bclexus

I haven't taken even a short trip yet of any distance in the GS 450h, so I don't yet know what to expect in terms of open road 70-85 mph driving gas mileage. I've only driven in the city with a goodly amount of stop-n-go driving which includes complete stops - and getting out of the car.

After refueling (fill-up) the multimeter displayed the driving range of 380 miles, but I don't know what that mileage is based on - maybe data already logged? Does that range compare about the same as your GS 450h after filling up?

Before filling up I always reset everything (mpg/speed) - though it's a little different resetting everything in the GS 450h compared to the GS 350, so I may be missing resetting something.

After refueling and driving around aimlessly for 30 minutes or so my 'after refueling' mpg was 34 mpg in Normal drive mode, probably averaging just 20-30 mph. Is that about what you see?

dkp993

Have had my ‘16 H for a little over a year. I commute 25-30k miles per year. Every full up I do I manually calculate my mpg. The vast majority of the time I average 30 to 31mpg and get about 420-450 miles out of tank. Mixed driving but on the freeway I’m usually going 80mph so I’d imagine if I drove closer to 70 I’d get a few additional mpg’s. After a fill-up my gauge usually says I have 505 miles of range.

bclexus

That's a big difference (380 miles vs. 505 miles). Apparently the range is based on data recorded that I didn't reset.

bclexus

I think I needed to clear (reset) the consumption data for both the 'Trip Information' and the 'Past Record' in 'Fuel Consumption'. (Rather convoluted compared to the GS 350!)

peasodos

iTrader: (1)

If you up-sized your tires The MPG, odometer, and speed, will all be off by some degree. The best I got with normal size tires was 36 mpg on a 240 mile trip. City obviously depends on how easy you are on the gas from a stop. ECO mode is actually useful in city driving.

bclexus

I still have the OE 235/45R18 Michelin Primacy mxm4 94V (500 Treadwear) tires on it. They have less than 6k miles of wear and appear to be wearing well. I had the alignment checked and it was nicely within specifications.

When it's time to replace the OE tires I'll likely replace the Michelin tires with one upsize like I had on the GS 350 - the Pirelli Cinturato P7 All Season 'Plus II' tires in 245/45R18 100V XLBSW size. Hardly much difference in circumference/diameter, making only a 1.3% (0.94 mph) difference at 70mph and 10 less revolutions per mile.

703

12km/l is the worse economy I got on mine. Short distance city driving no highways.

The range is inaccurate. Have never depended on it. It’s always an overestimate on all my Lexuses.

bclexus

I think your 12km/L works out to be around 28-29 mpg. That's what I'm getting (up to 30 mpg) with stop-n-go city driving, probably averaging just 15-20 mph. That's double the lousy 14-15 mpg I was getting with the GS 350 with stop-n-go city driving. I'll take double the mpg with the GS 450h!

bclexus

280 miles driven since last refuel - all stop-n-go city driving averaging 15 mph - 29.5 mpg.
So, why is my fuel gauge showing a half a needle width under ¾ full? I know I didn't drive 280 miles (that mileage is accurate for miles driven since my last refueling) on just ~4.5 gallons of gasoline (~25% of 17.4 gallons = 4.35 gallons). The mpg (if it really means per gallon of gasoline) must not be computing correctly. But...30 mpg is what should be expected from city driving in the GS 450h.

4.5 gallons x 30 mpg = only 135 miles, not anywhere even close to 280 miles which is the accurate distance I have driven since last refueling. How can the fuel gauge be reading almost ¾ full, and thus having used only around 4.5 gallons to travel 280 miles?

• The 280 miles driven since last refuel is accurate. ✓
• It appears the fuel gauge (at ¾ full) is about right based on my familiarity of filling up a GS 350 fuel tank. ✓ (It will probably take about 5 gallons to fill-up.)
• The 30 mpg fuel mileage displayed is about what should be expected from city driving in the GS 450h. ✓

So, where is the error in the summary?

703

Are you only on your first tank of gas? Sounds like fuel gauge is not linear. The mpg reading should be fairly close as it’s based on injector pulse width.

bclexus

When I got the car it had about ¾ tank of gas. I drove it a few days and filled up. I reset the trip data and consumption data, and I reset odometer A to zero which is a habit I do when filling up.

Today, odometer A is almost 300 miles since I last filled up. MPG since last refuel is about 29.4 mpg with 100% stop-n-go city driving, averaging a speed of 15 mph. The gas gauge is a little under ¾.

Here's some pics I just took so you can see the data I'm talking about.

I can't make sense of the mileage driven (~300) and mpg (~29.4) since last refuel with the fuel gauge registering close to ¾ full. That means I've used only about 5 gallons of gas to travel ~300 miles! That's 60 mpg, which is not possible! Something is amiss, but the only data point that seems to be flawed is the gas gauge.

Yet, as for the fuel gauge itself, I'm plenty familiar with both the 17.4 gallon fuel tank and the gas gauge on the GS 350, having owned a 4GS for many years and oftentimes filling up the tank with 5-7 gallons of gas when the gauge registers a little less than ¾ full.

Additionally, if I have 5/8ths of a tank of gas (~12-13 gallons) and I'm getting 29.4 mpg (which stands to reason is quite accurate), then why is my projected range only 246 miles? It should be about 350-370 miles (29.4mpg • 12.5 gallons = 368 miles.



It's got me confused!

703

Yea that doesnt make sense. Your gauge should be reading lower based on distance traveled and mpg.

bclexus

Yep, agree!

When you figure it out, please let me know.

dkp993

I will say that while not as exaggerated as yours my fuel gauge seems to be top half heavy too. While I’ve never taken the time to measure it there’s no question the first 1/4 tank reading lasts far longer then the last 1/4 tank. As I mentioned prior I drive a lot and pretty much alway run my tank to almost empty prior to refilling. But the gauge reading I’ve absolutely noticed before.

Im2bz2p345

+1 - Can confirm this.

~ im2bz2p345