Corrado Supercharger

[Princess Leia 0]

Hi ,On my Corrado G60, I was wondering if someone could explain, in laymans terms, how it all works. I have done a search and come up with a few things but I am still a bit clueless as to its operation. Please talk to me like a little school child as I know nothing about mechanics and I really want to learn about it.

Also how loud should my car be it makes a deep low huming sound when driving about normally but when you open her up it kind of sounds like a normal engine is this nomal?

bear with me on this I will get it in the end. thanks in advance for all your help.

 

PL :D

[funky 0]

i too have no idea what goes on inside a charger and to be quite honest i think its better that way,best left to people like darren(8vg60)

but the humming yes this is normal now mine has been stage 4 tuned the noise is awesome

hth

funky

[G60Jet 1]

it squeezes the air and make it more dense, the intercooler cools it, making it even more dense and then it gets used by the engine.......sorry did you want more detail.

 

basically it squezes the air throught the charger sqashing it, it uses a fix and moving scroll. the scroll opens and closes at the intake point and moves the air through it, squezing it against each of the scrolls to put it thorugh the charger and compress the air. it then moves out through the exit and into the charger hoses.

[Chris VR6nos 0]

The scrolls open & close Nigel?????

They are cast alloy and apart from them breaking or snapping off, which they often do, how do they move? Apart from that i'd agree with you.

It is a centrifugal charger, same as a turbo, just not driven by the exhaust.

 

 

 

Chris

[forcefed_vw 0]

Actually it isn't a centrifugal charger. The G-lader has a moving (recipricating) scroll which is driven by a crankshaft or cam. As the cam rotates, the exposed end of the scroll graps some air from the intake, then chases it around between the faces of the scrolls until it is forced out of the centre outlet of the charger casing.

[stormseeker 0]

The charger (whether it's a turbo-charger or a super-charger) is just a pump to get more air in the engine. Since the engine's basic job is to burn petrol to make it go, the more air you can force in the more petrol you can burn - hence more go :-)

[joebloggsVR69 0]

Heres a video animation which shows you what you need to know.

 

Hope you know some german though :D

 

http://www.polofreaks.de/G-Lader-Anim.AVI

 

btw, he calls it the 'gay larder' :lol:

 

Also:

[G60Jet 1]

The scrolls open & close Nigel?????

They are cast alloy and apart from them breaking or snapping off, which they often do, how do they move? Apart from that i'd agree with you.

It is a centrifugal charger, same as a turbo, just not driven by the exhaust.

 

 

 

Chris

if you look in the intake part of the charger chris, as the scrolls move they open and close, thats what i ment. the piccy above make better sense of it

[vdub 0]

How reliable are the G60's ??

What are some of the common issues with them and what can you do to try a prevent them ?

[G60Jet 1]

The Charger itself is reliable as long as its looked after and serviced like anyother part of the car.

[Princess Leia 0]

ok cheers for your input guys. I sort of understand it :shock: it looks like it is quite a complicated unit to make? What type of superchargers do they put on mercs then? is it the same as this? sorry about the million and one questions. and thanks to all who have helped.

 

PL :D

[Chris VR6nos 0]

Hmnn.....dodgy piece of kit that 'G' thing!

My centrifugal charger is more like a turbo though, what effect does the moving scroll have? does it aid in compressing the air mass?

Is the oscilating scroll speed relative to crank speed?

Never really conversed about the G-lader item but i'm interested more now!

Keep it coming lads, good graphic Joe.

Here is a pic of my charger, you can see the impeller straight on, with the centrifugal compressor chamber curling around it.

 

 

 

 

Cheers Chris

[forcefed_vw 0]

The scroll is, like all superchargers, driven by the crankshaft (in this case by a belt). The scroll IS the part that does the compression, there is no rotating compressor like you have. The one major difference in terms of air flow is that a centrifugal supercharger will make more pressure at an ever increasing rate as the revs rise, a G-lader is only an effective compressor up to a given point. Beyond this it only move air rather than compressing it. This is one of the reasons they are only designed of about 13K rpm.

[beavis 0]

The G-lader at any given RPM is just a 'Air mover', the compression is due to the air being forced in to a enclosed chamber, i.e. the boost hoses to the closed inlet manifold valves and the engine using a lesser volume of air than that is is being supplyed with. The structural integrity of the unit will withstand in excess of 20,000 rpm before grenades itself to pieces. The limiting factor is the tollerences of the bearings namely the centre scroll bearing. There is not a close enough tollerence to stabilse the scroll at high rpm and the cages in the bearings are the weak links as they cannot withstand the cenrifugal forces or heat generated at higher rpm's. G-laders do shift a large volume of air per cycle compared to a turbo etc.

This is not a recomended tuning mod but we did it so see just how reliable a charger could be under extreme rpm. We fitted a 58mm tooted pulley to a G40 charger and drove it to the 8000rpm rev limiter regularly thrashing it about with a suitable map and ECU mods to detect all 24psi of boost it was producing. The objective was to test some new modifyed/higher rpm top bearings, 17000rpm rated centre bearing we plan to use and see how long different brands of oil seals lasted at high rpm. All the bearings survived the 2000miles the charger lasted before burning out the lips on the oil seals as extreme heat is generated by the friction of the lips on the shaft as a lot of force is exerted to form the seal. Chargers are pretty strong, its is just the tollerences and service of components that are used to make them function that let them down and cause them to fail when pushed hard. Off the shelf components are adequate, so to get the best possible you have to get them made :lol: :lol: :lol: to keep everything in order.

Crank RPM is direcly related to charger rpm, in saying this the multi vee belt is only caperble of efficently turning the charger pulley at lower RPM as the charger has lot of back pressure being exerted on it at higher rpm which causes the belt to slip.

[GazzaG60 0]

hows about some of those bearings for the G60

 

i dont wanna rev to 8k but a mid 50's pulley on good bearings is up my street.

[W3RKD 0]

hows about some of those bearings for the G60

 

i dont wanna rev to 8k but a mid 50's pulley on good bearings is up my street.

 

:lol: :lol:

[beavis 0]

lol... ye, the problem at the moment being is that the centre bearing for the G60 is unique to that application, with the G40 VAG were thourtful enough to use a standerd sized bearing, after looking long and hard we have found a supplier that makes a bearing with a lot higher tollerences than OE. However with the G60, to go the same route we need to get the bearings made up ourselfs if we want a better quality unit as at the moment only OE bearings are avaliable in that size.

We are in the process of having uprated seals made to cope with high RPM/hammer head drivers which can take the stick, bearings are next on the list, the ball has been started rolling but the route we need to take will cost a lot of clean money.

[Kevin Bacon 5]

Got some interesting history on the G lader here if anyone's interested....some snippets from "VW Golf and derivatives":-.

 

The French invented the G Lader principal in 1905 for aero engines.

 

VW in the 80s, looking for ways to compete in the under 2.5 litre Rally classification rejuvinated the old G lader principal and designed their own version of it. The G60 engine displaced 1763cc which when multiplied by 1.4 (applicable to supercharged engines) meant it was comfortably less than the 2500 class limit.

 

Prior to VW taking on the G Lader principal, no manufacturer had been able to handle the the casting and milling processes with sufficient precision to produce the two housing shells in aluminium and the displacer in magnesium, with the required accuracy in large quantities.

 

The G Lader's key strengths are it's relatively low operating speed and quick spool up time. 80% of boost is available 0.4 seconds after opening the throttle and full boost is available a further 0.4 seconds later.

 

At the G60's launch, the engine was commended for providing a level of performance typical of a 2.6 engine from only 1.8 litres.

 

8)

 

Kev

[joebloggsVR69 0]

Some more G60 history, not my scans, I think I found this on vw vortex.

 

Hard to read, you might need an image broswer so you can view it at 200% :wink:

[Andy91 0]

Nice info guys !! good read !

[Andy91 0]

PS just read those GIF's, how old are they ? what year ?

[Chris VR6nos 0]

good one lads, however i like the way the centrifugal ones work, they have to make more power than the scroll type, have people tryed a centrifugal charger on the 4cly G60 engine? i recon if money allowed they would produce a mean output in comparrison? anyone got info on this?

Good thread, nice to see there is always someone with the info!

 

 

 

Chris

[beavis 0]

My friend is starting a course at Cranfield uni soon. We are gonna hijack there flow benches to get some CFM figures on ported G laders and how they compare to screw and centrefugals. Some facts and figres on the charicteristics of each different design.

[Chris VR6nos 0]

Shall be interesting for sure, look forward to the findings!

 

 

 

 

Chris

[trendy tramp 0]

here's a quick G60 fact - the G60 was voted International Engine of the Year when it was first introduced, and the guy who ran the engine programme says it was one of his proudest achievements in his career. Can anyone guess who it was???

 

My last boss also did some pre-production testing and dvelopment work on the G60 for VW at MIRA where he ran the test cells.

 

Beavis - steady state flow rig data will paint part of the picture, but more interesting would be transient flow data which is more difficult to measure. It's not very often you're running at constant speed, and flow transients can be wildly different to steady state counterparts.

 

tt