I’ve heard some reports stating the turbo boast sucks gas like crazy. Anyone seeing poor gas mileage?

Yep, 20-21

But the engine isn’t broken in yet.


Turbos force air, the more air the more gas. The more air and gas, the more power. Plus, it has a high profile and AWD. I am not really expecting good gas mileage, even though I think it will improve out on the highway.

from the wiki.

My numbers have been right on with advertised mpg. I have about 2200 miles on. Total 24.7.

2019 RDX Tech, FWD, bought 6/6/2018.

Trip Computer (algorithm, based on internal measurement of fuel flow & distance): 24 mpg ave, 3279 miles (actual odometer reading today). My trip computer has not been reset since new.

Fuelly.com (calculated from actual miles travelled➗actual gallons used): 23.9 mpg ave, 3060 miles (tracked via Fuelly), 67/33% Hwy/City.
Lowest calculation by Fuelly to date has been 20.8 MPG; highest 27.4.

Note that my trip computer reading is very close to the calculation by Fuelly.com, which I have not experienced with past vehicles.

FYI if you are really obsessed with MPG — “Car and Driver” published an article on the discrepancy between MPG reported by a vehicle’s trip computer, and MPG calculated from gas pump and odometer readings. It stated: “To determine fuel efficiency, the [trip] computer keeps a running total of both the fuel delivered to the engine and the distance driven.” It goes on to explain why the computer-reported MPG can vary from reality. And, that Honda adds compensatory factors to its algorithm for computing MPG, trying to get it closer to reality. The article gives a method for equalizing fuel fill-ups at different gas pumps, which might be useful in getting closer to an accurate manual calculation.
“Why Your Trip Computer Isn’t Giving Accurate MPG Readings (And How to Fix It),” Aug 21, 2013.
https://www.caranddriver.com/news/wh...-how-to-fix-it

Short answer: 20.8 mpg in spirited suburban driving in Sport mode. I have not done any long highway trips.

I've been looking at the trade-off of mileage, price, and octane. I miss the days when the spread was 10-20¢ per grade.

Anyway I'm finding that in suburban driving I gain 0.8 mpg going from 87 to 89 octane (20.0 mpg to 20.8), at a cost of 40¢/gal and gain another 1.0 mpg going from 87 to 93 at another 45-60¢ depending on the station. Around here few stations sell 91.

I can't say I really notice any difference in performance given the speeds I can normally drive. I don't have any roads here worthy of Sport+ mode... Few curves or hills in the Chicago area.

For now I'm pretty much just sticking to 89 unless I fill up at Costco where 93 doesn't carry such a higher price (and where it's a choice of only 87 or 93).

City driving in Seattle, WA. Mixed between highway and roads.

13 to 16 mpg so far with auto stop idle on, comfort mode and no fast acceleration (smooth slow & steady braking and acceleration).

FYI when you have a turbo engine and are under moderate load (using the turbo) the computer adjusts the air to fuel ratio to 11:1 or so. Therefore you’re not only using more air=more gas, but using gas at a higher ratio per amount of air.

FYI
Turbo cars require premium 91 or higher octane because the gas is more stable, not because it makes more horsepower. In a turbocharged engine, the turbo creates boosted air pressure in the engines combustion chamber. Without the stability of higher octane gasoline, the fuel mixture often explodes because of the higher pressure before the spark can ignite it at the proper time. The result is knock or predetonation. It causes tiny nicks in your pistons and cylinder walks. Over time it can destroy the engine. Your vehicle has a “knock sensor” it works by detecting the knock and de powering the car through timing to reduce it. I’ve had a computer on a car to observe this phenomenon. When the knock is happening, it’s in the order of 30-60 knocks per second.

The manufacturer, Honda, says the Honda 2.0 requires 87. Acura recommends 91, but a simple look at the fuel filler shows that it requires 87.

Some turbo engines require premium, for some it is only recommended, and for others, it is not even recommended by the manufacturer.

As I planned, I switched over to 93 at 3000 miles. It looks like I picked up just short of 10% better mileage for a bit more than 15% extra cost. I am not feeling more power on my butt dyno, but the engine feels and sounds like it runs smoother. I will keep using top tier 93 for the next 3K miles, then make a decision.

I posted this chart elsewhere (on the “other” mpg thread) but can’t hurt to add it to this one. Explanatory note is in the image; my own results to-date are part of my signature. On Fuelly’s chart, my RDX is one of the three that are averaging 25 mpg.

FWIW, I mostly use Costco’s 93 octane “top tier” product. On the road I use mostly BP mid-grade (89 oct), because I’m cheap—I prefer their quality gas over other brands, but BP charges as much as $.50 more per gallon for 89 than my Costco charges for 93; BP’s 93 is almost $1 more than Costco’s (at least, it is at stations I’ve used near interchanges on I-85 and I-95).

I’d like to find a reliable source for some good-quality, ethanol-free gas (intended for road use) to try over several fill-ups, but it is fairly difficult to find. I stumbled on some last month at a WaWa in FL, but haven’t found it elsewhere on the road. WaWa’s website says they plan to expand availability nationwide, but it is happening at a slow pace.


https://cimg7.ibsrv.net/gimg/acurazi...fcf3832f7.jpeg
From fuellly.com