blown5.0

Hi,
I was wondering what octane rating folks with the hybrid RX350h were using? For those using 87, is there a noticeable mpg or performance hit?

daryll40

Too new to really tell so far. But around Pittsburgh, premium costs 20% more. It’s unlikely that the vehicle will get 6-7% more MPG (20%). Probably not even 10% more MPG. Perhaps, for those who care (I do not), the performance will be better, and that will be worth the extra cost of premium, even if it doesn’t improve MPG. My guess is the performance buyers would rather want the RX500h.

blown5.0

Thanks. My thinking is pretty aligned with yours here. I wonder if the MPG takes a hit though with 87 vs 91?

daryll40

I ran my "new car dealer gas" down to near empty and filled up with 87. (I suspect even the dealer gas was 87.) I'm getting 31MPG around the hills of Pittsburgh on that 87 octane gas. The sticker quotes "36MPG City". Considering the car is still new, I've been often sitting in it, idling, it while playing with and learning to use the new technology, and I've used the remote start to warm the car up a few times (more idling), 31MPGs on 87 octane gas is fantastic. My old 202RX350 got about 17 under the same circumstances. I can't imagine that 91 or 92 octane would provide much more MPGSs.

aeromarkco

Is anyone running 85 Octane i.e. in Colorado or the front range?

Eagleboy99

RX350h
91AKI (Research Octane Number 96) or higher [recommended]
87AKI (Research Octane Number 91) or higher [minimum]

Using lower octane will void your warranty.

Hefty

I have run 3 tanks of 87. First one was 36 mpg according to the computer. Didn’t check actual. The next one, doing basically 6 mile trips on flat ground at a mix of 55 mph and 35 mph was 37 mpg per the computer but actual computed to 35. The next one was also 37 per the computer but computed to 36. My Highlander under the same conditions would be around 21 or 22 mpg. I notice no performance issues at all using 87, and as someone has said, I don’t think there is any way the additional mpg you may get with premium would pay for the additional cost. Not even gonna try the higher octane. Very pleased with the fuel economy even if I do drive like an old man.

RS91

I tried both 87 and 93 since costco doesn't keep 91. There is no difference in mileage. Mine is around 32-35 mpg.

Eagleboy99

Please keep buying high-octane fuel when it is not required and does nothing for mileage or performance. It is doing wonders for my oil and gas stocks.

Marqevans

I know the NX HYBRID did not require premium because there is no turbo. Does the 350h require premium fuel even though it doesn’t have a turbo?

Eagleboy99

350h does not need premium. No benefit to feeding it that either.

Marqevans

But the turbo RX’s do require premium?

Eagleboy99

The non-hybrid REQUIRES premium.

daryll40

Yes. Which means the MPGs on the sticker (of the turbocharged, non-hybrid RX350) really have to be reduced by 3-4 MPG to equate to “regular vehicles” that run on 15-20% cheaper regular gas.

hugsmindy

My experience so far....
Purchased car on 1/21/23. Dealer put in 87. I've been putting in 87 or 88 (one gas station near me offers 88...it's that slightly higher octane at a less expensive prices point, so I use it when I see it.) since original purchase.
I feel no issues with performance and my gas mileage has been between 32-41 MPG on just about every drive.

I'm happy with that and I see no reason to pay for premium when I'm getting great performance and gas mileage off of the regular.

As a side note, because maintenance is also important when discussing performance and MPG.: I maintain my cars in a very OCD fashion. Oil changes and tire rotations every 5k miles and all other needed maintenance on schedule or better. If something is not right, I get it fixed.