This is not really Histiorical but it has some significance, I think it fits well within the History / restoration board and I want to share some things which should increase your Fuel milage if your interested in doing so. There has been some concern about the fact that most of our cars do not get good milage, and unfortunately GM designed our cars so that they would not be hit with Gas guzzler taxes, and it appears that once they achieved that number they simply quit trying to improve on the economy...
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NOTE:
Making up ground on fuel economy is a lot harder than losing ground. For ecample, if you drive 10 Miles at 10 Mpg, you have to drive 30 Miles at 30 Mpg to get an average of 20 Mpg. THe math is pretty simple for this simple illustration actually.
10 Miles/10Mpg = 1 Gallon and 30 Miles/30MPG = 1 Gallon, thus You went 40 miles on 2 Gallons therefore 40Miles/2 = 20 Mpg.
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Make sure your brackets and pulleys are tight, if you have a rattling Pulley or bracket you can retard because your knock sensor thinks you have Detonation. I have actually had this happen to me, it would drive me nuts because under certain conditions my idle would surge, I could hear my pulley rattling and it was actually retarding my timing, it would get so bad it would stall. I would start the engine and while it was in high idle it was fine but when it went by a certain RPM it would rattle just a little, then the engine would retard the timing. Once the the idle would slow below 500 the ECM would add gas because it was below the threshold, on the up swing it would rattle just a little and the ECM would retard the timing just enough at the same time it was reducing fuel, it would continue this loops until it just stopped running.


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1) Obviously The easiest way to save gas is not drive the sucker... (Pun intended) This sounds reasonable, to get a second car, unfortunately it usually does not pay for itself once you calculate typical wear and tear, typical expenses like tires, full coverage insurance, etc. I calculated it out a long time ago. At $10/Gal will you save roughly $2000 a year to get a car that goes from 20Mpg to 30Mpg. At current rates you will only save about $700 to $1000 per year. If your planning on saving more money than that you have to go Electric...

Some tips
1A) If you get a 60K tire and they cost $100 each, if you drive 15K miles a year then you spend roughly $100 per year for tires.
1B) Brakes are the same way, Expect to pay $150 for a full set of Rotors and Pads which can last up to 60K miles... That same 15K equates to $37.50/Year.
1C) Transmission service Every 30K miles @$75.00 = $37.50
1D) Other Misc wear & tear things typcially cost about $100 per year...

So far your up to $275.00 per year for that extra vehicle and you have not figured in Insurance... Basically it has not paid for itself...
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2) When accelerating accelerate slow, taking a half mile to get up to 45 for example, if people are honking and giving you the finger as they race by you means your achieving optimum economy. Also try NOT to accelerate UP hills, instead let the car slow down, I even take my foot off the accelerator and let it slow over the overpass. If you live in a hilly area your screwed. Actually accelerating DOWN the previous hill and letting the car coast up the next hill saves gas, unforutnately there are Speed limits so do not exceed those.
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3) A Cold Engine really drinks gas, and letting it idle to warm it up is not much of a benefit as you are achieving 0 Mpg unfortunately it will take more gas to idle than just going and taking it easy. What is most interesting is if you drive 15 miles to work, a cold engine for one mile can decrease your milage by 2 Mpg or more and thats if you drive 13 miles on the highway. Short trips to the store are killer on Gas, try not to make as many trips.
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4) Plan ahead. When driving and if you know the area, planning ahead and timing the red lights so that you do not have to stop will help tons. Taking off from a dead stop to 10 Mph takes more gas per mile than going from 10 to 20 Mph therefore Avoid Stoping if possible, and using your brakes, again this takes planning ahead and some harder cornering, make sure its safe of course but it all helps. By using your brakes often means that you have just caused Newton to roll over in his grave, remember from high school " what is in motion wants to stay in motion." Of course you HAVE to obey the rules and laws and make complete stops at Stop signs. By using your brakes you just wasted all of that energy that you produced getting up to speed...
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5) AVOID Drive thru windows & Idleing. I know we are all lazy and prefer to get our Egg McMuffin while not getting out of the car, but by going thru the drive thru you can eat up to .5 Mpg in a weeks worth of gas (depends on how long you wait) Same thing goes for the Bank, Park it, you would be amazed. If there are 4 cars waiting to use the speaker to place an order typically you can get out of your car and back in your car before the 4th car goes thru to get thier food (of course this would depnend on your favorite franchise)
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6) Take the Crap out of your car, For every 10% increase in weight you get 8% worse gas milage. So if you should be getting 22.5 Mpg average as the Feds expect and your car weighed in at 3500# new then by adding 100# of crap, tools etc. you are instantly down to 21.986 Mpg. I guess losing some weight and avoiding those Egg McMuffins should help too... Conversly, if you remove 100# from your car you could break 23Mpg, for every 100# of crap you can get out of your car roughly equates to .5 Mpg. REmove the Back seat and try finding a lighter Spare tire...
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7) Slow down, Try Going 60Mph or 65 Mph instead of 70 Mph, Most cars best Fuel economy is between 35 and 60 Mph (with an Overdrive Transmission) every 5 Mph over 60 Mph you decrease your fuel economy drastically http://www.fueleconomy.gov/FEG/driveHabits.shtml states that for every 5 Mph you go over 60 Mph you decrease your milage by about 7%... Personally I have found it to be about the same as decreasing the crap in my car by 100#... Also consider that every time you double your Speed you Multiply the resistance by 4, so at 120Mph you have 4 Times the Wind resistance than you did at 60 Mph and 16 times the wind resistance than at 30... That and you decrease the chances of a ticket.
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8)Use the Quality Gas your car needs By using a lower octane fuel than what is recommended can A) Damage your engine and B) decrease your fuel economy. If your car has the LB9 or L98 use the Premium stuff and not the Regular. Typically Premium costs $.20 more per gallon, Thats about $2.00 per 10 Gallon fillup. If your spending $35.00 on Regular ($3.50 * 10 Gal), spending $37.00 for Premium ($3.70 * 10 Gal) and using the proper fuel will save you more than $2.00 over the tank of fuel. THe higher the price for Regular means that there is actually a less of a difference to use the Premium as it seems to be a constant $.20 per Gallon for the premium. Ideally if you increase your fuel economy by mere 6% it would surprise me, from what I have done it is usually a little more than that, and you will break even for the extra $2.00 you spent at the pump. PLUS you do not get the annoying Detonation which can actually knock holes in the top of your pistons, which I think will more than make up for the $2.00 you spent per fillup.
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9)Use the Cruise. by using Cruise on flater areas of the country it will help you save money. Of course if you are going FASTER than traffic it means that you will have to stop and slow down more often for those pesky slow drivers who are actually saving Gas. On the contrary if you are going slightly SLOWER than the Traffic it means that you are less likely to have to slow for those Slow Pokes becuse you are one, Ultimately it will save gas. This of course goes with the Whole Slow Down and Save Gas section as you have less air to push above essentially its parasitic, so the benefits are actually two fold.
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10) The typical stuff that everyone tells you, make sure you have a clean air filter, Change your oil, Trans Fluid, fuel filter, Tires are filled up to recommended tire specs.
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11) If you like a particular gas station see if they offer a Credit card that gives you a percentage back. I know Shell offers 5% rebate for every Gallon of SHELL gas you purchase. at $3.00 per gallon you save $.15 at $4.00 you save $.20/gallon. Over the course of a year I figured between My wife and myself we save about $400 with our Shell card. Unfortuantely it is sometimes a little more expensive, but usually I still come out ahead. Typically its no more than $.10 more, I still save $.05 at $3.00 and $.10 at $4.00. If you time it right you can get it when they are the least expensive and STILL get your 5%, then it really adds up.

Ultimately it depends on what your willing to put up with. We do not have any reason to Complain about the price of Gas, if its that big of a deal then start carpooling with a friend, and split the price of Gas. Or by a Moped if you can Stand the Stigma...

I thought I would share, I hope it helps with the pinch...

John

 

Using any higher octane than your car needs (neither my LB9 or L98 do, as evidenced by knock counts) is a total waste of money. The energy content in both is identical so unless you're experiencing a lot of detonation (unlikely if you're keeping your foot off the throttle), there is zero need for higher octane.

 

Quoting from the owners manual concerning LB9 and L98

"Your engine is designed to operate on premium grade fuel. However, with the electronic spark control system, you may use either middle or regular grade fuel at a slightly reduced acceleration performance"

Being that more then a few are modified on the msg board and may run more ignition timing you can't go wrong using premium.

Sure you might get away with reg or mid grade just fine but my car is high performance car in extremely great shape---I'll use premium. I don't cheap out on my ride.

Good luck with number 2! I don't hammer on the car all the time--but I use more moderate acceleration most of the time--not slow enough to hold up traffic though but if I want to get on it--the hell with the mileage.

But I have a daily driver car--so I don't put gas in the Firebird too much anyhow

I think you missed tire pressure. Make sure its at the manufactures specs or a bit more if you desire. This will make the rolling resistance of the car easier.

Good over all tips for those that are tight for cash

 

I've tried 60 mph and 75 mph and always found that 75 mph gets better mileage. A4 and 3.27 gears. I'm guessing at 75 mph, the torque converter is locked up pretty much all the time, while at 60, even a feathering of the gas pedal will unlock it. Perhaps it's the 75 mph = 2300 RPM = sweet spot for torque.

Cleaning the fuel system has always provided me with good fuel economy. I liken it to running a marathon after you quit smoking.

Recommended tire pressure is 30 psi. I found running 30 psi that
a) my tires wore on the outsides
b) felt a bit heavier than at 34-35 psi.

Tire Rack says for high speed driving on our cars, run them at 37 psi....but I found the car felt like a rock with no suspension. Too stiff.
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That shouldn't be a problem for the people with 305's.

 

Yes, you can. Ideally, you want the engine running on the edge of detonation at all times. A higher octane fuel is less resistant to burning and has a slower burn and may (and I emphasize may) not fully burn, yielding a power loss and excess emissions.

 

Also DO NOT use ethanol blended fuel. Besides the greater smog produced by such blended fuel, it also has less energy per gallon than gasoline. This often translates into a decrease in fuel mileage by as much as 25%. Thus you'll end up spending more $$$ for a fuel you'll have to burn more of to go the same distance (really great for the environment ). Keep our food on the table.

 

I agree and disagree with you on this.

If you realy read the Owners manual IIRC at the time Premium was rated at 91 Octane (at least it was in my 87's Manual IIRC) You can hardly find 91 Octane, Most of the Premiums around MI is upwards of 92 or 93 Octane and the really good stuff from Sunoco is 94 Octane. There usually is not a whole lot of difference between 93 to 94 but I have actually found that I do get better performance from the 94, not necessarily better Economy however.

I have found that my fuel systems stay cleaner with the Premium than the Regular grades. Especially if I used the el cheepo Gas from some stations. For example I find I get about .5 Mpg better economy from Shell, BP, Mobil or Sunoco, than I do Admiral Gas. If you do not have Admiral in your area they used to be called Clark, I am not sure how regional or national they really are. Of course I am not sure how much of a difference there still is because it has been a few years since I have tried Admiral Gas.

I never noticed a difference when I added the Fuel Additives that are suposed to clean your fuel system, However I know people that have used the fuel system cleaner and had their injectors clog up after they used it. I suspect what had happened is they used cheap gas and when theu used the cleaner it ended up sending a lot of junk thru the system.

As a side note (no I am not trying to push Shell) My roommate my first year at school his father was a test Engineer for Cadillac, He tested all of the brands of Gas and the Different Oils. I asked him (back in 1992) what the best gas and motor oil was and he said Shell was the best, and the Best Oil was Havoline (Yes the Texico Oil) and Quaker State. A lot has changed since then, but I thought I would share.

John

 

Regular unleaded here has always been 87-88 octane, even in 1987. The most you can get here at a typical pump is... 91.

 

I'm interested in this idea that you should go 55 or 60 mph instead of faster to achieve good fuel economy. I've even heard people say things like "The slower you go, the better the fuel economy" as a blanket statement.

But doesn't this all depend on your gearing and transmission? My daily driver for instance, has sort of short gears, and anything above 70 seems to suck gas pretty badly. But in the family's truck, the thing does significantly better at 75 than at 60-70, mostly because at 75 it stays in overdrive, whereas at 60-70mph it tends to downshift now and then.

I'd think that the best gas mileage would come near the bottom of gears when the car isn't lugging, but also isn't revving very high. Am I thinking of this all wrong?

 

Thanks John, I printed that for my records! Andrew

 

Its going to vary slightly depending on the gearing, yes. But you can travel too fast too, aerodynamic drag increases not in a straight line... but cubed so as you increase speed the drag goes up significantly.

 

Most cars are basically designed for between 35 Mph and 60 Mph for the best economy. I have had cars that would get best economy at 50 Mph just because thats right where the trans would shift into overdrive. If I experienced any hills however it would shift down into D and then the economy was not quite as good but ok.

The slower you go does not mean better economy, If your going 0 then you should be getting optimum economy, unfortunately if you are not moving you are not getting any economy. I get worse economy at 15 Mph than I do at 75Mph, its because of the gears as you suspected.

Above 60 Mph the Coefficent of Drag increases faster than the amount of efficency created to optimize economy...

John

 

I think the 55 mph = good economy thing is a throwback to the 1970's when cars were 4 speed manuals and 3 speed autos. Nowadays with 6 speeds, and 4 speed autos with 2.73's, 75 mph is still idling along at 1900 RPM.

I drove across the country one time and measured my fuel economy the entire way. 60 mph netted no improvement over 75 mph (in the GTA).

 

This is from http://www.fueleconomy.gov/FEG/driveHabits.shtml

Its from the Government so it can't be wrong

John

 

lol, that chart is awesome. chances are 55 is actually the worst fuel economy, and the govt is just tricking us into using more gas in the biggest conspiracy of our lifetime...

I'll stop now, lol.

 

Cool tricks, I will have to try a few of them.

 

Another tip on how to save gas is simply don't use all of your accessories. A car with seat heaters on, satnav fired up, the radio and amps pulling power, etc etc will do much worse than a car simply cruising along. The seat heaters in my daily driver alone pull about 2mpg.

And there is a huge debate as to whether air conditioning or open windows is better, but also try to do without either if you can. Just letting the vents blow in a bit of air without the A/C pushing it helps a lot too.

There was an episode of Top Gear in which the host was actually able to beat Audi's quoted fuel mileage on the A8 by simply turning off everything he didn't need, and only driving (very conservatively).

 

Where are you supposed to find gas that has little to no ethanol in it anymore? Everywhere over here in the east coast has signs saying that there is at least 10% ethanol and sometimes more.

is there a list of stations that do not pollute thier fuel (and sell it for the same higher price as pure) ?

that would be good info.

 

IIRC Shell, Mobil, BP dont use Ethanol...

Actually at one point the Ethanol actually corroded the Aluminum pieces and parts but I am not sure if that is still true with some of the additives in fuel.

 

All the pumps here have ethanol added, Shell and Mobil included (havent seen a BP but sure they have it if they are here.) Pretty sure all the major cities have the 'blended' 'lower emission' fuels as well. Some are seasonal, here its all year long.

How about driving downhill. Both ways. ?

 

All stations are now using or preparing to use 10%. By July, all stations, including Chevron will be 10% in FL. Chevron is the only gas in Central FLnot usig ethanol. Yes, ethanol still damages the car. I found this on another site.

"Alcohol will carry an electrical current and gasoline will not so the higher the percentage of alchol the more "galvanic corrosion" you get in your fuel system due to electrical current between unlike metals and also erosion of incompatible materials. Incompatible material are rubber and aluminum which alcohol is exceptional hard on over time. Basically the materials that are good to use in gasoline systems are bad to use in alcohol systems and vice versa. Most fuel systems not rated as "flexifuel" have incompatible materials in them. Running even 10% Ethanol (common these days) will have an impact on your car and reduce its useful life. There are also other problems... alchohol runs at about 19:1 parts (alcohol to air--by weight) gasoline at 14.7:1... so by running alcohol you are running lean...and the float that tells your system when the carburator float bown is full is no longer correct because of density differences. Electronic fuel injection systems can make on-the-fly adjustments to air fuel ratio because of a closed loop in the computer that constantly takes a measure of the oxygen levels in the exhaust gas and if there is oxygen then knows the system is running lean and increases the fuel amount injected. Running alchohol also decreases your fuel economy somewhat... pure E100 fuel econonmy is terrible (about half that of gasoline). The performance you can get out of alchohol is better with an Octane equivalency of about 108 octane for E100... about 103 for E10 (pump gas available nationally with Ehtanol)."

 

Another thing to consider is because Alcohol (Ethanol) does not have the energy that gasoline does so when you use fuel with it your Fuel milage would not be as good (Basically they are cheating you)...

As for the higher Octane Gas... Likewise higher octane gas does not have the energy that lower octane gas does. HOWEVER because it burns slower this means that you can advance the timing or increase the compression and your engine runs more efficently.

Max If I was able to drive down hill both ways to work and back I would consider a Bicycle...

John

 

Maybe I can use my vehicle's RPO R7F . . . GMC "TAP IN", NATURAL GAS VEHICLE (BI-FUEL)

Does that mean if I fart in the gas tank I'll improve my mileage?

 

Actually That kind of gas is Methane, LP is a by product of NAtural Gas.

John

 

I know, as in fart = methane, etc.
My sense of humour must have ran out of gas. Thought I'd get more mileage out of it.
(oooh, bad puns)