I'm running a manual Opel Corsa 2005 Sedan (engine code: C16SE, 1600cc). The problem I'm encountering is that the car won't reach its maximum speed of 200km/h as similar cars do. Instead, it stops accelerating at 150km/h no matter what I do even with the gas pedal floored. I have replaced my worn clutch and the new one works great (apart from this problem) so I exclude that. Here are some info and notices that might help:

  • The engine turns on normally and idles just fine
  • Accelerating from zero up to 130km/h is smooth. It is harder to go past that but eventually the car reaches 150km/h (i.e. takes more time to gather speed)
  • During idle, 1st, 2nd, 3rd, and (maybe) 4th gears, the engine RPM can reach 6400 and cut-off as designed. On 5th gear, however, RPM can't exceed 4500. So RPM stops at 4500 plus car speed stops at 150km/h.
  • Gas mileage is fine for that car
  • I'm using the recommended fuel as per the owner's manual
  • Using 10W-40 semi-synthetic oil, suitable for the engine
  • Air-filer was replaced 12 months ago and used for 9,000 km and was cleaned once since then
  • Fuel-filter was replaced 14 months ago and used for 10,000 km. The mechanic have cleaned it once few months ago and it was OK.
  • I sense some misfire even at idling like pulses that I feel them under my feet
  • Sometimes check engine light comes on at speeds between 130-150km/h then turns off when I slow down to below 130km/h
  • Timing belt was replaced 6 months ago and no sign of improper installation
  • Spark plugs last changed since 10,000 km (14 months ago). I also replaced the wires 7 months ago.

What could be the reason for the lack of acceleration bearing in mind the car's behaviour as explained above?

  • Is the car really 2005 with C16SE engine? I'm having some trouble finding information about this engine for a 2005 Corsa. According to Wikipedia, Corsa C has 1.4 litre and 1.8 litre engines but not 1.6 litre. Anyway, 200 km/h from a 100 hp engine may be asking too much. – juhist Apr 22 '18 at 10:33
  • Another data point: my 100 horsepower 2011 Toyota Yaris had maximum speed of 175 km/h... If you have lost some horses, that could explain the poor 150 km/h speed. – juhist Apr 22 '18 at 10:41
  • @juhist I mentioned it is Sedan version (manufactured in Brazil) which is different than the hatchback released in Europe. So yes it is 1.6 litre and generates 101 hp at 6200 RPM. The question because I know people with the same car who can reach 180-190 km/h speeds. Maybe 200km/h is theoretical or in stock conditions but 180-190km/h are realistic speeds for the same car which I can't reach. – Ahmed salah Apr 22 '18 at 10:44
  • @juhist Regarding horsepower loss, so you suggest a compression test. Am I understanding correctly? – Ahmed salah Apr 22 '18 at 10:45
  • Most modern cars use 5W30, 5W20, or even 0W20 motor oil. Using a thicker oil can cause you to lose HP due to the engine having to push it around. Using 10W40 could be robbing your engine of the HP needed to exceed light speed as it seems you'd like to do. – Pᴀᴜʟsᴛᴇʀ2 Apr 22 '18 at 12:51

I think I have enough data for an answer, so I'll provide it here instead of as comments.

200 km/h from a 100hp engine is way too much. Solar Mike noticed that the particular engine has 186 km/h top speed on an older hatchback. I'm not sure if this is valid for the 2005 sedan, as information about the 2005 sedan is hard to find.

My 100 hp engine in a 2011 Toyota Yaris hatchback resulted in a top speed of 175 km/h. Nowhere near 200 km/h. My 1989 Opel Vectra sedan with 115 hp engine had top speed of 198 km/h, but it was reached on the 4th gear, not on the 5th. Also, the 1989 Opel Vectra was more aerodynamic than most cars.

Based on this, I don't think you'll ever reach 200 km/h on a 100 hp sedan. A very aerodynamic car with 120 hp could reach 200 km/h. A less aerodynamic car (such as a hatchback) will probably require 150 hp.

Your engine may have lost some horses due to its age. The first thing to start investigating the issue would be a compression test. Of course, if you want to be comprehensive, you could measure the engine power on a dynamometer to give more direct power reading and especially the power at high RPMs.

Note also hill grade, outside air temperature (cold air is more dense and thus air resistance is higher) and wind speed and direction when determining the top speed. Additional weight in the car can also slightly lower the top speed.


Where did you get the max speed of 200km/hr from?

Is it just because it is shown on the speedo?

See wiki description here and it seems it was 186km/h, but with age that will be less - especially if the maintenance was not good... Also, the max speed is usually set with a minimum weight and other conditions...

  • You are right. The 200km/h is a word spreads about this car in my country but I know no one who reached it. I do, however, know people with the same car and age who can reach speeds between 180-190km/h (close to what you mentioned). So it should be capable. Again you are correct about the maintenance as a decisive factor here which is why I'm asking. What should I do to fix it? What maintenance is needed now to restore its full power? – Ahmed salah Apr 22 '18 at 10:49

Over time, a lot of top-end components can have a build-up of carbon. This can affect performance to a degree. If you're looking for another simple solution, it might be worth using an Top End Treatment like SeaFoam. A fuel system treatment may also be warranted.

Granted any results from this product will be specific to your situation warranting its use.

There are more advanced tests which can be performed such as Vacuum Tests, Leak-Down Tests, Dry and Wet Compression tests, which will give a more specific picture of the engines health but these might be out of the scope of the query.

Here's a link on how to perform a Vacuum Test

Here's a link on how to perform a Leak-Down Test

Here's a link on how to perform a Dry and Wet Compression Test

Here's a video on how to perform a Compression Test

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