Regular Or Premuiem Gas?

vanity | Feb. 24 2003 | self

[oceanperch]

Okay FReepers I need to know.

If price was not a factor why would I use premuim gas over the Regular?

Is there a diff?

I figure I am paying for a better quality which is better for the life of my van.

I want my van to last as many years as possible as it is custom with a WC lift and pop top ect.

I have had a few in the past and it is a big pain to factory order than go thru equipping it.

Must have transportation so I take my van in for service on a regular basis to Ford and use premuim gas. Just a little background.

But I do not know the actual differences between the two fuels.

[Myrddin]

It's a function of what the manufacturer recommends. If you choose an octane grade that is lower than the manufacturers recommendation, you may end up with pre-ignition aka pinging. This is caused by a more volatile combustion mixture igniting due to compression...before the spark plug does the job. It can destroy your engine. Higher compression engines require higher octane.

I live at a higher altitude (4600 ft). Our gas stations offer 85 octane. In San Diego (sea level), the lowest octane offered is 87. Buying a lower octane than required can result in engine damage. Buying a higher grade than required is a waste of money.

[Jeff Chandler]

. Buying a lower octane than required can result in engine damage. Buying a higher grade than required is a waste of money.

Agree. To which I add: buy the lowest octane your car will run well on. With modern electronic fuel injection and ignition, your car will adjust for the difference.

[oceanperch]

Thank You sooo much. I really did not have a clue.

I travel over the coast mountain range to get to Portland on a regular basis. Steep up and down to get over.

[Gilbo_3]

Ditto to #2 & #3. I would also recommend that you stay current on the maintenance as you say you have. keeping the fluids & filters {ALL OF THEM!!! } clean is the best bet for longevity ive seen. Use the Lowest recommended octane that doesn't cause pinging and throw in a bottle of techron on occasion for extra shot of injector cleaning. Hope it helps ease your mind...

[Gilbo_3]

Also, if you use full service stations, you might politely ask the manager if you could be given service at the self serve pumps instead, Ive always been more than happy to oblige someone who wouldnt mind pumping it themselves except for a disability, the price per gallon for you is huge in that van...

[Rain-maker]

If you are running too low of an octane for your motor, you will get
pinging. Pinging in its extreme form is also known as detonation. The
fuel/air mixture is igniting all at once and exploding instead of igniting
as a flame wave. The resultant "bang" is very hard on the pistons, head,
rods, and cranks. I've seen bent rods, cracked heads, pounded-out crank
bearings, cracked piston skirts, chainsawed crankcases, and thrown rods.

 

The only time higher octane is of any benefit is if the car pings on the

recommended grade, the timing is advanced, compression is higher
than stock, or the car has forced induction.

 

Newer cars  generally wont  knock or ping because they have

knock sensors that can compensate ignition timing for lower octane fuel.

[gonzo]

"...I travel over the coast mountain range to get to Portland on a regular basis. Steep up and down to get over..."

Todays' engines with fuel-injection will digest just about anything from 83 to 97 octane. Try it out with each grade, and use the grade that doesn't ping.

More importantly, after 3000 miles, add a quart of a Teflon-lubricant like Slick-50, and change yer oil every 3000 miles. Add the Teflon-lubricant every 30,000 miles thereafter. The engine will run for 300,000 miles, and never smoke, unless you haul elephants.

Don't forget the brakes!...........FRegards

[goodieD]

I would like to add here that you have to be very careful, because many unscrupulous gas stations have the exact same gas under different grades. You may be paying for premium and getting regular.

[Uncle Miltie]

Since the war is over gas, I'd stick with VX.

</sarcasm>

[Elsie]

I have two G-30, 1 ton Chevy vans (350 engines - automatics) that run on 87 octane, bought at the cheapest place available.

The '77 has over 304,000 miles on it, does not burn oil. I replaced the cam in it 15 years ago.

The '90 just rolled over 198,000 yesterday, does not burn oil.

Though many ACCESSORIES have croaked in this time, but the engines are strong!


What more could you ask for?

[oceanperch]

I went with Ford over Chevy for the one reason I could drop the floor.

I Also raised the roof which could be done on both makes.

Hope my Ford does as well as your Chevy. ;)

[Pining_4_TX]

You guys seem to know what you're talking about, so how about this - why do they sell the mid-range octane gas at all? Is it just a lure for people who think their Geo Metro will really have more oomph with a little higer octane?

[Elsie]

one reason I could drop the floor.

I don't understand........

Does this mean to be able to modify for installation of the wheel chair lift?

---

Raise the roof..

Headroom?

[Extremely Extreme Extremist]

Premium gas is a waste of money, unless you have a bucket of a car (think mid-80s Chevy Caprice Classics) that runs better from higher octane.

[1Old Pro]

87 Octane should be fine unless othewise recommended from the manufacturer, which I doubt.

[Crusher138]

Guy who sold me my Audi (which recommends you use premium) told me that the computer was good enough to handle any grade of gas and that they had an unpublished report of A4's running on a variety of highly flamable liquids, i.e. alcohol, just fine on a temporary basis.

Don't know if I believe him or not, but the couple of occasions I have had to put 87 octane in my car I have noticed no degradation of performance.

[Centurion2000]

I would also recommend that you stay current on the maintenance as you say you have. keeping the fluids & filters {ALL OF THEM!!! }

What exactly do you mean all of them ?? Oil and air filters get changed and then the fuel filter and fluids are easy to keep up with .... are you talking about greasing the chassis and the differential fliuds for the rear axle ?

[JG52blackman]

Two possible scenarios, one of them being my own. I recently built and installed in my 1982 suburban a 383 CID engine. You get this by putting a crankshaft with a 3.75" stroke (same stroke as the old 400 chevy engines) into a 350 chevy block. With flat-top (not dished) pistons and stock low-compression heads, it has about 9.2:1 compression. I also put a low duration/high lift cam in this engine for better low-RPM torque. You get more torque from higher cylinder pressure. Higher cylinder pressure makes premature detonation (pinging) more likely. I could retard the ignition timing to make pinging less likely but then I would be throwing away the performance potential of the engine. This engine will not run well and perform well without pinging unless I use 91 or 92 octane premium gas. It has a carburetor and no computer-controlled anything so it cannot automatically adjust to pinging or other negative conditions.
The other scenario is with a more modern car that has a fully computerized fuel and ignition system with the potential to develop high cylinder pressures. The Geo Metro engine as it comes from the factory might not be be able to develop enough cylinder pressure under any fuel flow or ignition timing advance to require premium fuel to avoid pinging, but other engines might. As was stated by a previous post, the detonation sensors that are part of these computerized systems will adjust to avoid pinging. What they will do is to retard ignition timing or cut back fuel flow automatically, thereby reducing cylinder pressure and the performance that MIGHT be possible if a higher octane fuel was used. I think in many cases that people do buy higher octane unnecessarily. I also have a 1995 suburban with a fully computerized ignition and fuel delivery system on a 350 engine and I only burn 87 octane regular unleaded. It never pings and performs almost as good as the 383 in my 1982.