What's the safest highest speed for a 660cc without getting it under harmful stress?
The cars are over engineered.
What ever speed any modern car can attain under normal driving conditions is within the safe limits.
Happy motoring.
That was the whole purpose of the post, to find out the upper safe limit of what you call an over-engineered vehicle without being too cautious. I'm certain that 80km/h is fine but would hundred be also fine on a motorway for an hour or two? That's what I was looking for... But thanks anyway
Unforeseen event can happen anytime anywhere. So speed within limits which is controlable is always recommended. I think 80 to 100 is manageable speed with good braking systems.
It was more concerning the load on engine, rather than the braking capability.
The speed limit of the road is the safest.
Doesn't depend upon displacement of your engine, but many other factors. IMO, if by 660 you mean PKDM 660cc, don't go over 100 kmpl plz, as there is no safety what so ever, and yes there will be less stress on the engine
IMO every car has certain weight limit to run car. Anything within that weight limit there is no issue with engine. The purpose and function of engine is to run. Doesnt matter what is the speed.
Sadly no one could come up with a definitive answer backed by scientific reasoning
660 cc engine has top speed of 140 km/h and it can be driven at 120km/h easily on motorway. They are engineered this way. The cars run at 100-120 km/h speed in japan and the engine does not get damaged.I owned a mira for 2 years and drove it above 100,000 km. I travelled from Lahore to Multan and murree a number of times and at times kept it on 120km/h throughout the journey. Nothing happened to engine just keep your air filter clean , change oil on time and wash radiator after long journer and you'll be fine.
That's something coming from experience and informative, thank you.
100 km/h is a good speed for PKDM. Because without VSA and Traction Control I don’t think it is safe to drive any small car especially light weight car above 100 km/h. You can even feel the air impact on light weight car during heavy vehicle overtake. I respect everyone opinions but 120 km/h seems bit high to me for cars built for city driving. With small body car characteristics changes very much on high speed as compared to normal sedan and can goes out of control much easier. It is also pertinent to mention that locally produced city cars have less road grip due higher ground clearance as compared to JDMs.Engines on the other hand are indeed well tested and reliable enough to push the car above 100+ on trade of fuel economy.
I terms scientific reasoning, you should keep the engine rpm controlled don't allow it to go near the red line... at normal rpm whatever speed you attain is safe for engine...
Apart from engine your tires and breaking system should be good.... (for your safety not for engine safety )
The red line is around 6500 but I think I can hit 120 at around 5500, don't think that's very safe?
