Does anyone know the most efficient gas mileage speed for the LS430? I would have thought it would be at 60MPH (100KMH) but I don't really know.

Thanks.

 

Not sure but I thought it was 55mph.

 

Too slow for interstate driving; in the 50-60 mph range though. The last time I drove my '02 to Florida (about five years ago) I got 27-28 mpg driving at 70-75 mph.

 

I find 70-75 also to be the best for my comfort zone in the best MPG range for interstate.
will be travelling to Tuscaloosa this weekend for the first Bama game so I will see what MPG she gets after tires/fluids check and car wash/wax.

 

Actually, 40 mph is probably about the best. But, who cares. Just drive this baby at the speed you want to and forget about saving a few bucks. Enjoy the car!

 

What I noticed is that driving up to 3000 rpm and taking easy on the throttle is giving me the best fuel economy. At 3k rpm the speed is 90mph - more than enough for highway driving. Tried the same route driving fast, lead foot syndrome - quarter tank's gone. Drove nice and easy up to 3k rpm - less than half a quarter used. More than twice the economy. Our 430's have great low end torque, you can drive normal in the city with no more than 2.5k rpm and get good pick up and 15+mpg.

 

I get 29-30mpg on the highway doing about 65-90mph as long as you don't floor it from a stop youll be ok city I'm around 17-22mpg

 

long term mpg on my car is 22.1 right now mix of gentle street and hwy use. Going 60-70 on long non hilly runs seems to run avg 26 mpg

 

I drive 80% clear level freeway at 70-75 mph. Last tank avg. mpg was 25.6 per the dash, 25.9 calculated on fuelly.

 

The EPA estimated 25 MPG (hwy) for the LS 430 seems WAAAY conservative to me. There doesn’t realy seem to be much of a “penalty” mileage-wise, for driving it at speeds of 70+ MPH on the open road.


I took 2 long road trips with my ’05 LS this Summer.

TRIP # 1: Minneapolis to Green Lake, WI. 603 miles roundtrip
- 1 tank of fuel
- Mostly Interstate
- Passenger + me and our luggage
- A/C on for full trip
- Cruise set at 70 MPH
- Averaged 27.5 MPG


TRIP # 2: Minneapolis to Custer, SD. 1,228 miles roundtrip
- about 2 1/8 tanks of fuel
- Mostly Interstate.
- Passenger + me and our luggage.
- A/C on for full trip.
- Speeds ranging from 65-75 MPH in MN to OVER 80 MPH across SD
- Still got 26.3 MPG!!

I do agree that gradual/moderate acceleration is key to getting the very best mileage. Just a few quick full throttle indulgences will knock a huge hole in your fuel economy.

.

 

The best that I have done is 26 MPG averaging 74 MPH. What would we get at 55 MPH? (does anyone drive that slow?)

 

on a 1000 mile trip on flat ground I set the cruise at 63 and finally reached 28.3,, on the same return leg I tried 68 and it hung around 27.4,, no wind in either direction according to the flags along the route,,

have never tried the below 60 experience,,

Derry

 

The "most efficient" speed is probably the lowest speed one can go in the highest gear without lugging the engine or downshifting. My guess - in my 2006 6-speed 430 LS - is between 42-44 mph when the rpms are about 1200 in 6th gear. Of course, with all accessories "off" and tires at max safe tire pressure... I'm not that puritanical, however, and still get 28 to 30 mpg at Interstate speed of 70 mph even with the AC! Above 50 mph the EPA and others suggest that each 5 mph adds about 5% higher fuel usage due to aerodynamics. That seems about right to me. That suggests that if you get 28 mpg at 70 you would get about 32.2 mpg at 55 mph or perhaps as much as 35 mpg at 45 mph if you extend the rule of thumb downward. Considering the weight and the comfort of the LS that's actually pretty darned good, in my opinion.

 

Hard to go 55mph in the LS on the highway. The car glides/rolls so well, it seems to want to go min of 65-70 on the hwy and sometimes a little more : )