lobuxracer

iTrader: (2)

Sure it'll do 30's for imperial gallons. But there are on 14 imperial gallons in the tank. Simple arithmetic - 30 mpg X 14 gallons = 420 miles. Still 80 short of 500. You'd need 35.7 mpg (imperial) to make 500 miles draining the tank 100% dry.

If you look at my spreadsheet, there are a few things you'll notice. Coming down from the Continental Divide is definitely to your advantage along with prevailing westerly winds. Add to this the stops are (save one) very short, so there's no penalty for cold oil or cold cycle operation. Finally, nearly every run was from full tank until the low fuel light came on without any stops whatsoever so these are about as ideal conditions as you can get. I used cruise control to take advantage of uphill and downhill segments equally. If you really play with your speed you can eek out a few more miles, but not a few more miles per gallon. To get a few more miles per gallon, you have to resort to hypermiler strategies.

The best indicated fuel economy I've seen on my F running on 93 octane fuel (not the super oxygenated California 91 octane crap) is just over 28 mpg being VERY judicious and taking my time. Simple arithmetic - 28 mpg (US) * 16.9 US gallons = 473 miles. To just break 500 miles you would need to consistently run at 30 mpg (US). Not going to happen. If you really want to try, just put a 2 gallon gas can in your trunk and go for it. You won't be stranded in the Mojave or forced to buy gas at Fenner off of Goff Road for $6 a gallon (yes, I did this, and I was happy to pay it at the time, but that was a different trip). As great as the F is, I seriously doubt anyone will ever make a 500 mile leg with just the gas in the tank. Honestly, I'd be happy to break 425.

CurryPot

+1

I agree. I've gone from Seattle to Spokane and back on one tank in a Prius, 607 miles at 57.7 MPG. I know how to squeeze the MPG. Driving 5 hrs at 60 MPH can be a challenge! As mentioned, I did Idaho and got 412 on a tank in the ISF, I was about 10 miles beyond the "you have 0 miles to empty" message. Yes, pushing my luck. Now that trip did involve about 60 miles of running around there. I travelled there at 70 MPH with the wife in tow and her horse stuff. I recogn that's a penalty of about 2 MPG if I did not have her on board and dropped it to 60 MPH.

Bottom line, on a complete tank, I doubt if anyone is going to get better than 27 MPG AVG. 16.5 gallons in the tank on fillup in Idao confirmed I was pushing it. 27x16.5 = 446 miles.

And for those wondering why an IS-F owner would be wanting to drive this slow? There is friggin nothing between Seattle and Idao!! The only thing to do is to see how much you can milk out of the IS-F and wave to the police as you go by them doing 70 MPH in a 70 MPH zone. One actually waved back!

archie

Own both an IS350 and an ISF. I know that the fuel economy in the is350 is a bit better than the isf. On a vegas and back trip for me, it can be done on a single tank of fuel. However, when arriving back at home and filling up it will take just under 16 gallons of fuel (avg 31.5 mpg no stops). Over the life of the is350, it seems like the average mpg city hover around 23 and for higway hover around 30.

On the same road to vegas and back is the isf it is a little different story. Home to vegas (about 245 miles) and filling up on arrival i will take just under 9 gallons. Vegas to home and filling up when arriving at my exit will take just over 8 gallons. So in theory 490 miles traveled/17 gallons = around 28.5 mpg. Over the ownership of the isf, it seems like the average mpg city hover around 19 and highway hover around 27.

As for an is250 the only driving experience i have with it are loaner cars. i will say this though that the mileage is crazy good on these cars. you can easily average over 25 mpg highway and at or above 35 mpg highway.

F BOMB

Just a preview of how well I did on my return trip. I'll post a summary once I fill up.

ISFer

iTrader: (2)

Not a lover of "indicated fuel economy. Sorry but if you're relying on that, you could be way off the mark. I'm surprised you'd rely on that method.

Let me explain what I do: I drive some miles (or pardon me , kilometers here in Canada) and put in some gas (liters here in Canada) and extrapolate the kpl to mpg (Imperial) to get the old fashione MPG's (Imperial) that I like the most.
This system doens't rely on something intangible and unreliable like indicated mpg's which can be only moderately acurate at best, but gives me acutal miles driven for the galllons pumped in. And yes I actually spend a few minutes extra to make sure the tank is full (the last gallon or so is difficult to get in but I get it in to be sure of accuracy).

That is a true measure of mpg's not a computer on the dashboard which I know to be only moderately accurate at best.
If yu don't believe it, try it. You'll find a distinct variation every time you measure.
Only way to be sure is to measure actual distance travelled by acutal liter/gallons pumped.

As to whether or not the 'F' will do 30mpg's (US)/ 35.7mpg's Imperial) :

That remains to be seen. If anyone can squeeze it out of the 'F' -- I can. I've put a few miles on a few cars, so if it's possible, I'll do it. Just waiting for a trip long enough to try it.

In any case, whatever it is, good or bad, whether 25 or 35 or 15......one thing you can count on is that I'll let you know right here.

BTW, I use Petro-Canada premium gas. -- 91 octane. How that compares to your "91 crap" or 93 - I don't know. I do know that it runs great in my car(s).

I also said that I'd be willing to bet (a small wager) on whether or not the 'F' would do it or not. I stand behind that too.

'nuff said......More when I've got results.

Cheers
Colin.

lobuxracer

iTrader: (2)

Apparently you failed to look at my spreadsheet. Your pooh poohing the Lexus indicated fuel economy is a mistake. The spreadsheet shows calculated and indicated. They're very close and only terribly inaccurate when you have multiple starts on a tank. When I'm looking at highway fuel economy, I'm looking at indicated from a warm start just before getting on the freeway until I reach my destination which is also only a few miles off the freeway with only two stop lights. So, it's reasonably accurate. Besides, the trip meter mileage and the fuel light never lie. I always reset my trip meter so I can calculate if I choose.

As for anomalies, I once drove from Lincoln, Nebraska to Council Bluffs, IA in my Supra on one gallon of gas for a calculated 60+ mpg. No indicated, just fill up in Lincoln and fill up again in Council Bluffs. Amazing what all downhill with a 35 mph direct tail wind will do for a mileage run.

archie

should have filled her up when you exited the highway to get a true highway mileage number. but either way it looks like it was still a nice run and calculating mileage i bet you would be close to the 30 mpg mark.

F BOMB

I'm inclined to defer to the technology for this leg. Engine fuel metering is precise, at least as good as the odometer you count on. When I fly planes equipped with fuel totalizers, it accounts for every drop passing through the fuel lines.

It's simple arithmetic thereafter. Counting gallons at the pump in my opinion is the least accurate option unless you average a very long trip across two or more fillings.

ISFer

iTrader: (2)

-- Looked at the spreadsheet more than once.....and then again.......didn't like it. -- too big. - atho perhaps accurate.....the indicated mpg's you've admitted can be way off -- Not my cup of tea -- may be yours but not mine.

So as I said - I rely on actual mpg's only. I don't see the point in knowing the indicated since it may be false. Fair enough?

"Pooh Poohing the lexus indicated fuel economy" -- that's your words not mine.
I called it inaccurate just like all the others I've tested. --
In any case, lubux, you've admitted to it's possible inacuracy so what's the problem with pooh-poohing it if that is in fact what I"m doing?
I'm not mincing words when I relate what I think. I tell it like it is and if it's not good enough or acurate enough fo me, I say so.
LOL, don't worry, along with my alleged "pooh-poohing" of the Lex, I have many more kudos for it.......Like I said- I call it as I see it.

BTW, fuel lights can come on at odd times depending on the car's attitude and abrupt acitivity. So I don't see how that would be very accurate either.

It seems that you are content with some incacuracies, and that's fine, but I'm not content.
It's just as easy for me to get the real numbers and not rely on incacurate measurements.

Oh yeah, to get acurate measurements I always reset my trip meter(s). That way I know it's acurate every time.

Don't get me wrong --- I'm not diss'ing anyone .....all I'm dong is choosing for acuracy every time .

As far as tailwinds and downhill is conserned -- I have to agree that it would be even more off the mark. No big secret there mate.
Under those conditions I've noticed that and immediate mpg's would go to max, thereby affecting the average mpg's computer calculation. That proves my point about the system's inaccuracies -- lex, infiniti, that I"ve experienced so far.
Hey if it's good enough for you, then hey that's fine. I"m just saying it's not for me, since it has it's inaccuracies. That we seemed to agree on.

In closing let me say that I appreciate what you've said about this and what mileage checks you've done, but I too have done some -- not enough on the Lex yet, they are to come, but I do know how to check mileage accruately and succinctly which is really what we're talking about here. You can't deny that.

As I said b4, I'll check my mileage (accurately) on an apporpriate trip long enough to get my accuracy, and post.

Thanks for listening, and understanding me.

Colin.