Torque data for Vauxhall petrol engines

These curves reveal several things...

1. Bigger engines produce more torque and power. I know that this is not startling news. However it is interesting to know that the 1.8 produces just over (1.8/1.2) times what the 1.2 produces. The larger engines have more output pro rata because the compression ratio increases slightly. The 1.3 is 9.2:1 whilst the 2.0 is 10:1.

2. The 1.4i and 1.6i introduced in the early 90s are pants when compared with the carburetted versions. The reason for this is that they have a puny central point injection system. A sort of electronic carburettor. The 1.4i has less power than the old 1.3S engine!

3. The 2.0 16v engine produces more torque and power than the 8v. The 16v engine is essentially the 8v engine with a 16v head and a different engine management system. Having two smaller valves in place of each original single valve allows a much larger valve flow area since the smaller valves have a diameter this is bigger than half the original one. An 8v engine can be tuned to nearly the same output as the 16v by use of high lift cams and a flowed head.

4. Fitting a cat does the performance no favours. The C20 XE and C20 NE are cat versions and are down on torque and power due to the increased back pressure in the exhaust system.

5. Tuning a 1.3 from 75BHP to 92BHP gives more power than a 1.6, but the 1.6 would still be a better car to drive. This is because the 1.6 has oodles more torque.

6. The 16v Ecotec engines aren't bad. Each engine performs almost as well as the next size up from the previous generation. The 2L unit doesn't match the original 16v engine however.

Engine data

Data taken from Haynes manual, owner's handbook, sales brochures and off the internet.

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