New Kei car owner, wants better mpg.
 

I just joined the ranks of Kei car owners with a Suzuki based Hyundai Atoz Prime. Sadly though, I am only touching 35 mpg US with it. It runs perfectly, timing is spot on, no check engine lights, and all the maintenance is done. I was hoping for better since it has no power steering, or A/C, but it is an automatic w/o tq converter lockup. Apparently the manual version is only rated at 38 mpg US so I've been told that I should be happy...:(

Anyway, I know the modding principles are the same with most cars, but I am wondering from other Kei car owners what mods gave the most benefit in fuel economy first so I can start from there.

Currently the car is bone stock (has no power steering, no A/C as mentioned), a new air filter, plugs, wires, timing belt, cam/crank seals, runs semi synthetic oil 15W-40 and....that's it.

If anyone has any tips, I'd be happy to hear from you fellow Kei car owners. I love the thing but am a little disappointed with the mileage.

THanks!

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I guess it depends on what kind of driving you do (sitting in traffic jams, for instance) but I'd be surprised if you couldn't beat those numbers just with some of the hypermiling tips on this site. I wouldn't have believed it myself, but just by changing my driving style I'm getting an extra 150 miles out of a tank of gas.

I also suppose it depends on what kind of gas you use...I am not sure what you have in Cambodia. If the ethanol is higher, the numbers will be lower.

Can you use thinner oil? Check the owners manual. My '97' Honda calls for 5W-30 and most newer cars call for even lighter oils.

Added a picture of the car to your post. Neat little machine.

Non-locking torque converters are the bane of automatic transmissions.

First bit of advice: get instrumentation. I'm not sure if the car is OBD-II equipped (for ScanGauge, Ultragauge, etc).

I'm aware that driving habits play a huge role in economy, and this car frankly is very dependent I imagine on the drivers foot. The automatic in this car only has three speeds and it's a very "lazy and slippery" transmission, meaning that it shifts very quickly into top gear (around 17-19 mph) but in so doing can vary rpm from 2200-3500 depending on how you mash the gas pedal. Also, no tq lockup plays a big part I am thinking. Also, while I try to keep the car at slow speeds, because of the minute 790cc motor, I am usually unable to keep it below 3000 rpm, whereas my old Toyota could be kept completely under 1800 the entire time.

As for the oil, I am not sure. I imagine 15W-40 might be too thick, but honest to goodness, I have no manual and can't find one online either. Fuel that we have is pure gasoline, no ethanol. That's why it's almost $6.00 gallon here!

I guess I'll have to get used to it as I only have 50 horsepower now to play with. :)

EDIT: ^^Added a "Thanks" but I like mine better. ;) Also instrumentation would be great, as all I have is a temp, fuel and speedometer gauge. As you might imagine though, aftermarket gauges are a little hard to come by here.

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Get some lightweight racing wheels and try to remove all the other unnecessary weight. If you only have 50hp (albeit in a small car), make those horses work less!

Looks like it's 4x114.3 so RX-7 and AE86 wheels might fit if the offset is right.

Air up the tires. Not sure on these small ones but most of us run 40+.
see my signature for info on scangaugeII

Sounds to me like the #1 problem is the slip-slidey automatic. Heck, a carb'd '84 Tempo with no OD, converter lock, and 3-sp auto can touch 35 on a good day. Is there something wrong with the transmission?

The lil engine simply is going to rev higher than your old Toyota, no matter what. It wants to. The short stroke causes the happiest piston speed to occur at higher revs.

Quite surprisingly for me to know that the automatic transmission was available for the basic versions of the Atos without aircon or power-steering. In Brazil it was available either with the manual, the semi-automatic or the full automatic, and the automatics usually had all the comfort features...


It might be very low-geared to provide quick acceleration on urban traffic, and these small tyres also seem to keep the final drive ratio very low...

Wondering if it's slippy due to defect or design.

Probably partly both. It's a secondhand, but even brand new old-school Suzuki automatics slip like hell. I had a van for a week that never locked up the torque converter in traffic... EVER. Annoying, and expensive to gas up.

The short gearing does play a role, but if it was only that, simply never going above 60-80 km/h should do the trick. I don't think it will.

I think the trans is mostly to blame, but also that the older Hyundais like this just aren't as good on gas for whatever reason. I don't know why, but that's the way it seems it is. I had an Elantra which was a fantastically reliable car, but it never saw the other side of 30 mpg on the freeway. 22-28 was all that ever came out of it.

Tires: As of now the tires are at 40 psi (max sidewall = 44), and the wheels are already alloys. I got a flat tire yesterday and changed it. The steelie in the boot was noticeably heavier. Also, in Cambodia there are no RX7s or AE86s and importing wheels would be too much for too little gain I imagine.

Package Features: This car came straight from Korea (I'm the first owner here in Cambodia), and it seems like the Korean market cars come in any shape, package, etc. Makes sense, seems how Korea is one of Hyundai's biggest markets.



Anyway, I am starting to think maybe I might be stuck with sub 40's for mileage, considering I'm not willing to go for a standard transmission.

Why would you avoid a manual transmission? BTW how hard might be to get a 4-speed (with overdrive) automatic transmission to retrofit into the Atos?

You've got some things working against you, but you still have some options. In my pickup, I was still able to get ~25% improvement even though it had an auto.

You can pulse and glide (Engine-on, it's an auto) and coast to a stop as well as abunch of other techniques.

Aero tweaks will help, especially for highway driving. Lose the mudflaps. It's not a side profile shot, but from the pics your spoiler looks like it is kicking upwards which won't help. Lose the spoiler or see if you can modify it to fit the aero profile a bit better. The usual grill block and air dam or belly pan would help. Look for tires with lower rolling resistance when these need to be replaced.

It's not one big magic pill, it's a hundred mundane motes.

Hi,

38 mpg sounds too low. Especially considering the small engine size.

My daughter's Toyota Echo MT was ScanGauged two years ago at 55 mpg at 45 mph on a dry, flat road, in the summer. Her engine size is 1.5L, and your's is almost half that.

Jim.

If you Google Cambodia Traffic, you'll see why. :) 4 speed? Probably no dice, there is barely any space for the miniature trans it has.

I would, but it's a cover to a frame underneath which is the structure to contain all the wires and such. That structure is bolted to the hatch and looks awful without it (all the holes, etc.)

For me I think the best mods are going to result from fuel maps and/or fudging with the O2 sensor/map sensor, etc. because my avg. speed right now on my scangauge equivalent says 14.5 km/h, which isn't even 10 mph. Any aero mods are going to be useless I am thinking, considering the driving I do.

P.S. I also adjusted the ignition timing (I noticed it starts to ping a little under a load when hot) and the mileage seems to be a little better. Usually at 100 km I am below 1/4 tank, but now I am slightly above. Anyway, I know the stock fuel gauge is inaccurate, but you can still judge vaguely on it.

I never went to Cambodia, not even considered to do so, but really, the comfort of an A/T in heavy traffic really pays back. Also, under certain circumstances, the higher expense with fuel is still cheaper than fixing a worn-out clutch :D

Haha, I am getting depressed. At 360 km I was out of fuel (just 5 liters left in the tank) which translates to 29 mpg. :(

I'm going to get the transfluid changed and switch over to synthetic oil, I am sad at my mileage. Although I can't complain I guess, my 1.6 Corolla only manages 17-18 mpg.

You could sell it and get something else..... Probably that's not a very doable option.

So does my V8 4x4 F150.

Bring it to Cambodia :) and things will be drastically different. My neighbor has a V6 (Ecoboost) F-150 here and it does 9 mpg according to him, haha. In comparison, I have a Ford Ranger 2.5 delivery truck as well and it barely tops 14 in the city and it's a manual. I also run a Daewoo Damas van (1.0 L) for small deliveries and it too only does 30 mpg (manual). Again it's down to the horrible congestion here.

As for a different car, well, I just got this, and frankly there is nothing else over here that can be had that does any better, except a motorcycle or a Kubota diesel pickup. At least it seems that way.

I just bought some synthetic oil ($16.50 a quart....:() a new oil filter, and trans fluid, so we'll see how it improves, if at all afterwards.

What liter to gallon conversion factor are you using?

3.785 liters per gallon, US. Last fillup went like this for the Hyundai.

364.2 km = 226.3 miles

29.411 liters = 7.77 gallons

226.3 / 7.77 = 29.12 mpg (US).


I'm from the U.S. so I use U.S. gallons.

EDIT @Frank Lee. Not bad mileage for a 302 4x4. I had a 300 (straight 6) F-150 years ago, and it barely did the mileage that your's seems to be doing.

I guess it's an overseas Ranger, which is actually a rebadged Mazda. Gasser or Diesel?

US market, 2.5 gasoline. Come to think about it, I am not sure if it's a 2.3 or a 2.5. It's a 2011, looks like this but silver and it's a 4x4. I think for the US market it's backwards, where Mazda rebadges the Ranger as the B series.

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Might be 2.3.

Here in the states you couldn't get a 4 cyl ranger with 4x4 since the 90s.

So, if it's an overseas 4WD, might have the 2.6L 4-banger.

Got the scoop on the truck. It was a wrecked fleet truck which was then shipped over to Cambodia sans the engine/ front. Then someone took a front clip, welded it on and then dropped the 2.3 Duratec motor in it because it then fits in a lower import tax bracket. That's why it was only $27,000 vs. $40,000. Haha, now that's what I call frankenstein.

According to the VIN it was originally a 4.0 liter truck.

Anyway, changed oil (20W-50 down to 10W-40 semi synthetic), filter and trans fluid on the Hyundai. Newest results?! 26.7 mpg US.....:( Not really sure what to make of it, at this rate I'll be getting negative mpg soon.

Couldn't you get some real kei-car back there, a real Japanese car with the 660cc engine? Some have a CVT, which is better for fuel-savings than the 3-speed slushbox :thumbup:

Funny you should mention it, my brother in law I found has a Suzuki Super Carry for his business, manual trans. I asked him how my mpgs he gets and his reply was (13 km/l) which translates to 30.5 mpg US. :confused: I guess it's just the country's fault then, because the only thing I know of here that can do any better while still being a "car" are the Kubota diesel swapped Kei trucks. They usually do 50-65 mpg, but I really don't want to drive around in a manual Kei truck all day, :)

Kei trucks can also be available with automatic transmission, altough many still have a 3-speed slushbox, while few ones have an overdrive 4-speed. Anyway, in a front-engine (or mid-engine as some folks quote the Kei trucks) RWD there's still enough space to adapt some auxiliary overdrive unit if you wouldn't mind to mess with the driveshaft. Or could eventually re-purpose a transfer-case of a 4WD Kei-truck just to have lower ratios when needed to compensate for a taller differential ratio in a 2WD one converted with a Kubota. BTW have you never considered a Diesel conversion for the Atos?

I guess I also forgot to mention that Kei trucks are $6k over here for a bare bones stripped model. My Atoz cost only $2,800 if that gives you an idea of the price gap. Kubotas are $8k.

I thought about it (diesel swap), but there are a few main problems that I've seen with swapping the Atoz, mainly it's space. Even the little petrol 800cc barely fits (this car is very annoying to repair), and then there's the issue of the transmission which has a cast in bellhousing. Of course it wouldn't be a problem if Hyundai had a same bell pattern diesel, but they don't, and I don't see an adapter being able to fit either.

It's alright, I'm not suffering with the fuel mileage, I only find it annoying. If I can break 30 mpg again I think I'll call it good and live with it. After all, the Ranger is pretty terrible as well.

I wouldn't disconsider some 800cc 2cyl Diesel if it was easier to overcome the transmission issue. Yesterday I saw a Hyundai Atos in my hometown and started to lurk about a setup similar to those rear-engined autorickshaws from India. There are even some with Kubota single-cylinder 9hp engines (altough I'd rather get a twin-cylinder if I were messing with an Atos)...


Hyundai even had some factory-fitted Diesel versions of the Atos, with a 1.1L CRDi 3-banger, but it was only available with manual transmission :mad:

Completely different generation too so nothing really swaps over. This Atoz I have is a lot more similar to the Suzuki Alto than the newer one which I believe is bespoke to Hyundai. Also the 1.1 is a good deal larger than the 800 (this motor really is microscopic) because of the block size, cylinder head height and related accessories, so getting it to fit without would be a nightmare. Maybe I should save up some cash and pick up a diesel 1.1 Picanto. THey're 9 grand still over here :( but it would save money with fuel :p.

Have you never considered to convert the Atos to LPG?

I did, but then the only place to fit the LPG tank (thought about CNG as well, but there is no CNG here) would be where the back seats are. I would need to keep the petrol tank because there are very few safe LPG refill places here and the boot is too small, even for something like a 10 kg cylinder. Kei cars really are difficult to modify in all reality.

As I've mentioned before, I think I'm just going to get used to the low fuel mileage. It's also worth mentioning that most modifications done to cars here aren't very safe or professionally done, so in a way, I'd rather sacrifice the fuel economy for safety. There have been many LPG explosions on buses and countless other problems when cars get swapped by shops so, I'm happy knowing I have a factory designed car at least. As a small example, my brake master cylinder started leaking so I thought that a shop would at least be able to install that much correctly. Two days later the new unit leaked dry because they didn't tighten down two of the four fittings. Simple things like that scare me away from shops, hence I do ALL of my own wrenching now.

Seems like it's time to start saving for a Diesel-powered car :D
Meanwhile, ride a motorcycle as much as you can, and if you could get a real Japanese Kei car with a CVT don't miss the chance...

Well, I think I'll have to start riding the bike a lot more anyway, just got in a wreck...:(

Atoz did pretty well (vs. a diesel truck running red light) but the front is kind of bashed in. Took it to a shop and they can't get it aligned very well because of how much the unibody was twisted. Been financially compensated already but now I need a new vehicle. Well that was short lived.

I'll update when I get something better!

Well, that's a bummer. Sounds like you're OK though... best part.

Get a manual shift car next time!