[tharian]

Since December weather is more prominent in January in Bangalore this time around, it is a good feeling driving the car in the mornings .

It has been around 14-15 Celsius during early mornings and my car just about reaches the usual coolant temperature just when I am reaching office which is 7 kms away.

The intake temperature does not go over 25c in the same duration.

Eager to rev and smooth while doing so.

[bluevolt]

Though engines are feeling better, I have observed significant drop in mileage since I use my car only upto 3 kms to park at nearest metro station and then back to home in the evening. Because the engine is not able to warm up properly, the fuel consumption is bit on higher side.

[SmartCat]

Has anybody noticed that the car seems to be a bit more responsive while driving on highways at night? Especially if it is a 2 + 2 highway, with moderate traffic that forces you to weave between lanes?



In most cities, the temperature difference between highs and lows is atleast 10 degrees centigrade.



So when we are driving at night, much colder air is entering the engine. So logically, it should increase the power of engine by 5 to 10% - not too different from how cold air intake works.



Is it just my imagination or does anybody else actually 'feel' the power difference while driving at night?

[R2D2]

In theory you are right, but I really haven't seen any noticeable difference in day/night of the same season. But the difference between seasonal for e.g. winter and summer performance is noticeable. Also, the AC works better alright.

[mayankk]

Not sure about nights, but winters, aye.

Originally Posted by R2D2

In theory you are right, but I really havenxt seen any noticeable difference in day/night of the same season. But the difference between seasonal for e.g. winter and summer performance is noticeable. Also, the AC works better alright.

My fiesta used to feel smoother somehow, especially on foggy days. Also, in one consistent-speed run on the moradabad road in winter, the temperature went down to half the regular level while doing those speeds, so the air definitely was cooler. I never felt the engine purr like that day ever again.

[sada]

I have definitely noticed the improved pickup in my Alto (800 cc) when the air is cool outside, like early mornings and late evenings. Perhaps it may not be more noticeable in a more powerful car.

[Rajeevraj]

Yes, there is definitely a difference. I am typically an early starter and start in the 4-5am time-frame from Bangalore- when it is typically quite cool. That initial drive before sunrise 'feels' good and mileage is also higher. Also mentioned by GTO in this thread related to night driving

Originally Posted by GTO

Advantages of Driving @ Night:

• You’ll usually achieve a higher average speed, despite maintaining a lower top speed. Primary reason = Lesser traffic.

• Lower probability of bullock carts, three wheelers, cyclists & animals on the Highway.

• Cooler air = Better engine! The density of cool air is higher than hot air. Thus, you end up with a superior burn, resulting in better performance. The engine feels noticeably crisper at night.

• Higher fuel efficiency due to lesser traffic & cooler air.

• You can see a vehicle coming around a blind corner due to its headlamps (assuming the vehicle has its headlamps running).

• This is down to personal tastes, but I find night driving very enjoyable. The pleasure of empty roads, cooler weather, crisper engine, feeling one with the car and some nice music playing is unmatched. However, safety comes first and it's best to limit night driving to as little as possible.

[bullrun87]

Originally Posted by smartcat

Has anybody noticed that the car seems to be a bit more responsive while driving on highways at night?
Attachment 1681955

Is it just my imagination or does anybody else actually 'feel' the power difference while driving at night?

From an engineering perspective a car ought to run better at night for two reasons
1) Lower temperature-
At night temperature usually drops by about 10-15 degrees on average. This means that air density would increase by about 3-5 percent. We all know that engines like denser air for combustion.
2) lower humidity-
Since night air is cooler, it is also less humid holding lesser water vapor. water vapor has adverse effect on performance.

All this will have an impact but I am not quite sure how they affect actual performance figures. One of the reasons you "feel the power" is that the roads are usually empty in the night

[Hayek]

Cars certainly are more responsive at night - but that's because the AC load on the engine is less, not due to lower air temperature. Car ACs need to deal with cooling a hot greenhouse - and face far higher loads when the sun is out (much more than the difference in reported temperatures that are measured in the shade). Hence cars feel more responsive at night even in cities like Bombay with negligible difference in day and night temperatures in the shade.

[V.Narayan]

Lower ambient temperature = better output horse power.

I do not know the figures for the ICE but a gas turbine - of the sort that powers aircrafts and warships the difference at sea level between 35 degrees and 15 degrees centigrade ambient is 25%. That is to say power output drops by 25% between 15 to 35 degrees ambient or increases by 33% as you move from 35 degrees to 15.

[Dr.Naren]

There is very good difference in my S-Cross 1.6 when outside temperature is cooler. Engine feels smoother and more free revving. I love driving the car early morning or at night

[Nikhilb2008]

Absolutely right. The difference is more on turbo charged cars. On my stock Civic, I didnt feel much difference, but with the turbo, it was a world of difference.

Reason: A Naturally aspirated engine sucks in air from the atmosphere and pushes it into the engine for combustion. The temperature doesnt change much in the journey between intake and cylinder.

In a turbo charged car, the air heats up massively when it is compressed by the turbo. This is why we have an intercooler. The intercooler though, can never bring hot air down to ambient air temperatures. So, the air reaching the cylinder is always hotter than the outside air in most situations. This is why in a turbocharged car, there is a reasonable amount of difference.

[airbus]

Couple of days back I was talking to a friend who completed Bengaluru - Guwahati - Bengaluru drive in mid 2016. He mentioned about better engine performance at night, so he took majority of his drives during night with extra lighting and reflectors. Another point we discussed about tyre heating under intense sun or high temperature. It appears, cooler temperature at night may reduce likelihood of tyre burst situation.

[tsk1979]

Feels are very very good. But actual data and scientific research is even better.
Here you go, a detailed scientific paper researching and providing a mathematical formula for Atmospheric conditions vs Engine performance
http://www.scielo.br/pdf/jbsms/v25n3/a10v25n3.pdf

The atmospheric pressure was observed to be a more relevant
parameter to influence the engine performance than the air
temperature. Road tests confirmed that the acceleration time is
increased with increasing air temperature and decreasing
atmospheric pressure

This is a simplified conclusion. The paper has mutiple graphs on how engines compensate for temperature and pressure.

[bluevolt]

My Baleno's average (as per MID) increased by 2-3 KMPL in winters. Currently, it is 25.2 KMPL.

Even tankful method calculation results in - 22+