Hi

[Sgt_K]

Hi, I am an American service member living in Germany. I have a 40 mile round trip to work with about 95% of it on the Autobahn. I drive a 2007 Lexus IS 250 with a manual trans, the crazy thing is the automatic cars get better mileage than the manual. The car is rated for 29mpg on the highway, I mean autobahn.

Anyway, I am getting 31 to 32 on a warm day going back and forth to work at about 65mph. I replaced the stock 18 inch wheels with 17's removing almost 50 pounds from the drive train. I also blocked off the huge rear grill, pulled back the rear view mirrors. I removed the spare tire, removing another 35 pounds from the car. I also changed out the stock air filter and intake pipe to a K&N filter and a aluminum intake tube, which makes a nice warm air intake and I run synthetic 5w-20 engine oil.

My future plan is to replace the very heavy stock drive shaft with a light weight carbon fiber unit. Install a light weight battery, the stock one is almost 50lbs. Change out all the fluids to synthetic and finish what the factory started by extending the stock belly pan from the back of the oil pan all the way to the rear of the car. I would also like to change out the final drive gear, its 3.73 to the European IS gear ratio of 3.00 to drop the RPM's while driving on the autobahn. Right now the car sits at 2500rpm at 65 mph, kind of high for a V6. I am also debating about putting on rear wheel skirt, but I really think the car will look silly. Also the stock cd is .28 according to the Lexus home page.

Anything else I should think of doing?

[Daox]

Well, driving slower would probably help you most. But, I realize that may not be possible. Pulse & glide would greatly help you out.

For mods, the regearing would definitly help as well as any aero mods for the speed you are driving. Check the list of 60+ mods for other ideas.

What do you mean by a rear grill?

[Red]

Kewl

2.5k is bit high for a V6. Most six poppers spin around 2-2.5k at cruise

[MetroMPG]

Welcome to EcoModder.

Sounds like you're already forming a decent plan . I agree that (aside from driving technique) aero mods & gearing are where you'll see the biggest gains.

About those automatics: they may be rated for better efficiency, but in real life a motivated ecodriver can do much better with a manual. More options.

[Sgt_K]

Sorry, that was suppose to say "block the huge lower grill".

I agree that speed helps a lot, I set the cruse at 65 and I draft and pass the trucks on the autobahn. There are a few spots on my drive home with a very long high sloping grade so I take the car out of gear and coast. One slope is over a mile long and I usually pick up speed and a few tenths of a mile per gallon.

The cool thing with my car is that it has a display with over all gas mileage, current tank mileage, and an active bar graph gauge that is updating in real time, kind of cool.

[groar]

Hi, happy to see someone in Europe

Your tires are of course pumped-up at sidewall My coasting in neutral is a brand new experience since I pumped-up my tires at near sidewall. My wife also appreciate it.

I had to improve my driving techniques during 2 months to equal the single tank I made with rear wheel skirts. I didn't mind about the look, but I understand that on a luxury car your prefer having clean aeromods. My wife and I are sharing our cars and she doesn't want to drive with non-clean rear wheel skirts

From these pictures I would say :

• transparent material behind the fog lights
• flat hubcaps
• rear wheel skirts
• fill-up upper part of the hole around the door handles
• wiper deletion, or masking them to remove them from the air flow when not used.

Denis.

[Sgt_K]

I don’t have the tires filled to the max. The door sticker says 35 in the front and 38 in the rear, but I run them at 40 all the way around. The wiper blades are actually very recessed in the cowl, they look like they are sticking up more in that picture but from behind the steering wheel it is very obvious that they are not putting a lot of drag on the car. I like the idea of wheel covers, but it would have to spend a lot of time making them, I am not about to slap some cardboard on my car. I am also considering lowering the car too.

What do you mean by "transparent material behind the fog lights"? The fogs are flush with the bumper and the black area on the next to them is a piece of black plastic, the Japanese lens covers the entire area but the US spec car has a different fog lamp.

[groar]

Originally Posted by Sgt_K

What do you mean by "transparent material behind the fog lights"? The fogs are flush with the bumper and the black area on the next to them is a piece of black plastic, the Japanese lens covers the entire area but the US spec car has a different fog lamp.

When I look at the pictures, the bumper isn't drawn with a single convex arc. It has a concave part around each fog lights. But thinking about it, this may prevent some air to go under the bumper directly to the tires...

My lack of aerodynamic knowledge will never permit me to say what is the best.

Denis.