Help with improving my fuel economy (Ford Mondeo Zetec 2008 2.0 Petrol 5 speed
 

*If any of my questions are answered anywhere else, please point me in the right direction, thank you

I've started a job that's actually a bit of a drive (for me in the UK anyway). It takes about an hour to get there if I leave early and miss most traffic. Just over half of the distance is on motorway, about 17 miles. I've been doing 60mph on there cruise control because I almost never have to change speed as the limit is 70. I was going to try 55mph and see how it affects it when I refuel, but so far my MPG is 35.8~. I also do shorter distance driving around town for my other job which is closer, and shopping.

I was wondering how high I could effectively get my MPG if I used other techniques for this car, and what they would be? There's a lot of traffic when I finish work, but I try to miss it by going gym after work and miss maybe half the traffic.

Specific questions would be:

Is it more fuel efficient to speed up to my preferred speed at any point in time and cruise, or slowly speed up?

What's the most optimal speed on a motorway (or RPM), with my car that has 5 gears?

I was going to test different methods each week and refuel on Monday to get a baseline each week.

Thanks in advance.

Welcome, Bm93!

Your engine generates the most power per unit of fuel used at relatively high load & low RPM (research "peak Brake Specific Fuel Consumption -- BSFC). So, some members here will suggest you should accelerate briskly, but at low/moderate RPM to get to your target speed. BUT it's more nuanced than that -- operating at highest engine efficiency doesn't equal lowest fuel consumption. And if you are forced to slow/brake shortly after accelerating quickly, your fuel economy will be much worse compared to slower, more gentle acceleration.

In the end, your acceleration technique isn't as important for best MPG as your gear choice (always upshift to the highest possible gear), and crusing speed (lower is better for MPG).

https://metrompg.com/posts/photos/gcc-autobild1.gif

Your best fuel economy will be at the lowest speed you can reasonably travel in top gear. Lots of discussion & graphs illustrating this here:

Thread: Speed vs. MPG charts (post 'em if you got 'em)

The info you'll see in that thread underlines why so many people here focus on modifying our cars to reduce aerodynamic drag. Wind drag is the primary cause of increasing fuel consumption above around 25-30 mph.

Just keep in mind as you're watching your numbers that your fuel economy can vary dramatically from tank to tank even if you use the same driving techniques on the same route. Weather has a huge impact: temperature (dropping temps = declining MPG); dampness (rain = much worse than dry); headwind/crosswinds are bad. They all have a big impact.

Good to see you're monitoring your results. That's key to improving. Keep records & make a graph - use our fuel economy tracker, or one on another site.

Make it a game!

Average is 34MPH. What is the other 17 miles like? Stop and go? Uphill and/or downhill?

The motorway part is the most efficient. Have or obtain instant MPG readout. Drive without brakes and don't slow down for corners.

There's about another 13 miles, and it's largely urban. Not a length of road more than a mile I'd imagine with most being under half a mile. Plenty of traffic lights and roundabouts.

All I have now is my car's MPG reader which only gives the average since it was last reset. I'll have a look though at the instant readers.

What are the lowest cost options I can do to modify my car in any way to improve fuel economy? Any modification that costs money will pay itself back, but obviously the cost will influence how long that takes, and I currently am aiming to minimize immediate costs until I've settled a bit more with my job.

Where to start? An attitude adjustment of the nut behind the wheel is free. The air in the tires can be free with a bicycle pump.

What you are asking for is ROI (return on investment); consider it a search term. You can't manage what you can't measure ==> Scan/Ultra Gauge/Arduino/Raspberry Pi reTerminal.

ecomodder.com/wiki/Vehicle_Coefficient_of_Drag_List
Modifications fall into airframe and powerplant. Changes in one can mandate changes in the other.

The Journey Is The Reward - Tao Te Ching Quote