So, with the summer coming up, we are about due for our annual "accidental" refinery fires and other oil industry set-backs. :rolleyes: This year we are projected to hit over $4/gallon for gas (a couple places in CA should be doing so in the next month or so). Well, this said, here are but a few simple ways to improve your mileage. A few are nearly impossible to pull-off for most people since they are not much fun, but some self-restraint might lead to a beefier wallet! That aside, it does less environmental damage for the hippies here (that's me).
What pray-tell can you do to save gas then? Well, without further ado...
0) TIRE PRESSUREMake sure they are properly inflated! Seriously, this is THE #1 reason people have mileage suffer. I keep mine at 31psi front, and 32psi rear. Check them weekly. It takes all of 2 minutes, and will save you gas and tire costs!
1) Shift at 3000RPM when accelerating. - This one is tough, I know. However, friction within the engine is due mainly to a couple things. One is the fluid resistance inside from the oil and coolant being pumped, and it increases exponentially with engine speed. The other is from the piston rings rubbing on the cylinder walls. As RPM gets higher, they rub more times per second, increasing the amount of drag versus shifting and continuing to accelerate at a lower RPM. The fluid resistance also plays a part in the transmission due to the input shaft and the gears it is coupled to.
2) Do not use Air Conditioning - Aside form making the car really sluggish, it definitely impacts mileage. Now, I can understand some people shaking their heads at this...especially if you live in the kind of climate where A/C is necessary for not dying! If you can tolerate a little discomfort though, leave it off. Crack the windows and drink lots of water...it won't hurt mileage like A/C will.
3) Keep Highway Speeds under 70mph - This is a HUGE one for those who spend time driving on highways. The mileage difference between 70mph and 85mph is HUGE. I really cannot stand going 70mph on the highway, but it is the difference between 27mpg and 32mpg when I avoid going 85mph. Self control is a tough thing to exercise, but it pays off. /cliche
4) Maintain ONE Speed on the Highway - yet again, a HUGE one for highway drivers. As much as it is fun to pass and whatnot, it kills mileage. Stay in the right lane (you should anyway) and maintain one speed. I know the feeling...there is a car ahead in "your" lane. You are not gaining on it, but its presence drives you to want to be ahead of it anyway. So, you speed up and pass, then slow back down to the same speed. Don't do it (I am notorious for this).
5) Use a Thinner Weight Oil - Unless you are tracking your car, run thinner oil. The factory spec of 20W-50 is overkill. Some people have run 10W-30 and been fine. I typically use 10W-40 or 0W-40 and it seems to suit me just fine. It has seen many summer auto-crosses just fine.
6) Don't Fill-Up Completely - That's right. Maybe fill to 1/2 tank (sucks if you commute, I know). That is just extra mass you are moving with you as you accelerate. Consider it weight-reduction (kinda). Anyway, it helps a little.
7) Make sure all your fluids are fresh (the car's) - If you are low on tranny oil or differential fluid, this can increase drag and wear on parts. Check them, and if they are horrifically dirty, replace them.
Thermostat - This is not too common. Does your car NOT heat up to the half-mark on the gauge (at least half way between the 1/4 and 1/2 marks)? You are DEFINITELY going to see some reduced mileage. If it is taking your car too long to warm up, you are wasting gas, gunking up the cylinder head and wrecking your catalytic converter. The ECU runs warm-up enrichments when the motor is in the blue temperature range, so if it takes forever to warm up, then think about replacing the thermostat.
9) Oxygen Sensor - If it has been a long time since you have replaced it, you might want to consider doing so. The typical life on the sensors is ~15000 miles (in reality, driving hard). This is a big one when it comes to killing mileage.
10) Spark Plugs & Wires - If these are worn, mileage will hurt. Though they do not directly cause it, they cause the driver to use more gas. If there is a weak spark, the car will not have as much power, and the driver will need to press the gas harder to accelerate at a given rate.
