Do you run regular or supreme-differences?
 

This question was thought of due to maleficio's topic-essentially the price of gas.

Do you run regular or supreme gas.
Have you experimented.

What were your findings?
Curious.

I ran regular in my 80, and premium in my 85. I don't experiment with an engine that is worth more than my car.

I do not think whatsoever anyone will destroy their engine due to a few differences in #'s.

I have experimented with both.
The conclusion is......................nothing! No differences whatsoever!

I run 89 mid grade in both my 928's. Just my preference.

I usually run 92 Octane, just because it's my weekend toy...so, I just give it the good stuff.

Does it make much difference? Probably not....

US runs fine on 89 or 87 which is Calif Reg, the Euro needs 91.

I was using 93 when I first got the car but since I am using 87 and no difference at all.

There is a plug on the computer to adjust for lower octane. I do put in some injector cleaner every so often.

I too have switched from Premium to the mid grade. For 15 years I only used the Premium Grade fuel, but decided to try the mid grade last year. I haven't found any difference except the $/Gal. I'm not yet ready to try Regular.

not true at all. When I bought my used motor some of the ring landings were broken. I was told it was due to detonation. The higher comp motors generally have ecu's that can detune the motor in the event of low octane gas if the detune is still not sufficient there can be damage due to detonation. It all depends on which motor your running.

I run what ever the highest grade they pump has. 91, 2, or 3 . the difference is like 4-5 bucks on a half tank of gas. I have not tried 87 in it, but I do notice a difference when I run different grades in my truck. It seems to drive better, I had played around with the grades in my truck before I had my car. once i got the car I just threw the good stuff in it. It says in the manual to use 87 octane but what do you think the 87 octane of 1980 is compared to the 87 octane of 2012....

not sure with newer cars but 80 and older calls for 91ron that is equal to 87us. these are low compression engines and do not need high octane. but feel free to use what ever your wallet allows!

My Porsche mechanic said "Hell No!" when I asked him this same question. He said that 87 octane was like there was a little man inside your engine with a hammer just beating the hell out of the internals. That was good enough for me. Premium only in my 87 928s4, and 84 944.

If you have a 32v engine in your car, don't be that guy us mechanics love. The one that puts in the cheapest stuff and then cries when the cars break. Lower octane gas results in timing pulled from the ignition, resulting in lower power and lower gas mileage.

Where is the gripe over premium, gas here is like 87/89/91 $4.19/$4.29/$4.39 I even put premium in my wifes car from time to time, but it detects the quality of gas and takes advantage of the 91 with a bit more power, we just really rarely floor it.

Fair chance when I get into sharktuning etc on my 85 Euro that I run more than one tune and have one that likes race gas, and one that is ok with pump 91.

i have been running 91 in my 86 stock 3.2 recently tried 87 havent noticed any difference in it at all. if the book says use 87 why not?

I daily drive with 87. I have a us spec S3 auto and I keep the rpm's between 2k and 3.5k . As long as you're not lugging, or trying to redline every gear 87 should be fine IF your car is in good running condition (no vacuum leaks, bad sensors,etc).

I run what the manual calls for which is 87 in my '82. If I had a later model with knock sensors, I'd use 93 as the car can actually take advantage of the increased octane.

Octane is like an oil thread. I own a Hayabusa motorcycle which makes 175 HP stock and the manual calls for 87 octane. On a Busa forum I belong to, guys have done 1/4 mile tests with 87 vs. 93 and 93 was slower every time. They then put the bikes on a dyno and compared the 93 which had slightly lower HP each time. People have gone out of their way to prove you're flushing money down the toilet by putting premium in a vehicle not designed for it and yet boneheads still insist on "treating my baby with the best" premium fuel. No doubt the same guys who think the sugar pill is a cure all. :)

Avoid Ethonal ?
 

I kind of rotate between all three grades of gasoline and have found that the 89 octane is a reasonable compromise for overall performance vs operating cost. A seat-of-the-pants evaluation does seem to indicate that the 85 928 is happiest on 91 octane. Can anyone find gasoline without ethonal in your area ?

Many automotive evaluations recommend that you try to avoid ethanol product blends. From what I have read, the reason for ethanol is overwhelmingly out weighed by the negative side of the argument. Just the fact that it is more expensive to produce, generates less energy when burned and takes more to travel the same distance is enough for me. But when you throw in the grain shortages produced by the ethonal program which increases the cost to anything and everything related to corn, yikes.

Michael

I run whatever is cheapest most times, but I use Lucas Octane Booster. I'm not sure if it really gives much of a boost, but the cars seem to run a little better with more power. I buy Shell V power from time to time and run it by itself. I use the Berryman's Chemtool once in a while to keep the fuel system clean from petroleum deposits. Usually just a cap full or a little more. My cars start every time. The longest, I've let one go down is three months. I charged the battery and it fired right up.

We've had nothing but 10% ethanol since the late 70s. Started appearing about the same time as emission testing began. As a little kid, I remember seeing the corn symbols on the gas pumps and everyone panicking over "gasohol". Sometime in the 1990s gas changed again with some type of oxygenated blend which has a very acrid smell. Pump nozzles also got a vapor barrier flap.

If I go further south into Indiana where there is no emission testing, I can find fuel without ethanol, without oxygenated blends (smells like good old fashioned gas) and the pump nozzles have no flaps. It's getting very difficult to find these days and even the pure gas type of websites don't list many places.

That said, I've never had fuel system issues. I've not had carburetors from the 1960s dissolve internally. No issues with the lawn tractor, snowblower, weed-eater, leaf blower and chain saw...seasonal items that I simply park in the spring or fall and they start right back up again come next season with the old gas. Most are over 10 years old and I've never had a carb apart on any of them. Same goes for winter storage of motorcycles and cars and I never bother to use Stabil type additives.

The 10% ethanol horror stories are way overblown. Power loss is there but you'd practically need a dyno to see. While traveling with a fuel efficient car I can see a marked mileage increase once I use up the gas I bought in my area and begin filling up with non ethanol fuel in other parts of the country. That's the one reason I would like to see ethanol disappear. But I hear some areas are wanting to push the limit to 15%.