I regularly drive a VS (ecotec) and a VZ calais (alloytec190) and the VZ is heaps smoother, and definately feels more powerful as well, although the ecotec feels better down low in the revs (which could be because the car is so light).
Never had a serious problem with either engine, but I would assume the newer alloytec would be more reliable and it is obviously more powerful
I vote alloytec overall, although I have never driven the 175kw version
after getting out of the vs and into the ve the power of the 195kw donk was evident from the beginning, it was responsive and torquey down low and really pulled hard from 2200rpm and continued to wind its way to up to 5500rpm which is where the needle would launch to 6500rpm where it meets peak power.
The 6 speed manual available with the high output engine delivers a sporty and direct feel, especially given its heavy dual mass clutch setup and short ratio low gears. The 5 speed transmission was less than exciting, its slightly taller ratios still allowed good acceleration and effortless overtaking, the sports style active select is slow to react and gives the car a lethargic feel when driven hard.
The omega 4sp case is more refined version of the same gearboxed used all the way from the VN. Its tried and tested.
The induction roar of the alloytec is not so much a rumble but an asthmatic pur and a 2400 onwards wheeze that makes the car sound like its building a tiny amount of boost...only to disappoint. For a capacity of 3.6lt the power house does well to move the heavy vz/ve with such ease and fuel economy.
The ecotec behaves like one would expect an Aussie engine to perform, with its good low down torque and mid range tuning, it makes any car feel larger and faster than it really is capable off. With much of its power available from low revs it made hard launches and respectable speed figures, making the ecotec powered cars a cheap option for younger drivers who wanted reliability, torque, and the availability of cheap parts without the need for 5lt status.
The heads of the ecotec are left with alot of casting flash which when milled and flowed respond well to breathing mods.
The ecotec was available with the choice of either manual or auto. The auto's have become cheap to rebuild over the years, which is a good thing because given ever and moderate drive are prone to exploding after 150,000kms. The manual was originally the T5, but was later upgraded to the Getrag box. Both are expensive to repair, but the Getrag box will require attention on a more regular basis.
The Sounds of the ecotec is deep and meaty, not as deep as the 5lt, but alot deeper and more defined than the alloytec engine.
It really depends on what your after, if you want a smooth, effortless drive with plenty of power in reserve for when you hit the hills or for when your getting yourself out of trouble then the alloytec is for you. But if the price of the newer cars is out of reach then you wont go past a vx-vy. They are around with as little of 60,000kms for less than $12000.