Fuel economy
These tips are gathered by me looking at my scanner while driving in various conditions. For reference these are all for G13BB engine (1.3L/1300cc).
Fuel economy tips
In general, do not upshift quickly. If your goal is light foot, it is much better to be light foot at ~2800-3000 RPM range than to be light foot at 1500-2000 RPM. (Excluding 5th gear).
For example, I get ~13L/100km in 2nd gear at 1500-2000 RPM. But, at 2800 RPM, I get ~7L/100km. When driving in sectors I keep driving in 2nd at 2800 RPM rather than 3rd gear at 1500-2000RPM.
As a rule, a certain percentage of throttle increase in a higher gear will result in worse fuel economy than if the same throttle increase happens in a lower gear.
Gearing
2nd gear for lower speeds
When driving in 2nd gear (in sectors, small roads etc), RPM less than 2800 has the worst fuel economy. However, at ~2800 RPM the fuel economy increases greatly. Do not shift to 3rd gear until you go above 3000 RPM in 2nd gear.
4th only if 3rd is screaming
Compared to 3rd gear torque difference from 2nd gear, 4th gear torque is marginally less than 3rd. If I’m driving on a road, I usually continue driving in 3rd until I go past 3000 RPM. Only then do I shift to 4th. 4th gear loses a lot of torque and even with light foot you have to press throttle a bit more to keep the car going the same speed.
Do not use 5th gear unless at motorway
If your speed is less than 80km/h, 5th gear gives bad fuel economy regardless of how light your foot is. It does perform slightly better than 4th if on completely straight road with light throttle. But any increase in throttle makes it perform worse than 4th.
On our roads, with constant flashes and speed changes, using 5th gear on highways is not a good choice. Keep using 3rd or 4th to get better economy with changing speeds.
Believe me, I can confidently say I drive with the lightest foot where TPS angle remains < 15 degrees. Yet 5th gear does not provide good economy unless I’m at a very high speed.
Fuel cut-off
Referred by many names such as Deceleration Fuel Cut off (DFCO) or simply Fuel cut. This is when the ECU shuts off the injectors while the engine is still running.
This was useful before, but has become mandatory with recent petrol hikes :’)
This is done when ECU sees the following:
- Engine RPM > ~1350-1500 (I didn’t analyze exact number; but is certainly in this range)
- Closed throttle position switch is ON
- Engine coolant temperature is > 60-65C (The needle starts moving from C at ~60C, so if you see the needle start to rise, DFCO should start working)
It will not work if:
- TP sensor is faulty and does not turn on Closed throttle position (CTP) switch
- Desi mechanic has removed thermostat (I don’t know what temperature range engines run, but if it goes lower than 60C, it won’t work)
This really just means when you’re driving, you can let off the throttle and the injectors will shut off if the engine speed is > 1500RPM. Fuel economy 0L/100km at that time.
Some areas where it’s helpful:
- Going downhill, shift to a shorter gear and coast in gear downhill using zero fuel. When going from ISB-LHR through M2, I cross Kallar Kahar using almost zero fuel in 2nd gear. Fuel-cut all the way.
- Slowing down on highways. If a car in front starts slowing down or I see that I might have to slow down, I let off the throttle and coast in gear. Zero fuel and brake use. Although be wary that there isn’t an idiot tailgating since you’re not braking so no brake lights. Remedy by slightly pressing brake just so the lights turn on.
Random
No need to turn off fan before starting car
You do not need to turn off blower fan before starting car. When rotating key towards starter, there is a point just behind it where it turns off the relay for blower. You can verify yourself by turning on the blower motor and then either:
- when engine is running, very slowly turn the key back from ignition, it will first turn off the blower motor, and then go a bit more back, and then engine will shut off.
- when engine is not running and key in ignition, rotate towards starter. Before starter there will come a point where it will turn off blower motor, and turning a bit more will then engage starter
Found out about this when I was waiting for radiator fan to turn off. I was slowly turning key back to prepare turning it off. Blower motor turned off and engine was still running. Imagine my surprise. So I tested the above 2 things and learned this.
Rev-matching with AC = Aura kill
Rev-matching with AC running will kill all of your aura. ECU shuts off AC when it detects >80% throttle increase in 3s, and when RPMs starts rising and I have left off throttle, it turns AC back on and the RPMs yank down. No rev-match. All aura lost. Replenish by turning off AC, sweating and recovering aura.
Last attempt at overheat protection
Radiator fan turns on at 98C. If temperature keeps increasing, there is a point (I don’t know exact temp) where needle will go above center to 3/4. At that point, ECU turns on the AC condenser fan as a last attempt to try to cool down coolant in radiator.
Had noticed this when my radiator fan relay stopped working, and when I came home and stopped, I heard a weird fan sound that didn’t sound like my radiator fan. Popped the hood and saw AC condenser fan running and radiator fan sleeping. Saw temp and it was 3/4.
Verified by another baleno user as well. I did not find this behaviour mentioned in the manual. Just something we found ourselves.
Overheat jugaar
If you notice the temperature is going above the normal range. There is one last attempt that can be done by you as well.
Turn on heater and fan to FULL. Sweat, so your engine doesn’t. The heater is a tiny radiator. When the outer radiator is struggling for any reason, the last attempt is to turn on the tiny radiator inside your cabin and have it cool down the coolant.
Did the above when my radiator fan stopped working and I had to go to mechanic (as mentioned in previous point). Temp was 3/4. I turned on heater and fan to full, temp dropped down to center.
Might not work always. Should work if radiator fan relay stopped working. But if low coolant, this will not work fully. Ask me how I know :‘)