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Steve

Fuel Consumption On The Sc400

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Does anyone have any links where i can see tech specs on the SC400 such as Fuel consumption?

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It depends on the year, 92-95 18city-23hwy 19-24 for 96-00 (not sure for HWY). Over the years the mileage and HP got better.

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It depends on the year, 92-95 18city-23hwy 19-24 for 96-00 (not sure for HWY). Over the years the mileage and HP got better.

Does the 18 City/23 Hwy jive with everyone's personal experience? I just read where a 400 owner reported 30 MPG on the highway. 23 seems a bit low, considering that C5 'Vettes and LS1 Camaro's get 27-ish on the highway with 2-valve motors and almost two more liters to feed.

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i also heard somebody claim upper 20's mpg with their LS400(yea right!!) and honestly i think it's either bs or poor math skills. fuel consumption is affected by many factors including driving habits, quality of fuel (93 octane does vary from region to region), vehicle condition, etc...even driving too fast has a negative affect on mileage. i recall reading that optimum driving speed is 40 mph, in terms of fuel consumption, since faster velocity = higher shear stress = larger drag forces. then again, those mileage ratings are figures from toyota and most of us have a hard time realizing those numbers in real world conditions B)

Migirdech:

http://www.fueleconomy.gov/!Removed!/driveHabits.shtml

As you can see in the graph the ideal speed is about 45mph-55mph. About having MPG in upper 20's, wish I could get that much in city or hwy. But then again I have 146,000 miles. But there are alot of people in LOC with very low miles and with excellent maintaince history, they might get that much. Also www.fueleconomy.gov shows that LS400 should get 18mpg city, and 22mpg hwy.

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i also heard somebody claim upper 20's mpg with their LS400(yea right!!) and honestly i think it's either bs or poor math skills. fuel consumption is affected by many factors including driving habits, quality of fuel (93 octane does vary from region to region), vehicle condition, etc...even driving too fast has a negative affect on mileage. i recall reading that optimum driving speed is 40 mph, in terms of fuel consumption, since faster velocity = higher shear stress = larger drag forces. then again, those mileage ratings are figures from toyota and most of us have a hard time realizing those numbers in real world conditions  B)

Migirdech:

http://www.fueleconomy.gov/!Removed!/driveHabits.shtml

As you can see in the graph the ideal speed is about 45mph-55mph. About having MPG in upper 20's, wish I could get that much in city or hwy. But then again I have 146,000 miles. But there are alot of people in LOC with very low miles and with excellent maintaince history, they might get that much. Also www.fueleconomy.gov shows that LS400 should get 18mpg city, and 22mpg hwy.

Good source.

Migirdech:

I'm getting upper 20s on my high-mileage LS400. Let's see, it's the LS400, and most of my friends call it a grandpa-mobile, so I drive mine like a grandpa would, with an occasional burst to make sure I'm still alive. <_<

Oh yeah, 93 octane doesn't vary from region-to-region. Different companies offer different chemicles with their fuel. The most efficient fuel being used is from Shell, and the Feds use Shell for DOT and EPA ratings.

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Fuel consumption in earlier SC is lower compare to the Chevys mentioned above. Corvette and Z28/T-AM barely idle at 60MPH compare to the SC (earlier model). SC400 has aggressive (some what) gearing to better the performance, which is a trade off for less MPG. My ‘96 average 20 in combine driving in Washington area traffic with plenty of spirited driving so that is consider very good for its weight and HP. Gas mileage varies with condition but its respectively ranged. We had '90 LS since new (not now) and it averaged about mid 20's on HWY so upper 20's may be miss calculation or the mileage was achived at 40-50mph on route 40 in Texas where its flat flat flat flat :rolleyes:

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No, I haven't miscalculated the figures. I'm averaging 28mpg, and I drive in the "Washington area traffic with plenty of spirited driving"[sightdev's comments]. My mode average is 70mph and I stay in the right lane most of the time--unless passing. My dad owned this car before me and he was averaging 26-33 (mostly highway mileage).

Migirdech:

What makes you think auto-manufacturers make unreasonable mileage ratings on the sticker? The factory drivers are trained to take the most aggressive drivings numbers for the sticker. The average person will range near those figures, and the over-achiever will beat those numbers.

Sightdev:

I agree with your logic, where to get the best gas mileage, but I don't agree with the "miss calculation". Flat land, especially in the Texas Desert helps stabilize, weight dynamics including weight dist., lag, several engine combustions and Latitude, but what most people don't understand is when you press on that throttle, you are leaving a constant speed, and applying more torque--more combustion, and a change in the weight dynamics of the car. There are more factors that apply towards this statement, but I don't have time to go over them.

Just in case you're wondering what makes me an expert on this subject, I am a qualified SCCA and FIA Driver. Experience on the track and in the field makes me an expert.

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After a year with my SC I'm getting an overall average of 17.91mpg (doesn't include NY to SF road trip). When I drove from New York to San Francisco (about 4,500 miles in near perfect conditions - temps in the high 40's to low 50's and interstate driving at 75mph) my average was around 23mpg. My LS managed an average of 24mpg on the trip from Houston to San Francisco but the weather was in the high 60's to high 80's with mostly interstate driving at about 75mph. Now my LS is averaging 17.75mpg over the last seven tanks but I only have a 30 mile round-trip commute with quite a bit of traffic.

:)

P.S. I'm not disappointed with those numbers. Having owned a bunch of big trucks I'm quite happy to be in the high vs. the low teens!! The power difference between the LS and the SC makes the 0.16mpg difference in the SC's favor easy to live with!

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I average about 20-21 in mixed city/highway driving. On my last road trip to Dallas I got 26MPG. This is not the best nor the worst MPG of cars that I have owned. Our gas mileage is not that bad being a V8 and geared for performance. My CL Type S gets about 25-26 in the city/highway mode and 31 on the highway, but it is at 2,500 RPM when I am going 80 on a road trip.

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hm...nice numbers, i'm getting 12mpg...some thing is wrong...all tuned up too...oh well, gotta live with it

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On returning to WA from TX, I tracked my mileage pretty closely. Of the sectors I kept the slips for, I got the following gas mileage results:

26.2 MPG

25.8 MPG

25.7 MPG

23.4 MPG

26.6 MPG

Most driving was done with the cruise set to 75 MPH, (The speed limit on most of the trip) except for when I had to brake for idiots driving slow in the left lane, and the 55 MPH stretch through Denver. I drove ~23 hours/day, and encountered little to no traffic, stopping only when I needed gas/food/bathroom. The low MPG was through a mountain pass in WY, so the results are as one would expect. I would also expect to be able to break the 29 MPG mark if I were to have set the cruise at say, 60 MPH. I also had some "moments of indiscretion" where I let her rip up to about 110 or so while listening to Santana's "Europa.". All in all, pretty good for a car that is only rated for 22 Hwy, but I could have done better with more self-control. At least we know what the car is capable of.

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On a long highway trip of 500 miles I got 22mpg in my SC400 with an ave speed around 70 mph. Later, I put in mobil one 5W30 with prolong, iridium plugs, and a foam FX air filter and got 26.7 mpg on a 750 mi hiighway trip wiith an ave speed of 70+mph. I don't think it was poor math or just the above changes; proper tire pressure, temperature conditions and a good tail wind probably helped. There was little mpg change, if any, for city driving.

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The Ram FX foam air filter(approx $16) was obtained on Ebay. The sellers were accomodating and had good feedback with quick service. Go to Ebay automotive parts and accessories and search under Lexus SC400 filters to see if they are listing more filters. If you can't find them let me know and I'll try to find their website for you.

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