I noticed something about using different fuels, do you notice the same?

fox1x · Feb 1, 2006

I have a 2000 MGT, since I bought it (about 4 months ago) I have used just 87 octane. The car runs suberb. I get about 19 MPG mixed driving, and on my trips back home I'm getting around 23 MPG. However, I decieded for shats and giggles to put some 89 in the car. It *seemed* (maybe just a placebo) to have slightly better throttle response. The car, to me, felt like it was running better on 89. So, for the next 3 fill-ups I put in 89. My mileage dropped to 17 MPG mixed and 20 on my trips home. I was trying to drive as consistant as possible.
I decieded to try 93 octane. Didn't notice a difference drom the 89, milage remained about the same as with the 89. Only did that for 2 fill-ups, then went back to 87. I just filled up this morning with 89 again and the car feels smoother. Do the MGT's prefer 89? Anybody else noticing this with their car? Or, am I full of it? I swear though, this car feels more responsive with the 89.

(I know with my previous cars 93 was all I used, it even states in the manual and on the fuel door "premium fuel only." However, those were high compression motors; I thought the 4.6 was designed to run on 87.)

Mustang5L5 · Feb 1, 2006

it is designed to run on 87 octane. Only the 4.6L DOHC in the Mach's and Cobras (and certain Lincolns) require premium.

Engineeringwise, the engine should make more power on 87 octane. The motor is not really a high compresson motor so running higher octane shouldn't really do a thing for you.

Some guys expeirence detonation on 87 octane, myself included. Cars has done that since 9000 miles. SO every now and then i put it a little bit of 89 octane to keep that under control.

the98stang · Feb 1, 2006

Don't mean to steal the post, but my stang seems to run worse with "cheap" gas. I thought all gas came from the same company/place....

Mustang5L5 · Feb 1, 2006

Maybe it's time for a tune up??

They say gas is all the same, but i don't beleive that. Each company adds different additives and lubricants and such.

fox1x · Feb 1, 2006

Not all gas comes from the same company. There is *some* validity about gas coming from the same place... there are only so many places it is currently being harvested from. There is crude oil from South America, Middle East, Gulf of Mexico, etc.

Anyhow, maybe it is just my imagination, that's why I posted here. I swear though, it feels a little more peppy with that 89.

USMstang · Feb 1, 2006

I never noticed much difference in any brand I used while out on the road (first 40,000 miles). When I reprogrammed with the Predator, I noticed a huge difference in brands of 93. The difference was in detonation not peppyness.

jayssilver4.6 · Feb 1, 2006

The only time I ever run the good stuff(ie 93 octane ) is when I bump my timing up with the timing adjuster. Other wise I can't feel any differance in the 3 grades. Every so often I'll run 2 tanks of the good stuff and a can or two of Chemtool to clean it up a bit. I've not ever noticed any detonation on the cheap stuff. As for the brand of gas thing, I live in Texas and we have refineries there on the gulf and there is a company called Coastal Petrolium Deliveries ( or something like that ) that delivers a lot of gas. I see that truck at every gas station in town except for the valero and Wal-mart, so what does that say...

The Stang GT · Feb 1, 2006

The 4.6L is a Sports Car, You should only run 91-93 octane in your car.

jimfitzgerald · Feb 1, 2006

A stock Mustang GT is designed to run 87 octane. Higher octane fuel is harder to ignite and will actually lose power. If you bump your timing with a timing adjuster or tune, you will need to run higher octane to prevent detonation.

03ghoststang · Feb 1, 2006

Mustang5L5 said:
Maybe it's time for a tune up??

They say gas is all the same, but i don't beleive that. Each company adds different additives and lubricants and such.

yup thats true each company throws in a blend of additives but most are used by all except for a few.....example like the winter blend for certain states that their fueal is oxyginated

ocbaud · Feb 1, 2006

i usually run 89 in mine because with 87 i get detonation under wot

jcint · Feb 2, 2006

I tryed 87 and my 96 gt stock and it runs crappy you hear knocks on the engine when i floor it. 89 runs ok depending where i got the gas but 93 ALWAYS runs good on my stock GT.

40oz · Feb 2, 2006

jimfitzgerald said:
Higher octane fuel is harder to ignite and will actually lose power.

That might sound good, but it makes no sense. Once the spark fires, it all burns. Octane rating only means it takes a higher pressure to ignite without a spark. It doesn't mean they added dirt and water to make it burn poorly :/ Higher octane gas might indeed have less energy per liter than say, 87, but the difference is so minimal you could make it up by cleaning out your glove compartment. A bigger issue concerning energy density would be oxygenated fuels used in the winter in most cities. Oxygenated fuel has less energy than non-oxygenated fuels, per liter, and you will get noticeably worse mileage.

AFAIK, the flash point of a fuel is unrelated to the amount of energy it stores. And octane has nothing to do with the speed at which the flame front propogates.

All gasonline isn't the same once you include additives, so one brand's 87 might knock, while another brand's doesn't. Every station in an area might get their gas from the same refinery, but use different additives to get the octane numbers they sell.

sgarlic · Feb 2, 2006

The Stang GT said:
The 4.6L is a Sports Car, You should only run 91-93 octane in your car.

Wow.. wrong, wrong and wrong.

First off, the 4.6L is an engine, not a sports car.. but assuming that was just a typo, let's move on. That particular engine is found not only in Mustangs, but other cars as well. Do you consider the lincoln town-car a sports car? I sure don't, but it has the 4.6.

Secondly, you should run what the manufacturer recommends (which is not 91 or 93 octane in the GT's) unless you have reason to run otherwise, which has been addressed in this thread numerous times already.

I apologize to the original poster for getting off topic.

Master_Chief · Feb 2, 2006

I experimented a little, just put like 5 buck worth of gas at a time, my car HATES regular, so I usually use 89, abd every once in a while, I will fill it with 91/93, it does seem to react better, plus, when you think about it, you really aren't dumping an extra c-note by upgrading to better fuel, I think it is worth it.

40oz · Feb 2, 2006

i figure the cost of a new engine from knocking and detonation is far more than what I spend on the extra $2 or $3 buying premium, so I run it. I'm certainly not suggesting it makes sense, or everyone should. However, i did have an 80's 2.2 turbo that detonated itself to death on 92 octane a number of years ago, so I might just be overly concerned about it

Basically, according to every technical article I could find, just because your car says 87 octane in the manual doesn't mean it won't knock with some 87 octane gas in some conditions. So it would make financial sense to run the lowest octane that never detonates in your car.

I noticed on long trips between Chicago and norther MN that the car seemed to run smoother on 91 than on 87, but mileage was not noticeably different. So I run 91 all the time in my 03. The fact that it doesn't "need" it is just a nice thing to know.

dustang50 · Feb 2, 2006

BP gas is crap. I've been told by my Ford dealership to steer clear of the big green...

After tuning my car I've had to use 91+ octane. It "seems" that my car runs better on Shell & Sunoco, but I think it's all in my head...

Kilgore Trout · Feb 2, 2006

Your "study" was hardly scientific and your "results" are anecdotal at best.

Anyway, for the stock tune best to use 87.

In any case, use the lowest octane your can use without getting detonation.

BooWFO · Feb 2, 2006

I haven't noticed any real measurable difference in grades of gas. Now where the gas was purchased I have noticed a difference. If you for example purchased the 87 and the 89 and 93 at different places then that may explain the differences you saw.
Also oxygneated fuels SUCK I get stuck using it most of the time. I get worse mileage and when I'm planning on spraying I have to go outta town and get good fuel.

Mustang5L5 · Feb 2, 2006

The Stang GT said:
The 4.6L is a Sports Car, You should only run 91-93 octane in your car.

Why?

I disagree 100% but why make such a bold statement and not back it up with any supporting facts.

I noticed something about using different fuels, do you notice the same?

New Member

That is…until I whipped out my Bissell

Active Member

That is…until I whipped out my Bissell

New Member

Member

New Member

New Member

New Member

Well-Known Member

Member

Member

Member

New Member

Member

Member

Fried or Broiled ?

New Member

That is…until I whipped out my Bissell

Similar threads

Privacy & Transparency

Privacy & Transparency