Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - '11 Kia Soul 1.6L 32-36mpg

B440 · 06-23-2022, 02:08 PM

2011 Kia Soul base model with 5-speed and 1.6L engine.
EPA stats: 26/31mpg.

I could only best about 30-31mpg with stock tires 195/65-15 and my aftermarket ones of 205/60-16 (+2.8% diameter). This was driving on the highway at speeds of 60-63mph and over the course of several years, just keeping track with onboard mpg and calculated mpg when refueling.

Modification: Took the old rims/tires from the Mazda CX-5 and put them on the Kia. New tire size is 225/70-16 (+13.6% diameter).

New best: 32-36mpg at 60-63mph. 32 is what the car says. 36 is what I calculate when adjusting for the 13.6% difference.

Reasons for going bigger:
The 5th gear ratio sucks. You can always skip 4th and go straight to 5th. On the highway I am at least 500rpm higher (3500+rpm) than the Mazda when driving 70mph.

Issues:
Tires are nearly bald, so this is a summer-only experiment.
Warmer months skew the data towards better.
Big potholes and square-edge bumps cause tire rub on the fenders.
It is noticeably slower to start off, not as peppy, and requires more clutch on hills. I suppose a good compromise between mpgs and pep would be a 215/65-16 tire.

As an aside, I found the gear ratios on a Kia forum, and the 6-speed Kia used on later models didn't solve the high rpm issue because they also changed the final drive ratio. It would appear that if I replaced my 5th gear with the ratio of the later model 6th gear (it would remain a 5-speed gearbox), then all would be well and I wouldn't have to use larger tires and 4th gear would be useable again.

06-23-2022, 02:08 PM	#1 (permalink)
B440 EcoModding Lurker Join Date: Oct 2013 Location: Thompson, CT Posts: 32 none - '15 Mazda CX-5 Sport Thanks: 4 Thanked 5 Times in 4 Posts	'11 Kia Soul 1.6L 32-36mpg 2011 Kia Soul base model with 5-speed and 1.6L engine. EPA stats: 26/31mpg. I could only best about 30-31mpg with stock tires 195/65-15 and my aftermarket ones of 205/60-16 (+2.8% diameter). This was driving on the highway at speeds of 60-63mph and over the course of several years, just keeping track with onboard mpg and calculated mpg when refueling. Modification: Took the old rims/tires from the Mazda CX-5 and put them on the Kia. New tire size is 225/70-16 (+13.6% diameter). New best: 32-36mpg at 60-63mph. 32 is what the car says. 36 is what I calculate when adjusting for the 13.6% difference. Reasons for going bigger: The 5th gear ratio sucks. You can always skip 4th and go straight to 5th. On the highway I am at least 500rpm higher (3500+rpm) than the Mazda when driving 70mph. Issues: Tires are nearly bald, so this is a summer-only experiment. Warmer months skew the data towards better. Big potholes and square-edge bumps cause tire rub on the fenders. It is noticeably slower to start off, not as peppy, and requires more clutch on hills. I suppose a good compromise between mpgs and pep would be a 215/65-16 tire. As an aside, I found the gear ratios on a Kia forum, and the 6-speed Kia used on later models didn't solve the high rpm issue because they also changed the final drive ratio. It would appear that if I replaced my 5th gear with the ratio of the later model 6th gear (it would remain a 5-speed gearbox), then all would be well and I wouldn't have to use larger tires and 4th gear would be useable again.