Octane and other fuel questions...


paqman
06-27-2010, 04:46 PM
Hey, I just bought a 2001 Mustang GT, it's all pretty much stock, except the guy put a Magnaflow exhaust on it. He said I should run the high octane stuff, but the manual says 87 is recommended. I know I shouldn't run the low stuff, but what should I be running?

Also, in most of my other cars, I run a can of 44K fuel cleaner through the tank about once a year. Can I still do this to my mustang? I'm just trying to figure out how to treat her right so she runs good for a long time.

Also, what type of oil should I use? I know full synthetic, but any particular brand everyone likes?

paqman
06-29-2010, 10:01 AM
Man, these forums aren't as active as they used to be. Bump.

Blue)(Fusion
06-29-2010, 10:39 AM
Motorcraft full synthetic is just as good as the other Group III synthetics (i.e. Mobil 1, Castrol Edge, etc.). Royal Purple or Amsoil are Group IV synthetics (true synthetics) if you want to go that route, but I think it's overkill.

Do not run higher than 87 octane if you do not have a tune to support the higher octane. The higher octane will kill your catalytic converters and will result in lower gas mileage with no increase in performance. If you want to use higher octane, get a computer tune supporting it which will have advanced timing which will be able to extract more power from it without detonation. You will still lose gas mileage since higher octane has a lower BTU per quantity.

paqman
06-29-2010, 10:46 AM
Motorcraft full synthetic is just as good as the other Group III synthetics (i.e. Mobil 1, Castrol Edge, etc.). Royal Purple or Amsoil are Group IV synthetics (true synthetics) if you want to go that route, but I think it's overkill.

Do not run higher than 87 octane if you do not have a tune to support the higher octane. The higher octane will kill your catalytic converters and will result in lower gas mileage with no increase in performance. If you want to use higher octane, get a computer tune supporting it which will have advanced timing which will be able to extract more power from it without detonation. You will still lose gas mileage since higher octane has a lower BTU per quantity.

Thanks, that's great information. I'll stick to the Group III synthetics then. And thanks for the info on the fuel. One more question. What about a fuel system cleaner like 44K? I've been using it about yearly on all my other cars, but they've all just been regular cars, nothing like this, and I've known people that swear by it. Should I do the same thing on my mustang?

paqman
06-29-2010, 10:52 AM
Oh I forgot. I heard someone tell me that if you start using full synthetic, that you shouldn't go back. Is that correct? I'm not sure if the previous owner has been using it or not, but I've emailed him to find out.

Blue)(Fusion
06-29-2010, 12:49 PM
You can use a fuel system cleaner. I run half a bottle of Seafoam in a half to 3/4 full gas tank and use the other half through the PCV valve to clean out the cylinders. I NEVER add it or any other solvents to oil. The only oil additive I use is Auto-Rx which is not a solvent.

You can go between dino, semi, and full synthetics just fine. The argument is actually to not go from non-synthetic to synthetic because synthetic oil molecules are smaller can can fit through older seals easier. I've used Mobil 1 5W-20 for a few changes in my car which ran Motorcraft semi-synthetic 5W-20 since new. I had no leak issues or any other change is driveability or oil consumption.

Since Mobil 1 was still pretty clean after 4,000 miles when I changed my oil, I switched back to Motorcraft semi-synthetic since I prefer shorter OCIs to more quickly detect any problems before they cost me money, such as watching for nylon and aluminum in the oil from the crappy timing chain tensioner arms Ford used in some 4.6L engines from 00-03, atleast in Crown Vics and Marquis'.

paqman
07-07-2010, 02:46 PM
You can use a fuel system cleaner. I run half a bottle of Seafoam in a half to 3/4 full gas tank and use the other half through the PCV valve to clean out the cylinders. I NEVER add it or any other solvents to oil. The only oil additive I use is Auto-Rx which is not a solvent.

You can go between dino, semi, and full synthetics just fine. The argument is actually to not go from non-synthetic to synthetic because synthetic oil molecules are smaller can can fit through older seals easier. I've used Mobil 1 5W-20 for a few changes in my car which ran Motorcraft semi-synthetic 5W-20 since new. I had no leak issues or any other change is driveability or oil consumption.

Since Mobil 1 was still pretty clean after 4,000 miles when I changed my oil, I switched back to Motorcraft semi-synthetic since I prefer shorter OCIs to more quickly detect any problems before they cost me money, such as watching for nylon and aluminum in the oil from the crappy timing chain tensioner arms Ford used in some 4.6L engines from 00-03, atleast in Crown Vics and Marquis'.
Thanks for the info, that's very helpful. I think I'll continue my yearly 44k tradition then. And I think I'll just stick to full synthetic, I did talk to the previous owner, and he was using mobil 1. And I've always just let this great little shop down the road do my oil, because they could do it cheap and quick for me, but maybe I'll start doing it myself so I can have a good eye on the innards more often than I normally would.

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