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Sugggestions for DIY upgrades for improved MPG wanted

Model Years 2012 to 2017 
3K views 16 replies 9 participants last post by  Bluefoton 
#1 ·
Hi,
I have a simple question, I think. I want to modify my 2017 Crosstrek to improve mpg and performance of I can do so without harming my mpg. I currently average 29.4 mpg, but have to drive like I’m 90.
Any suggestions are much appreciated.
Thank you in advance,
Alec
 
#2 ·
These are already about as fuel efficient as they will get. Driving more efficiently is the best way.

You can remove all extra weight from the vehicle and lowering it like the Impreza will help but not a ton.

Lowering it is the best option and also tires with less rolling resistance is probably second. Also if you over inflate tires by a little bit they are more efficient too.
 
#3 ·
Nothing will yield a significant improvement. All you can do is play with physics to your own advantage, hypermiling forums are full of little tips and tricks. Reduce the vehicle's mass: remove anything and everything that's useless, drive with a half-empty fuel tank at most. Stay at or below speed limits. Maximize engine braking. Add a few PSI to your tyres to decrease rolling resistance, install lighter mags / tyres. Lower the car to decrease its frontal cross-section. Fill the trunk with helium baloons. Etc.
 
#4 ·
I want to modify my 2017 Crosstrek to improve mpg and performance...
Tell us more about the car; what have you already done? LRR tires are a ~10% effect, tire pressure more like 5%, but those benefits are only available once. If you have LRR tires at increased pressure, there's no benefit to be had.

The one common and effective mod is closing off all the front grill openings to reduce drag. Cars generally have enough cooling capacity that you never notice (I didn't), but climbing mountains in hot weather or towing are clearly contraindicated, so make them removable.

Another is to change your routes. Speed is expensive. I've found a couple cases where rural roads are shorter, as well as more efficient, fuel-wise, so there's no time penalty.

If you get really high mileage, you may also benefit from ethanol-free fuel, although it'll never pay for itself.

Have fun!
 
#5 ·
Tell us more about the car; what have you already done? LRR tires are a ~10% effect, tire pressure more like 5%, but those benefits are only available once. If you have LRR tires at increased pressure, there's no benefit to be had.

The one common and effective mod is closing off all the front grill openings to reduce drag. Cars generally have enough cooling capacity that you never notice (I didn't), but climbing mountains in hot weather or towing are clearly contraindicated, so make them removable.

Another is to change your routes. Speed is expensive. I've found a couple cases where rural roads are shorter, as well as more efficient, fuel-wise, so there's no time penalty.

If you get really high mileage, you may also benefit from ethanol-free fuel, although it'll never pay for itself.

Have fun!
How do you propose to close the grill? Any success with that?

Also to OP, roof racks add drag. Remove it if you have one installed until needed.
 
#7 ·
Thank you everyone for your replies. I will be checking the tire pressure in all 4 tires and since my car is mostly empty, there’s not much I can do about the weight. When it comes to replacing my tires, I’ll also look into LRR tires as suggested.
I’ll also be changing oil and air filler this week. Although the oil only had 3k-4k miles and was changed 5 months ago.

Thank you again for your help.
 
#10 ·
Improving performance while maintaining/lowering MPGs? It's kind of asking to have the cake and eat it too. Most mods that would allow incremental improvements for this (weight reduction in general, reducing intake/exhaust restriction, using higher quality gas, tuning, etc.) are largely debated wheter they bring useful/significant improvement or not and you will never be able to repay your investment with the gas saved.

Unless you are willing to strip the interior, get rid of the spare tire and remove the AC completely, I think your best option is to leave it like that.
 
#11 ·
Taking it easy with acceleration and deceleration are very helpful. Anticipating stop lights, moving vehicles, etc. goes a long way as well. If you can manage to coast to a light and not come to a full stop, that will be more efficient that coming to a stop and having to get back up to speed. I've got the hybrid, so I've been playing these games for 3 years now as well as finding routes that are slower speeds and allow me to coast and regen brake. I've noticed from the suspension setup, the shoulders of the tires are wearing more than the center at the inflation pressure on the door. I've been riding at least 1-2psi higher to even the wear a bit better and it's been fairly efficient. Just remember if you raise the tire pressure, you will sacrifice some contact patch and handling characteristics. Probably not by much if you go 1-2psi, but I could notice a bit in the steering.
 
#12 ·
I might be a little late to the party, but on long drives on the highway i like to tail a semi thats riding at around 65-70 mph with my eyesight. Basically im using them to break the wind for me and it actually increases my ACTUAL mpg by a couple. I measure by filling my tank to its fullest and then going to the nearest next dollar, i reset one of my trip meters (i keep one for oil change intervals), then i drive it until nearly empty. Repeat the process with filling the tank to nearest dollar (consistency is key) and then take your trip meter miles and divide it by how many gallons you put into it. This is your real MPG. The computer MPG is awfully inaccurate.
 
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