Golf GT 1.4TSI: Supercharger + Turbocharger

[kawei]

Everybody knows mechanical superchargers are good for low end output but short of efficiency at high rev, while exhaust turbochargers works strongly at high rev but reluctantly at low rev. For decades engineers want to combine supercharger and turbocharger. This was tried once in history – the 1985 Lancia Delta S4 rally car. The car was successful in motorracing, but the technology never extend to production. Now Volkswagen finally introduce a supercharger + turbocharger system to production. The first car to use it is Golf GT 1.4 TSI. The “TSI” stands for “Twincharger Stratified Injection”. It combines the Twincharger system with FSI direct fuel injection. The latter allows a 10.0:1 compression ratio, the highest ever for turbocharged engines. The 1390 cc 16V engine is based on the existing 1.4 FSI engine. Thanks to the twincharger system, its power is boosted from 90 hp to an astonishing 170 hp, which translate to 122 horsepower per litre. This might not be very high compare with Japanese rally cars, but by the standard of mass production engines, especially at this bread-and-butter price, it is undoubtedly astonishing. The 1.4 TSI engine also pumps out 177 lbft of torque from 1750-4500 rpm, equals to a 2.3-litre normally aspirated engine. Besides, its fuel consumption is 20% lower than a 2.3 engine. The Golf GT 1.4 TSI runs to 136 mph and 0-60 mph in 7.5 seconds, slotting between Golf GTI (200hp) and Golf 2.0 FSI (150hp).How does the Twincharger system work ? The Twincharger system is actually developed by supercharger maker Eaton. It connects a supercharger and a turbocharger in series. At low rev, the supercharger provides most of the boost pressure. The pressure it built up also speeds up the turbocharger so that the latter can run into operating range more quickly. At 1500 rpm, both chargers contribute about the same boost pressure, with a total of 2.5 bar. (If the turbocharger work alone, it can only provide 1.3 bar at the same rev.) Then the turbocharger – which is optimized for high-rev power – started taking the lead. The higher the rev, the less efficient the Root-type supercharger becomes (due to its extra friction). Therefore a by-pass valve depressurize the supercharger gradually. By 3500 rpm, the turbocharger can contribute all the boost pressure, thus the supercharger can be disconnected by an electromagnetic clutch to prevent from eating energy. The Golf GT won't be the only car adopting this technology. Next year, VW Touran will offer a detuned version of the engine, with 140 hp and 162 lbft. Then a 1.6 TSI engine is also in the pipeline. It will produce 195 hp. Lastly, the 2.0 FSI engine will also receive the same treatment to upgrade to 240 hp. Hopefully the latter will be used for GTI.The development of the Twincharger system is part of the effort to meet the European car industry's voluntary goal of 140 g / km carbon dioxide emission. Src: autozine.org

 

[OSFlanker]

When are they going to bring this to Malaysia? I want a 140bhp car with road tax of less than RM300 per year!!!!

 

[Alvin]

Sounds really interesting. If put in the GTI to boost to 280bhp even better!

 

[kawei]

There is also twin turbo system. Smaller turbo operate in low-mid rev range while bigger turbo kick in mid-high rev range.

Supercharger + Turbo system or
Small Turbo + Big Turbo system better?

 

[The Necessary]

N/A is best! hehehe.

 

[kawei]

Originally posted by The Necessary@Aug 30 2005, 12:18 PM
N/A is best! hehehe.

There is no replacement for displacement B) , but, these Super/Turbocharger are getting better and better.

Makes me feel like getting one

 

[supergripen]

that engine in the new Polo will be fantastic!!!! hope it happens..this'll make me rethink my 2nd car purchase..

 

[fabianyee]

wasn't the Nissan March a super+turbo??? and it was mass produced as well... IIRC, it was a 1.0...

 

[adliz]

Originally posted by fabianyee@Aug 30 2005, 02:19 AM
wasn't the Nissan March a super+turbo??? and it was mass produced as well... IIRC, it was a 1.0...

yup.. they even call it 'surbo'.. s/c + turbo.. hehe..

 

[supergripen]

Originally posted by kawei+Aug 30 2005, 12:23 PM-->QUOTE (kawei @ Aug 30 2005, 12:23 PM)

 

[kawei]

That's why alot of big displacement car actually don't have road tax

 

[fabianyee]

Originally posted by adliz+Aug 30 2005, 08:04 PM-->QUOTE (adliz @ Aug 30 2005, 08:04 PM)

 

[nelsone30]

sound interesting, but still a front wheel drive......