How to improve mileage of Honda City (current: 18 kmpl; goal: 23 kmpl)?

Engine braking is important mostly in ghats/ mountain driving, because sustained application of brakes results in brakes getting heated and we end up with a smoking car like Bobin's Padmini . Braking by the engine also results in the energy getting converted to heat, but then the heat sink is the entire engine, and its thermal inertia is huge. So there engine braking helps. It also is helpful in hybrids, where it is called 'regenerative braking'. In this, the energy is converted to electricity, and is stored back in the batteries.

For a non-hybrid, manual tranny I don't understand the particular 'handling' benefit when engine is put in gear with respect to neutral, when all we want is to reduce the speed of the vehicle. I never have felt anything amiss when handling a vehicle in speed, and in neutral at the same time.

Guys, Long time since I posted on this thread - exactly a month of silence here... So thought I post an update (to give a small idea of what to expect), and also posting a small query to help progress the project.

1. Tank status - 670 km on the trip meter and quite some distance to go... At each trip me and wifey (all my trips are with her in the passenger seat) keep peeking at the fuel meter and odo to guess whether I indeed hit 805 before hitting reserve - my goal of 23 kmpl. All I have done is changing my shift points for acceleration, with some help from this thread at crxmpg.com and this thread at ecomodder. Karan, buddy, we will have to change our ideas about what style of acceleration is good for FE. Look at the links, and also read up something about Break Specific Fuel Consumption (BSFC) charts - turns out exciting acceleration is also good for FE... But let me reach the goal to tell you how everything fits together, rather than dig a hole for myself...

2.Can I know if this type of racing disc hubcaps are available in Delhi/NCR? They are used to reduce aero drag due to the fancy alloy design (derisively called air-blender in aero community) or just plain bad steelies. I would like to buy pop-on type to avoid issues when wheel balancing.

Use of pop-on hubcaps is kind of dicy in Indian context (at a signal in Delhi, I got asked whether I would like to buy one or more tyres complete with alloys for specifically MY vehicle - all this when waiting for the green signal peering over half downed glass of driver window... there are all sorts of people!) Are instances of stealing pop-on hubcaps rampant?

This particular modification yields about 4-5% of FE increase due to reduced drag and smoothening of air flow over the tyre.  (guys measure it, and sincerely report doing multiple rounds of A-B-A testing, so one has to agree about the figure) To take this modification to ~10% improvement, wheel well covers (wheel skirts in aero lingo) are also required, but this is more complicated business, to be attempted later. If I reach my goal before that, I can say good riddance to some crummy modification work, spending at least two weekends (I am not all that gifted in the mechanical workshop skills dept.)

So guys, please let me know about the hubcaps, and go through the other links too. Thanks for reading through!!

Good to hear that all's well at our resident 'hypermiler'!!

About the 'hub caps' seems quite unlikely to source the same off the shelf in India(guess the crude prices heading south might have played spoil sport-other wise anything and everything that increases FE would have been ubiquitous!).

Krishna,

I was thinking about your thread over the weekend. No update since long.
Voila!! I get to see your post.

The hubcaps can be sourced via courier or via a friend from US. Do drop-in a mail to them. I dont think it would be very difficult. Just pull the rights strings with a dash of Maska-marring.

Regarding the theft, this is not a flashy one which would attract a theft. It doesn't look all that costly, So I guess you can remove that tension from your mind. The hubcap reminds me of the one our famous ambassador used to have.

Binoy, Ami, Thanks for the feedback!

From the stated sources, the hubcaps are $85 and international shipping is $80. This means landed cost is $165, excluding incidentals (customs?). Translated to rupees, about ~ 9k INR.

I use INR 1500 worth fuel a month, and taking the 5% improvement, it is INR 75 a month of saving. - Calculate and you get a 10 year payback period. This makes it not worth it.

I see that the price for a single hubcap, with all overheads turns out to be 2250 INR. This is excessive for a hubcap when we consider Indian ones. If I am able to reduce the payback period even to 4 years, I would go for them, because of the pleasure of stretching my tank (would give me ~30 km extra range on each tank, at my FE rates) and also for the looks (Ok, they look beautiful to ME at least! )

That was my background behind asking you guys for an Indian substitute. Keep an eye open for it, will ya?

Sure dude.

News! I hit reserve at 775 km this morning! That makes it 22.14 kmpl, taking reserve threshold to be 35 litres from a clamp-off topup. On one hand it is good news - I am ~ 2kmpl higher on this tank than the earlier one. On the other hand, it is bad news- I came 30 km short of my goal - this will prolong my agony of reaching the goal... 

I used normal petrol for this tank, saving myself a pretty packet in the bargain. And look what - this tank took me 90 km beyond my earlier tank - 685km @ reserve threshold. So it is now officially proved that if the fuel quality is not suspect, driving style contributes waaay more to FE than fancypants expensive fuel.

 The good things I did were changing pulse profiles - fast jackrabbit pulses, taking rpm to 2.5k before shifting. I sometimes went up to 3k rpm, so I could achieve good speed inthe same gear (occasionally upto 65-70 km in third gear - It was insane, going against all my earlier convictions about what is good for FE...). So my pulses occured only in third and fourth gear. Didn't touch 5th except for highway travels (even there it was mostly single-gear pulses in the fourth, going from 40 kmph to 70, occasionally 80, and coasting down to 30 kmph about half the time, when I felt like it.)

I am short of my goal by exactly the same amount as discussed above in the hubcap discussion - 30 km a tank , so some such improvement is really needed to push myself over the fence on this.

I am servicing the car this weekend, and like we discussed keeping it low on reserve would be a good way of avoiding any siphoning of gas. I will then tank up and resume recording. I also have to fix a broken undertray that is bad for aero drag. So the next tank is probably going to make it to the magic figure of 805, or so I hope...

OH                MY                      GOD!!!!!!!!!!!!!

Gosh, you missed it by a whisker. I am pretty much sure that the service would get the car to a good condition and get you the magical figure of 23 kmpl.

All the best dude.

One word - Amazing!

Your efforts have prompted me to find how much the MJD will give with sedate driving, currenly getting 21.67kmpl with 'aggressive' driving. Will try pulsing and gliding for some time and report.

Sorry to interrupt you all. You guys know so many things. It is really intimidating for me many times, I be honest! This 11 pages (and still going) long thread itself is like a ‘book’ to me. I am sure there are many more threads on diverse topics in the forums that are still to be searched. I have read, re-read, re-re-read, many comments on this thread and still remained clue-less about some points.

I am lovin’ it!