Some Opel Engines come with something called TwinPort Technology.
I guess that this increases power, as the original Z12XE (1.2) engine has 55kW, and the TwinPort (Z12XEP) version engine has 59kW of horsepower.

How does it work?

Why does it work?

Is this computer controlled?

What are the differences between the standard and Twinport engines?

Are there any disadvantages or other benefits of this system?

1 Answer 1


The Twinport Ecotech engine is the second generation of the GM Family 0 engine technology (also called Family Zero ... haha, could even be "Family Zed" in the right parts of the world, eh?). It works by having the ability to close off one of the two intake ports near the intake valve at low engine speeds, which speeds up the air entering the cylinder and causes a swirl of the air fuel mixture as it enters. This produces better low end torque. Coupled with advanced exhaust gas recirculation allows for better gas mileage without engine misfires (from the extra exhaust gas). As the engine speeds up, the secondary port is opened. Here is an image of how the air flows into the engine with (left) and without (right) the port open:

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Since this should not affect high end horsepower output, I'd suggest the difference between the two engines is the compression ratio bump (10.1:1 vs 10.5:1 for the Twinport) and probably tuning. As a rule of thumb, every point of compression is worth approximately 3% change in horsepower, so that alone would not make up the 7% difference.

The WorldCarFans.com says this about the Twinport:

The new 1.2-liter engine also features a number of notable improvements over its already extremely fuel efficient predecessor. The Corsa's 1.2 TWINPORT ECOTEC with Easytronic has 5 hp or nearly 7 percent more power, yet needs only 5.3 liters fuel per 100 kilometers - 0.7 liters or around 12 percent less than the 1.2 ECOTEC offered to date. In conjunction with the 5-speed manual transmission, consumption is reduced by 0.3 liters (5.8 instead of 6.1/100km) or around 5 percent per 100 kilometers. At the same time, performance has been improved: the Corsa 1.2 TWINPORT accelerates from 0 -100 km/h in 12.5 seconds (down from 13 seconds), while maximum speed is 5 km/h higher at 175 km/h. The new 80 hp engine complies with the Euro 4 emissions standard and comes with a five-speed manual transmission. The Easytronic automated manual transmission is available as an option.

  • Does this not reduce the amount of air entering, besides increasing speed? Apr 28, 2016 at 7:57
  • @IhavenoideawhatI'mdoing - It creates greater vacuum, so would assume it could reduce total air intake somewhat. The idea is to speed up the air going into the cylinder, which will allow the engine to produce more low end torque. I'm sure GM has a lot of tricks up it's sleeve which it isn't publishing, considering the newer version of the engine gets better fuel mileage and makes more power than its predecessor. Apr 28, 2016 at 11:16

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