SLKman

Posts: 1,063

Country:

Thanks: 261

Thanked 73 Times in 35 Posts

I am mechanically challanged and have wondered how the kompressor works.

Is it always working or does it kick in at certain RPM's?

Thanks

ierax

Posts: 293

Country:

Thanks: 1

Thanked 0 Times in 0 Posts

Always working, giving a constant boost . I have just the link for you

http://auto.howstuffworks.com/supercharger1.htm

SLKman

Posts: 1,063

Country:

Thanks: 261

Thanked 73 Times in 35 Posts

ok, thanks for the link.
So it is constantly working.

So there is no "boost" per say when I give it a lot more acceleration from it engaging?

Just solid flow of air at all times. right?

ierax

Posts: 293

Country:

Thanks: 1

Thanked 0 Times in 0 Posts

Let me give a practical example on the m271 kompressor engine of the slk200.

With turbocharged engines that work with variable boost, you usually press the throttle hard enough ,revs increase along with the exhaust gases running the turbocharger, you get a momentary overboost of say 0,8 bar and then a steady boost of say 0,6 until the end of the engine's revs (the boost may decline in the end, it depends on the mapping of the engine etc ..). Whatever the scenario the turbocharger can be made to work harder or less so and deliver various amounts of boost.

With a kompressor engine, i.e the M271, the kompressor has a steady boost of 0,6, with the maximum torque of the engine being ata 4500 revs and maximum power at 5500. No matter the throtle position the eaton type kompressor produces the same amount of boost.

There is a steady flow of air at all times but as the revs of the engine increase, the supercharger must work harder in order to provide the increased volume of compressed air necessary for the engine to work. When tuning a supercharger we make it work harder by using a pulley that will allow for more revs of the supercharger,and thus increased volume of air delivered per engine revolution.


The major difference between turbochargers and kompressors, are that the first utilise exhaust gases to spin the turbocharger and thus increase the power input of the engine, while the kompressor is driven by using a belt driven by the engine itself.

The kompressor thus has the added advantage of having no lag in spining up since
it is directly related to the revs of the engine and does not need the exhaust gases to spool up
its internals and help compress air. It also does not need the more intricate cooling solutions of the turbocharger that has to deal with the hot exhaust gases.

The main disadvantage of the supercharger is that it is more parasitic to the engine than the turbo, i.e consumes more power from the engine in order to work. Advanced design and manufacturing nowadays has helped a lot in that regard.

For me the biggest advantage of the supercharger is its abilty to provide instant power with a partial throttle and power that is more linear as relating to the engine's revs, for that all important positioning of the car in a corner through drifting,power-sliding etc .....


Then again a 450 bhp turbo rally car is a brutal thing of beauty

Please correct me with any inaccuracies. I have been typing too fast

etyu

Posts: 5,306

Country:

Thanks: 381

Thanked 283 Times in 174 Posts

That was a GREAT explanation ierax. Thanks a bunch. (BTW, only about 20 days left from delivery )

__________________
Eddy

To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts.

Pewter/Beige, PIII package, Airscarf, Hands-Free Communication System, Lighting package
Designo Black Leather Cover on e-brake handle, (
To view links or images in signatures your post count must be 5 or greater. You currently have 0 posts.
Bill T), SmartTop v1.0, Kleyman 3BFM (NoRegret Custom), Green Air Filters, Mod. R170 ant., EuroClear sidemarkers w/PIAA PlasmaIon lamps, chromed front & rear turn indicator lamps, PIAA SuperPlasmaGTX front parking lamps, bilateral rear fog lamps enabled.

SLKman

Posts: 1,063

Country:

Thanks: 261

Thanked 73 Times in 35 Posts

Gotchya! Very understandable. Thanks for the info.
I now know what I am dealing with.

So that all ties into a larger pulley, right?

Is it the larger pulley turns the kompressor faster making more air flow resulting in more power?

dsb

Posts: 1,176

Country:

Thanks: 67

Thanked 121 Times in 42 Posts

Nice post Ierax!

I was just going to post an easy link:
http://auto.howstuffworks.com/question122.htm

ierax

Posts: 293

Country:

Thanks: 1

Thanked 0 Times in 0 Posts

Great link dsb Thanks!!!

etyu my friend..Yes it is only 20 days .... I hope that my precious will come on time..This bremen factory shutdown due to holidays, has me a bit worried, but my car is set for production as we speak..so fingers crossed.

slkman, it ties to a different pulley as far as the revolutions of the eaton type compresor is concerned.You will have noticed in the first link the two counter-rotating lobes that spin towards each other.

Nevertheless,it goes without saying that once you maximise the amount of air going into the combustion chamber you need the necessary amount of fuel, and the exact timing to detonate it....
Sometimes the standard ecu can compensate for that (in the case of the m271, mercs come with an 143,an 163 and an 193 hp variant of the same engine.
You will see tuners like carlsson, that tune the standard engine from 163 to 195 hp,only provide what amounts to a pulley kit, leaving the stock ecu to compensate).

If you are going to tune the engine further and until a point where you are sure that your internals (pistons, conrods etc) will hold, then you will need a differently mapped ecu,or a parallel ecu.

The ease of going from 163 to 195 without ecu intervention,just with pulley ancillaries, is something typical of eaton type kompressors who are more efficient in the lower rev band,providing more torque etc.

By changing the pulley, you fill up the upper rev band,but parasitic losses are higher...
You may encounter the eaton kompressor referenced as a modified roots type kompressor.

Root was a copatriot of yours , and a root kompressor was not a forced induction device as the turbocharger or the eaton kompressor, since it did not produce any vacuum (in layman's terms boost)...

I believe roots was initailly invented as an air pump to circulate air in furnaces

bejak

Posts: 145

Country:

Thanks: 0

Thanked 0 Times in 0 Posts

Interesting reading!
First: the standard boost level is as I understand 0.6 bar and with a pulley kit 0.8 bar. Is it possible to get say 1.0 bar with or without lowering the initial compression ratio of 9.5? The higher boost, more power or?

Second: is there any known gauges that one could use monitoring the actual boost level just to confirm that everything is running as expected? Perhaps one that shows 0 - 1.0 or 0 - 1.5 bar.

N4PWJ

Posts: 1,417

Country:

Thanks: 1

Thanked 4 Times in 4 Posts

i know you can buy aftermarket boost gauges which read from anywhere from 0 to 2 bar of boost.
i would recommend 'autogauge' for quality and very well priced.