cyber_scriber
1 AYC Bar
- Location
- NSW
- First Name
- Bruce
- Drive
- 2000 Galant; metallic dark blue; manual; Recaros; Momo steering wheel; and sunroof!
We own circa 1,500kg, twin turbo, V6, AWD beasts - never a good starting point for decent fuel economy.
Despite this, the massively long fuel consumption thread shows that most of us care about fuel economy to some extent.
This guide is intended to set out the little and not so little things you can do to improve your economy. Steps are listed in order of cost and / or complexity. The guide is not intended to be slavishly followed to the letter without reference to reason and common sense. The guide simply lists those things that may improve economy, some by a lot and others by a theoretical SFA amount. Choose what works for you, your budget, your preference, your driving conditions and what common sense dictates.
The basic principles for good economy are to remove weight, increase aerodynamics, or improve engine and drive train efficiency.
Don't forget about the laws of diminishing returns, which state that at a certain point, the cost required does not justify the return. In simple terms, there's not much point in spending $5k on those super lightweight forged magnesium wheels to save $1 a week on your petrol costs!
Please feel free to comment and I'll update the original post. If you find this post useful, send some rep love
1) The free or tight ass things you can do
a) Increase tyre pressure - Ideally, you want something around 38psi for the front and 36psi for the rear. Use an accurate (and preferably calibrated) tyre pressure guage to measure.
b) Nitrogen in tyres - In theory, nitrogen should slightly help with economy. It certainly won't hurt economy.
c) Remove unnecessary weight - Take out those old tools, the esky and the dead body in the boot. Most of it is dead weight (pun intended). Don't remove your jack or wheel brace - no point recording awesome economy if you have to pay $300 to get your car towed because of a flat tyre! Consider whether removing sound deadening is worth the extra noise trade off. If you're a sound nut, plan your system using amps with a small footprint and slim line subs.
d) Remove or rectify items that disturb aerodynamics - This includes roof racks, table top spoilers, panel gaps, keeping the aerial down etc. It might also include getting streamlined side mirrors, flush side indicators etc.
e) Adapt driving behaviour - This is probably one of the biggest things you can do to improve economy. Don't accelerate or brake hard. Anticipate red lights and gaps so you can slowly roll towards them and then subsequently accelerate without stopping. Shift up before boost hits and get to top gear ASAP without labouring the engine i.e. don't struggle at 45klm/hour in 5th! The aim is to keep the revs below 3,000rpm.
Where possible (e.g. downhill), remove your foot from the throttle completely, as the ecu will cut virtually all fuel on overrun. Drive at a lower rpm and higher throttle percentage (within reason i.e. dont drop engine revs excessively or punch full throttle) - in other words, where conditions allow, use a taller gear and more throttle rather than a shorter gear and less throttle.
f) Avoid high speeds, especially on highways and motorways - Between 75-90klm/hour is ideal for our cars' engine and gearing characteristics. You'll record far better economy between these speeds than you will at 110klm+/hour. Make sure you drive to the conditions though and don't sit in the fast lane below the speed limit!
g) Avoid peak hour traffic and switch the engine off - Speaks for itself. Plan your trips so you drive in light traffic conditions. If you are stuck in traffic or stopped for a while (e.g. in a carpark where no one is moving), switch the engine off. I have read that the extra fuel used in starting the car is negated if the engine is stopped and not idling for at least 6 seconds. From 7 seconds on, it's money time ... lol!
h) Slip streaming and drafting - Drive close to the vehicle in front to be pulled into their slip stream (preferably a van, large truck or bus that will take the drag hit for you). This step is not really recommended because of the risk of rear ending someone.
i) ECU reset - Disconnect the battery and pump the brake pedal a few times with the ignition in the "on" position. This removes any excess charge in the system. The thinking behind an ECU reset is so the ECU can relearn and compensate for the driver's behaviour, the state of mods, the quality of fuel etc. For example, if you have a bad tank of fuel, the ECU will pull back the timing. However, if you subsequently use lots of tanks of high octane fuel and the ECU detects no knocking, it will add the timing back. Unfortunately, it doesn't necessarily do this quickly and may take some time to "unlearn". Think of it as rebooting your computer to get a clean slate on start up.
j) Air con is a luxury - Using the air con places additional load on the engine and increases fuel consumption by up to 10%. Only use air con if absolutely necessary and consider whether it's still bearable with a/c off and the windows and sunroof open. The exception is where you are doing high speeds on the highway. Here, the aerodynamic drag caused by open windows is likely to outweigh a streamlined car with windows closed and a/c on. If your car has been parked in the hot sun, drive off first with a/c off and all windows down to remove the hot air from the car. Then turn a/c on to reach the desired temperature and then switch the a/c to economy mode.
k) Remove spare tyre - It is possible to replace your spare tyre with the tyre repair cans. Yes, this saves weight but may not be a good idea if you drive on roads that increase the risk of a flat or if you drive outside of metro areas where the goop in a can isn't going to be that helpful e.g. You're in the middle of the Nullabor.
2) The low cost things you can do
a) Use 98RON fuel rather than 95RON - In theory, the denser 98RON fuel should give better economy (as well as more response and power and better injector clean). This needs to be balanced against the higher cost of 98RON fuel. In any event, I'd recommend only running on 98RON for piece of mind.
b) Use low viscosity oil - Something around 0w30 or 5w30 and fully synthetic. Change the oil filter while you're there.
c) Change spark plugs - It's likely that your rear plugs are rooted because they're harder to get to. Change all 6 and experience a better bang and a better buck ratio.
d) Change ignition leads, O2 sensor, air filter and fuel filter - For the air filter, use a panel replacement filter from Ralliart, K&N or HKS. Pod filters are generally a no go zone.
e) Tune up and injectors - Keep the engine in a good state of tune and get an injector clean.
3) Now we're starting to get expensive
a) Aftermarket ECU or retune factory ECU - Get an aftermarket ECU and appropriate tune. Alternatively, provided that your factory ECU can be retuned, have this done so that the car does not run too rich.
b) Lower the car - This improves aerodynamic efficiency and decreases drag. Note that if you're in NSW, you may be subject to certain lowering restrictions. More info here - http://ozvr4.com/forums/showthread.php?t=6598&page=4.
c) Exhaust and intercooler - Get a free flowing exhaust and uprated intercooler. For the true weight saving slaves, make sure the exhaust is made of titanium. Not only does this make you part of the cool crowd, but it's much lighter than your conventional exhaust systems.
d) Lightweight smaller diameter wheels - Grab some lightweight Rays forged magnesium wheels to help with economy, unsprung weight, cornering etc. You'll look hard too. Go for a smaller size over a "you're a girl unless you go 18 x 9.5" size. 16 inch rims require less power to move than big and heavy fully sik rims.
e) Lightweight brakes - These will cost you.
f) Skinny, low rolling resistance tyres - For example, Michelin specifically make a tyre for fuel economy. Note that you'll probably sacrifice outright grip and braking with economy oriented tyres. The upside is better fuel consumption and a quieter ride.
4) I just won the lotto!
a) Carbon fibre panels and parts - Save weight by getting a carbon fibre bonnet, boot, doors, guards, mirrors and interior bits. In addition to saving weight, you'll look tough.
b) Underbody diffuser and full engine undertray - This helps with aerodynamic flow under your car.
5) Yeah right!
a) Hit the gym and sauna and lose some weight. Only offer to drive supermodels and not sumo wrestlers.
b) Sell the Galant / Legnum and buy a hybrid or diesel.
Cheers.
Bruce aka Cyber_scriber
Despite this, the massively long fuel consumption thread shows that most of us care about fuel economy to some extent.
This guide is intended to set out the little and not so little things you can do to improve your economy. Steps are listed in order of cost and / or complexity. The guide is not intended to be slavishly followed to the letter without reference to reason and common sense. The guide simply lists those things that may improve economy, some by a lot and others by a theoretical SFA amount. Choose what works for you, your budget, your preference, your driving conditions and what common sense dictates.
The basic principles for good economy are to remove weight, increase aerodynamics, or improve engine and drive train efficiency.
Don't forget about the laws of diminishing returns, which state that at a certain point, the cost required does not justify the return. In simple terms, there's not much point in spending $5k on those super lightweight forged magnesium wheels to save $1 a week on your petrol costs!
Please feel free to comment and I'll update the original post. If you find this post useful, send some rep love
1) The free or tight ass things you can do
a) Increase tyre pressure - Ideally, you want something around 38psi for the front and 36psi for the rear. Use an accurate (and preferably calibrated) tyre pressure guage to measure.
b) Nitrogen in tyres - In theory, nitrogen should slightly help with economy. It certainly won't hurt economy.
c) Remove unnecessary weight - Take out those old tools, the esky and the dead body in the boot. Most of it is dead weight (pun intended). Don't remove your jack or wheel brace - no point recording awesome economy if you have to pay $300 to get your car towed because of a flat tyre! Consider whether removing sound deadening is worth the extra noise trade off. If you're a sound nut, plan your system using amps with a small footprint and slim line subs.
d) Remove or rectify items that disturb aerodynamics - This includes roof racks, table top spoilers, panel gaps, keeping the aerial down etc. It might also include getting streamlined side mirrors, flush side indicators etc.
e) Adapt driving behaviour - This is probably one of the biggest things you can do to improve economy. Don't accelerate or brake hard. Anticipate red lights and gaps so you can slowly roll towards them and then subsequently accelerate without stopping. Shift up before boost hits and get to top gear ASAP without labouring the engine i.e. don't struggle at 45klm/hour in 5th! The aim is to keep the revs below 3,000rpm.
Where possible (e.g. downhill), remove your foot from the throttle completely, as the ecu will cut virtually all fuel on overrun. Drive at a lower rpm and higher throttle percentage (within reason i.e. dont drop engine revs excessively or punch full throttle) - in other words, where conditions allow, use a taller gear and more throttle rather than a shorter gear and less throttle.
f) Avoid high speeds, especially on highways and motorways - Between 75-90klm/hour is ideal for our cars' engine and gearing characteristics. You'll record far better economy between these speeds than you will at 110klm+/hour. Make sure you drive to the conditions though and don't sit in the fast lane below the speed limit!
g) Avoid peak hour traffic and switch the engine off - Speaks for itself. Plan your trips so you drive in light traffic conditions. If you are stuck in traffic or stopped for a while (e.g. in a carpark where no one is moving), switch the engine off. I have read that the extra fuel used in starting the car is negated if the engine is stopped and not idling for at least 6 seconds. From 7 seconds on, it's money time ... lol!
h) Slip streaming and drafting - Drive close to the vehicle in front to be pulled into their slip stream (preferably a van, large truck or bus that will take the drag hit for you). This step is not really recommended because of the risk of rear ending someone.
i) ECU reset - Disconnect the battery and pump the brake pedal a few times with the ignition in the "on" position. This removes any excess charge in the system. The thinking behind an ECU reset is so the ECU can relearn and compensate for the driver's behaviour, the state of mods, the quality of fuel etc. For example, if you have a bad tank of fuel, the ECU will pull back the timing. However, if you subsequently use lots of tanks of high octane fuel and the ECU detects no knocking, it will add the timing back. Unfortunately, it doesn't necessarily do this quickly and may take some time to "unlearn". Think of it as rebooting your computer to get a clean slate on start up.
j) Air con is a luxury - Using the air con places additional load on the engine and increases fuel consumption by up to 10%. Only use air con if absolutely necessary and consider whether it's still bearable with a/c off and the windows and sunroof open. The exception is where you are doing high speeds on the highway. Here, the aerodynamic drag caused by open windows is likely to outweigh a streamlined car with windows closed and a/c on. If your car has been parked in the hot sun, drive off first with a/c off and all windows down to remove the hot air from the car. Then turn a/c on to reach the desired temperature and then switch the a/c to economy mode.
k) Remove spare tyre - It is possible to replace your spare tyre with the tyre repair cans. Yes, this saves weight but may not be a good idea if you drive on roads that increase the risk of a flat or if you drive outside of metro areas where the goop in a can isn't going to be that helpful e.g. You're in the middle of the Nullabor.
2) The low cost things you can do
a) Use 98RON fuel rather than 95RON - In theory, the denser 98RON fuel should give better economy (as well as more response and power and better injector clean). This needs to be balanced against the higher cost of 98RON fuel. In any event, I'd recommend only running on 98RON for piece of mind.
b) Use low viscosity oil - Something around 0w30 or 5w30 and fully synthetic. Change the oil filter while you're there.
c) Change spark plugs - It's likely that your rear plugs are rooted because they're harder to get to. Change all 6 and experience a better bang and a better buck ratio.
d) Change ignition leads, O2 sensor, air filter and fuel filter - For the air filter, use a panel replacement filter from Ralliart, K&N or HKS. Pod filters are generally a no go zone.
e) Tune up and injectors - Keep the engine in a good state of tune and get an injector clean.
3) Now we're starting to get expensive
a) Aftermarket ECU or retune factory ECU - Get an aftermarket ECU and appropriate tune. Alternatively, provided that your factory ECU can be retuned, have this done so that the car does not run too rich.
b) Lower the car - This improves aerodynamic efficiency and decreases drag. Note that if you're in NSW, you may be subject to certain lowering restrictions. More info here - http://ozvr4.com/forums/showthread.php?t=6598&page=4.
c) Exhaust and intercooler - Get a free flowing exhaust and uprated intercooler. For the true weight saving slaves, make sure the exhaust is made of titanium. Not only does this make you part of the cool crowd, but it's much lighter than your conventional exhaust systems.
d) Lightweight smaller diameter wheels - Grab some lightweight Rays forged magnesium wheels to help with economy, unsprung weight, cornering etc. You'll look hard too. Go for a smaller size over a "you're a girl unless you go 18 x 9.5" size. 16 inch rims require less power to move than big and heavy fully sik rims.
e) Lightweight brakes - These will cost you.
f) Skinny, low rolling resistance tyres - For example, Michelin specifically make a tyre for fuel economy. Note that you'll probably sacrifice outright grip and braking with economy oriented tyres. The upside is better fuel consumption and a quieter ride.
4) I just won the lotto!
a) Carbon fibre panels and parts - Save weight by getting a carbon fibre bonnet, boot, doors, guards, mirrors and interior bits. In addition to saving weight, you'll look tough.
b) Underbody diffuser and full engine undertray - This helps with aerodynamic flow under your car.
5) Yeah right!
a) Hit the gym and sauna and lose some weight. Only offer to drive supermodels and not sumo wrestlers.
b) Sell the Galant / Legnum and buy a hybrid or diesel.
Cheers.
Bruce aka Cyber_scriber
