During the second leg of a 2K trip, using regular 87octane gas and cruising at 80 up I-81,
my gas mileage was a shocking 33.7mpg.

I was so surprised that I had my wife use my Iphone to record the event.
I only mention this as most everything I have read from the experts is a requirement to use 93 octane for best milage, guess that shoots that theory....

Another observation, when filling the tank and you get the auto shutoff, wait for about a minute and then continue the filling at a slower rate. This will give you another 75+ miles on the tank. My remaining tank mileage was registering at 525.

My previous Acura's have never given what this RLX has, my current mileage is 23,503, and everything is just humming along.

 

Please do not listen to victorber, NEVER overfill gas tank... your evap system that includes the charcoal canister will be damaged... AUTO SHUTOFF is for a reason..
87 octane... come on man, please don't do that, especially for DI engine ...

 

I know, it's amazing isn't it?
My highest mpg so far is 35.9 mpg on a 160 mile trip to Palm Springs..must have been a lot of level/slightly down hill going on there.
My smaller engine lighter weight TL's best ever on same trip was 32.
I usually fill up several gallons worth after the auto shutoff.
I also usually have a mix of 87/89 in the tank...I tried a few 91 octane tanks and could not tell the difference in mpg. I'm not very hard on the pedal, so I can't tell if there is a performance difference or not...but there most likely would be.

I am very pleased with the mileage and available driving range with this car

 

Knew there would be a flamer on here as soon as octane was mentioned.
DI does not care what the octane it is injecting into the engine, and the computer system will not allow the engine to perform in such a manner as to damage it.
And he never said he over-filled the tank.. The auto shutoff activates at about 14 gallons...3 gallons less than what the tank holds
The auto shut-off is to prevent any spillage; necessary because of some tree-hugger organization like the EPA who thinks the world will come to an end if a few vapors are released into the air by someone filling their tank

 

Just to be informed, When filling the gas tank using the auto shutoff feature, as the tank approaches the fill point the full rush of gas forces the auto shut-off to prematurely activate and all I am doing is compensating for the early shutoff, not overfilling the tank. There is about a 75-100 mile range difference between the two positions stated above.
In my previous 09 TL, I would top-off the tank and recover the loss without overfilling.

I have currently 23.5K on this RLX, four coast to coast round trips, been between SeaLevel and 14, 260 ft. and have not had a sputter.

The trip thru Deals Gap, (Tail of the Dragon) 311 switch-backs in 11.2 miles will test both the driver and the P-AWS system and the vehicles ability to negotiate a very trying stretch of road.
This vehicle will undoubtedly handle just about anything you as a driver can handle.
I agree with the above statement referring to the charcoal filter, and not flooding the system.
I truly believe in this car and the biggest problem I see is the 10% Ethanol content we are forced to use. In certain southern states there are gas stations which sell Non Ethanol gasoline, there aren't many but there are some. The gas is also cheaper....

Hope I provided some clarification.

 

don't tell me you are serious about 14 gallons You re running your tank dry? LOL... anyways, DO NOT fill after your shutoff is activated
I am not going to discuss about octane Do you you want to do. Just don't tell anyone it is ok, because it is not
You have luxury car, feed it with luxury gasoline

 

Here is the information from the OP:

 

Now, let me get this straight.

Your trip where you got that phenomenal mileage...included two ways through Deals Gap?

If that's true, all I can say is.... You're doing it wrong!!

Haaaaa ha ha ha ha ha ha!! :-)

I have about 10,500 now and lifetime average is 24.7 mpg. Nowhere near your phenomenal trip mileage, but considering how much of my driving is urban, I think that's pretty good.

Octane: I buy locally available 93 octane, and have no judgement to offer for people who do otherwise.

Overflow: I don't have time to play with 75 miles of extra travel. There's gas stations everywhere, and I just get off the phone, get out of the car, put the thing away and drive off when the flow stops. :-) No judgement if anybody wants to do otherwise!

 

The last time I went through Deals Gap was in my old ITR #110. I believe I got something like 8 miles per gallon.

:-)

 

I'm in agreement with Dzionny. Overfilling the tank CAN result in damage to the breather filter and should be avoided. That said, you can definitely safely add some fuel past the autostop but overdoing it in an attempt to obtain the absolute maximum cruising range has the potential for doing damage and in most cases is not worth the risk. Victober is an intelligent fellow and I would suggest that he is not overfilling the tank but filling it to the highest safe level.

I run 91 octane all the time (the highest grade available) - Acura recommends/requires it for a reason. Premium fuel also contains more fuel injector cleaners etc that help your engine perform at it's best.

My two cents.

 

I've done several trips and I don't see anything north of 30mpg going 80mph. Barely get 30mpg at 75

and that is always with premium

 

Seriously? I've done only one long road trip, and running Mid-grade I got several tanks over 33 mpg, and that was at interstate speeds of 80.

I tried one tank of Premium gasoline and saw absolutely no difference in performance or mileage, so all I've used since in Mid-grade. The dealer told me that Acura held training classes on the RLX where they told them Regular gas is okay for this car. I split the difference and use Mid.

Oh, and yes, I add gas after the pump shuts off. I'm not worried about damaging the charcoal filter since i don't run it over.

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I had a trip where I got just over 30, but I never went 80.

 

I would have damn near killed to get 33 mpg on my 4k mile road trip just completed today. You got really great mileage! For a road trip king like me--I've done four road trips this year already and have another planned in a couple of months--a FWD PAWS RLX is really all I need.

The main advantage to the sport hybrid is the vast improvement in city mileage.

 

And hopefully the handling.......that is why I have been waiting but it seems like a useless pursuit. My '05 RL is getting very long in the tooth. I still love my RL but I have been ready for a new car for quite some time. I was hoping the RLX Would be right for me but the just OK handling is a deal breaker for me. Otherwise the RLX would be great.

I feel very abused by the delay and lack of information about the SHAWD hYbrid.

I like the brand (I have had 7 Acuras since the original one ) but they have have really disappointed me with the way the roll out of the hybrid has been handled. They just seem to keep stumbling all over themselves.it doesn't inspire much confidence in the brand. Little they say about the timing or availability has come true. Then they just clam up. Frustrating for their loyal customers.

 

Here's a couple of pix I snapped during my trip last month:

This one at only 76 miles into a tank ...



... but this one was after 445 miles:



You can see the speed I was going. These were taken three days apart, so they're not the same tank of gas, either! (oh, and I also have it set to zero the trip meter on fillup.)

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I have found that the actual mileage (my calculation of miles driven/# gals) comes out to about 1 mpg less than the Acura readout. This has been true of all four of my recent fill ups. I have about 2,000 miles on the car.

 

I hear people say this all the time (about various cars), but overall it hasn't been my own experience. The computers in the cars I've checked have all been pretty accurate - maybe a tenth or two difference one way or the other.

Given that the computer bases it calcs off of actual fuel flow and miles traveled, the primary opportunity for inaccuracy is odometer error. I've checked my odometer, and it appears to be about 2-3% fast, so I expect at most a 3% error in the mileage calculations.

That said, I suppose at 30mpg you could actually be looking at something more like 29.1, so maybe your own calculations are good.

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A few years back Honda had a class action suit against them for inaccurate odos in 2007. The settlement I believe added 5% to the warranty time period mileage - so 2500 0n a 50000 mile manufactureres warranty.

http://www.bigclassaction.com/settle...settlement.php

I suppose 3% is probably wihin acceptable range but that equates to 1500 over the 5 /50000 warranty.

 

That's been my experience as well.

http://www.fuelly.com/car/acura/rlx/2014/argus/272568