pdaeng

1) Being ironic does not help your situation at all. Cruising in heavy traffic using only electric motor, you can get almost 99mpg. 40mpg is actually way too modest.

2) Using ACC at heavy traffic is not impossible as you said. RX's ACC is full speed ACC. If you dare not to do so, that is your problem.

Last weekend, I went to NYC (way much heavier traffic than Chicago, FYI, I have lived in Chicago City for 8 years), I use ACC all the time and get a 31mpg in the whole trip (about 250miles). I use Normal at first, but when I feel cold, I change to Eco (as the AC is not that strong under Eco). Even use normal, I can get 30mpg all the time.


Also, go to http://www.fuelly.com/car/lexus/rx450h
The average for 16 450h is currently 30.4 mpg, which is about right according to my experience.

pdaeng

BTW, if you only drive short trips, like less than 5miles/trip You mpg will be bad because ICE need energy to warm up.

JosersRX

Thanks again for your input. My commute isn't on the expressways. Cruise control is not an option. I understand you can cruise in EV mode in heavy traffic. However, the car usually switches to engine and high idle while I'm stuck in traffic for long periods of time. So, I can't really tell it switch it to battery when there's no juice left in them. I never use anything other than eco mode. So, again I just don't understand how getting anything over 28mpg is even possible unless you are driving at snail pace barely hitting the gas pedal, windows down, no AC/Heat and not using anything that could possibly use up the battery charge.

ericsan13

You gave a very definitive statement that you should use the ICE as little as possible.

However I do agree with you that you should use ICE during acceleration and then as little as possible during cruising/coasting, which contradicts your previous statement.

gorcorps

That doesn't make any sense. If that were true then there wouldn't be an impact to city mileage on the hybrids (stop and go traffic where you're accelerating from stops constantly). Since the biggest impact to mileage is to city driving, we know that's where the electric motors make the biggest impact.

ericsan13

I am not sure that I get it either - this is just what the prius forums said.

I think they said that gas is more efficient at acceleration, while electric is more efficient when cruising. What I think helps most in city driving is regenerative braking, the engine turning off when idle, and low wind resistance. I will watch the video above tonight.

AZisHOT

First tank - very gentle while breaking in the engine - 25.5 mpg. But, I have to admit to a whole lot of sitting in a running car playing with all the tech.
Third tank - still not hitting it hard - 22.4 mpg. Keep in mind we're talking 110+F driving conditions, mostly stop and go freeway commuting.

My altima hybrid (toyota hybrid system in it) was 100% linearly MPG/outside temp related. So, I'm hoping for much better results as the outside temp comes down to merely "really hot".

What tire pressure are people at? I'm running at 40 now, probably go up a few PSI.

Curryolla

Hmm...25.5 is not bad (OK, I guess), but 22.4 is terrible. This guy in Arizona is seeing 105-115F temperature and is getting 27 mpg, but he does have a base model RXh.
Personally, I would not risk going 5 psi or more over the recommended value. It is also important to consider that higher tire pressure may yield better MPG, but at the risk of far too many things. The ride will be harsher, the tire wear may be uneven, and the suspension takes a beating. Also, a reduced contact patch will increase braking distances!

What some people don't seem to understand is simple Ideal Gas Law (PV=nRT). As the Temperature (T) increases, the Pressure (P) increases. So...as you drive down the highway, the friction makes the tire hotter and increases the PSI. Add to that the fact you live in Arizona and conditions may be a bit dangerous for you. Just my two cents.

AZisHOT

Yeah, I get the PV=NRT, with a master's degree in engineering, I've run across it a few times

Tire traction is a curve, with the best traction happening right near the listed max inflation pressure (both cornering and braking). In this case, that's 51 psi. Typical heavy vehicles run best around 40-44 psi for wear. We'll see with this vehicle/tire combo. The F Sport has much firmer cornering, so the sidewall scrub should be reduced - another factor to look at when setting tire pressure. Years of SCCA solo II have taught me how to set tire pressure for performance, I just don't have the long term wear experience with this vehicle yet. Eventually, I'll see if the shoulders or the center is wearing faster - that will indicate which way to go with the set pressure. I was just hoping to get some heads-up from someone with more than 800 miles on their tires.

The recommended pressure is 33 psi, with a caveat that if you drive really fast (I forget the mph number), then up it 11 psi more = 44 psi. Not saying I drive fast , but I have no fear of being above 33 psi...

Some tires do heat up and increase in pressure much worse than others. The great thing about the TPMS is that you can monitor that and account for it. I'll get a few PSI difference cold-to-hot, about normal. I had a set of Kuhmo's on my corvette which would go up 6 to 7 psi cold-to-hot. They were actually really good tires, but that could cause problems if you don't account for it...

As for mileage - well, as you may be able to tell, performance is just a bit more important to me than mpgs. I definitely bought the hybrid for mileage - but the performance bump (and the F sport suspension) doesn't hurt either!

Curryolla

Good to hear you know what you're doing! Some of the things I read online just drive me nuts! Keep us updated on what you see with tire wear. I'm curious about running the car around 40 PSI.

Seeing as you're somewhat of a tire pressure "expert," are you running your font tires at a higher pressure than your rears, to counter the corner scrub. I've been doing that in my FWD Honda Accord and it does seem to have benefits all around.

I'm surprised that the RX is recommended at 33 PSI. That does seem a little on the low side but Lexus may be prioritizing ride comfort over performance.

AZisHOT

I'm hoping to take it a bit easier on this large vehicle - so tire wear should be more even

One of the simple tricks is to buy some white shoe polish - the kind with the sponge-looking applicator on the bottle - and mark the edge of the tire you're looking at. Usually at a few (3 or 4) spots around the circumference. You don't have to go nuts with it - a nice solid dab right on the shoulder where the scrubbing occurs is all you need. Then go have fun. Check to see how far down the wear is. Repeat with various air pressures and optimize each corner individually.

You can also mark the inside shoulder too - that will tell you how much you need to crank in negative camber to make the wear more even inside/outside. Of course, that is overkill for an SUV, and you'll never be able to put in as much negative camber as you need to balance off the weight of a SUV. If you try, you likely run out of adjustment room, as well as set up a pretty hairy alignment for normal road use. Plus, you'll have to make friends at the alignment shop to get them to set the camber that far off stock...

As for your honda, it sounds like you are helping to reduce the scrub, or roll-over, with higher pressure, and the fact that you have better traction at higher pressures also adds to that increase in control. But I think we have digressed pretty far from the mileage topic....although I do agree, higher pressure is better for mileage too.

Hope that helps.

roadrider

1st tank of gas - eco mode, 70 MPH mostly trip over Snoqualmie Pass from Seattle area to Coeur d'Alene, Idaho we got 26.9 MPG
2nd tank - Premium - eco mode, 70 MPH back over the pass we got 30.1 MPG

I drive a Prius, so am familiar with hybrid increased MPG techniques.

SurfCat007

I bought my new loaded RX450H specifically for the mileage listed. I gave up my BMW 750IL which was getting 16 city/22 highway (which got better mileage highway at 85mpg then 65mph) in search for better mpg.

​This RX450H is only getting around 14mpg city, and maxing at 24-26 highway. It gets much worse at speeds over 75mpg (like 23/24 at 85mph). I'm regretting the purchase.

As most of my driving is around town, the 14mpg avg around town is hugely disappointing, especially when it's advertised at 30mpg. I've tried all modes (eco, normal, sport) and no real difference. I've tried driving like a grandma/limo driver and just normal light footed driving. No real difference.

I live in Southern California, by the beach. Climate is mild. All streets are flat (no hills). Gas is premium. Summer fuel mix. What gives?

Oldfart

Maybe it is not switching to electric and keeps on using gas engine? 14mpg is what you'd get using gas not electric. I'd take it to dealer.

linkmant

I am European and my Lexus RX450H official figures are 5.5 l/100km (42,77 mpg). But i am getting close to US official figures of 30 mpg which seem much more realistic.
Tried both Eco and Normal. Eco did not provide superior economy just frustrating driving and NORMAL was a good balance of fun and economy of 30 mpg
In the beginning i made mistake by trying to start off in EV mode for as long as possible but that used to deplete the battery quickly and the engine motors kicked.
Now i use EV mode to move the car till 6 mph from at green light and then accelerate normally to desired speed and lift off pedal and touch it again and EV mode activates automatically and I gently press it to maintain the speed using EV only. If conditions change and the uphill is upfront i do not put any load to EV and straight accelerate uphill and once reached decelerate and keep gliding in EV mode and if i need extra power the slightly press accelerator but no to exceed EV more.
I was pessimistic to the whole hybrid physolophy and did buy one as the other option in Europe was 200t engine which maybe was powerful but also very high consumption.
In the end i am happy with 450H as it one of the most versatiles vehicles on market. When i was to save fuel i can, but when I want to have fun i can do so but avg consumption drops to 17 mpg. It is all up to me
https://www.clublexus.com/forums/new...te=1&p=9591550