what kind of gas?

[chingador]

For the tau V8 owners, what octane level gas do you use and why?

 

[TJPark01]

87. Tried both 87 and 91, couldn't tell a real difference.

 

[moose66]

I use the regular. I guess I am giving up the perfomance gains. Not like I am flooring it on a regular basis and needs those extra horses. Oh well.

 

[wallymn]

I use 93 I try to buy at my local BP (support small town business) but if I need gas when at the office I use 93 from Super america.

I noticed a difference between 87 and 93. (I only ran 1 tank at 87 as a test).

 

[ctrcbob]

For my type of driving, I've found NO DIFFERENCE between the 87 and 93. With the 87
I have 7 hp less than when using the 93, and I can live with the 7hp less.
(368hp vs 375hp)

 

[TJPark01]

I use 93 I try to buy at my local BP (support small town business) but if I need gas when at the office I use 93 from Super america.

I noticed a difference between 87 and 93. (I only ran 1 tank at 87 as a test).

Regular is still 3 bucks in SoCal. If it was cheaper, I would be tempted to use super

 

[Dimitry]

91, or 93 where available. I like using my ponies.

 

[HughH]

91, or 93 where available. I like using my ponies.

I have tried both on my Lexus GS 350 with no discernible difference in performance or milage. I just give the minimum amount of my money to the OIL COMPANIES. Just enough to get around!

 

[scottdk]

I have tried both on my Lexus GS 350 with no discernible difference in performance or milage. I just give the minimum amount of my money to the OIL COMPANIES. Just enough to get around!

What are you using to measure the performance difference between octanes? Science shows in certain engines that a higher octane fuel will provide more horsepower vs a lower octane fuel. A turbo charged or supercharged engine would be a great example of this. Others would be an engine designed with performance in mind such as the V8 Tau, or LS1.

A 25HP boost is power you can feel. 7 HP is not possible to feel the difference, except at the track, on the street where the setting has a form of measurement such as numbers.

Milage on the other hand is up in the air, or maybe too small of a difference to matter.

 

[wallymn]

What are you using to measure the performance difference between octanes? Science shows in certain engines that a higher octane fuel will provide more horsepower vs a lower octane fuel. A turbo charged or supercharged engine would be a great example of this. Others would be an engine designed with performance in mind such as the V8 Tau, or LS1.

A 25HP boost is power you can feel. 7 HP is not possible to feel the difference, except at the track, on the street where the setting has a form of measurement such as numbers.

Milage on the other hand is up in the air, or maybe too small of a difference to matter.

What I noticed during the tank....

It felt more powerful at the low end (from 2k rpm ) which isn't a peak #, I would like to see a dyno run on 87 followed by a run on 93 to see the bottom end of the power curve.

It also seemed to rev more quickly....

Just my seat of the pants experience.

The difference in price 2.52 for reg 2.68 for 93 isn't so high as to make me drop grade... If we get back to 4$ gas, ask me again.

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[Sayantsi]

Imo you'll be hard pressed to feel a 7 hp difference in this car between normal and premium fuel - its a 2% power difference. Maybe you see a bigger mpg gain with premium, which is why I'd use it - I have seen bigger gains in mpg when using premium then when using regular.

On a side note, I've never understood why people equate switching to and from premium based on the price of gas. While the base cost rises and falls, premium is always ~20¢ more expensive regardless.

And turbo/supercharged engines (any engine with high compression ratios) need higher octanes to avoid predetonation - octane is more about controlling detonation than giving more power.

 

[OBCT]

87/89 all the way over here.

 

[HeavyG]

I'll use premium gas if it's cheap enough. When I do use it, the engine does feel a little more responsive (more "peppy" for lack of a better term).

 

[scottdk]

noticed on the way to work yesterday that regular unleaded was $2.49 and 93 octane premium was 2.59. Enough said right?

 

[PINGGOLF]

Personally...because I DO keep my foot to the floor...ALL THE TIME...I use 93. The difference for me is night and day. I usually purchase from either Shell or BP.

The major difference, in my Gen, is hesitation. I can floor it with 93 and it is solid as a rock all the way. 87, I hesitate from the get-go. It is almost like the car boggs down or floods itself. I have tested this at least 4 times now and the results are the same. I will add a small thing of octane booster in order to help me get through the tank.

Anywho, thats my 2 cents.

 

[HughH]

Some years back, Car&Driver used to have a TV show on one of the "cable" stations.

They ran the experiment of draining the gas tank and refilling, first with high octane and then with low octane. The cars were a Porsche 911 Turbo, a Corvette and another American car I can't remember now. The loss in milage/performance was higher in the American cars than in the German car.

Their recommendation: Save your money for high octane for when you take your car to the track. For around town and highway use, you will probably never feel any discernible difference. If it makes you feel good by using high octane, by all means use it. In cars where low octane is the gas recommended, high octane is not going to make any difference one way or the other.

 

[PINGGOLF]

Some years back, Car&Driver used to have a TV show on one of the "cable" stations.

They ran the experiment of draining the gas tank and refilling, first with high octane and then with low octane. The cars were a Porsche 911 Turbo, a Corvette and another American car I can't remember now. The loss in milage/performance was higher in the American cars than in the German car.

Their recommendation: Save your money for high octane for when you take your car to the track. For around town and highway use, you will probably never feel any discernible difference. If it makes you feel good by using high octane, by all means use it. In cars where low octane is the gas recommended, high octane is not going to make any difference one way or the other.

Thanks for the imput...but I whole-heartily RESPECTFULLY disagree. Its not a "feel-good-ism" for me as I would rather use the 87. BUT...it does "feel-good" not to have that hesitation!

I guess every single road out there is my "track!"

For example. This weekend my wife and I celebrated our anniversary in Nashville--about 150 miles away--we took our Lexus RX400h. About 10 miles into the trip and merging into interstate traffic...something felt weird. There was no knocking or pinging...just hesitation. I asked her what she had used to fill up and she said "regular." To me, a performance guru and one whose foot is huge...the difference is night and day. My wife would never know the difference.

So to wrap things up. If you drive your car like you stole it...you would want premium. If you dont, regular will do you just fine.

Again...thats my 2 cents. Maybe I can make a video...but how do you record hesistation? HA!!!

 

[HughH]

So to wrap things up. If you drive your car like you stole it...you would want premium. If you dont, regular will do you just fine.
Again...thats my 2 cents. Maybe I can make a video...but how do you record hesistation? HA!!!>>>

Personally, I have not used high octane gas regularly since a '77 Audi 5000 that was the first car with "mapped" fuel injection. Prior to my present '07 Lexus GS350 I had a '04 BMW 330. If any of those cars had any hesitation I would've seen to it that the service department would fix it. I will say, I don't drive like you anymore. My wife took away my F1 wannabe license and I had to trade my Bimmer for something more sedate, hence the Lexus GS 350. Since we are now both retired, we only need one car. Looking at Genesis as well as Jaguar XF and a couple of others like Audi and Mercedes. Since I am not a "brand" snob, I wouldn't hesitate to be seen in a Genesis or even a Chevy if I found I could live with one of those.