Fuel Economy

[Jem_hadar]

Originally Posted by ricko

I was once told that to get the best mileage you imagine an egg between you foot and the gas pedal. Lots of scrambled eggs in my car.
I really think it is the stop and go stuff. The only time I see that kind of driving up here is on the "Elvis" weekend.

FUCK Elivis! (LOL... i suppose)

I still wish back in 04 I had gotten to see a kandi raver get in a fight w/ an elvi impersonator! That woulda MADE my weekend! It was so great escaping the Elvis weekend because WEMF was held at the dates (and in our neck of the woods too!)


Jem

[/hijack]

[swng]

Originally Posted by why?

Then it just might be the top speed. The last question is how do you accelerate and decelerate?

Do you use lots of throttle position, and do you find yourself always slamming on the brakes.

Yes, yes! A top speed in the region of 130km/hr can mean 15%+ more fuel consumption as compared with travelling at 90km/hr because there is a lot more headwind(=air friction) to overcome. I am stating it conservatively. The difference can in fact be much greater.

[swng]

Originally Posted by ricko

My experience is that fuel gauges are never very accurate. The one in my Yaris is very misleading. It seems safer to use the tripmeter.

Thanks a lot for the opinion. For the long term, I fill up the tank, set the trip odometer to zero, drive until the tank is quite empty(but I always try to leave a fuel reserve for about 100km in the tank), then fill up again, and record the trip odometer reading and the amount of fuel bought and then use those figures to calculate the fuel economy of the car. I do the same every time I fill up so that I can know how well my car does in the long term on average.
I believe many friends here use more or less the same method.

[Ziv]

Originally Posted by swng

Yes, yes! A top speed in the region of 130km/hr can mean 15%+ more fuel consumption as compared with travelling at 90km/hr because there is a lot more headwind(=air friction) to overcome. I am stating it conservatively. The difference can in fact be much greater.

My, my. I wil keep that in mind! Thanks!

[why?]

Originally Posted by Ziv

I never floor mine when the lights turns green. My buddy does, he have the RS. And the strange thing is he have the same milage as me.

slamming on the brakes.... not that I notice, although I like turning corners at a higher speed than my old car. I felt I can do MUCH better cornering on my Yaris than my old altima.

As I have said. I will check the tire pressure after work today. 'why?', what PSI do you suggest for tire pressure? mind you, I am still on those 14 stock wheels.

I am pretty sure max tire pressures should be written on the tire. Go by what the tires say, not the manual.

And the higher the better.

[Ziv]

Originally Posted by why?

I am pretty sure max tire pressures should be written on the tire. Go by what the tires say, not the manual.

And the higher the better.

At the side of the car behind the door, it actually mention 32 PSI.

Is higher actually better? because I heard the higher it is, the greater chance of your tire can get bust.

[foober]

Originally Posted by swng

Thanks a lot for the opinion. For the long term, I fill up the tank, set the trip odometer to zero, drive until the tank is quite empty(but I always try to leave a fuel reserve for about 100km in the tank), then fill up again, and record the trip odometer reading and the amount of fuel bought and then use those figures to calculate the fuel economy of the car. I do the same every time I fill up so that I can know how well my car does in the long term on average.
I believe many friends here use more or less the same method.

thats the method I use. I'll fill up after about half the bars are gone or 2/3 of the bars are gone. YOu just have to remember to redo the trip meter everytime you fill up.

[NickNickNick]

43.57mpg when I filled today. All city driving - very hard at times.

[swng]

Originally Posted by NickNickNick

43.57mpg when I filled today. All city driving - very hard at times.

Good number for all city driving! I guess you must be enjoying some warm weather and there may not be too many hills and traffic lights in your city hehe........You must have done something right anyway! I guess the gas companies won't like you.

[why?]

Originally Posted by Ziv

At the side of the car behind the door, it actually mention 32 PSI.

Is higher actually better? because I heard the higher it is, the greater chance of your tire can get bust.

Tires are created to withstand a certain air pressure. This is what is written on the tire.

Go by what is on the tire, not what the car says.

As long as you make sure to keep the pressure within those limits, then the higher up in that range you go, the better it is for gas mileage.

And while too much air pressure is a bad thing, there are rumors of some tires being overinflated too 100 psi, etc, and the tires not having a problem.

In general, if you try to overinflate a tire the air pump will blow long before the tire does.

[punch]

umm how do i do the math, I got 598Km on my first tank, it took 38l to fill it, whats the formula?? 598/ 38= 15.74km/l I then took 100km/15.74 and got 6.35

so if this is correct I got/used 6.35l per 100km, which is close to sticker epa ratings..

[Ziv]

Originally Posted by why?

Tires are created to withstand a certain air pressure. This is what is written on the tire.

Go by what is on the tire, not what the car says.

As long as you make sure to keep the pressure within those limits, then the higher up in that range you go, the better it is for gas mileage.

And while too much air pressure is a bad thing, there are rumors of some tires being overinflated too 100 psi, etc, and the tires not having a problem.

In general, if you try to overinflate a tire the air pump will blow long before the tire does.

Understood. Thanks for the advice, I will just do that.

One really stupid question tho, should all tire pressure to be the same to get best milage?

[Idjiit]

Originally Posted by Ziv

Understood. Thanks for the advice, I will just do that.

One really stupid question tho, should all tire pressure to be the same to get best milage?

No, typically people inflate the front tires between 3-5psi higher.

[Ziv]

Originally Posted by Idjiit

No, typically people inflate the front tires between 3-5psi higher.

Really? glad I asked. Then how should I match the tire pressure? if the tire said it's 32 let's say, and should I get the front up to 35ish?

[Idjiit]

Originally Posted by Ziv

Really? glad I asked. Then how should I match the tire pressure? if the tire said it's 32 let's say, and should I get the front up to 35ish?

If you want to follow the "max pressure" guidelines of the tire and the max is 35psi, then set the front to 35psi, and the rears to 32psi or so.

[Ziv]

Originally Posted by Idjiit

If you want to follow the "max pressure" guidelines of the tire and the max is 35psi, then set the front to 35psi, and the rears to 32psi or so.

Is that your current settings? Does anybody else find this best for fuel efficient?

[Idjiit]

Heh, I think mine are set ridiculously high right now because I didn't let air out after the rallycross I cranked them up for. :O

[Tankota]

Yes you might get some better milage by increasing your tire pressure above the factory recomended settings - but remember you will also increase uneven wear (the centers will wear out before the edges) your braking will be reduced and your corner grip will be reduced - plus the harshness of the ride will be increased... all cause by overinflating the tires.

The numbers on the door are a result of lots of testing with that size tire on that excact style of car - it's the pressure that gives you the best milage along with the best contact patch of rubber on the ground that size tire for that car. Reduce that, and you get less milage, more wear on the edges, and slop and roll on curves. Increase it, yes you might get some milage, but less rubber and control on the ground, harsh ride, and wears the middle. So keep that in mind.. Oh yeah, drive a car with tires inflated to the max in rain? That's just asking for loss of traction in either braking or corning, and even hydroplaning. Those numbers are not just random that they post on the door.

As for the max tire pressure listed on the tire? It's just that, it's the max the tire should ever be inflated under any condtions, it's what it's tested to at the rated speed. Go over that or the speed rating and the tire could fail is what they are saying. Just because your engine is rated for 6500 RPM max before redline does not mean you should drive it there all the time. The most I'd go over the door sticker is 5psi, that might gain you some milage but still have a good contact patch. You can also increase it if you have a heavy load in the car. And it usualy is correct, the front will be higher than the rear due to the engine weight, but if so the door sticker will list a higher number for the front than the rears. Toyota has already paid engineers the money to figure out the correct tire pressure for the car, why go around guessing on your own?

There is some tests you can do to find the right pressure for a modified vehical, I do this all the time with modfied trucks with oversized tires for street use, but the point is on a factory Yaris with the factory sized tires it's all been done for you by experts, listen to it.