[AbhiJ]

My i20 CRDi has become more fuel efficient.... is the CRDi mill BS4?
???

[lamborghini]

Hey guys,
sorry to bump up this old thread.
I checked out our Fiesta's FE for the last 2 refills, and it has been hovering around 12kmpl.
Even though there are a lot of factors affecting this, such as shorter city drives, increased traffic in commute, etc., there is no denying that there has been a reduction of around 1kmpl here as well.
AbhiJ, if your i20 has a 6speed gearbox, it is BS4. Also, if you car is new, and the run-in period just got over, there should be an increase in FE.

[mtnrajdeep]

Even I was wondering what the reasons for my Swift's reduced mileage could be! Then I see this thread! For the last 3 months, I too have observed that my Swift VDi's mileage has dropped by about 1-1.5 kmpl! I was getting close to 16.5-17 kmpl in my daily routine drives and now this has come to 15-15.5 kmpl. Anyway, the car is due for a service and once I get the service, I will recheck the mileage.

[babhishek]

hmm, interesting feel a subtle drop in mileage worth investigating...

[mohan41]

This could be true. I checked the FE of my Getz (tankful to tankful method). I was trying to drive very carefully and used AC very less, hence was expecting I will get 12kmpl (used to get 11-11.5 earlier). I have got 11.5 now. This time I filled from Shell. Will see if Shell regular gives same or better FE

[CPH]

Originally Posted by babhishek

hmm, interesting feel a subtle drop in mileage worth investigating...

Read post #8! I wrote this post not for nothing.

The presence or lack of elements/molecules in form of additives or as part of what the crude oil contains affects how the chemical reactions take place. The complexity is beyond what the human capability can comprehend. What we can comprehend is the way it influences the flame front development.

Since time is of the essence and expansion as a result of the combustion process must not exceed the boundries of a set window in terms of crank shaft angles related to the piston - it will become quite clear that the different additive package/crude oil residues, would shift the combustion out of the window. The fuel becomes for the set-up inefficient.

The flame front speed is for any set fuel constant regardless of the rpm. The problem is that with increasing rpm the window is exceeded further one or the other direction.

Therefore the ignition timing has got to be corrected.

It is known to the industries for many years. Even magazines have made endless tests on fuels, where some fuels made more power than others on the very same engine and showed different fuel consumption figures. Differences of up to 12% have been measured.

The fuel coming out best in one car does not need to be best on a different engine as the map in the ECU will most likely be set for a different fuel.

When we re-map cars, which we do only on the dyno we usually tell the owners of the respective cars that if they want to have the best result they need to use one type of fuel and this is the one they should come with in the tank, but it has to be at least the third tank load as cross contamination might affect it very badly.

High octane fuels do not necessarily male the car more fuel efficient. They contain flame inhibitors that allow for higher compression without spontaneous combustion (pinging).

To get the best result for your engine use what is specified or have the ECU re-mapped accordingly.

[chittybang]

My Fiesta TDCI too is down on the FE by 2-3 Kmpl. Is there something we can do about it?

[asdon]

I take my words back, I just changed my 4 tyres which were 38000km old, and put xm1+, and went to goa with 5 adults on with full boot in an Alto and because it was a night drive AC was off, and I drove 655km with 30Ltr normal Petrol filled from BP.And before the journey when I started from Petrol pump to home odo reading was 31, so it was 686km in 30ltrs, milage - 22.86

[sgiitk]

Originally Posted by raghosh

.....
, it shows 2 different FE figures for BS-III & BS-IV . Does it mean Hyundai has 2 different engine variants to offer or the same engine with 2 fuel grade figures ? .....

...There has been a slight upward pricing of the both petrol & diesel after the enforcement.

Due to the tightening of the pollution norms the position and size of the Cats etc. has been revised. Changes are more for the diesel than petrol vehicles. One example of lateral thinking is Toyota Innova. Instead of re-jigging the exhaust, they added an inter-cooler to increase the power, and then changed the final drive ration.

What I understand is that the PSUs are having problems in scaling up production to BS3 from BS2 rather than from BS4 to BS3. There was a demand to defer the latter. The price increase is also more due to the BS2/3 issue.

Can anybody confirm that the old BS2 is history and petrol / diesel in non-13 cities is now BS3.

[CPH]

Originally Posted by chittybang

My Fiesta TDCI too is down on the FE by 2-3 Kmpl. Is there something we can do about it?

Re-mapping is the most efficient way to do this