Where is my gas going?

[Keith Tinari]

When I bought this car I was averaging around 40mpg. Thats great maybe almost worth the WRX trade in. I did some small mods, lowered, light wide wheels with a tire comparable in height to the stock ones, the TRD exhaust, and a K&N drop in. Reset the ECU and now I'm getting around 30mpgs. It never gets driven hard because its a Yaris, I'd still get there late lol. I also did the break in, and the 1500 and 3000 mile oil changes. I'm running 5-30 oil and 87 octane like Toyota suggests. Any ideas?

[Tamago]

probably all those "power" mods you've been blowing your money on :biggrin:

in all seriousness, it's the wide tires that are doing it.

[Keith Tinari]

youre kidding me really? when I was on the advans I was running the same tires and still getting around 40! too much rolling resistance?

[thebarber]

wide tires hurts the mpgs for sure.

im running 205's and im down a couple mpg's

[Tamago]

yes, and those silly "power" mods are doing it too. what's your AFR's looking like?

[Keith Tinari]

I have no clue to be honest. I didnt buy either of them for power. I just didnt want to ghetto the car up with a big tach so I put an exhaust on it to hear it. Im not used to quiet cars like this. My old Subaru used to set off car alarms. and the K&N I thought would help MPGs get better.

BTW Barber I am running 205 50 15s on 15x7.5s, I guess the footprint is rather large for a car this size. This pretains to nothin but with a half tank of gas and me in it my car weighs 2520. I thought that was cool.

[TLyttle]

My guess would be the tires: wide tires eat gasoline, simple as that. Colder weather doesn't help. I've used K&N filters, to the detriment of fuel mileage. I don't think the exhaust system change helps much either.

Anything you do to increase performance (acceleration) is going to show up on your pump bills. Performance means ALL PHASES of the car, not just acceleration, and includes fuel economy. The Yaris seems to be a very tightly-balanced car, and changes are likely to upset that balance...

[Tamago]

I have no clue to be honest. I didnt buy either of them for power.

you didn't buy them for better fuel economy either ;)

oh, and if you're lowered, you've created a great deal of toe-in at the rear of your car. this is another cause of bad fuel economy. get that rear toe fixed

[b_hickman11]

you didn't buy them for better fuel economy either ;)

oh, and if you're lowered, you've created a great deal of toe-in at the rear of your car. this is another cause of bad fuel economy. get that rear toe fixed

and thats the only 2 reasons?? I think not.

[jambo101]

Coming from a WRX and with all the mods you've put on the car i'm suspecting your idea of easy driving is whats netting you 30mpg,i'll bet if my idea of easy driving were put to your car you'd be back up to 40+mpg.Doesnt take much to ruin a good mpg result on a tank of gas.

[SpaceShot]

Use a digital gauge and check the tire pressure. With a wide low profile tire you might not even notice it being toward the low side. Try it for a week with 32psi (if not already there), and then a second week at something closer to the max sidewall rating.

Consider an ecometer or scangauge II. You don't think you are driving hard, but the near instant feedback may tell you otherwise. With some practice you can get used to coasting with the terain along your route and see your trip average Mpgs start going back up.

Also as the weather gets cooler you will drop a couple Mpg. Look at your route and see if you can find a way to be on the side roads a few extra minutes before hitting the freeway in the morning. For the winter consider blocking the lower grille below the bumper.

[Tamago]

and thats the only 2 reasons?? I think not.

english lesson time. i said "another" not "the only other"

[Keith Tinari]

Use a digital gauge and check the tire pressure. With a wide low profile tire you might not even notice it being toward the low side. Try it for a week with 32psi (if not already there), and then a second week at something closer to the max sidewall rating.

Consider an ecometer or scangauge II. You don't think you are driving hard, but the near instant feedback may tell you otherwise. With some practice you can get used to coasting with the terain along your route and see your trip average Mpgs start going back up.

Also as the weather gets cooler you will drop a couple Mpg. Look at your route and see if you can find a way to be on the side roads a few extra minutes before hitting the freeway in the morning. For the winter consider blocking the lower grille below the bumper.

I actually have them set currently at 32 psi, using my very expensive gauge at work. (I'm a mechanic) I tried closer to 40 and it made the car a little too rough. I used to run 45 in my Subaru but it wasnt as uncomfortable as this car is at that PSI. I have to admit I dont do much coasting because my drive consists of mostly hilly windy backroads. And when you get off the throttle it takes forever to get back to 45. I equate this car to a small motor with a large turbo at very very low boost lol. I just wanted to make sure there wasnt something wrong with this car. Our Motis at work cannot connect to my car so I cant see fuel trims. is there any software for our cars?

Subarus use a program called open ECU where all you need is the free software, a Tactrix cable and a laptop to see everything and tune. My tuner used it reliably to tune my car at 21psi with 565cc injectors and still keep the IDC at around 75% and optimal AFRs.

[Tamago]

yes, it's called a scangauge. already mentioned in this thread. ;)

[Loren]

I'm running 215/45-15 Toyos and can still net 40 mpg regularly around town and 44+ on the highway.

My guess is the OP's problem is that he's made significant "sound" mods. A car that SOUNDS good inspires the driver to drive it such that it can be heard.

[Tamago]

Loren! good to have you back!

[ROCKLAND TOYOTA]

It never gets driven hard because its a Yaris, ?

:laugh:

[1stToyota]

I actually have them set currently at 32 psi, using my very expensive gauge at work. (I'm a mechanic) I tried closer to 40 and it made the car a little too rough. I used to run 45 in my Subaru but it wasnt as uncomfortable as this car is at that PSI. I have to admit I dont do much coasting because my drive consists of mostly hilly windy backroads. And when you get off the throttle it takes forever to get back to 45. I equate this car to a small motor with a large turbo at very very low boost lol. I just wanted to make sure there wasnt something wrong with this car. Our Motis at work cannot connect to my car so I cant see fuel trims. is there any software for our cars?

Subarus use a program called open ECU where all you need is the free software, a Tactrix cable and a laptop to see everything and tune. My tuner used it reliably to tune my car at 21psi with 565cc injectors and still keep the IDC at around 75% and optimal AFRs.

yes, it's called a scangauge. already mentioned in this thread. ;)

Or a Genisys :redface:

Just hooked mine up a few minutes ago for fun; full datastream info for my engine, etc...and my tires ranged from 68-70 degrees, 33.4-33.7 psi

[Keith Tinari]

I'm running 215/45-15 Toyos and can still net 40 mpg regularly around town and 44+ on the highway.

My guess is the OP's problem is that he's made significant "sound" mods. A car that SOUNDS good inspires the driver to drive it such that it can be heard.

LOL, I know what you mean but I can promise you my driving habits are well behaved.

:laugh:

Yeah, going from 400hp to 100hp warrants that. Not nearly as much fun to drive.... So I don't bother for the most part. I like my little car, just not that much. I'm not quite sure what was so funny.

Also, I'm not a fan at all of the sound of this car, in fact it sounds like a VW sohc 2.0. And I seriously dislike VWs. My fiance had a Turbo Beetle, big mistake.

[Loren]

Loren! good to have you back!
Thanks! I spent the last week getting really poor gas mileage. 6.5-8 mpg in the RV for 2200 miles, and 9-11 mpg in the race car for about 19 hours. Can't you just feel the global warming I've caused?

[Tamago]

Thanks! I spent the last week getting really poor gas mileage. 6.5-8 mpg in the RV for 2200 miles, and 9-11 mpg in the race car for about 19 hours. Can't you just feel the global warming I've caused?

warm and fuzzy thinking about it.

[MUSKOKA800]

I run that TRD exhaust + K&N drop in combo. No significant mileage changes notices since the install.
If you dropped it without correcting the FRONT toe angle you could be plowing your way to crappy mileage, and prematurely worn front tires. Rear toe remained within spec. after the install of my TRD suspension.

[ROCKLAND TOYOTA]

LOL, I know what you mean but I can promise you my driving habits are well behaved.



Yeah, going from 400hp to 100hp warrants that. Not nearly as much fun to drive.... So I don't bother for the most part. I like my little car, just not that much. I'm not quite sure what was so funny.

Also, I'm not a fan at all of the sound of this car, in fact it sounds like a VW sohc 2.0. And I seriously dislike VWs. My fiance had a Turbo Beetle, big mistake.

"It never gets driven hard because its a Yaris" thats what is funny....

[Keith Tinari]

I run that TRD exhaust + K&N drop in combo. No significant mileage changes notices since the install.
If you dropped it without correcting the FRONT toe angle you could be plowing your way to crappy mileage, and prematurely worn front tires. Rear toe remained within spec. after the install of my TRD suspension.

Im actually running zero toe. I did the alignment myself. I was going to run it a little positive since its so twitchy but its not that bad.

[YarisSedan]

I noticed when i put 205s driving pretty much the same my mpg dropped between 1 to 1.5 mpg than it used to be depending on the week which i attribute to increased rolling resistance.