Fuel Efficiency Mods
Awd cara are heavier and require more power to move all 4 wheels as opposed to two. This we all know. Make more power while using less fuel is the goal. Build a very conservative tune and run that all the time. When you want power reflash the ecu.
I have Miata making 250whp and gets 30-32 mainly city driving. My tune is super conservative when under 35% throttle
Anything over is richer to save the motor
I have Miata making 250whp and gets 30-32 mainly city driving. My tune is super conservative when under 35% throttle
Anything over is richer to save the motor
Evolving Member
Joined: May 2010
Posts: 244
Likes: 0
From: sweden
I usually get around 400km per tank doing short trips to work and some longer with usually some spirited driving from stop lights a few times etc.
When the triangle lights up theres still alot of gas left, probably around 10 liters cause I have never filled the car up with more then 47 liters or so and it's supposed to have 55.
When I REALLY want to save gas I get 0.7-0.8 L/km and just cruising at around 80 km/h and resetting the avg meter I get as low as 0.5-0.6 L/km.
It always shows 20-30 L/km when you first start the car and drive and it slowly decreases. I know a car uses more fuel when it's cold but I dunno if this is true numbers. Takes forever to get back to a decent average fuel consumption (according to the trip computer) when it registers these numbers.
Usually just reset it after a min of driving to show a better average.
It really requires a feather light touch on the throttle to save gas on this car btw. You guys that don't get these MPGs probably just have a heavy foot.
When the triangle lights up theres still alot of gas left, probably around 10 liters cause I have never filled the car up with more then 47 liters or so and it's supposed to have 55.
When I REALLY want to save gas I get 0.7-0.8 L/km and just cruising at around 80 km/h and resetting the avg meter I get as low as 0.5-0.6 L/km.
It always shows 20-30 L/km when you first start the car and drive and it slowly decreases. I know a car uses more fuel when it's cold but I dunno if this is true numbers. Takes forever to get back to a decent average fuel consumption (according to the trip computer) when it registers these numbers.
Usually just reset it after a min of driving to show a better average.
It really requires a feather light touch on the throttle to save gas on this car btw. You guys that don't get these MPGs probably just have a heavy foot.
400KM = ~250Miles... I regularly exceed that with my RASB in Los Angeles traffic (90+ minutes to go 25 miles (40KM) anyone?), but don't consider that to be great fuel efficiency for 13 gallons (~49 Liters) of fuel used. It's good fuel efficiency, but not great.
I've got a road trip coming up for the Thanksgiving holiday. I think I'll finally be able to break that 300 mile (482KM) barrier on a tank of gas.
I've got a road trip coming up for the Thanksgiving holiday. I think I'll finally be able to break that 300 mile (482KM) barrier on a tank of gas.
I have two maps high boost and boost all the way off on e85 in my evo 9 on the 10psi map I get like 25-27mpg on e85 so if u do two maps on pump I'd imagine 30mpgs should be well within reach. This is on a 400whp built motor car too hope this helps
Evolving Member
Joined: May 2010
Posts: 244
Likes: 0
From: sweden
As I said 400km a tank mixed driving while Not trying. Would be no problem reaching 600-650km with effort but thats boring and not the purpose of these cars.
Last edited by gloom; Nov 16, 2010 at 10:15 PM.
I haven't seen a really good answer to the OP's question, so I felt like I should chime in. You have a few options to improve your gas mileage, and some require greater sacrifices and greater investments in time/money. I'd say that most of the fuel efficiency mods will fall into one of four categories:
Driver Behavior
As others have said, the greatest improvement you will see in mileage is simply changing driving habits. I've actually seen my greatest mileage improvements by driving solely in manual mode; normal mode is too aggressive for economy driving. Also, you should:
Depending on your previous driving habits, you could see as much as a 20% improvement in gas mileage.
ECU Tuning
For our cars specifically, we can gain decent mileage simply by leaning out the AFR through the ECU.
I would not recommend using Cobb's "economy" map because, in my experience, their economy maps reduce power, which can actually be less efficient in many circumstances. Essentially, you will see improved mileage in ideal driving scenarios (straight, flat road with few starts and stops); however, your mileage will actually go down if you are forced to tax the engine.
The potential mileage improvement for ECU tuning is about 5-10%.
Improved Rolling Resistance
One area that many people overlook is improving rolling resistance. Rolling resistance is, essentially, the amount of energy the car loses through tires. This is one of the reason so many agencies encourage people to keep their tire pressure up to spec. In simple terms, the harder the tire, the less energy will be lost. For example, a train, which rides on steel wheels, has very low rolling resistance.
For us, this modification comes with a lot of sacrifices, because if done properly, we will lose contact patch area, tire performance, and often need to downgrade rim sizes. My recommendation would be to keep a spare set of rims with (low rolling resistance) LRR tires for use on long road trips, winter, and any non-performance driving.
Quality LRR tires can offer up to a 7% improvement in mileage.
Aerodynamics
Aerodynamics is one of the most complicated and involved ways of improving gas mileage, but it has a huge potential impact on fuel efficiency. In addition, a side benefit is that most aerodynamic changes that improve mileage also improve performance. It's like having your cake and eating it too.
You can look to race cars or even the EVO for inspiration on some of these mods. The following are some potential aerodynamic improvements that can be made on our cars:
Most of the aerodynamic mods will probably only result in < 5% gain in mileage, but the improvement in style, performance and efficiency might make them worth it.
Topics I'm not going to broach: inefficiency of AWD platform and weight reduction. While AWDs do lose more power and efficiency through the drivetrain that FWD and RWD, the cost, time, and sacrifice of that type of MOD is not worth it. Also, while weight reduction can improve mileage in stop-and-go driving, it has very little affect on overall mileage.
Driver Behavior
As others have said, the greatest improvement you will see in mileage is simply changing driving habits. I've actually seen my greatest mileage improvements by driving solely in manual mode; normal mode is too aggressive for economy driving. Also, you should:
- Avoid peak traffic hours whenever possible.
- Avoid speeding from stoplight to stoplight (added benefit: longer brake life).
- Avoid boost whenever possible.
- Coast whenever possible.
Depending on your previous driving habits, you could see as much as a 20% improvement in gas mileage.
ECU Tuning
For our cars specifically, we can gain decent mileage simply by leaning out the AFR through the ECU.
I would not recommend using Cobb's "economy" map because, in my experience, their economy maps reduce power, which can actually be less efficient in many circumstances. Essentially, you will see improved mileage in ideal driving scenarios (straight, flat road with few starts and stops); however, your mileage will actually go down if you are forced to tax the engine.
The potential mileage improvement for ECU tuning is about 5-10%.
Improved Rolling Resistance
One area that many people overlook is improving rolling resistance. Rolling resistance is, essentially, the amount of energy the car loses through tires. This is one of the reason so many agencies encourage people to keep their tire pressure up to spec. In simple terms, the harder the tire, the less energy will be lost. For example, a train, which rides on steel wheels, has very low rolling resistance.
For us, this modification comes with a lot of sacrifices, because if done properly, we will lose contact patch area, tire performance, and often need to downgrade rim sizes. My recommendation would be to keep a spare set of rims with (low rolling resistance) LRR tires for use on long road trips, winter, and any non-performance driving.
Quality LRR tires can offer up to a 7% improvement in mileage.
Aerodynamics
Aerodynamics is one of the most complicated and involved ways of improving gas mileage, but it has a huge potential impact on fuel efficiency. In addition, a side benefit is that most aerodynamic changes that improve mileage also improve performance. It's like having your cake and eating it too.
You can look to race cars or even the EVO for inspiration on some of these mods. The following are some potential aerodynamic improvements that can be made on our cars:
- Lowering springs
- Smooth underbelly/skid pad
- Fender/wheel-well vents (see EVO)
- Airdams
- Diffusers and vortex generators
- Side mirrors
- Antenna
- Airfoil (Be careful with this one because our stock one is better than nothing at all, but the wrong airfoil can actually hurt performance and mileage.)
Most of the aerodynamic mods will probably only result in < 5% gain in mileage, but the improvement in style, performance and efficiency might make them worth it.
Topics I'm not going to broach: inefficiency of AWD platform and weight reduction. While AWDs do lose more power and efficiency through the drivetrain that FWD and RWD, the cost, time, and sacrifice of that type of MOD is not worth it. Also, while weight reduction can improve mileage in stop-and-go driving, it has very little affect on overall mileage.
