Audi 100 CS quattro wagon
 

I have 1992 Audi 100 CS quattro. EPA ratings are 16mpg for city and 20mpg for highway. I usually get 17-20mpg in city and 23-25mpg. My all-time average is 19.3mpg (60% city 40% hwy). Best trip was 28.0mpg (180 miles with 2 persons, a dog, about 150lbs of luggage, 45mph average speed).

I'd like to get my average over 22mpg and 45mph average trips over 30mpg. What should I do first? I've done all general maintenance and blocked a part of radiator because of cold winters here in Finland.

Specs:
2.8 V6, done 203000 miles
4spd automatic gear box with TC lockup on 3rd and 4th gear
4-wheel drive
0.32cd
~3400lbs curb weight
98E5 fuel (USA "93" with 5% ethanol)
Original 15" wheels with 205/65r15 studded tires

have you aired the tires up to maximum sidewall pressure? Does it have a mechanical fan that you could switch over to electric? Lawn edging air dam and one of the biggest differences you can make is being able to monitor your fuel economy on the go with a scan gauge or mpguino

-My tire pressure is 36psi (2.5bar). Maximum sidewall is 43psi but I don't want to increase pressure as I'm afraid of decreased traction in winter.

-It has two electric fans.

-Air dam could be done.

-On-board computer shows instant consumption and average consumption. Average seems to show +5% mpg compared to real mpg.

Edit. Added more information in first post

Hot air intake.
Air dam.
Tire spats.
Wheel/rimcovers.
Remove mudflaps.
Grill blocking instead of blocking radiator.
Kill switch for engine off coasting
Wheight reduction: remove all unneeded loose stuff out the car.
Go full belly pan.
Cammback
Choose the right roote

In city driving, your single largest area for improvement is timing. Timing traffic, timing traffic lights, even timing stop signs. Try to drive >>SAFELY<< without using your brakes.

How do you time a stop sign? If the stop sign ahead has three cars backed up, let off the gas and coast with the goal of getting to the stop sign as the last car is leaving.

If you are making a turn, try to coast down to the proper speed so that you do not use your brakes.

Even with those studded tyres?

Thank you for advice and ideas :).

First I'll try increasing tire pressure, block the grill and ditch the spare tire and replace it with tire repair bottle. I'll also try to improve my driving :). I will do the air dam in summer.

I don't have any summer tires, so I need to buy them soon. Do you have any suggestions for low rolling resistance tires? The size should be 185-225/60-70r15.

Not sure if I'd feel comfortable getting rid of the spare tyre, but anyway, have you already considered replacing the stock wheels of your car with lighter ones?