Premium or not Premium, that is the question

[Smedley]

hello group, Ive always put premium gas in my 2005 tbird. Its getting shockingly pricey, what are folks thoughts on this, experience with mid range ?

cheers

Smed.

[Gobird]

To me price doesn't matter. Been using HT for 22 years now.

[ambitio]

I always use premium on all three vehicles (one specifically asks for it). I don't drive as much but I agree with the point about the cost burden.

[Hippie-Dog]

hello group, Ive always put premium gas in my 2005 tbird. Its getting shockingly pricey, what are folks thoughts on this, experience with mid range ?

cheers

Smed.

Well you need high octane fuel because of the compression ratio of your pistons and the cam design and computer is also tuned for 93 octane.

If you have a 2003 or above you can get a tuner that has a regular gas tune feature but that changes spark and I not only wouldn't trust it you will be lacking the former power if it even works.

Spark knock will wear your engine out in short order using regular gas in a premium engine and power lost is power lost until a rebuild. Your only alternative is to mix octane booster with regular gas but human error and the cost difference isn't worth the chance as far as I'm concerned.

Just do the math...

...in my area:

Premium gas $3.77

Regular gas $2.96

so 10 gallons you saved $8.10

Octane booster for 10 gallons costs $5.99

You saved $2.11

It's best to use the correct fuel for your car, it will be listed in the owners manual. Most people don't understand the difference but it is in fact the difference between problems and no problems.

[Quickdraw]

I had a 2002 Lincoln LS at the same time as I had the 2002 bird, both engines were the same. I put over 100,000 miles on the LS and always used 87 octane. I used high test the first 4 or 5 years for the bird as the HT gasoline was much closer in price and everyone else was using 93 octane for their birds. Around 2007 I started using 87 in the bird. I never once heard spark knock in either vehicle.

[JerriLampon]

I use 87 octane in my '02 'Bird, '04 BMW X3, and my "new" '01 Jaguar XJR with no adverse affects. Modern engines
are designed to prevent engine knock under all driving conditions, so I let them.

[007Cruiser]

I had a 2002 Lincoln LS at the same time as I had the 2002 bird.

Are you saying that the bird has flown the coop?

[BLACK BEAUTY]

For the additional cost I'll stick with the best

[DavidA]

I've used mid-grade (89) since it was new. Never had a problem.

[#007Tbirdsteve]

We are on our 5th retro and have NEVER used anything but 87 octane. Never had any knocking and performance is fine for me. The just completed Bayou Thunder with 2000 miles on our 007 confirmed my decision…..no problems. “TRY IT….YOU’LL LIKE IT”!

[ambitio]

This article might be relevant to this conversation : https://www.aaa.com/autorepair/artic...ne-and-quality

The article states:
Contrary to popular belief, premium grade fuel does not contain more power than regular. The energy content of premium gasoline is actually a little lower than that of regular due to its additional anti-knock additives.
The belief that high-octane fuel offers more power came about because automakers require premium gasoline in high-performance engines. However, it is not the fuel that provides the added power, but the engine's "state-of-tune," which involves a number of mechanical design factors. When these elements are optimized to produce more power, the possibility of engine knock increases, and with it the need for premium fuel to prevent engine damage and an expensive auto repair bill.

The article also reminds us that all regular gasoline is the same at the base and advocates for use of high quality (Top Tier) versus high octane gasoline. It defines high quality as the quality of the additive formula various brands add to reduce carbon deposit in the engine. It however refrains from identifying brands it considers Top Tier.

The article concludes:
Here's the bottom line. If your premium-fuel engine runs fine on regular, you never hear any knocking, and the power it produces is acceptable, your car is unlikely to suffer any problems. However, any time you hear engine knock when using a lower grade of gasoline than that recommended by your vehicle’s manufacturer, you need to step up to a higher-octane fuel. Failure to do so will save you pennies now, but may later cost you hundreds or even thousands of dollars in auto repairs if engine damage occurs. It is also important to read your owner’s manual; on some cars the use of regular gasoline where premium is required can void the vehicle warranty.

[Hippie-Dog]

Simply speaking the higher the octane rating the slower it burns (many people think it's the opposite) but it's actually a measure of time. Bigger number, slower burn.

All things being equal lower octane fuel has quicker explosive force than premium.

The purpose of raising the octane is to prevent the piston and pins from being stressed and help to stop the pistons from banging into the cylinder walls. That is what knock is.

In very high compression engines like my built 600+HP GTO you run 102 (airplane fuel) due to the ultra high compressions generated by power addons.

In my 1973 460 Torino anything less than premium would cause the dreaded detonation and destroy the engine.
This is due to timing, high compression pistons and a stroker crankshaft.

The retro birds do have computer control and so you may get away with a lazy drive around town without hearing any knock but if your driving hard you will begin to hear it and overtime you will drop in compression as it wears.

2003 - 2005 has VVT (variable valve timing). So the computer may try to adjust to regular fuel and you may not hear a audible knock or ping.

But over time you will decline in compression in those engines trying to run regular fuel.

Once you wear the cylinders down you will not experience knock but the power lost is gone forever unless you rebuild.

You will also begin to use oil even if you don't see smoke of a leak.

This is not opinion, these are facts known by any good mechanic.

Just because the car runs doesn't mean it's the right thing to do.


BTW some think regular gas is cheap gas but the fact is there is only 1 gas pipeline line to your area and the fuel is blended locally into the different grades and then delivered to the stations.


In any engine it is simply a matter of piston compression that determines the grade of fuel you should use for the best longevity, performance and fuel economy.


You may find by simple testing that the milage loss when trying to use 87 negates any real world saving you think you're getting at the pump.

[BillyL]

Most of us do not put enough miles on our birds for the cost savings from using the cheaper gas to make a difference. I have always used the premium gas, preferably Shell premium. But my wife will tell you I am anal that way, especially when taking care of my T-bird.

[RustyFrye]

A bunch of us are approaching 200,00 miles and have used premium all these years. No negative or positive comment either way, just thought I would post to be part of the crew that just seems to like making posts,

[#007Tbirdsteve]

We missed you in Lafayette, Rusty. So you MUST go to Pappasito’s next year that Issy is going to plan.