Regular gas in place of premium?

[iced_earth]

As has already been mentioned, it depends on the engine. I have a V8 and my wife has a turbo I4 and both cars are "Premium Recommended," but they both have knock sensors and can handle Regular. I've read that there is only a performance hit, not a MPG hit, but I can't really confirm if that is the case.

Regarding fuel ratings, they are different between the US and Europe (go figure ):

http://en.wikipedia.org/wiki/Octane_rating#Regional_variations

[AdRock]

. . I have no idea,but love to run that in my STi.

ps: 5W-20, sounds like you have a Honda or Ford. I was told only to run that specific weight,asked the tech when I bought my 02 civic. Because of the very close tolerences do not go heavier. The thicker the oil the slower it gets to the top of the motor,the thinner oil helps at start up so parts get oil faster.
Also a thicker oil may effect gas milaege as well,I'd stay with 5W-20 per manufacturer recc. Unless you live in Arizona etc,extreme heat all year round.

I do know that with Fords, the early 4.6's had a requirement of 5w-30 oil. In 1999 they changed it to 5w-20. The tolerances didn't change in the engine at all. The only reason they went to a thinnner oil was because CAFE standards were giving tham a hard time. They were able to eek a little more mileage out of the thinner oil to satisfy CAFE. I have an 02' GT and I use 5w-30 because that is what these engines were originally meant to have.

[Cleveland Metal]

Somewhat related question...my car's manual "recommends' 5w20 oil. Would 10w30 hurt it or would it just need an oil change more often?

Aside frompreviously mentioned good facts, a difference YOU may be notice is in the physical feel you get through the shifter when changing gears... Changing fluid types may make the trans feel sluggish or on the other hand "notchy" while moving the shifter, and maybe display these characteristics at different RPM levels as well. Both will lubricate properly.

I'm a fan of synthetics, because they arent effected by temps (for one reason). Some people don't like how the trans feels with it tho... I've seen some trans's pop out of gear once going to synth, but that is another internal issue (just might not show up otherwise).

Amazingly, a lot of it is in your perception of how you want it to feel. If you're used to one way, the other way may not be appreciated

[Cleveland Metal]

As sorta touched on, regular gas in a modern car may run without damage, but the knock sensors will alter timing so much that mileage will seriously suffer.

On another note, a car that is made to run on regular gas, will often get worse mileage on premium since premium is actually harder to combust in a low compression engine.

Some lawnmowers wont even run on upper premium.

[Spivonious]

Aside frompreviously mentioned good facts, a difference YOU may be notice is in the physical feel you get through the shifter when changing gears... Changing fluid types may make the trans feel sluggish or on the other hand "notchy" while moving the shifter, and maybe display these characteristics at different RPM levels as well. Both will lubricate properly.

I'm a fan of synthetics, because they arent effected by temps (for one reason). Some people don't like how the trans feels with it tho... I've seen some trans's pop out of gear once going to synth, but that is another internal issue (just might not show up otherwise).

Amazingly, a lot of it is in your perception of how you want it to feel. If you're used to one way, the other way may not be appreciated

Interesting...it does seem to pop out of gear more often than my old Toyota pickup which took 10w30.

I do know that with Fords, the early 4.6's had a requirement of 5w-30 oil. In 1999 they changed it to 5w-20. The tolerances didn't change in the engine at all. The only reason they went to a thinnner oil was because CAFE standards were giving tham a hard time. They were able to eek a little more mileage out of the thinner oil to satisfy CAFE. I have an 02' GT and I use 5w-30 because that is what these engines were originally meant to have.

FYI, it's the 2.0 Zetec engine...don't know what oil they originally took.

[DonP]

Aside frompreviously mentioned good facts, a difference YOU may be notice is in the physical feel you get through the shifter when changing gears... Changing fluid types may make the trans feel sluggish or on the other hand "notchy" while moving the shifter, and maybe display these characteristics at different RPM levels as well. Both will lubricate properly.

I'm a fan of synthetics, because they arent effected by temps (for one reason). Some people don't like how the trans feels with it tho... I've seen some trans's pop out of gear once going to synth, but that is another internal issue (just might not show up otherwise).

Amazingly, a lot of it is in your perception of how you want it to feel. If you're used to one way, the other way may not be appreciated

Engine oil effects the way the transmission works? Never heard that before.

I use Mobil 1 Synth in the Acura. For as much money as that car costs, I'm taking very good care of it.

[CharvelRocker]

I don't buy into Synthetics. We've never junked a car with an engine failing due to something oil could prevent. And we've run ours into the ground; our Ford had 245k miles and the engine ran great. Also, we had an ld Nissan that had around 185k on it. Our Pontiac had 195k on it before it was junked. Next, our Hyundai had 175k on it. The engine still runs fantastic on our 15 year old Toyota at 150k. All of those cars were/are still running GREAT until it either stopped being cost effective to maintain them, or in the case of the Hyundai, the transmission came apart. Cars have run great and lasted for years and hundreds of thousands of miles without synthetics. Why change now?

[DonP]

Why change now?

Because I can and it makes me feel better

[Cleveland Metal]

Engine oil effects the way the transmission works? Never heard that before.

I use Mobil 1 Synth in the Acura. For as much money as that car costs, I'm taking very good care of it.

No, I was talking about some cars run engine type oil in the manual TRANSMISSION gearbox. (some use gear oil, 30 weight oil, ATF or factory recommened stuff like synchromesh etc)


Onthe ENGINE side of things
The advantage of synthetic engine oil in the ENIGNE, is that the viscousity stays teh same regardless of how cold it is (no slow cranking in sub zero weather), how hot it is (doesn't thin out at extreme high heat), Has superior lubrication properties and lasts longer (does not break down fast at all).

[SEEGERMANY]

"Castrol GTX 10W-30 works for me!"

[dg]

I use synthetic because I change my own oil and would rather do it at ~7500 miles than every 3 - 5K, plus I get better mileage and the engines run a bit cooler, both of which indicate that is is a better lubricant.

[jwoods986]

If you can use premium, it will say it's recommended. If you can't, it will say it's required. We ran into this when we were looking at a new car, and were interested in a couple Nissans, and the dealer told us you can put regular in it, but it will probably hurt the amount of power you get somewhat.

+1. It's all about the terminology, whether the manufacturer says premium is "required" or "recommended". We bought a new Murano last year, and Nissan "recommends" premium for maximum performance, but it's a freakin' SUV not a 350Z, so we've been putting regular in from day 1 with no problems so far, 1 year and 13,000 miles into it. On the other hand, I'm considering an Infiniti G35 and would definitely put premium in - I want to make sure I'm getting all 306 horsies!

As far as synthetics, I think (again) it depends on what/how you drive. If you drive a regular, day-to-day car, regular oil is fine. But I would go with synthetics on a sports car, especially a turbo. Synthetics are more expensive, but they allow you to go longer between changes, so it kinda evens out price-wise but you get better protection. I had a Boxster that used Mobil 1 and oil changes were recommended every 15,000 miles! And that's from Porsche itself, not some backyard mechanic.

[joelayres]

I run synthetic oil in my Harley, which has had it since the first oil change. Benefit is that at 22K mile, the engine when tested and put on a dyno performs as well as a newly broken in engine. Plus, living in AZ with all of the dust, the synthetic is definitely worth the few extra dollars.

[Spivonious]

I had a Boxster that used Mobil 1 and oil changes were recommended every 15,000 miles! And that's from Porsche itself, not some backyard mechanic.

Yeah, my Dad's BMW 328xi just needed its first change - at 19,000 miles!! The car has a computer in it that tells you when it needs to be changed.