Octane Rating for Gas

"Gumby" wrote in news: snipped-for-privacy@rogers.com:

Use whatever the owner's manual specifies. Unless it's pinging, there's absolutely no advantage to using a higher octane.

Joe Calypso Green '93 5.0 LX AOD hatch with a few goodies Black '03 Dakota 5.9 R/T CC

I wish I had extra bucks to waste, pumping mid-grade fuel into Charlene. I am debt-free and fairly well-off, but I'll be damned if I'll voluntarily hand over extra money to oil companies for a product I don't need.

Check your owner's manual. 2004 GT's specify 89 octane, which they are specifically designed for. Higher octane fuels won't yield more power. All they will do in a car designed for 89 is suck extra money out of your wallet.

If you ever end up with a preignition/detonation problem, repair the faulty engine components rather than masking symptoms with expensive, high-octane fuel. The extra money you needlessly spend on 92+ octane fuel to cure a pinging problem would be better spent repairing the problem.

-JD

Rule of thumb - Use the lowest grade of gas you can without pinging... For most production cars these days, 87 or 89 is fine.

Heath

And I wished I lived somewhere that 92 was mid-range. Here in ecofriendly California today it's

87 - $2.48 89 - $2.68 91- $2.88. I put 89 octane in my 1989 5.0L

Howard

89 ?? I thought they all still needed 87 ? anyways, anything higher than what your manual said is a waste of money.

Remove NO-SPAM from email address when replying

What the hell is going on in this wonderful sun shiny state of ours???

Gumby619

Drive it IF you can afford to, wax it if ya can't

The octane rating is the number given for the resistance of the gasoline to ignite. The higher the rating, the harder it is for the gasoline to burn. Your engine may knock if you are using a lower octane rating than is recommended by the manufacturer. Also, as an engine ages carbon tends to build up within the combustion chamber to the point that it increases the compression ratio. Therefore, older engines sometimes have a tendency to knock when burning the recommended fuel octane. The reason for the knocking is that the fuel/air mixture is igniting too EARLY. Engines are designed (compression ratio/timing) for a specific octane rating - it is usually a HUGE waste of money to use a higher than recommended octane rated fuel.

Therefore, the easiest answer to your question regarding the proper octane fuel to use is to use the octane rating as close as possible to what the manufacturer suggests for the engine. This mindset assumes you have not made major modifications to the engine (compression ratio/timing).

Entering into the unknown, V'ger seeks information used to maintain his Vintage Burgundy 1965 Ford Mustang 2+2 w/289 ci 4v oem A Code V8, C4 Trans,

16x8" Vintage 40 wheels, with BF Goodrich gForce T/A 225/50ZR16 tires, American Racing "Mustang" Centercaps, and a whole lot of other stuff; )

I use 87 octane in my 2002 GT with out any problems. Martin

243rwhp 285rwtq

Gumby opined in news: snipped-for-privacy@rogers.com:

Using a higher rating than necessary can be hard on ANY year engine... anyone remember Gulf Crest?

Running a good quality fresh gas is the best answer as long as it doesnt ping regularly.. a little doesnt hurt!

I always hated BP gas but ran a few tanks since they switched to the ARCO formula (in the States, anyway) and it runs great.

OH MY FREAKING GOODNESS!!!!!

I just paid $2.00 a gallon for 93 octane yesterday at Sams Club. Diesel has skyrocked out here, it's up to $1.99 a gallon. I have never seen it that high. In some places it's $2.06

How in the world to the compainies get away with raping California like they do? I believe it's because the residents do not stand up to the government and oil companies and tell them to knock it off.

Damn I'm glad I moved!

*former Californicator*

Kate

I'm thinking Shug needs a GOOD coat of wax LOL

| > And I wished I lived somewhere that 92 was mid-range. Here in ecofriendly | > California today it's | > 87 - $2.48 89 - $2.68 91- $2.88. | > I put 89 octane in my 1989 5.0L | >

| > Howard | >

| >

| > --- | > Outgoing mail is certified Virus Free. | > Checked by AVG anti-virus system

| > Version: 6.0.775 / Virus Database: 522 - Release Date: 10/8/2004| Being in Low Cal myself I was wondering if you had any idea why gas went up | 30 cents in the last 3 weeks? All of the sudden it was expensive again.... | Also have you noticed that Bacon and Butter both arte in the 4-5 dollar a | pound range now? | What the hell is going on in this wonderful sun shiny state of ours??? | | Gumby619 | | Drive it IF you can afford to, wax it if ya can't | | |

That's all I used in my 89 5.0. No problems.

Al

What the owner's manual specifies.

Probably not; if you're not pinging and your engine control unit does not automatically retard timing based on detected knock, then higher octane won't help. As far as I know, the current GT does not use a knock sensor, so no pinging means enough octane.

(I have first-hand experienced a vehicle where pinging is not normally audible but is occurring enough to cause ignition retard by a knock-sensor-equipped engine control unit. In this car, using a higher octane gas detectably improved low and mid- range throttle response because timing was no longer being retarded)

As far as any pump gas you can commonly buy, running too high an octane will *not* damage the engine. There's plenty of FUD on the topic but I have yet to see one credible report of damage or even reduced performance due to using high-octane pump gas in recent US history.

Sure, there are instances where people have poured "octane booster" additives in their ranks and fouled plugs, O2 sensors and/or cat converters. The same is true of older aviation gas (which used to be loaded with TEL (lead)). But commonly-available quality pump gas is not going to damage your car.

Dana

Entering into the unknown, V'ger seeks information used to maintain his Vintage Burgundy 1965 Ford Mustang 2+2 w/289 ci 4v oem A Code V8, C4 Trans,

16x8" Vintage 40 wheels, with BF Goodrich gForce T/A 225/50ZR16 tires, American Racing "Mustang" Centercaps, and a whole lot of other stuff; )

Still is.. 100 octane "low lead" aviation fuel has approximately 16 times the lead as leaded car gas used to have.. Our only restriction to burning it in jets is a certain number of gallons per time between "Hot section" (turbine) inspection due to lead build up on turbine blades.. (but to me.. anything that is THAT hot, turning 33,000 rpm, should sling lead off..) enough trivia for the day Chuck...

Octane is a measure of how 'hot' the fuel burns, the higher the octane the colder it burns. Sounds rather counter productive, but the colder burning fuels were developed for the higher compression engines. You should run as low an octane as you can without the engine pinging.

No it's not! It's a measure of a fuel's ability to resist knock (detonation) during combustion in a spark-ignition engine. A single-cylinder four-stroke engine of standardized design is used to determine the knock resistance of a given fuel by comparing it with that of primary reference fuels composed of varying proportions of two pure hydrocarbons, one very high in knock resistance and the other very low. A highly knock-resistant isooctane (2,2,4-trimethylpentane, C8H18) is assigned a rating of 100 on the octane scale, and normal heptane (C7H16), with very poor knock resistance, represents zero on the scale. Octane number is defined as the percentage of isooctane required in a blend with normal heptane to match the knocking behavior of the gasoline being tested.