What did improve the fuel economy for you?

[jblackburn]

On my new (to me) '99 V70XC I've been thinking about mods that can be done to improve aerodynamics. Driving it on the highway causes quite some wind noise, and probably also lots of resistance (= less MPG). Compared to my old Land Rover Discovery (headwinds make it feel like you're pushing your living room up a hill, by hand, while being hungover) it's much better but the wind noise made me wonder if anyone has experience in modding certain bumper parts, adding skirts, or whatever to reduce the sound and improve MPG?
From previous experience with the Discovery as well I am very sure that driving with under-inflated tyres and a roofrack really put a significant dent in your MPG.

Take a look at some newer MPG-focused cars. Underbody aero panels would almost certainly help. Perhaps a chin deflector. Some cars even go as far as to put little 2" wind deflectors in front of the tires.

One thing I would NOT do on these cars is attempt to block off any portion of the radiator. They need all the cooling help they can get.

You may look as far as going to a low rolling resistance tire, although several manufacturers have LRR tires that really aren't compared to others.

[matthew1]

bump

[abscate]

Replace the egg rate grills with waterfalls

Higher HP
Better cooling
Higher mpg
Attract better looking partners

What’s not to love ?

[BlackBart]

Replace the egg rate grills with waterfalls

Attract better looking partners

..wait...does that work??!

[matthew1]

Replace the egg rate grills with waterfalls

Attract better looking partners

..wait...does that work??!

It does. It works along the same principle as this:

2fxas197dva41.jpg (276.76 KiB) Viewed 810 times

[Cees Klumper]

I was surprised that adding a bottle of injector cleaner to a tankful increased the mileage in both our 2001 C70 and 2002 S80 by something like 5%. I always thought of this as a gimmic but it really worked. I maintain the cars according to schedule, so plugs, filters etc are never beyond their 'sell by date'. Since experiencing this a couple of years ago, I now routinely throw it into any new old car or motorcycle I buy. Here in the US I stick to Techron for some reason, in France whatever brand has the best packaging.

[Clemens]

I was surprised that not going into boost whenever possible and paying attention to speed limits improved my mpg... But then, where would all the fun be.

Seriously speaking, along my neverending journey to stage 0 I never noticed anything majorly to improve mpg except for smooth driving, avoiding short distance trips to a store or kindergarten and city traffic in general.
And except for the MAF both of my wagons are pretty much close to stage 0.

[callahanoffroad]

Very interesting thread! I'll weigh in here.

My NA '96 wagon (manual) averaged 24-26 mpg city, and 32-34 highway.

My current '95 NA sedan (manual) does 21 mpg city and 26 highway. All day and night with no variations what-so-ever.

Both were stage 0, well maintained etc.

The '96 had a motronic ecu setup. My '95 has a Jetronic ecu. The ecu difference makes a huge economy difference IMO. Motronic was comparably more advanced. In the '96 octane mattered. In my '95 it makes little to no measurable difference.

The only time the mileage in my '95 goes down is when I turn the A/C on and then it drops to 19mpg all day and night. Hypermilling doesn't work on the car at all. It simply "IS"

It's quite a fascinating phenomenon. Same engine, different ECU setup = different performance. Whodathunkit?

I had looked into retrofitting the motronic to the Jetronic car and it'd be easier to just buy a different car

[Oly850]

The #1 thing a driver can do to save gasoline while driving a 3000-6000lb Swedish brick is to SLOW DOWN. The faster one tries to push (say) an XC90 through the air, the more fuel it takes to push said SUV down the road. This isn’t just linear but exponential. To wit:

https://www.mpgforspeed.com/

[abscate]

Somewhere here I documented the mpg chamge on a T5 at 65 mph vs 60mph. It was something like 25to 28 difference.