60MPG Yaris

[ltwargssf]

I do a lot of highway with my 2014 Yaris CE and I wasn't pleased with the stock mpg.

I started with a few small things but once I made my own custom undertray, results really started to show. Now with my current setup, I have no problem maintaining 42-45mpg city and 50mpg highways. With some hypermiling, I've had my scan gauge hit 60mpg a few times now which was impossible when the car was stock.

The front grill and part of the bumper were also blocked off along with a rear diffuser (No fins just cover) and the gas tank. All I have left to cover are parts of the floors to complete the undertray.

High-speed stability has also improved dramatically along with side winds and road noise. Not the prettiest but its functional, secure and cost me under 50$

[mitch9521]

Interesting.

I can barely get 37-38 highway when I run my summer wheels, but that's to be expected since they're 205s and a way softer compound than the stock economy tires.

[ltwargssf]

Interesting.

I can barely get 37-38 highway when I run my summer wheels, but that's to be expected since they're 205s and a way softer compound than the stock economy tires.


I was going to keep the 16" SE wheels at 195 but they were almost 38lbs. My stock 15" with only 175 at 29lbs makes the car way more nimble but also helps a lot for fuel economy.

With the 16s I was having a hard time maintaining 42mpg on the highway and as soon as I put the 15s, I was clocking high 49-50mpg without issues. The almost 10lbs difference in rotational weight will be very noticeable on these small cars.

[mitch9521]

I was going to keep the 16" SE wheels at 195 but they were almost 38lbs. My stock 15" with only 175 at 29lbs makes the car way more nimble but also helps a lot for fuel economy.

With the 16s I was having a hard time maintaining 42mpg on the highway and as soon as I put the 15s, I was clocking high 49-50mpg without issues. The almost 10lbs difference in rotational weight will be very noticeable on these small cars.

I ran a set of 16" SE wheels in 2020 for my summers(have since sold them) and they were indeed incredibly heavy. I have a set of 16x7 Enkei RP02s now, not sure how much they weigh but I would guess 20lbs or less per side.

[rayfloyd170]

Still full-tank-filling method is more accurate than scan gauge i guess. Most of the time they are way off the marks if you coast. I am using both and can say that the manual method is more accurate. Although the digital one gives you a good real-time consumption and will be really beneficial

[mitch9521]

Still full-tank-filling method is more accurate than scan gauge i guess. Most of the time they are way off the marks if you coast. I am using both and can say that the manual method is more accurate. Although the digital one gives you a good real-time consumption and will be really beneficial

I still use a Scangauge in my F150 lol, its nice having a digital coolant temp readout, especially under high load.

[mannycheckers]

Pardon my ignorance, but how does adding an undershield increase MPG?

[ltwargssf]

Pardon my ignorance, but how does adding an undershield increase MPG?

Most modern cars use this, the smoother the underbelly of the car, the less drag you get. The new Prius has an amazing drag coefficient and a lot of it comes from the underbody being completely covered. The tesla however definitely has the best underbody on the market it seems with it being almost perfectly flat resulting in an even better drag coefficient than the Prius.

[ltwargssf]

I still use a Scangauge in my F150 lol, its nice having a digital coolant temp readout, especially under high load.

I mainly got the scan gauge to monitor coolant temp like you since I wanted to block off most of the front grill and didn't want to overheat. I completely blocked off the upper grill and the lower grill has 2/3 left where I made a custom air shroud to guide all the air to go into the radiator. During the freezing winter weeks I have the entire grill blocked off and made a hot air intake taking air from the exhaust side to keep the mpg high. I've since switched to my summer intake where I ran 2.5" piping from the stock box into the driver side fender where I got noticeable colder IAT's and I made sure to get it as high as I could to prevent hydro locking.

Another benefit of the underbody covers is they keep the engine bay clean. When I first got the car, the engine bay would just be full of salt after any highway driving so I needed to resolve this.

[ltwargssf]

Still full-tank-filling method is more accurate than scan gauge i guess. Most of the time they are way off the marks if you coast. I am using both and can say that the manual method is more accurate. Although the digital one gives you a good real-time consumption and will be really beneficial

Yes that is correct but the scan gauge can give me accurate results if something is working or not. Stock I was never able to clock anything near 50mpg and now it can do it without a sweat. We still have cold days here and I do a lot of idling to warm the car up but so far my best tank with it was 680km and that's with mixed city and highway driving. With the warmer temperatures coming, I hope to see some more consistent numbers.

[ltwargssf]

Interesting.

I can barely get 37-38 highway when I run my summer wheels, but that's to be expected since they're 205s and a way softer compound than the stock economy tires.

Btw, do you have a short-throw shifter? I just order a Cosmo Racing one and hope the install isn't too much of a pain

[IndestructibleYaris]

Someone displaced my undertrays and I'm pissed. I've been meaning to make my own flat bottom for a while. Great work.

[matt4x4]

Btw, do you have a short-throw shifter? I just order a Cosmo Racing one and hope the install isn't too much of a pain

Sounds like a solid choice, quicker shifts, tighter shifts, better feel.
How much did that cost ya?

[LangFut]

How has the short-throw shifter upgrade affected your driving experience, and was it worth the investment?