Kia Sorento Plug-In Hybrid Sport Mode: Medium Distance Highway Drive Test

I am bound and determined to thoroughly test my Kia Sorento plug-in hybrid’s fuel efficiency in Sport mode, because I want to definitively prove whether, or not, there are driving circumstances where the use of Sport mode might be more fuel efficient.

It is likely that I can do no better than build a case, one way or the other, and that others may make claims to the contrary and offer proof, because none of this testing is an exact “science”. It's fine that people may have different opinions on this, and different experiences that are behind those opinions. But for myself, to satisfy my intellectual curiosity about the complex engineering involved in any plug-in hybrid, I just want to test what I know.

The other day I tested the very specific circumstance of driving over a mountain pass in Sport mode, and the week before that I tested Sport mode in a relatively short loop of about 21 miles, roughly half on the freeway. Now, I am testing my Sorento PHEV on a medium distance highway drive of a little over 38 miles through gently undulating hills with only minor elevation gain or loss, mostly at a speed limit of 60 MPH, but with approximately 10 miles of 35-50 MPH sections too. I’ll drive most of the distance in Sport mode the first time through, intending to regenerate enough charge in the battery to cover the distance at slower speeds in EV mode (when I am driving through a few small towns along my drive). I’ll use cruise control wherever I can and set it to 3 miles per hour over the limit and when I drive the same stretch of road on my return trip I will use HEV mode for the same distance that I used Sport mode on the first time through, and again use EV mode on the slower stretches going through small towns. A few other details: this is on the same trip as my mountain pass test, so I have all the same parameters except that it is now getting close to 8pm. It’s still hot enough to be running the AC the whole time and my tires are showing a PSI of 41 lbs and there wasn’t much wind to speak of.

Here’s how the Sport mode trip went: At the end of the 38+ mile drive, my fuel economy display showed 32.4 MPG. This was after switching into EV mode for about 12 miles. I know I said 10 before, but I actually somehow ended up in hybrid mode, automatically, for a couple miles even though I hadn’t pressed hard enough on the accelerator to activate it, nor did I press the button to do so. The car just decided to run in HEV mode itself so I just kept it in EV mode until I had used up the 10 miles of range I regenerated from driving in Sport mode for roughly the previous 20 miles. Did I ever mention these tests aren’t an exact science? Still, 32.4 mpg wasn’t bad considering my friends in their Mazda CX-9 managed all of 21 MPG along the same stretch (granted, they had an extra 200 pounds of people and stuff).

Here’s how the return HEV mode trip went: At the end of the 38+ mile drive, and after I manually switched into EV mode for 10 miles or so of slower driving through small towns, my fuel economy display showed 43.1 MPG. That is more than 30% better fuel economy (and more than double what my friends were averaging in their Mazda). Note, this part of the test had a couple other things that may have been of minor impact too: The vehicle was lighter coming back by about 100 pounds and it was about 5 degrees cooler and earlier in the day. I expect these things to have made minor differences, at best, though.

I’ll end with a few other details worth sharing. For this road trip I drove 365.4 miles in total (from the point of gassing up the night before I left). I fully charged my hybrid battery once before and once during the trip and used a little more than ⅔ of a tank of gas. My average speed was almost exactly 50 miles per hour for that total distance driven and about 37 miles of the total distance was in Sport mode, the rest in either HEV or EV modes. My total range for the tank of fuel plus 2 full charges of the battery would have come out to about 483 miles till empty, or around 450 miles had I not charged up the battery in the middle of the trip. That is very close to the EPA rated range of the Kia Sorento PHEV, which as I wrote in a previous article is attainable if you simply drive at a slower rate of speed (or “cheat” and charge up the battery a few times before using the whole tank of gas). I predict I would have gotten slightly better range had I skipped the use of Sport mode, too, but I intend to test that further with a still longer test in an upcoming piece.

Whether or not you agree that Sport mode is less efficient, I welcome your questions and comments below. Cheers!

Image courtesy of Justin Hart.

Justin Hart has owned and driven electric vehicles for over 14 years, including a first generation Nissan LEAF, second generation Chevy Volt, Tesla Model 3, an electric bicycle and most recently a Kia Sorento PHEV. He is also an avid SUP rider, poet, photographer and wine lover. He enjoys taking long EV and PHEV road trips to beautiful and serene places with the people he loves. Follow Justin on Twitter for daily KIA EV news coverage.