filled my tank up with regular (996 C2) because of hurricane Sandy the gas station only had regular. Any issues/risks in doing so ? thanks.

 

Go out and get some octane booster now, and put that in and you should be ok.

The long & short of it is this:

You'll burn a hole through 1 or more of your pistons / detonate your engine.

As odd as it may sound, 91 octane burns at a cooler & much more predictable rate. If you run 87 octane, the car will be constantly trying to retard the timing & this will cause constant knocking / pinging. Eventually that WILL damage your engine. The pistons are usually the first to go, but it can also warp/bend your camshaft, or cause a multitude of different seal / gasket leaks.

in this situation, you will see negative effects that could be even worse. Using low octane fuel in a high octane engine will result in severely reduced performance because the engine will attempt to adjust to the lower octane gasoline. In extreme cases, or with prolonged use of low octane gasoline in these engines, pinging or pre-detonation can occur and can eventually destroy your engine. Pre-detonation causes very hot conditions in your engine and can melt sparkplug and pistons.

 

You will be fine with a tank or two of regular. Just don't run it all the time.

 

I believe the car comes with anti-knock sensor so you can run low octance fuel.

 

If I use half the tank and fill it back up with 93 octane, will that help ? or should I just burn the entire tank of regular and then fill it back up with 93 ?

thanks for your responses.

 

if you fill it half up with 93 octane it will mix out to give 90 octane (93+87/2=90). You will be fine to top it off or burn it out. There are knock sensors for this very reason so you wont damage your engine, however I would say you should only use lower octane when its your only option

 

You'll be fine. I would fill with high-octane (the number varies with your location/altitutude) once you get the chance.

 

Although I have the utmost respect for my forum buddies, I have to respectfull disagree, you should get the octane up as soon as possible, IMO.
Almost all cars use four-stroke gasoline engines. One of the "strokes" is the compression stroke, where the engine compresses a cylinder-full of air and gas into a much smaller volume before igniting it with a spark plug. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, by creating excessive and premature wear to the piston and cylinder walls, so it is not something you want to have happening.
Yes, the 996 and later Porsche's will advance/retard the timing with the EMS it's not something I would reccomend being 100%, in any car. If you hear any knock it's not good in any car much less a high reving performance engine. To your point, if you run the gas down fill it with high octane.
And yes, perhaps one tank of 87 won't hurt, but I wouldn't be willing to risk it.

Just my 2 cents

 

FLA996TT, you've got me a little bit nervous. Right now I have a full tank in the car. What if I left the gas tank open while the car is parked, would most of the gas evaporate ? Then I could drive to a gas station that has premium and balance out the octane ? let me know what you think. (Starting to regret ever putting regular in the tank)

 

ok, the gas evaporating thing is unrealistic, just googled it. Is there any way to syphon gas out of these cars ? If thinking that my only option if I want to remove half of what's in there and replace it with 93 octane. let me know what you think. thanks.

 

Here you go.
http://www.caranddriver.com/features/regular-or-premium
Again you WILL be fine.

 

Sorry, I didn't mean to make you nervous. Drive the car as normal and you should work through 1/2 a tank in no time, then put 93 in her.
I wouldn't rile out some octane booster though.
These are high reving high compression engines and that's how Porsche get HP that's why the high octane requirement.

 

Some states premium is 91. So, again a few tanks of 87 won't hurt anything. I would not go run it on the track with 87 but around town you will be fine.

 

If I were in your position I would do the following:

1. remove the battery cables and stand on the brakes for ~ 20 seconds (to remove all stored energy from the car's electronics, ie ECU).
2. replace the battery cables
3. drive the car normal, just avoid WOT
4. when you are able to run premium again, do steps 1 & 2 again.

The ECU will re-learn the burn of regular fuel and help prevent knock. You will probably be okay to go WOT, but I personally wouldn't take the chance. Best of luck with everything Sandy caused you (beyond the fuel issue).

 

I would siphon out as much as I could when high test is available...sell the regular to someone and gouge the **** out of them