Kompressors?

[Slaphead]

Thsi might seem like a dumb question but...

the kompressor is a supercharger right?
what's the difference between a supercharger and a turbocharger?

 

[mercmonkey]

supercharger runs from a belt off the crankshaft, but a turbo runs off the exhaust, both do the same thing in principle only in different ways

Im sure someone will offer a far better explanation

 

[littlebrooklyn]

I think it must be Slaphead. We have a kompresser and a couple of months ago we had to have a new supercharger fitted so I am guessing it's one and the same thing, but I'm sure someone else will know for sure.

 

[jberks]

yes as Merc Monkey says "Kompressor" is a supercharger and Turbos run off the exhaust. The difference is in their delivery and relative cost in terms of power. A turbo is effectively free as it uses the exhaust pressure which would otherwise be thrown down the exhaust pipe. The supercharger requires a few hp to run it so saps some power though as it also increases engine efficiency, it produces in excess of that used. The supercharger is instantly 'on'. As engine speed picks up, so does the supercharger. A turbo has a lag by comparison as it takes longer for it to catch up.
Turbos are quite common now on most makes and essential on modern diesels whereas I suspect MB use a supercharger on the petrols, possibly more for historical and marketing reasons than any technical ones. I believe they invented the thing (though I'm sure someone will tell us that it was actually invented in a shed in Hertfordshire!) and were the first to use one on their racing cars in the ?30's, trouncing the racing bentleys of the time.

 

[maldon]

I thought Bentleys had the blower and did the rouncing.

 

[jberks]

They did, but only after they got trounced by the Mercs! They differed initially I believe in that the MB solution came in only on full throttle whereas the Bentley had it on all the time and blew up as a result. Sorted it in the end though.

 

[maldon]

Take it away JB

In 1900 Gottlieb Daimler (of Daimler-Benz / Daimler-Chrysler fame) became the first person to patent a forced-induction system for internal combustion engines. His first superchargers were based on a twin-rotor air-pump design first patented by American Francis Roots in 1860. This design is the basis for the modern Roots type supercharger.

 

[maldon]

Well at least the piccy is of a Blower

http://en.wikipedia.org/wiki/Supercharger

 

[angus falconer]

I suspect MB use a supercharger on the petrols, possibly more for historical and marketing reasons than any technical ones.

Hmmm....I am not so sure - one of the reasons that Mercedes and Jaguar like them is that for real world applications superchargers give a better power spread than turbos - even the most sophisticated turbos tend to have a lag a lower revs and then a surge at higher crank speeds. Superchargers give a nice linear boost all the way through. The cost is the power needed to drive them as opposed to that needed by a turbo. So from a purist perspective supercharging is the next best thing to stonking V8. Note that AMG only use V8's or supercharged V8's and never turbos.

 

[jberks]

I can see that the supercharger is better suited when you have enough power to run it, say on a V8. But in that case, the C180k against say an audi 1.8T - who's right?

 

[television]

Turbo's work from the exhaust,where as super chargers work from the engine. the dis advantage with turbo's is that the device is in the exhaust flow, the very thing we need to keep as clear as possible and power is lost getting the exhaust gas past the turbo. there is also a lag that varies from different cars. Worst thing is you cant turn it off. My Volvo does 31 mpg at a constant 60mph, at 75mph it drops to 24mpg.
Superchargers do need power to work and will force more air in than in the normal aspriated condition. Here BHP is lost to drive the thing so your V8's have no problem.
I used to play with the Roots supercharger years ago that one could switch off.

The MB 1921 model 28/95 sports racer was supercharged.

Malcolm

 

[clive williams]

I can see that the supercharger is better suited when you have enough power to run it, say on a V8. But in that case, the C180k against say an audi 1.8T - who's right?

JB,

I recon both. The characteristics of a supercharger and a turbo are different. The power delivery of the supercharger from low down the rev range is suited to everone's perception of MB motors - torquey grunt. The TT has a noticeable 'on boost' feel to it, which gives a more sporting? character. Although, Audi have worked hard to get some boost at lower revs.
Of the two supecharging should be more reliable as it revs at a slower speed and doesn't have the heat of a turbo to contend with and is also able to cope with joe (dumbo) public, who are not generally sympathetic to a turbo's operating requirements.
In a (small - less than 10ltrs) diesel application the turbo is king because the lag is well hidden by the diesels slow acceleration and limited revs. Also they are difficult to abuse and the high pressure/relatively cold exhaust suits the turbo well. Greater than 10ltrs say, and the turbo needed makes manufacture difficult due to the stresses involved.
Basically, in a nutshell a supercharger is an air (k)compressor driven mechanically by the engine and a turbocharger is a compressor driven by the exhaust gases. Both pressure fill the engine with more air so that more fuel can be burnt to produce more power.

Clive

500E
E320CDIT210

 

[E320C]

Supercharger

I have a ltd edition MK2 Golf G60 (basically a mk2 GTI with supercharger). Amongst the VW fraternity it's commonly advised that the supercharger requires a precautionary rebuild at 40k, especially so if modded with smaller pulleys.

I know times have moved on since the old MK2, but what is the recommended rebuild mileage on MB supercharged cars if any?

Regards

E320C

 

[Charlotte001]

Another difference between a super charger and Turbo Charger is a Super Charger (Kompressor) needs a certain amount of BHP to run, example the big SL needs 125BHP just to turn the super charger on.

Everyone is correct that a Turbo runs on exhaust and Super Charger runs on belt or chain drive. Turbos will burn out quicker than a super charger due to the build of a turbo being either oil or water cooled and both run at different powers @ figures .

Charlotte

 

[Charlotte001]

Another difference between a super charger and Turbo Charger is a Super Charger (Kompressor) needs a certain amount of BHP to run, example the big SL needs 125BHP just to turn the super charger on.

Everyone is correct that a Turbo runs on exhaust and Super Charger runs on belt or chain drive. Turbos will burn out quicker than a super charger due to the build of a turbo being either oil or water cooled and both run at different powers @ figures .

Charlotte

 

[Slaphead]

all very informative and interesting... thanks.

 

[jimsinessex]

I have a ltd edition MK2 Golf G60 (basically a mk2 GTI with supercharger). Amongst the VW fraternity it's commonly advised that the supercharger requires a precautionary rebuild at 40k, especially so if modded with smaller pulleys.
E320C

Going purely on memory I seem to think the supercharger used on the Volkswagen was a completely different scroll type design compared with the Rootes type.

It wasn't long before it was dropped by VW, probably because of the 40k rebuild requirement.

Jim

 

[SLinKyjoe]

i had a 1.8 20v Turbo AUDI engine in my SEAT. it gave boost from 1850rpm...but it didnt do much beneath that, and the problem was that it kind of gave it all at once. so it got a bit jerky to drive in normal traffic. the first SLK i had had the 2l Kompressor. pulled smoothly from 1000rpm and gave decent torque levels,

when i got the R171 with the 1.8K they had moved on, it felt a lot better and gave the auto box enough torque to pull away properly. was good for real world driving. I also had recently a 1.8 Class. this was suprisingly good to drive.

In contrast, the Subaru WRX with the 2L turbo i had was a nightmare. at anything below 1500rpm it was dead. absolutly no power, it gave you the worries at junctions where you were still rolling to pull out. it improved in performamnce up to around 2750rpm and then you bascially had to hang on as it disapeard into the distance.

Got a non-forced induction V8 now. it works from 800rpm and pulls your face off, or drives normal depending on your pedal pushing.

all the other cars above did around 28-33mpg, with the odd 25 and the very once only 42mpg.

the V8......hmmmm 23mpg in general. and a once only of 35.

Strange how AMG bolted on Turbos to the V12 tho? I think that may be due to the fact the engine was going in the Myabach and the Turbo engines are a lot quieter!

 

[philharve]

Amongst the VW fraternity it's commonly advised that the supercharger requires a precautionary rebuild at 40k, especially so if modded with smaller pulleys.

I know times have moved on since the old MK2, but what is the recommended rebuild mileage on MB supercharged cars if any?

Regards

E320C

My supercharger is approaching 100k miles and is still sweet. My indie says that they can last the life of the car, if looked after. However, they can give trouble at far fewer miles and you will know it from the 'rattly' sound they make.

Turbo rebuilds are far more common and I've never heard of one lasting the life of the engine.

I would agree with an earlier comment about driving a supercharged car is like driving a normally aspirated car with more cubic inches. The torque increase can be dramatic and is present from low revs right up through the speed range. However, the 'redline' is comparatively low - 5,700 in the C230K - compared with non-supercharged vehicles.

I once drove a turbocharged Seat and it was a lot of fun. Very responsive with negligible lag due to the low inertia turbocharger. However, this car had a 'frantic' personality and wanted to go everywhere fast. I decided it was not for me because it threatened my driving license. It was also bright yellow. Within a week I bought my dark blue Mercedes.

I have no doubt my Merc' will be around long after the yellow peril has oxidized or been recycled as spare parts.

REGARDS Phil