Superchargers Vs Turbochargers

[R-PWR]

Screw Beastmaster, Faceless Void FTW!

[rob82]

each has their place in the car performance world

there is no such thing as " no lag " and " 0 rpm lag" its a load of rubbish

each has lag and takes time before the compressor is efficient

Thats untrue - positive displacement supercharges have zero lag they run a bypass vavle so that there is little/no flow throught the charger. As soon as the bypass vavle is closed you have boost. Also it is possilbe to control boost on most posivite displacement chargers as manufactures generally run a double sided vacuum actuator - so all you need to do is remove or apply pressure to vary the amount of air that is bypass from the compressor. We often do this on the VS-VT V6 superchargers.

The biggest compliment to the FSI engine is that it is direct injection so that higher compression ratio's can be used as chamber quenching is optimised. Another neat idea is the clutched supercharger as this will reduced the forces required to drive the charger once the turbo is brought into action.

To me the best thing nissan could do would be to introduce direct injection, crank the compression ratio up to 10:1 and add varaible cam timing.

[GeeTR]

...did anyone catch the episode of Top Gear where some mensa woman was doing the "Star in a reasonably priced car" bit and she asked Jeremy what the difference was between a turbo and a supercharger, and he had no idea?

For a guy who gets to drive some beautiful cars, and has done so for decades, he really is clueless.

Useless twat, bring back the TIFF!!!

[Dale FZ1]

To me the best thing nissan could do would be to introduce direct injection, crank the compression ratio up to 10:1 and add varaible cam timing.

I believe that is exactly the technology they introduced with the VQ25 engine series. Naturally aspirated compression is somewhere up around 11:1 and it's reputedly a pretty good bit of gear - for the power it is producing.

[rob82]

I believe that is exactly the technology they introduced with the VQ25 engine series. Naturally aspirated compression is somewhere up around 11:1 and it's reputedly a pretty good bit of gear - for the power it is producing.

I would then add 15Psi of boost pressure on top of that. That way you can produce lots of drivable toque plus top end - you also gains lots of response.

Also has anybody seen nissan's new variable vavle control - what a bucket of shite. You cant help but think it was designed by the law department in order to get around current patents!!!!

[tridentt150v]

Just as an aside, the GM diesel trucks [dirty GM's they are called], run a supercharger and turbocharger together. They are a V6 and make as much power with this setup as much bigger motors. Oh and they are two stroke deisels as well. Downside is they do like a drink!!!!!

PS They have been around for a long time, +30 years, I'll do a search and confirm when they first came out to confirm that, but I drove one at least 30 years ago [there goes my age now].

[StockyMcStock]

Some of you guys have a lot to learn. Others are getting there, very few actually know what they're talking about.

Go build a twincharged engine - ask lots of questions and learn as much as you can along the way. That's what I did, and the result is quite simply spectacular. It really is the best of all worlds. Snappy transient boost response at ANY RPM (even at 1000rpm you can have positive manifold pressure), good fuel consumption (for a 400hp car), giant midrange torque with NO compromise to top-end power (235rwkw from a stock-cammed RB25/30 on 9psi) and a much safer engine compared to a turbocharged-only setup because it runs so far from the detonation threshold. During valve overlap, if you have more pressure in the inlet tract than in the exhaust manifold, you get positive pressure sweeping the chamber clean of incredibly hot exhaust gas residuals - hence a cleaner, significantly colder charge. More power, less chance of detonation, more efficient engine.

Comparing superchargers to turbochargers and asking which is better is a bit like asking whether an apple is better than an orange. At what? When? On which engine? For what purpose? Which supercharger type? Which turbocharger? The list goes on.

If I had to choose between a street 500hp RB26 running an Opcon twin screw blower and a 500hp RB25 running turbochargers, I'd choose the supercharged one. If the car's purpose was drag racing, i'd go the turbo and run a giant stall convertor because top-end power is all that really matters for a drag car.

Essentially the "debate" boils down to three simple words;

Horse For Courses.

[Slim Mat]

each has their place in the car performance world

there is no such thing as " no lag " and " 0 rpm lag" its a load of rubbish

each has lag and takes time before the compressor is efficient

Although, some manufacturers, eg Porche, are finding ways to minimise it a lot. I have recently driven a new Hyundai Santa Fe turbo diesel and you can hear the turbo spooling up even when you only just holding your foot on the throttle at 900rpm constant. It's bloody amazing, honest you can hear the whistle it makes at 900RPM!!!

This is due to their new VGT's(Variable Geometry Turbo). Works something along the lines of changing the diameter of the exhaust turbine using a vacuum actuator, so that at low engine speeds it is the right size to boost and at high engine speeds it changes to stay efficient and increase flow.

I don't think it is that new though, Porche have been using it for some time.

[Cubes]

Nissan have been using the VNT/VGT turbo's for ages on their diesels.

The 100series Landcruiser Diesel with its auto trans is a very pleasant drive. Goes extremely well.

[Slim Mat]

Also good to see that we have some DotA players out their.

Send me your xfire username or msn email so that I can add you. Perhaps we could tee up some games.

[Slim Mat]

Horse For Courses.

Horses perhaps?

Also, never asked which one was better. Just asked what people thought.

Edited June 2, 2007 by Slim Mat

[BAMR33]

Also good to see that we have some DotA players out their.

Send me your xfire username or msn email so that I can add you. Perhaps we could tee up some games.

How is this anything to do with supercharging or turbocharging.

[rob82]

Although, some manufacturers, eg Porche, are finding ways to minimise it a lot. I have recently driven a new Hyundai Santa Fe turbo diesel and you can hear the turbo spooling up even when you only just holding your foot on the throttle at 900rpm constant. It's bloody amazing, honest you can hear the whistle it makes at 900RPM!!!

This is due to their new VGT's(Variable Geometry Turbo). Works something along the lines of changing the diameter of the exhaust turbine using a vacuum actuator, so that at low engine speeds it is the right size to boost and at high engine speeds it changes to stay efficient and increase flow.

I don't think it is that new though, Porche have been using it for some time.

Most diesels dont run a throttle's that's why you can hear the turbo spool at idle as there is either boost or atmoshpeheric pressure. And yes I am aware that some modern diesels run electronic throttles. The new triton even has stepper motor control varaible vane turbo.