Re: Volkswagen Jetta : Test Drive & Review Did some research on this 1.4L engine.
The version they've brought to India for the Jetta is the regular turbo-charged version and not the 'TwinCharger' version that also has a SuperCharger. I would've personally preferred to have seen the TwinCharger engine in the Jetta - which happens to feature in this year's Polo-R-Cup anyway. When they already have this engine in their Polo cup cars, I think it would've been easier to just also cascade them down into the street cars, perhaps in a lower state of tune (140/160/170ps maybe). Features of the 1.4L Turbocharged engine: The regular 1.4L turbocharged engine that the Jetta now has in India has a cast aluminium alloy, four valves per cylinder (16 valves total), low-friction roller finger cam followers with automatic hydraulic valve clearance compensation, roller chain driven Double Overhead camshaft (DOHC), Continuous adjusting Variable intake Valve timing, and a cast alloy throttle body with electronically controlled Bosch "E-Gas" 'drive by wire' throttle butterfly valve, not to mention a two-part plastic intake manifold and a Turbocharger incorporated in exhaust manifold with maximum boost pressure 1.8 bars (26.1 psi). The engine also features a water-cooled intercooler integrated into intake manifold , reduced frictional losses, optimised camshafts, new intake ports, new high-pressure injector valves and is also 14kgs lighter than the TwinCharger models, in order to improve fuel economy and reduce emissions. States of tune for the 1.4L Turbocharged petrol:
122ps @ 5000rpm, 200NM~210NM @ 1,500-4,000 rpm - this is what we have in India and in many cars abroad
131ps @ 5500rpm, 220NM @ 1,750-3,500/4,000 rpm - this is available in select cars abroad
- These engines apparently require a recommended 95 RON ultra-low sulphur unleaded petrol (ULSP). I think we were given the former 122ps state of tune as it must run well with 91 octane as well. Features of the 1.4L Twincharger engine:
Shares most of the features of the regular turbocharged version, but in addition features a multi-ribbed belt-driven fifth-generation Eaton Roots-type positive displacement SuperCharger operated by a magnetic clutch integrated in a module inside the water pump, internal step-down ratio on the input end of the synchronisation gear pair, and KKK turbocharger with integrated wastegate connected in series administrated by a control flap, 2.5 bars (36.3 psi) pressure at 1,500 rpm and a front-mounted intercooler (FMIC). The mechanical supercharger compressor, driven at 1.5 times the speed of the crankshaft, mainly operates at low engine speeds from tick-over up to 2,400 revolutions per minute (rpm) to increase low-end torque. At engine speeds just above idle, the belt-driven supercharger provides a boost pressure of 1.2 bars (17.4 psi). The turbocharger assumes full effectiveness at middle revs, and the engine map disengages the clutch-controlled supercharger at a maximum upper limit of 3,500 rpm; the supercharger will then be bypassed once the turbocharger spools up and reaches sufficient speed to provide adequate boost in the upper rev-ranges. States of tune for the 1.4L TwinCharger petrol:
140ps @ 5800 rpm, 220NM @ 1,750-4,000 rpm - street version
160ps @ 5800 rpm, 240NM @ 1,750-4,500 rpm - street version, higher end cars
170ps @ 6000 rpm, 240NM @ 1,750-4,500 rpm - street version, higher end cars
180ps @ 6200 rpm, 250NM @ 2,000-4,500 rpm - GTI, RS, Cup versions only
- All the above Twincharger engines need 98 RON 'Super Unleaded' ultra-low sulphur unleaded petrol (ULSP) - 95 RON may be used, but will result in lower power output. This is most likely one of the reasons why the TwinCharger wasn't chosen for street use in India, but I'm glad the Polo-R cup atleast received the 180ps engine as I'm sure they can equip them with the right fuel required.
So, fuel economy, emissions & petrol quality/octane content seem to be the motivating factors for choosing the 122ps turbocharged engine for the street Jetta, in lieu of the TwinCharger models.
#Sources compiled from: many websites ;-) |