There have been many discussion on premium vs regular (91 vs 87 octane) discussions but nothing on 88 octane gas (E15). For the record, I used premium in my 2017 RDX when I first bought it used in September 2020. I switched to regular several months ago when gas prices went up and haven't had any issues and no drop in gas mileage.

One of the local convenience stores, Sheetz, is selling 88 Octane gas (E15) ahead of the 4th of July weekend for $3.99. In the owner's manual, it mentions (n the sidebar) that you can use up to 15% ethanol in the RDX. It's nice to save money but I wnat to find out if anyone has used E15 (88 octane) gas in their RDX and did it affect performance or gas mileage?

Thanks

 

The owners manual is probably the safest bet for accuracy, I'd say you're fine. You may see slight performance or gas mileage differences, but I would imagine they'd be negligible. The ECU is able to adjust the engine in real time (air/fuel mix, spark, etc) based on what gas you're using.

 

What I said above was slightly incorrect, as it's just the knock sensor that is taking a reading and possibly adjusting timing, based on the octane of fuel you are using.

 

I gave it a try and still workng on the tank of gas. Considering that it was $0.80 cheaper than regular (87 octane), it was worth a try. So far, no issues. It's driving normal and the gas mileage is the same. It's only one tank......

 

The E85 is supposed to use in engine with flex fuel. One time might be ok, but you should stop doing it again in your 2017 RDX!

 

Not sure what you are refering to. I'm talking about 88 Octane (E15) gas not E85 flex fuel. They are not the same.

 

My bad! I would rather use the 87 instead of the 88 (E15) in my vehicle. I saw 85 in Colorado, but have not pay attention any gas station with 88 (E15).