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Discussion Starter #1
Although I realize that gas mileage may be a minor concern for a sports sedan, I wonder why the projected mileage is so much lower than any car in its class. Have the real numbers been released yet? I would expect to see something in the 19/27 range, unless the gearing is so low that it cannot achieve good highway numbers. Any theories as to why it is projected so low?
 

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I have been wondering that myself.

I had reason to believe that the 18/23 were preliminary, but so far everyone else (Edmunds, etc.) are reporting the same numbers. Lets hope that it isn't that bad.
It would be surprising for the IS300 to have worse gas mileage than the heaver GS300.
 

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Discussion Starter #4
According to the window sticker on page 5 of the gallery, the mileage is still 18/23. The GS300 is 19/24 and it is heavier. Even the Toyota Sienna minivan gets 18/24 with a 4 speed auto and 500 extra pounds. I would expect a car of this size and coefficient of drag would get better highway numbers. Are Toyota's engine management systems not as advanced as BMW's, Honda's, and Audi's?
 

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The Gas milage on my GS400 (according to www.lexus.com)is 17/24. My car weighs more than the IS, is slightly less aerodynamically efficient, and has a 4.0 liter 300hp V8 engine and the fuel economy is 18/23..... My dad's 4,300lb 740iL BMW does better than that on the highway... My sister's A4 2.8 Quattro does 27mpg on the highway (and that's with all the added hardware of ALL WHEEL DRIVE!!) ... This has got to be a mistake.. What gives?
Eric......
 

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We all have to take into account that the mileage is determined by EPA test cycles. They may not necessarily reflect real-world (i.e., YOUR OWN PERSONAL) driving habits.
 

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yes I understand what you're saying but the EPA does in fact quote 17/24 for the GS400 and 27MPG on the highway for the Audi A4 2.8 quattro..... You would think that EPA would quote a higher figure for the IS300 than the GS300...
Eric....
 

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HOWEVER... The BMW 528i Automatic is rated at 18/26..... The 328i Automatic is rated at 18/27... Hardly a difference there.. But Still 23mpg on the Highway isn't that nice. I guess engine efficiency and gearing play a part...
Eric....
 

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It just might be that Lexus is conversative about their mileage estimations and that BMW and other car manufacturers are optimistic. For example, I have a friend with a 2000 328 automatic, and she has been getting around 18 mpg.

I currently have a 95 Camry, and its mileage is supposed to be 22/28, however I've gotten 29-30 mpg on the freeway; lately, I've been driving all city, and I still get around 24-26 mpg. This is with aggressive driving too--or as aggressive as you can with a 4-cylinder Camry. 8^)

--k


[This message has been edited by chiem (edited June 03, 2000).]
 

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It says 18/23 on the factory sticker. I think the mileage on those stickers is standardized by the EPA, so I doubt Lexus is putting down overly conservative numbers.

Although I am baffled, my guess is that maybe one of these things is hurting mileage:
1> Engine tuned for "certfied low emissions" which might include extra rich warm ups to get the first catalytic converters up to best operating temperature. (that shouldn't hurt the hiway mileage though)
2> High performance tires are causing some excess rolling resistance?
 
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