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How does a supercharger work?

bone

bone

"bangle for president"
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i decided to write an essay about the supercharger :)

To start with, there are 4 types of superchargers used (i know of), the centryfugal type, the roots type, the vane type, and the screw type.

the centryfugal is the most known, inside, it looks almost identical to a turbocharger, but is connected with the engine by a belt or a shaft.
supercharger.jpg


The roots type, is shaped overal. in each of the outher sides, there is a rotor, which are again driven by a belt or shaft. this is the same was as how an oilpump works (sometimes these rotors each have 3 lobs)
Blower.gif
supercharger.jpg
rootes.jpg


the Van type, consists of a metal housing, with inside a metal tube, placed as far as possible away from the intake, and as close as possible to the outlet. on this tube there are 3 or 4 plates which can slide in, but are pressed out by a spring. as you can see on the pic is the intake positioned so a maximum amount of air can enter the compartement. since the metal tubes (and so also the metal plates) are moving, the compartiment gets smaller and smaller, with the air no where to escape, until it reaches the outlet, and it's pushed out.
0107scc_supercharger06.gif
internalview.jpg


the screw type, is again a metal housing, with inside 2 long rotors, one with 3 lobs, one with 6 lobs. these screws are again mounted so there is maximum capacity near the intake, and high compression near the outlet. since the screws turn, they push the air towards the outlet.
lightning9.jpg
twinscrew.jpg
0107scc_supercharger08.gif


the very first ones were shaped like, and worked pretty much like a rotary engine
0107scc_supercharger09.gif


The discussion about what is best is going on for ages, and wil go one. the way a turbo works is simpler, needs less maintainance, last more miles, ...
on the downside, there's the turbolag
a supercharger is more expensive in every way. in contrary to the turbocharger, the supercharger takes power from the engine. but if you have an engine with enough power to begin with, i think a supercharger is better, there's no lag, if set well no worry it'll overspool, or overboost, caus it's propelled by the driveshaft, ...

but don't get my wrong, i'll get a turbocharger over a supercharger anyday. a BOV is a MUST :twisted:
 
superchargers are just so complicated... rather have turbo's. :D ... Superchargers also have more reliability problems because of the high wear and tear in the bearings because of more movable parts
 
Yeah but they provide low end torque, and most high-end v-1919109 engines prefer superchargers. I think the supercharger is best fitted for the rotary than a turbo.
 
hmm... Since bone seems to know pretty much about this stuff I'll provide the question for this thread:

Can you explain how Lancia Delta S4:s engine worked? I mean, it was a 1.8 litre engine with a Roots-type supercharger(for low-rev power) and a turbocharger(for peak power in high revs). Now, I've heard that the supercharger was set up so that it faded down as the revs built up and was switched off altogether in high revs. But how would this work, exactly?
 
I don't know for sure but it is probably just a clutch on the supercharger and it is turned on and off electronicly. The turbo is just set to come on at a certaint RPM higher up in the rev range

I THINK
 
you're right, it worked with a clutch, but that's also all i know about it

i almost know nothing about specific cars, but ask me sth about cars in general, and i will be able to reply :)
 
zyran said:
Yeah but they provide low end torque, and most high-end v-1919109 engines prefer superchargers. I think the supercharger is best fitted for the rotary than a turbo.
Click to expand...

I prefer the turbo... I never need the low end torque cuz if I'm racing off the traffic light... i usually drop the clutch and by the time the car is moving... my turbo is already giving me boost.
plus if you practically floor the throttle... the turbo spools up really quick... at like 2500rpm because rx-7 have sequential turbos...(1 small turbo and 1 big one)
 
Superchargers work really well on your peaky, impractical engines, like the honda vtec's, and the hard tuned toyota engines (a blown elise would be magic!). The Aerial (Ariel?) Atom now comes with a blower that really pulls the bottom end of the torque curve out. Gives you great elasticity and drops the 0-60 time significantly. :)

Turbo's are fidgety, a bit switch-like at higher boosts, which causes some instability on a circuit. They also amplify the peakiness of an engine. Not my style.

The AW11 SC is a great car. The 4AGE fitted with a supercharger really lights up the performance, and made it a much easier car to drive fast. Brilliant little car. Seems a shame that after that car, they just wasted the 4AGZE on fwd's. :)
 
I always thought a turbo is very unpractical at a circuit, when the turbo kicks in at the end of a corner with your RWD car you get a big boost and the car is sideways...

I thought because most people floor it when they come out of a corner..

Btw, welcome cubits, and does your GTI have air? Is that an extra option Down Under? We get air for free here..
 
The only thing I don't like about Turbo's is it has mid-range engine power... no top end or bottom end... I remember my old Subaru Impreza with STi Engine swap's horsepower peaked at 6400rpm when my redline is 8000... so after it reaches 6400... it takes some time to get to the 8000rpm red line
 
Yeah, my car has air, says so in my sig. They came standard with air con here, but they couldn't fit the power steering in alongside the aircon until the series 3 205's were released here. I can't remember if you could get both on the same car in europe, ever. It was a local solution.

FYI, my car is really old, series 1 (1987). No power steering, that's for girls. :)

To keep on topic:

Since turbo's only increase the torque in the upper reaches of the rev range (how high up depends on the flow of the head), they're only any good for showing off on a dyno, or accelerating really hard with a close ratio gearbox. You can get quite a bit of torque.
 
FYI, my car is really old, series 1 (1987). No power steering, that's for girls.
Click to expand...

Off Topic again:
Do you have racetracks in Australia? I know quite a few guys who go to the Nuyburgring with their 205 GTi's, they say they're not that bad around the track.
 
Oh come on! Of course we have racetracks in australia!!

There's this tiny unknown racing series we have here called the V8 Supercars... maybe you've heard of it?

There's also this track, called Bathurst... quite a famous one too.

Oh, and the Adelaide F1 circuit, phillip island circuit (motoGP), Gold Coast indy circuit, and the albert park F1 circuit. I know we have about 50 or so racetracks in our country... but those are the most famous.
 
Sorry for digging up this older thread, but I'm going to add one supercharger, you forgot Bone. I hope you don't mind ;)


Since you have discussed the vane type supercharger, you can also add the G-charger (or scroll type supercharger), VW used in their G40 en G60 models. This type of blower was originally patented by a French engineer a long time ago. It uses a housing with two spirals and a sort of G-shaped rotor that acts like a displacer. This displacer is driven by two eccentric shafts, so it doesn't make a rotating movement, but a 'left-right' movement so it draws air, compresses it, and pushes it into the intercooler and intake manifold.

glader.jpg



And then of course you have the real special compressors like the rotary piston compressor (not used in a recent automotive application as I heard of) and the Comprex, although the comprex isn't really a supercharger, nor a turbocharger.


bone said:
the way a turbo works is simpler, needs less maintainance, last more miles, ...
Click to expand...
I have to disagree with you on this one. A turbocharger (on a petrol engine) is highly dependant on the owners care. Due to the high exhaust temperatures and extremely high rpms (120.000 to 220.000 rpm, against about 15.000 rpm for a Roots-blower or screw-type supercharger, or about 40.000 rpm for a centrifugal supercharger) the reliability of the turbocharger is an issue if the owner doesn't take care of it properly. Shutting of the engine immediately after a quick run is a killer for a turbocharger on a petrol engine.

The main advantage of the turbocharger is it's efficiency. If you would place them on one line you could roughly say you would have this order concerning efficiency:
turbocharger > centrifugal compressor > screw-type/Lysholm > G-charger > Roots-blower


But I agree with you as you would pick a turbocharger over a supercharger. I just like turbochargers more :mrgreen:



Hazardous said:
Can you explain how Lancia Delta S4:s engine worked? I mean, it was a 1.8 litre engine with a Roots-type supercharger(for low-rev power) and a turbocharger(for peak power in high revs). Now, I've heard that the supercharger was set up so that it faded down as the revs built up and was switched off altogether in high revs. But how would this work, exactly?
Click to expand...
The air flow path was as follows: air filter - turbocharger - intercooler 1 - Roots supercharger - intercooler 2 - engine intake manifold.

But the air could bypass the supercharger. At low rpm the turbocharger doesn't create much boost so the supercharger has to do the boost work. At mid range rpm and mid load, the bypass valve progressively opens, reducing the flow through the supercharger. At high rpm the bug turbocharger creates lots of boost and the bypass valve is fully open, all air bypasses the supercharger. The Roots-blower is freewheeling now, so power loss is minimal. I don't think they used a electro-magnetic clutch to reduce the power loss of the Roots-blower to a minimal when it is not needed, like on modern road cars. But I'm not really sure about that.
 
but then superschargers don't provide a boost pressure as high as a turbo.And a turbo is more efficient.A turbo on a Merc I forgot the model sucks 60KW beofre it can supply anything.And besides like the new Mazda6 MPS 80% torque is available at 2000 RPM.
 
thx for the bump... please read the posts before yours... everything you said has basically been mentioned ;)
 
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