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2,500 Mile Odyssey In A Kia Sorento PHEV: Day 2, Sport Mode Can't Beat Eco Mode

It’s my second day into a 2,500 road trip and I find myself surprised again! This time it is only a small surprise: Sport Mode turned out to be less efficient than I thought. This casts doubt on my latest theory, even though we still got good results.


I started the day early with a full battery and a gas tank that was 91% full (according to the Kia Access app). For the first 5 miles of the drive, to Interstate 5 South, I kept our Kia Sorento PHEV in EV mode. Once up to the 70 MPH speed limit on the freeway, I switched to Sport mode until I had recharged our battery to 30 miles of range showing on the dash (about 95% state of charge). I then drove in EV mode for about 25 miles, until the display showed 5 miles of battery range remaining before switching back to Sport mode. The drive between Olympia, WA and Portland, OR is just about 99 miles (the distance I intended for the test), and I-5 follows an undulating path along riversides and hills here. It doesn’t have the steep climbs that the section of I-5 between Seattle and Olympia has, but it is roughly comparable in terms of amount of uphill distance as such. The main difference is that between Seattle and Olympia the speed limit on I-5 is mostly 60 MPH, and between Olympia and Portland it is mostly 70 MPH. I drove 60-65 MPH most of the way to Olympia, and I drove 65-70 MPH to the Portland area (there are a couple short stretches in there where the speed limit is 60 and occasionally I got stuck behind some slower traffic for a stretch). To try and equalize the two tests a bit, I did what I could to drive more efficiently on the way to Portland in Sport Mode. I drove a little slower than I would have otherwise, I drafted 3-4 car lengths behind semis for about ⅓ of the distance, and avoided letting the cruise control power me up hills (which typically works the engine harder, instead I only gently increased pressure on the pedal and let the vehicle slow down a few MPH while going uphill). But even with all that, I still saw significantly worse MPG figures using Sport Mode for this 2nd 99 mile test than I did for my reference test, yesterday. I only managed to get 38.4 MPG today, versus 60.8 yesterday (not that 38.4 MPG is terrible for a 3 row SUV). I only covered approximately 30 miles of the 99 mile test running on the battery, compared to 45.2 miles yesterday. 

Here’s the main reason for the difference, my average speed for the first 99 miles today was almost 64 MPH, whereas yesterday it was about 50 MPH. There is no doubt that the faster average speed results in lower efficiency (and EV range). The difference in conditions (steepness or length of hills primarily) also may contribute to the difference as well. But ultimately, I conclude from this first test of the day that Sport Mode can only give you as good or slightly better efficiency results in very specific circumstances. I was thinking that on long highway drives the efficiency differences between Sport Mode and regular Hybrid (HEV) operation may be slight. But that may only be true when one is doing more demanding driving like driving over mountain passes. That theory may have some additional merit given the other tests I performed today.

For the second 99 miles of today’s 740 mile drive to Sonoma, CA I switched our Sorento into Smart Mode. Interestingly, Smart Mode first defaulted to using up the few remaining miles of range I had on the battery (I was driving 55-60 MPH on I-5 through Portland at the time Smart Mode used up the last of the battery range). After the battery was depleted, Smart Mode drove in HEV mode for the duration of the 99 miles except for a short stretch of about 5 miles where I switched back to Sport Mode in order to see if I could detect differences in engine RPMs or other behaviors between Smart and Sport Modes. It seemed like Sport Mode RPMs were just a little bit higher (maybe 100-500 RPMs higher). That may just be a fluke and I don’t consider that brief test to be definitive, but those higher revs and slightly slower speed are likely why Smart Mode returned 40.3 MPG for the second 99 mile stretch of the day, traveling at an average speed of about 61 MPH, compared to Sport Mode’s 38.4 MPG at almost 64 MPH.

Finally, I tested the Automatic “mode”, which is toggled via the EV/HEV button that is between the front seats. What was interesting to me is that while Smart Mode opted to use up all my remaining battery range, even when I was on the freeway, Automatic mode did not do this. I drove about 20 miles in Sport Mode before switching to Automatic mode to add 9 miles of EV range to the battery before I started going up steep mountain passes in southern Oregon and northern California. Automatic mode did not switch to EV mode until I was coasting downhill or braking, thus preserving the battery charge or even adding a couple miles (I ended up with 11 miles of range left in the battery after I made it down the Siskiyou Pass). Thus I would say that Smart Mode doesn’t seem so smart, to me, since EV range is best reserved for slower speed driving (50 MPH or slower) in order to maximize efficiency. I would opt for Automatic mode then, if I was the kind of person who wanted to “set it and forget it”. 

Any questions or surprises about my findings from day 2? Please leave your comments or questions below.

Image courtesy of Justin Hart. 

Justin Hart has owned and driven electric vehicles for over 15 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 for regular electric and hybrid news coverage.