About the Toyota Yaris Hybrid (In US Prius C)

[Jyden]

This last tank I broke the 50 mpg mark, and I belive tha car here just under 3.000 km's is now broken in, and the baseline is areound the 48 - 49 mpg.

So modding begins:

- First the standard "racer look" hubcaps hit the bin, and some aftermarked more smoot ones are now mounted.



Seceondly, I've sealed with wheaterstrips on top of the headlights in both sides, as there was a small gap here where air could get in to the enginebay.



After that I placed a stiff thin form board with relfexive alu down, on top of engive inside the hood. Idear is to trap heat, so that the engine takes longer to cool down. This works great.

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Last - I did an upper grill block, It's just a small opening, so I just stuffed some foam in there and covered the whole thing in black PVC tape. Hard to see at all standing next to the car.



All of the above was done today, and testdriving showed that IEC intake temp doubled fra 6 to 12 deg C, and engine temp vent from 86 to 89 deg. C.

Too early to say anything about milage, but the butt-o-meter tells me it glides a bit better, and that wind noise is a bit lower.

As temperatures rises here as spring come along, I'll see what to do about the lower grill block, which is just temporary done, with some pipe isolation. Ive got to see if I can block more or need to remove some the keep engine temps at the right levels.

With warmer wheater I also expect to see better milage the coming months. First goal is 22 km/l (52 mpg) - which I hope to get on this tank, and long time goal will be 25 km/l. (59 mpg).

Car still looks total OEM, temporary lower gill block excluded.

[gone-ot]

Originally Posted by Cobb

No rear seats you say? I had removed mines for some time for more cargo room and people thought I was crazy.

FWIW, I have always driven with the REAR seats down/reclined in all of my fastback/station wagon vehicles for instant "covered" pickup utility...but, also for easier rear-view visibility (no headrests blocking vision).

[Jyden]

Apart from retaining heat in the engine when ICE is off, gliding is key to good milage in the Yaris Hybrid.
It took me a long time to figure out how it's best done, but now that I've found to teknique it's quite easy and effective.

As on whiches to enter a glide, ease off the speeder to the point where neither ICE og EV motor is pulling. It's a bit different depending on the speed, but usually on the "ECO" meter it just below the on on ECO on the meter.
Keeping the needle there the car will glide.



On the left meeter, between CHG and E in ECO is the zone where the can can enter a glide. Nearer to the E than to the C.

And it glides well, and it acounts for some of the improved milage on the last tank.

[vskid3]

Pulse and glide is the key to good city and lower speed driving in the Prius. Depending on your route, you'll gain at least a few MPG's when you get it figured out. It became second nature to me before I got my Insight, now I have to think about it a little (I try to do stead speed in lean burn in the Insight).

I like that analog gauge cluster. Digital can look pretty neat, but there's nothing like watching a needle sweep as you accelerate.

[Cobb]

Thats about the same for the insight. You need to apply light pressure on the throttle, just enough to remove the play so it is not assisting, not regen braking or in EV mode. Yes, light throttle will engage the IMA system only, maybe its an easter egg? That allows you to coast as best you can, however you are still spinning the engine, but the valves are closed.

[Jyden]

It only spins the eninge in coasting if going faster than 73 km/t. Lower than that, ICE stops. If for instance gliding downhill, and going faster than 73 km/t ICE will fire up again. It has to spin to remove heat from the Hyperdrive

[Cobb]

The inverter has a manual coolant pump? I know those who back feed the hybrid battery have to be careful of how full they try to make it as once hte SOC climbs above a certain % it also uses one of the electric motors to spin the ice to burn off the excess charge.

I wouldnt mind one one day to play with. Lots of mods for the gen 2 prius out there.

[RedDevil]

Nope, both systems are so different that they are hard to compare.
The HSD gearbox is a planetary gear system where the electric motors/generators operate different gear-rings than the ICE.
These rings and shafts can be locked in different ways to produce 3 physical gears for the engine.
It also allows the electric system to operate independently of the engine.
In fact they do that all the time to simulate gears in between the fixed ones, by making one motor work as a generator to power the other.
The battery can smoothen it out further by storing or adding power. This way the HSD system can finely regulate the amount of torque it puts out, hence the smooth deployment of power.

The Honda IMA system has the single motor/generator bolted to the crankshaft, as a flywheell. When driving at a constant load it will not do much, just generate a bit to keep the electric systems powered.
When coasting the engine cuts and the generator will store some energy in the battery. To glide it neutrally you just have to press the accelerator ever so slightly to make the charge needle move out of the green zone.

Cutting the ICE means the IMA electric motor has to take over at once, so this system cannot make the transition as smooth as the HSD system does, where the torque stays the same (even though the electric power consumption does change).

[Jyden]

The last tank gave 52,6 mpg, so the mods really made some difference. I also changed the stock stick antenna for a cheap chineese sharkfinn one. Works fine. Bought on Aliexpress for 8 dollars.
It's irritaded me from the very beginning that the car had a stick antanna adding wind resistance.
Temps are rising, and spring is hopefylly on its way.
Looking foreward to see what influence summertires will have om mpg. Hopefully good.

[CFECO]

I've been reading your results with your new Toyota, and I begin thinking about comparisons with our new one, a 2013 Tundra 4x4 double Cab pick up. We filled our first tank last Friday and got 18.3, just figuring miles and gallons added. Our truck figures out to be almost 2 1/2 times heavier than your car, with a frontal area about 1 1/2 times as large, obviously ours is not a Hybrid, with a 5.7 liter V-5 @ 381 HP. Ours has DOHC, dual Variable Valve Timing, and is E-85 Flex Fuel rated, with a 6 speed auto transmission, and a 4.3 to 1 rear axle ratio. I drive normal, coasting to Stop signs and Red lights, but do not P&G, or drive less than the speed limit, which here is 75 mph on the highway. It will be interesting to follow our progress!