[stylnTang]

A few days ago, I switched my oil from Catrol, GTX, perolium oil to Mobile 1 Synthetic oil, and I've experienced a few things that seem negative. First let me give a small background. My Mustang is a '05, GT, and was first run on Castrol GTX, 5W-20, and I ran it fairly hard, to give it a good break-in. I did not abuse it, I just opened the throttle up a few good times. Once I reached over 4400 miles, a few days ago, I decided to do change the oil, and switch to Mobile 1, full synthetic, and I ALWAYS change the filter when I do oil changes. I always use WIX filters. My car also has the SLP Loudmouth axel back exhaust. Before I stopped using the Castrol, my exhaust was real loud, you could feel the power in gas pedal, and the engine was loud, and the gas pedal was real sensitive.
So, I put in my Mobile 1 sythetic and I noticed some things. First, the engine seems to run a lot smoother. When the engine is cold, and hasn't been run in a few days, it used to run fairly difficult until it warmed up. Now, with the synthetic, even when it is stone cold outside, and the engine is stone cold, it runs extremely smooth. By the way the engine runs when it is cold, you would not know that it isn't warmed up yet. Second, the exhaust is not near as loud, now that I'm running sythetic. Before, it was VERY loud, and when I down shifted, you could feel the power surging through the car, and the exhaust. Since it put the sythetic in, the exhaust is almost quiet! Loudmouths are supposed to be LOUD, but since I switched to synthetic, it seems to have quieted down a lot!
Third, at definately not least, the car seems to have LOST power. Before the car was real quick, and was powerful. But, since the synthetic was used, the car seems sluggish, slow to respond, and not as powerful.
The manual calls for the car to run on synthetic, and I have given it a good break in with petrolium, but I feel like the car ran better on the petrolium oil, than the sythetic. Most of my racing friends say that when they switched to synthetic, in their race cars, they dynoed a 3-4 horsepower gain, but my car seems slower and sluggier. Does anyone have an experienced, and thoughtful reason for these differences I have noticed? By the way, these changes were noticed IMMEDIATELY after the oil change; and yes, I used 5W-20.

[nonsensez9]

Originally Posted by stylnTang

I always use WIX filters. My car also has the SLP Loudmouth axel back exhaust.

is the WIX filter supposed to be used specifically with synthetic oil? A lot of people say a regular petro-oil filter won't do. might be marketing bs, though.

[Zenmervolt]

The continued use of "seems" indicates that you've made no actual measurements. The "seems" is often wrong and the only way to know for sure is to dyno the car before and after or to have acceneration runs before and after the switch.

In response to what nonsensez9 said, it's pure marketing BS. You can use any good filter with any oil, regardless of synthetic or regular.

[65sohc]

I have used Mobil1 in every vehicle I've owned since Mobil ! came on the market and have never had any bad effects on the engine. I cannot see how how of the changes you have mentioned could possibly be caused by any kind of oil, synthetic or not. Much of the previous power improvement enjoyed by synthetics was due to their ability to provide the same or better protection with less viscocity and thus less drag and pumping losses. Now that our engines use 5w20 much of the drag effect advantage has disappeared. The exhaust being quieter? That just doesn't make sense. Less power? Ditto. I am a psychiatrist and, frankly, this sounds a little crazy.

[stylnTang]

For whatever reason, the exhaust did get quieter, and for the life of me, I don't know why. From the time the engine is completely cold, at start up, to a full day of runs up and down the strip, the exhaust got quiet as soon as I switched to synthetic. Yes, I wrote 'seems' because I do not have a dyno, and no one around me does, so it has not been actually shown to be slower, it's just that the engine was more sluggish, and 'seemed' to be slower than before, and it takes it longer to get up to the higher rpms to get to the higher amounts of horsepower. Maybe when I go to change the oil again, I will add some paint thinner to the mix, so that it won't be so thick.

[Zenmervolt]

Originally Posted by stylnTang

For whatever reason, the exhaust did get quieter, and for the life of me, I don't know why. From the time the engine is completely cold, at start up, to a full day of runs up and down the strip, the exhaust got quiet as soon as I switched to synthetic. Yes, I wrote 'seems' because I do not have a dyno, and no one around me does, so it has not been actually shown to be slower, it's just that the engine was more sluggish, and 'seemed' to be slower than before, and it takes it longer to get up to the higher rpms to get to the higher amounts of horsepower. Maybe when I go to change the oil again, I will add some paint thinner to the mix, so that it won't be so thick.

Or, you know, actually get some real data.

The simple fact is this: 5W20 is 5W20 is 5W20. In order to be rated at those numbers, the viscosity must meet a certain specification. A 5W20 synthetic will be exactly the same viscosity as a 5W20 standard oil at the specified measurement temperatures. The only difference is that the synthetic will flow better in extremely cold temperatures and will not break down as much at high temperatures.

What's going on here is not going on in your engine, it's going on in your head.

[Tominator]

I am a psychiatrist and, frankly, this sounds a little crazy.

I will add some paint thinner to the mix, so that it won't be so thick.

Some people pay good money and NEVER get a proper diagnosis and here we get it for FREE!:thumbsup

AFM

[FoMoCo]

hey 65sohc I have this friend...................................

[Teddo]

Not to be nitpicking, but CONVENTIAL (not referred to as petroleum) and SYNTHETIC oils are made from the same stuff. Synthetic is further refined than convential. It also includes different detergent/additive packages.

As for your other problems, I don't think the oil would cause the engine to be any quieter, unless of course the engine is spitting oil into the exhaust somehow.

In terms of the issues of power, my dad says his '05 GT is slow to respond if you are just driving around normally. Once you step on it a few times, it seems like the computer responds and adjusts the fuel/timing curves and the throttle response (remember it is a fly by wire, so there is no physical connection between the butterflys and the pedal).

[Tominator]

Not to be nitpicking, but CONVENTIAL (not referred to as petroleum) and SYNTHETIC oils are made from the same stuff. Synthetic is further refined than convential. It also includes different detergent/additive packages.

There are various types of synthetics, part and full, but most FULL synthetics have not a drop of petroleum in them.

[FoMoCo]

Motor oils typically are 75-85% basestock with the balance being additives. That’s why basestock quality is such a critical contributor to the performance of the final blended product. There are four different types of base stock used in the motor oil market today.
Group 1 - Conventional - Mineral oil derived from crude oil
Group 2 - Hydroprocessed - Highly refined mineral oil
Group 3 – Severe hydroprocessed - Ultra refined mineral oil
Group 4 – Full synthetics (chemically derived) - Chemically built Polyalphaolefins (PAO).

As it infers Groups 1 – 3 basestocks are derived from crude oil pumped from the ground whereas Group 4 basestocks are chemically derived, most often from ethylene gas, and contain none of the contaminants present in mineral oils. Just as distilled water is pure water derived from gas so Group 4 basestocks are pure oils derived from gas.

[stylnTang]

So, then which one is the best to use, in terms of better performance, AND protection at the same time?

[Zenmervolt]

Originally Posted by FoMoCo

Motor oils typically are 75-85% basestock with the balance being additives. That’s why basestock quality is such a critical contributor to the performance of the final blended product. There are four different types of base stock used in the motor oil market today.
Group 1 - Conventional - Mineral oil derived from crude oil
Group 2 - Hydroprocessed - Highly refined mineral oil
Group 3 – Severe hydroprocessed - Ultra refined mineral oil
Group 4 – Full synthetics (chemically derived) - Chemically built Polyalphaolefins (PAO).

As it infers Groups 1 – 3 basestocks are derived from crude oil pumped from the ground whereas Group 4 basestocks are chemically derived, most often from ethylene gas, and contain none of the contaminants present in mineral oils. Just as distilled water is pure water derived from gas so Group 4 basestocks are pure oils derived from gas.

Note that most "Synthetics" are Group 3 oils. Also note that a "synthetic blend" only needs a single drop of full synthetic added for it to qualify as a "synthetic blend".

[Tominator]

Originally Posted by stylnTang

So, then which one is the best to use, in terms of better performance, AND protection at the same time?

Amsoil is the best in every test by every independent lab, BUT[don't you hate that word! ] ANY Pure Synthetic is better than ANY other type of oil.

Unless you change an extended intervals as I do, just pick your favorite brand. They are all good!

[Zenmervolt]

Originally Posted by Tominator

Amsoil is the best in every test by every independent lab, BUT[don't you hate that word! ] ANY Pure Synthetic is better than ANY other type of oil.

Unless you change an extended intervals as I do, just pick your favorite brand. They are all good!

Funny though how those "independant tests" are only ever found on AMSOIL-sponsored websites though.

The fact of the matter is this: The proper weight petroleum oil, for a street car with a liquid-cooled engine and a 3,000 to 5,000 mile drain interval will offer more protection than is necessary. Synthetic's benefits only come into play in engines that are highly-stressed or that are "air" cooled (air-cooled engines are more accurately called "oil-cooled" and can run oil temperatures nearing 400 degrees), or that have forced induction (synthetics will not "coke" in a turbo housing), or that are used in severely cold temperatures (well below zero, if you don't need block heater, this isn't you), or where extended drain intervals are desired.

A quality petroleum oil with a 3,000 to 5,000 mile change interval and a quality oil filter will give you all the protection you will ever need on a street engine.

That said, Synthetic is very cheap "insurance".