Am I wasting money on premium fuel?

turbotim2 · Post by **turbotim2** » 10 May 2007, 10:45

WHAT???!!! 15 -20 hp ??? That is absolutely absurd. Though I guess that is how you are able to smoke those Chevy Cavaliers huh?

Post by **kelvin6** » 10 May 2007, 10:52

I use premium fuel on my non-turbo.
Whenever I use regular I notice a dip in my MPGs anywhere from 1-4mpg!
I did the math, and took into account the price difference between regular and premium here.

I may save three dollars at the tank, but I discovered that with the better fuel economy from premium, it was overall cheaper to run premium. I drive in city enviroments, with stop and go and steep hills (San Francisco). My average MPG for city (90%) is roughly 15-16MPG.

zenmervolt · Post by **zenmervolt** » 10 May 2007, 11:18

turbotim2 wrote:WHAT???!!! 15 -20 hp ??? That is absolutely absurd. Though I guess that is how you are able to smoke those Chevy Cavaliers huh?

Who said a damn thing about smoking anything? You need to deal with that anger issue buddy. It's OK for you to be wrong.

On the 5-cylinder non-turbo you're talking about 168 hp when running premium. Retarding the timing sufficiently to reduce knock with 87 octane on a hot day and under load a 10% drop in power is pretty normal. 10% of 168 hp is...

Now, will the average person notice the difference between a 151 hp engine and a 168 hp engine? Under normal circumstances it won't be a problem, but the car will definitely feel more sluggish if you've got a full load of passengers or cargo.

It's very clear to me that you're getting your information from the same kind of place that is perpetuating the BS that you should fill up in the morning to get extra gasoling because it's cooler.

turbotim2 · Post by **turbotim2** » 10 May 2007, 11:29

Yea...hehehe sounds like you're the angry one, my friend.

And when does the engine produce 168hp? At 6000 rpm. When does anyone reach 6000 rpm? Only when they are racing the engine, I doubt you do it often in the hills of SF or when you have a child strapped into the back seat.

Lets drop it - we're talking about family sedans and wagons. Horsepower and high test fuels are arguments for a different forum.

Oh - and I'm right!!!

zenmervolt · Post by **zenmervolt** » 10 May 2007, 11:46

turbotim2 wrote:Yea...hehehe sounds like you're the angry one, my friend.

And when does the engine produce 168hp? At 6000 rpm. When does anyone reach 6000 rpm? Only when they are racing the engine, I doubt you do it often in the hills of SF or when you have a child strapped into the back seat.

Lets drop it - we're talking about family sedans and wagons. Horsepower and high test fuels are arguments for a different forum.

Oh - and I'm right!!!

Interesting how a coldly-reasoned argument is "angry". Must be a new definition of the word.

The engine suffers a similar percentage power loss across all RPM ranges, it's not that the peak simply falls, the whole curve falls. So at 2,000 RPM, you're still losing power. The engine is just a little softer, especially under conditions that create detonation when the engine management pulls back timing (and boost if turbocharged) most; heavy loads and/or hot days. It's noticeable. Just like how noticeable the difference between a RWD and a FWD car is when going through a corner. It's there; it's subtle, but it's there.

You're "right" that running regular will cause no damage, but that's pretty clearly not what I was referring to. What's wrong is your evaluation of how much power is lost and that's not going to change.

dejongmc · Post by **dejongmc** » 10 May 2007, 13:51

I agree with kelvin6, have same experience.
You pay a little more for premium, but it does give you better mpg. At the end it is a little cheaper to run Premium.

Also, my car runs smoother with Premium, much better ride.

But be carefull were you get Premium, because I noticed that there can be a quality difference between different gas stations, as less people use premium, so the Premium can be too old sometimes.

five40i · Post by **five40i** » 10 May 2007, 18:46

I have a '98 XC70. I drive 160 mile round trip to work every day and I have used regular and premium gas (87 and 93 octane). I get the best mileage with premium by about 50 miles.
If I fill up with regular I can get about 480 miles on 17 gallons. If I fill up with premuim I get about 530 miles on 17 gallons. I usually run till the low fuel light comes on and then fill up. All my driving is highway driving, not much stop and go except for some construction.
And by the way, my other Brick gets about the same mileage, it is an '89 740 with 140,000 miles
So I would go for the premuim everytime, it costs a bit more at the pump but you save with the mileage and the wear and tear on your engine.
I would never recommend running regular gas in a turbo engine. The reason you have a turbo is for increased performance. Use it....Volvos get great mileage.
My wife drives an '04 Vibe and it doesn't get near the mileage I get with my bricks. I doesn't drive as good either...Thats my 2 cents.

Hugh Wilson