Thanks for the lecture and for straying off point. :D

I will simply remind you again to be polite. If you disagree with the advice, you can certainly say so. It is HOW you say so that matters at this point.

Make your point and then, move on.

Agreed?

No save here,Flavor 987s I am not (jcb 986), I am jbs 986, there are some cars that you can run 87 Oct., Are Boxsters use a higher Oct, because are motors are high compression motors, lower Oct, will cause "Engine knock" not a good thing for any Engine. let alone the M96.

I figure if you're in a pinch or in some backwater place where they don't have the octane you need, I imagine the car will run on 87, but first chance you get to throw the proper octane in, it should be done.

The way I see it, and read it in some cars' owner's manuals, most modern cars that are meant to run on a higher octane can run on something lower, though it is not recommended for regular use because over time that will cause damage. So again, in a pinch, you do what you have to do rather than be marooned in the middle of nowhere, and simply fill your tank with something higher when you can.

While not verbatim, I'm pretty sure our manuals say something along the lines of "use premium fuel, or the highest octane fuel available to you". Around my neck of the woods that is 93, though some places will only have 91, and there's not many, if any, stations left around here that aren't using ethanol additives, so I have to bite the bullet on that one. But I'm using the highest octane available to me, 93. If I end up on fumes in some random place like Yellville, Ark., and they only have up to 89...well, that'll have to do until I can get to a station with something proper.

Take a Jeep Liberty, for example. The manual essentially says the car can be run regularly on 87 without any issues, but if you're going to be doing any towing, that will require optimum performance from the engine, so they recommend using 89 for that. By the same token, you could also fill up on 89 regularly and be just as well.

If someone's looking to cut their fuel costs and seeing if they can live on commuting or joyriding on 87, well they picked the wrong car for that...if it could've been run on 87 regularly they would've built it around being able to do that. A Corolla the Boxster is not, so you have to give a premium car premium fuel.

No offense meant to anyone who happens to be from or near/around Yellville, just picked a random place. ;)

So to stir the pot a bit more, which would be better?

91 octane
or
93 octane with 10% ethanol

We only had 91 around here but saw the 93 blend recently.

Trying to save a couple of bucks by filling up with lower octane doesn't work for high(er) performance cars. The ECU will just adapt the mixture so that the engine power stays the same. Lower octane will lead to lower mileage. We've been driving Saabs for many years and decided that the highest octane will cost the same in the long run and results in a smoother engine.

I'm new to Posches but my other vehicles built within the past 15 years all have knock sensors that detect motor knock and adjust the ignition timing as needed to prevent it. Can anybody confirm whether or not Porsches have knock sensors? Does the 2000 S model like the one I bought a month ago have them?

I doubt I would use regular gas anyway but it would be nice to know whether the engine can actually be damaged on low octane fuel. I've used regular in my Corvette and couldn't hear any knock or feel any power loss but I decided high test would only cost me about $100 a year and there was no point to the cheaper gas.

You will get better MPG's with the 91 octane (no ethanol) vs the 93 (with 10% ethanol). Did this experiment last year. 93 is probably still the best bet. 93 pure gas (no ethanol) is ideal. It is very easy to find in places like Wisconsin, maybe due to all of the RV's and boaters.

Dale K, look in your trunk (back one) and you should have a sticker in the middle that says your car has knock sensors etc. I have a 2000 S and it does.

The most we can get is 91. Which really surprises me with all the farm equipment etc. Actually that's just given me a thought. I'm going to check the non-tax co-ops. I'll bet they have higher octane. For those out there that must have the torpedo-juice stuff, why don't you consider your local airport?? I know ours will probably sell the av-gas. So just fill'er up with the blue stuff! (disclaimer: I'm sure this isn't a good idea)

sean

How about a bottle of octane booster add to the tank? Any suggestions?

Yes the Boxster does have knock sensors and by design your smart ECU will retard the timing to prevent detonation and engine damage. It is a band-aid that should not be relied upon every day but it is there to prevent damage in the event that you put 87 gas in. Performance and mileage will also suffer with retarded timing due to the knock sensor so you won't save any money running cheap gas.

When I had FVD build my ECU mapping I made sure to tell them all of my mods and that run 93 octane exclusively. I assume they tweeked it a little to take advantage of that.

There is one gas station near me that sell 100% gas. I try to go by there when I can. It is a little more expense but if you do the math…

Ethanol has about 75% the caloric value as gas… At most stations, 10% of the gas is Ethanol… that is 97.5% the “power” of 100% gas.

A 280 Hp Boxster S will see a 7 Hp gain running 100% gas over a 10% Ethanol mix. Is that worth an extra $0.10 a gallon or $1.50 a tank? Less than $0.40 / Hp gain. Show me a better deal out there.

I have heard that the ethanol mix is much harder on fuel system components.

That's an old wife's tale from the problems in the 70's when ethanol first appeared. With 30 yrs of development under their belts, automakers wouldn't put components on their cars that can't handle ethanol.

Kind of like graphite shafts in your golf clubs. People still say they may be inconsistant. Was true when they first came out 25 yrs ago but there's too much technology out there now for that to be true today.

I would beg to differ. On brand new cars, ethanol is likely safe and may keep your fuel system cleaner than other mixes.

That said, older cars can have issues. I lost a fuel injector recently (had just moved to Iowa and started using ethanol blend). I found out that the Lexus techs will NOT use ethanol in any older car. Seems like they are tired of replacing fuel systems components on older Lexus cars and don't want that to happen to their own.

Word to the wise.

Local Sunoco station just added 104 octane race fuel to its lineup. There are apparently enough racing boats in this area that use it to justify adding the pump. Its over $6 a gallon. I've only seen 2 people buying it -- both with newer Ford Mustangs. Go figure.

I'll pass. Everything I've read says that Porsche sets the cars for performance at standard octane ratings. Good enough for me.

I did this experiment with my previous car (toyota solara). The car recommends 91 octane (but can take 87 with some engine output reduction/increase fuel consumption per owners manual). I put 91 un-oxygenated fuel when I was in Minnesota and I put 93 with ethanol when I moved to MI. No noticeable power difference, but 91 with no ethanol returns at least 2-3 MPG better on highway.

I was wondering if higher octane would work or not.. I've run turbo blue 104 in my harley before and it makes a difference plus it gives off that amazing smell. Love the stuff but its hard shelling out over $7 a gallon.

The stock DME settings on the Boxster are calibrated for the engine to run on pretty low Octane fuel -- obviously the car is base tuned to a somewhat low common denominator so if you get caught in a place with 87, you do no damage.

I think if you flash tuned the DME with Softronics or another product you could probably tell at least a little difference with a higher octane. I know that one of the side effects of Flash tuning is that you need to runner "higher" octane fuels thereafter as the tuning impacts detonation/timing. I doubt "higher" means 104 -- but probably 91+.

I think high octane fuel is to men a little bit like what anti-wrinkle cream for women: expensive hope in a bottle!

Quote of the day. Thanks for the laugh, mike. :cheers:

I have to use premium because the Autothority chip I am running requires it,

:cheers:

Ed