jhumbo

I have a very specific MPG question for all of you. How many miles per gallon do you typically get (not your best ever or anything like that), when you are cruising on a long highway trip (100 miles or more) at 70mph or 75mph. Please answer in the following format. I'll start with my 04 TL as an example.

Car: 04 TL (please specify if you have a 250 or a 350 and note the year)
Cruising speed: 70mph - 32 MPG
Cruising speed: 75mph - 30 MPG

I'm considering an IS and am curious what the MPG spread is between a 250 and a 350. Your help is appreciated.

Jake

2006 IS 350:
70 mph: 28-27mpg
75 mph: 27-26mpg

edgeucated

iTrader: (4)

Car: 06 IS350
70 mph - 27 mpg
75 mph - 26 mpg

KillaIS250

iTrader: (1)

Well it's more then just the speed of the car, if you're driving in a hilly area you'll get less MPG then a car driving on mostly flat or downhill roads.

I haven't really measured the difference in MPG between those 2 speeds, but going about 70mph on a road trip I took a while ago I got 33MPG for the whole tank (calculated MPG, not computer read out). That was driving up hill half of the way and then downhill the rest of the way. Constant Up hill driving will really put a noticeable drain on your mpg.

So...

07 IS250: 33MPG @ 70mph

Kurtz

iTrader: (1)

Yup... driving back from a mountain trip (coming down hill a fair portion of the trip) was the only time I got over 30 mpg.


I don't keep records (or drive that way) to tell you the difference between 70 and 75.

I'd say on a "typical" long highway trip though my typical IS350 mileage is in the 28-30 mpg range


There's several insanely long threads already existing on mileage, so I can tell you right now the "typical" mileage difference between the 250 and 350 (assuming both automatic RWD) is around 10-15%... which is pretty "cheap" given the 50% difference in horsepower.

don

iTrader: (2)

I went from Tahoe to Oakland, about 200 miles in my 350. On cruise control around 75, i got 34 mpg. That's the computer readout, not my actual calculations though. It was a lot of downhill and flats.

bob4256

iTrader: (17)

The best Ive gotten was 32.8 MPG (calculated, car computer said 38) and I was going 60mph with the cruise on for 95% of the tank.

Ive driven about 70% of the a tank of gas at 70 mph with the cruise and I got 28ish MPG (calculated, car computer said 33).

These numbers are without using A/C and while dropped on 20s

UniSlayEX

I completely agree. You need to factor the roads you’re driving on. A majority of my long trips are very hilly roads so it varies. I like to put cruise control on and let the car do its thing on long trips.

So:

2008 IS 350:
70 mph: 28 mpg
80 mph: 26 mpg (I know its not what you asked but 5mph is negligible)

echrist0

On a recent round trip from Kansas City, MO, to Des Moines, IA, pretty flat country, I drove at 80 almost the entire way in my IS 250 AWD, and averaged 31 mph (calculated).

jhumbo

Thanks all. This is helpful information for me.

I read through a few of the mileage threads and it seems that the 350 is worth the slight sacrifice in mileage, but I just wanted to ask the same question in a more specific way. I care a lot about mileage when highway cruising. I pretty much could care less about city MPGs. Give me a car that does 40 MPG highway and 15 MPG city and I'm okay with that.

Icy350

iTrader: (18)

i really want to know how everyone gets such high milage... I cruise like 70~80 for a 200 mile trip and my avg was 22MPG...
My city driving which i do daily i get 15MPG.

06 IS 350.

I live in Queens NYC.

kumquatism

iTrader: (10)

It was a while ago, but I remember doing several trips from San Jose to San Luis Obispo (roughly 185 miles). i clocked in around 30MPG. I don't remember my actual speeds, but I generally drive 70-75 on long trips. Dash readout was like 32-33MPG I believe. Car is IS250 manual transmission

circuitt

iTrader: (3)

Is350 on 405 (all freeway) 23 miles each way daily commute.

70mph = 28/ 29 mpg
75mph = 28 mpg
80mph = 25/27 mpg

GoGiantsNJ

I just bought a new 2012 IS-250-AWD for my Wife in Maryland. We drove it home to South Jersey in rain between 60-70 mph,and to my amazement I calculated 26 mpg at fill up(close to the dash computer calculation).
A bit more than my 2012 RX-350-AWD that I have for nearly a year already.

soupdawg

drive between san jose and los angeles a lot. with my 350 i was getting ~27 usually going 80-95.