Junk in the trunk

[Ziv]

How much of a difference does 30 pounds of stuff in the back of a RAV4 make?

My mpg is pretty poor in my work vehicle (2007 RAV4 L4 gas), around 18.5 in the winter and about 19.5 in the summer. I drive 85% in town with occasional road trips to see family. I have 30-35 pounds of stuff I used nearly every weekend in the trunk. I could take it out but I would have to put it back every weekend. I would like to get my average over 20 mpg and was wondering how much of a boost 30 pounds less would make.
Second issue, I have finally found a cold air intake for a RAV4, would that give me 1 (or maybe 2) more mpg? Would getting one for my 350Z deliver a boost in mpg?
I really do drive the RAV gently, but even using hypermiling techniques (pulse and glide, stoplight timing, slower speeds) I have only been able to get my city mpg to around 21 mpg.

[MatrixDom]

According to statistics, 100 pounds of cargo will only affect a car's fuel economy by 5-10%, even less sometimes. I don't think taking out your cargo will make a big difference.

Many people think Cold Air Intakes will give better MPG but when it comes to having it installed they want to here it thus revving the engine more and more... that kills the point of having it to save fuel.

If you really think it's worth the try you can do it but the biggest factor in saving fuel economy is the way you drive.

[MMUK]

The 30 pounds won't make a big difference, you may get a slight improvement in city (stop/go) driving.

> have finally found a cold air intake for a RAV4, would that give me 1 (or maybe 2) more mpg?

It won't help at all. The air intake is not a bottleneck when driving economically. Just make sure your OEM air filter is not clogged up.

[MMUK]

> I drive 85% in town

Town driving is obviously going to be much higher on fuel consumption than highway/rural driving. The other big factor is the length of each trip - your vehicle will have much higher fuel consumption when the engine is still cold.

[Ziv]

Thanks very much for your feedback! I was hoping for some easy improvement in my mpg but it is becoming obvious the problem is looking at me in the rear view.

I don't worry as much about my 350Z mpg because it is supposed to be just a 'weekend car' but I am hoping to get my RAV4 mpg up this spring. But looking at the graph and how many miles I am actually putting on the Z maybe I should reconsider.

The short commutes I have are a mixed blessing as well. I only drive 12,000 miles a year but most of my trips are just 3 or 4 miles so the car doesn't even get a chance to start operating efficiently.

Thanks again! I think I will go back to pulse and gliding and see if can get the RAV back over 20!

[Ciderbarrel]

CAIs can increase HP. The colder air is more dense than warmer air and as such, you use more fuel and get more power.

WAIs can increase MPG. The warmer air is less dense than colder air and as such, you use less fuel.

[DTMAce]

My black beretta has a WAI right now, but its winter, so MPG is still ugly. But it should get better. The aqua beretta always gets better mpg, and it has the stock airbox. Both have the same engine and transmission.

[chucksunder]

I'm sure we all have our favorite stoplights where you have to wait up to 2 minutes before the light changes. I have started to shut down the engine whenever I come to these. It helps your mileage considerably and is not that much trouble to do.

[cbwrnchtrnr]

30 lbs in the rear is insignificant, however 30 lbs of unsprung weight is huge! By eliminating as much weight from your tires / wheels and your drivetrain you will notice a drastic (positive) difference in performance as well as mpgs. This can be done just by using less aggressive and / or skinnier tires, or an aftermarket upgrade of rims most often will shave a substantial amount of weight when compared to factory wheels.