Join Date: May 2009
Location: east coast
Car: OBW H6 VDC, Tribeca, XT6
Feedback Score: 1 reviews
The great thing is you don't need to read or decide. Subaru says "Recommended" which means the door is open for 87. So, go test drive the car and see how it does for your driving with both choices and see what works for your engine condition and driving environment.
If 87 causes issues, then run premium. I run 87 95 percent of the time. I've never noticed a difference in at least 5 different Subaru H6's over 10 years including my current 270k and 190k cars.
If it's in poor running condition maybe higher octane would mitigate issues....but that's like swimming with a cheap band-aid and it needs maintenance not premium.
My daily commute is rough, low elevation, mountain switch backs so maybe that dumbs down the numbers and I don't notice small benefits, but I've seen zero difference. 27.xx mpg on flat Ohio roads a couple times a year, which is as high as average H6's will go, and again no change with premium or 87.
A time or three a year I try premium and non-ethanol premium during high load times to mitigate the engine work outs during towing/interstate/heat/humidity/mountains, usually I'm hoping to see a little difference....and I'm always disappointed..."was that better...different....faster....i think maybe..." but the gas mileage never changes. A decade and about 5 different H6 vehicles and it's been the same every time.
H6 OBW VDC, H6 OB Sedan, Tribeca, Lifted XT6