. could be the clutch or bearings. prolly both. which is why I deleted it. a clutch assembly is prolly dealer only , and cost 500$.

c230Kompressor3 · #14 04-07-2012, 11:43 PM

hey guys, i seem to have the same problem with my 2005 c230 as well. can someone post a picture of where exactly the electromagnetic plug is located? there are so many i cant seem to know which one it is... pls advise...

c230Kompressor3 · #15 04-07-2012, 11:53 PM

made a video to show my issue....

pls help!!

C230 supercharger weird noise - YouTube