Sir,
With no offense, i would much like to mention that the average you are getting from your JDM is very much acceptable. I m not claiming in any way that the averages mention above are not correct but i presume that you cannot calculate an exact average of your vehicle and claim it to be 100% correct, considering these below mentioned parameters how can you explain/understand the average consumption of your vehicle to be 100% and i.e:
City driving/highway driving? What if you are having the mixture of both? How will you calculate?
Filling station. One or multiple? You fill it full or partially? If partially how can you claim the volume of filling station/stations to be 100%?
What tyre size are you using? factory specs or a bit heavier?
What tyre pressure you keep?
What grade oil you use?
How often do you change your air filter?
You drive alone or with passengers?
Is the ODO reading you have advised is absolutely correct? i.e 2 lac thirty thousand KMS?
You say you use light foot, do we have any gauge to measure light foot or heavier foot? i mean how should we know that the throttling you are calling light foot is really foot? How do you explain this?
My friend i have JDM 2007 CVT Mira with me, i drive it normally reverbing it on 3-3.5K engine RPM and it gives me an average of approx 15KM in winters in city with/without AC, no traffic jams.
Tyres: 165/65/R13
Oil: 10w-30
Air filter: Every 6K kms replaced
Plugs: Factory recommended plugs (NGK/Denso/Bosch) whichever.
My GLI 2012 manual gives me 11kms in city, all factory specs, maintained from Toyota.
My civic 2013 vti oriel prosmatec auto 1800cc gives 12km all factory specs.
I would rather advise you not to mingle with these things considering that the factor or result you are trying to achieve is dependent upon so many factors which i personally think is near to impossible.
Enjoy happy driving. People claiming their 660ccs giving averages of 20kms or plus must be super humans/super drivers/hyper milers Still you cannot verify that by any means.
Thanking you.