Hypermiling a 7th Gen Accord in Bangalore Traffic
Ever wanted a D segment long ass old school sedan as a daily but been putting it off because of its horrendous fuel economy?
Well. While it’s no Maruti Suzuki, this 2003 7th Gen Accord really did surprise me quite a bit in this regard.
Back when I got this as my new daily, I never really cared or still care for fuel economy. But with a bit of curiosity (and necessity as for some reason, the car did not come with an economy gauge), I decided to take 3 days to conduct an experiment on how much I can squeeze out of this 2.4L motor.

Distance:

My office commute is about 16.6 kms one way. 33.2 kms two ways multiplied by three would be about 99.6 kms covered. The tank to tank method was used ofc but I also wanted a way to figure out instantaneous fuel economy so that it will help me optimise the fuel consumption on the go. One way to do this was to get an OBD scanner and directly talk to the car. However, I was not gonna splurge on a new Autel scanner(some models which would almost cost as much as my car’s value) just to measure fuel economy as they are incredibly expensive.

The scanner that surprised me:

Scouring through online products, I came across this thing. It’s an OBD scanner that uses your phone to connect and show you info and since it uses the OBD ELM 327 protocol, there are a host of apps on the AppStore that you can use to connect to it. And it was quite inexpensive at ₹300 ish, so I thought why not. Would double up as a review of accuracy for this thing as well.

K24A4:

The 7th gen Accord came with the K series K24A4 2.4L engine mated to a 5 speed torque converter. Enthusiasts would like you to believe that this is the same legendary K series K24 that’s capable of producing almost 500bhp without any forced induction and is the same thing that’s found on the later Accord’s and Acura’s. However, that couldn’t be more false.
Apart from sharing the same block, there’s very little that’s common between this and the K24Z2 or the K24Z3 that’s found in the 8th gen 2008-2013 Accord. The K24A4 uses an economy trim of VTEC and also produces less power and torque than the 2008 one. While both the engines have the same bore and stroke and hence the same displacement, the K24A4 has a lower compression ratio and is tuned differently hence produces almost 25hp lesser than the 2008 Accord. It also has a lower redline at 6700rpm.
A notable characteristic of the K24A4 is that unlike the Gen8 K24Z’s VTEC that has 3 lobed VTEC only on the intake side, the K24A4 has a staggered VTEC 4 lobed setup with lobed cams on both the intake and the exhaust valves. While this reduces it’s power efficacy, it also significantly decreases the hit on fuel economy when VTEC is engaged and as a bonus(or not, as I personally don’t like it), you get a distinct whine when VTEC crossover happens, something that’s unique and not present in other Honda’s.
The end result is a motor that’s down on power compared to the newer Accord but with significantly higher fuel economy.

Experiment begins:

Started off with a full tank, 3 days of office commute, I ended it at the petrol station with exactly 100.9 kms on the trip meter. The scanner read an average fuel economy of 9.33km/L. The fuel up was around 11.06 liters to the full tank.
Comparing this to the real values, 100.9/11.05 = 9.13kmpl. I was plenty surprised, not just by the car but also how accurate this ₹300 scanner was. Definitely a well worth purchase.
I should add this as a disclaimer, this was tested under rigorous hypermiling conditions with no bumper to bumper traffic and all the commutes on odd hours. With ample steady acceleration and maximum engine braking used with a whole lot of coasting and zero pedal to the floor acceleration. It was also the result of being very calculative when I had to slow down abusing the deceleration fuel cut-off everytime I had to shed speed and I’ve never used the brakes this less in my commute. Needless to say, it was torture for me to drive the car this way, with no flooring it or hitting the rev limiter and with me fighting the urges to open it up and send it or going anywhere as fast as I wanted to. So while I probably will never get this economy figure as a regular number, it was good to know what it’s capable of.

Interesting findings:

This leads me to also mention, while this is an economy trim of the K24, it is also, at the end of the day, a 2.4L engine. Something I’ve noticed is that, this car is incredibly sensitive to how it’s being driven, much more so than any other car I’ve driven. Despite the 9.13kmpl economy, driving it normally(not even fast, just slightly faster than me hypermiling it) results in a steep drop to 7.9kmpl on the scanner. Driving pedal to the metal, I have seen it drop to 6.3kmpl. Never have I seen fuel economy numbers drop that fast with just a slight change(not even a big difference) in driving style.
Something even more interesting is that this car basically makes zero difference if you leave the AC on or turn it off. I have seen cars whose economy increase by even 3-4kmpl with the AC turned on. Not sure if ya something specific to this car or it’s how it is with all Accord but yeah, found that quite interesting. So all things considered, I get around 7.5kmpl in my regular driving around the city.

K24A4, useless for performance. Or is it?

For the enthusiasts out there, I know your thinking and no this motor isn’t completely useless compared to the 2008 8th gen Accord. Well, depends on what you’re looking terms of mods.
Yes it produces less power. Yes it’s the economy trim of Vtec. However, there is a silver lining. With purely bolt on mods, the K24Z on the 8th gen Accord will produce more power as expected.
But if you have enough money to spend, the 7th gen Accord has significantly more potential than the 8th gen. The K24Z on the 8th gen has its exhaust manifold cast on to the head which means no aftermarket headers. It also has a plastic intake manifold so you can’t port and polish or extrude hone it like you can with the aluminium intake manifold on the older K series motors. Not to mention the compression ratio is higher than the older 7th gen so it won’t be as boost friendly. The 7th gen has multiple companies like Hondata offering bespoke and retrofit custom ECUs however there is no such support for the 8th Gen K24Z motors.
Here’s a 702bhp 7th gen Accord made by RaceConcepts in Bangalore reviewed by The Drivers Hub. The aftermarket for the K24Z on the 2008 8th is really weak compared to the civic and the earlier Accord.
So if you’re looking for an old D segment car that you can daily without breaking the bank on fuel costs or if you’re a hardcore enthusiast looking to build the fastest car that eats drag strips for breakfast, consider the 7th gen Accord!
PSA: Just stay away from the V6 of this generation. Not only does it return horrendous fuel economy, it’s also notorious for transmission failures to the point that there was a class action lawsuit filed against Honda back in 2004.
Cheers and happy motoring!

I knew we were trading in our car for the next one but it’s only after coming home from work that I was told the new one’s been paid for and that this car’s going to the dealer the next day.
Coincidentally, I’d taken the car to work that day so that ended up being my last drive with it. This car has taken me to graduation twice, been the facilitator of many dates, been my safe space in unfamiliar areas and has been an integral part of my family’s and my life for the last 7 years.
Knowing a drive with a car was your last one after said drive, is an odd yet satisfying feeling. This 2016 Honda City is loved and it will be missed dearly.
Thanks for listening!