driving efficiently

[ScottyB]

i know we're a motorsports club and its alot more fun to talk about tearing ass around the track but for many of us we spend 98% of our time just driving around like every othe Joe Blow trying to get from point A to B. especially in light of current gas prices, does anyone else try to consciously make their everyday drives pretty efficient? any cool tips? maybe we can learn something.

personally i actually enjoy the challenge of seeing how efficiently i can drive on my daily commute and on road trips, if not for the financial benefit too. i'll track my milage tank to tank and try to use a couple different tactics to boost my milage. that said, i still waste alot of my efforts by gunning it up any merge ramps that happen to be uninhabited

some things that i do that i've found help alot. i've verified much of this in my parent's car which has an instant-MPG feature on the dash display.

- coast in gear as long as possible before throwing it in neutral. when your engine is idling it's using fuel, when its coasting down in gear it doesn't use any...plus you get the braking effect.
- let your momentum carry going downhill if conditions permit. often i'll keep my foot in it after cresting a hill and gain 10mph or so going downhill, then instead of using more throttle going uphill i'll keep it steady and let my speed bleed off until i have to use more to maintain a minimal speed. then do it over again. hard to do in traffic because you're constantly gaining and losing speed.
- keep the AC off in traffic, and the windows up on the highway
- keep the toe-in as minimal as possible on your alignment. this helps your tire life too, at the cost of stability on the highway and in crosswinds.
- don't let your car warm up past about 30 seconds to a minute when you start it after sitting all night or day. i've found that my car especially will dump lots of fuel to warm up on a cold start if you let it sit. instead, drive it gently until the oil is warm, then drive normally.
- if nobody is behind me, i like to time the stoplights. instead of driving the speed limit right until the very last second, i'll start coasting as soon as i see a red light, even if it's very far ahead. usually it's green by the time i'm almost slowed down and at the car ahead of me. this will buy you a free couple hundred yards.
- i've never driven a car that's had good gas milage over 70 mph. if you can, keep it between 65-70, that tends to be a sweet spot.
- filters/tire pressure
- maintain your speed in corners if you can help it, instead of slowing down, speeding up. my favorite type of efficiency

things i've found that don't work as much or stupid advice:

- don't draft anything, for obvious reasons. keeping a good distance also allows you to keep a steady speed instead of speed up/slow down/speed up.
- shifting early....shift too early and you'll bog the engine and end up flooring it to keep up with traffic since you're out of the powerband of the engine. i just try to keep the thottle opening to a minimum
- oil changes may help but i think that's really really splitting hairs.

[.RJ]

Driving efficiently? Get a bike

And you cant wheelie a subaru

[WRXtranceformed]

Good tips Scott! I've been getting extremely good gas mileage out of my IS300 since I've owned it. It's funny, there are a ton of threads on it on the IS forums and so many people gripe and complain about how they only get 16-18mpg in their ISs and how expensive it is to keep fueling it up with premium. The absolute best I've gotten is 27.6mpg, and I usually average around 25-25.5mpg with a mix of city and highway driving. Here's what I always posted up to help people out.

1) In my opinion, 95% of people who claim they have gas mileage problems can fix them by changing their driving style. As much fun as it can take out of driving, it goes without saying that the less aggressively you drive the easier your car will be on fuel. I drive like a grandma on a daily basis and my gas mileage reflects that. Don't do jackrabbit starts, ease into acceleration, don't brake very heavily (if you are, you're probably going too fast / using too much fuel).

That is definitely the single largest influence on efficiency that exists.

2) Keep your car maintained, with good fluids. Following the regular intervals is key, changing out the filters etc. as well as keeping your tires inflated and keeping up on your alignments. This particular part irks me because my car drops out of alignment every 15-20k miles, sometimes sooner if I'm hitting some potholes. I dunno if that is normal or due to an accident in its past history.

I'm not promoting any particular fluid, but I noticed a 2-3mpg increase in fuel mileage instantly after swapping out all of my fluids to Royal Purple. I'm using Mobile 1 this go around in my engine just to see if I notice a difference.

3) Brands of gas make an impact. I notice poor fuel mileage with generic fuel and noticeably better mileage with certain brands. The fact that my car requires 93 octane or better might play a part in it too. Winter fuel also decreases my gas mileage noticeably.

4) Removing excess weight. I try not to keep a lot of crap in my car. Spare tire and jack removed (new wheels are 18s so it wouldn't work with them anyway), I keep a can of Fix A Flat for emergencies and a cell phone for tow truck if needed. Some people take it to the extent of never filling their gas tank more than 1/3 full, but I think that is foolish and unwise.

5) Smaller wheel / tire combo. I broke this rule because I wanted the look of 18s, but you can save a lot of weight by going to smaller wheels, as well as improve acceleration with less wheel diameter.

Those are the big ones I can think of that I do. I'm sure I'll think of more, but again IMO the #1 factor is in how you drive.

[ScottyB]

^^ good call....i'm guilty of the gas/weight most of the time. i try to stay away from Sam's club gas, etc. and i have a problem with keeping too many useless tools in the car.

and RJ...where the hell do you find this stuff, and why don't we see it more often?!

[Ginger]

What's this "winter gas"?

[Evan]

WOT at every shift.

[BLINGMW]

FWIW, I like all your tips and use them all myself. It's fun! I think looking ahead is probably the most beneficial, trying not to stop, avoiding acceleration and braking as much as possible is obviously the largest benefit. Doing that, plus allowing a little speed loss uphill to get it back downhill, I was getting 40+ MPG the other day in the Mini (because we were almost out of gas and I wanted to see how far we could go. :wink: )

- shifting early....shift too early and you'll bog the engine and end up flooring it to keep up with traffic since you're out of the powerband of the engine. i just try to keep the thottle opening to a minimum

But this is the only one I'm 180 deg the other way on. In our Mini, my 318, and the old Accord, I'm pretty convinced the best fuel economy comes if I floor it almost all the time when accelerating and shift as early as possible.

The Mini's economy gauge seems pretty accurate, I've verified it quite a few times at the pump and trust it now. When Jess drives, she holds each gear longer, is often in a higher gear with lighter throttle. I'll drive the same or similar stretch, flooring it all the time, often driving even more aggressively, and I'll get better MPG. I can't say we've scientifically tested this, there are certianly other variables, (I am also usually looking further ahead and holding higher corner speeds) but I'm pretty convinced.

We didn't come to a consensus before on this either, oh well : <!-- m --><a class="postlink" href="http://mmsports.org/forum/viewtopic.php?t=5436">http://mmsports.org/forum/viewtopic.php?t=5436</a><!-- m --> :dunno:

[WRXtranceformed]

What's this "winter gas"?

I don't know the science on it, but the gas we buy in the winter is of worse quality than that in the summer... I THINK due to some additional additives they use because of the temperature change.

[Andy]

Most of what you guys say seems to fall into the common sense umbrella of "don't drive like a jackass"

I don't buy that different gas yields different mpg's. Gas is gas. The only difference is an additive package and if one manufacturer was somehow able to produce a additive that gave better gas mileage, the other manufacturers would've picked up on it now.

Scotty-Do you know for a fact at coasting in gear uses no gas? It doesn't make sense to me that the engine would cut off all fuel.

[WRXtranceformed]

I don't buy that different gas yields different mpg's. Gas is gas. The only difference is an additive package and if one manufacturer was somehow able to produce a additive that gave better gas mileage, the other manufacturers would've picked up on it now.

I'm sorry, but I'm 99% confident that this is completely false. I'm on a dialup connection at work so I don't feel like doing the research, but not all gas is created equal.

I would never buy generic gas for any performance car I own after a bad experience with a no-name gas in my old WRX. My car pulled timing and stuttered badly until I put some fresh gas in it from another station. And this was on the stock tune with no modifications.

[mrbaggio]

I don't buy that different gas yields different mpg's. Gas is gas. The only difference is an additive package and if one manufacturer was somehow able to produce a additive that gave better gas mileage, the other manufacturers would've picked up on it now.

I'm sorry, but I'm 99% confident that this is completely false. I'm on a dialup connection at work so I don't feel like doing the research, but not all gas is created equal.

I would never buy generic gas for any performance car I own after a bad experience with a no-name gas in my old WRX. My car pulled timing and stuttered badly until I put some fresh gas in it from another station. And this was on the stock tune with no modifications.

I am with Andy. Pretty much all gas in this country is coming from a few common points. Only at the end of the line do they put different additives in the fuel. I think it was a Modern Marvels show where the talked about how gas is transported. It all came from a few common points. Texaco gas was mixed in with exxon gas when it goes in the pipe. When it came out on the other end there was no guarantee exxon was getting its gas back.

I have also heard problems of people getting a bad tank of gas from a certain station. But i think that is more a result of bad equipment and storage at that station.

[ScottyB]

Scotty-Do you know for a fact at coasting in gear uses no gas? It doesn't make sense to me that the engine would cut off all fuel.

actually...i spoke too soon. only some cars have it, i think. for instance in my parent's audi, if i coast the MPG readout goes straight to ___ to represent "infinite" milage. it appears that some cars still inject fuel during coast to keep the cat at operating temperature, especially since the intro of OBDII

<!-- m --><a class="postlink" href="http://www.cleanmpg.com/forums/fuel-economy/t-injector-fuel-cutoff-during-decel-7512.html">http://www.cleanmpg.com/forums/fuel-eco ... -7512.html</a><!-- m -->

[HAULN-SS]

I don't know if I buy that - my subaru's readout goes to --- when coasting as well, in gear or not. The engine is still turning over, for sure. I think the --- is to represent that if you had an infinite downhill, your car wouldn't stop moving. To think otherwise is to think that your car is jump starting itself every time you coast down a hill? Pfft.

[WRXtranceformed]

I don't buy that different gas yields different mpg's. Gas is gas. The only difference is an additive package and if one manufacturer was somehow able to produce a additive that gave better gas mileage, the other manufacturers would've picked up on it now.

I'm sorry, but I'm 99% confident that this is completely false. I'm on a dialup connection at work so I don't feel like doing the research, but not all gas is created equal.

I would never buy generic gas for any performance car I own after a bad experience with a no-name gas in my old WRX. My car pulled timing and stuttered badly until I put some fresh gas in it from another station. And this was on the stock tune with no modifications.

I am with Andy. Pretty much all gas in this country is coming from a few common points. Only at the end of the line do they put different additives in the fuel. I think it was a Modern Marvels show where the talked about how gas is transported. It all came from a few common points. Texaco gas was mixed in with exxon gas when it goes in the pipe. When it came out on the other end there was no guarantee exxon was getting its gas back.

I have also heard problems of people getting a bad tank of gas from a certain station. But i think that is more a result of bad equipment and storage at that station.

God damnit you fucker don't make me go researching on dialup!!!!!

[.RJ]

You could shut the engine off while coasting downhill, and nothing would really change. The drive wheels will spin all the rotating bits... you keep small amounts of fuel going through it for emissions and driveability.

[ScottyB]

When Jess drives, she holds each gear longer, is often in a higher gear with lighter throttle. I'll drive the same or similar stretch, flooring it all the time, often driving even more aggressively, and I'll get better MPG.

no kidding....well i'll give it a shot. i've heard of people talking about less "pumping losses" doing the floor-it method. sounds like fun flooring it everywhere....i dig it

i'm still looking for stuff on whether or not injectors stop firing during coast, it's really difficult to find actual, documented info...or i suck at searching

[.RJ]

Hook up an OBD-2 diagnostic tool to your car as you drive

[ScottyB]

Hook up an OBD-2 diagnostic tool to your car as you drive

bah! effort + money =

[HAULN-SS]

Well, I am sure injectors shut off on cars that advertise that injectors shut off, but I don't think they all shut off, and I dont think this is in any vehicle except direct inject vehicles. At coast, i think every other vehicle is using the same amount they take to idle

[ScottyB]

Most of what you guys say seems to fall into the common sense umbrella of "don't drive like a jackass"

we need more people like that down here. i swear people actually speed up to red lights.