Due to the hurricane that hit TX recently, most gas stations around here are out of 91+octane fuel. So recently i put about a 1/3 of 89 octane fuel into my 997 pcar to get around. So my question is, if its ok to temporally use 89 octane in the pcar even if the manual says to only use 91+ octane. If its really bad i can easily siphon the fuel out.

thanks a bunch!

-chris

 

It's really bad. I'd suck it out.

 

drove 2 miles with the 89 octane, you think i might have some issues with the car later on?

 

I doubt it could be that bad, but someone else with more knowledge will hopefully chime in.

 

+1. I don't think a tank full of lesser gas is going to do long term harm to the engine. I thought all of these engines have computer controlled knock sensors which would just retard the power as opposed to actually damaging anything.

 

I'm no expert - but if you're concerned about damage - probably not, given the computer controlled knock sensors. Why not try an octane boost in the interim if you're still concerned?

 

I was going to mention that. Maybe an octane boost would not be a bad idea

 

Do you really think that the octane is going to kill your engine with one tank?? The worst your going to do is slow down the performance of the engine and maybe here a slight knocking, which i doubt since the knock sensors are computer controlled.

Now if you pour sugar in your tank than you've got problems.

 

really...., just pour some octane booster and it would be fine?

 

Porsche recommends against using fuels with a common octane booster called methylcyclopentadienyl manganese tricarbonyl (MMT), since it can cause problems with the emmissions systems and you may get a CEL some Octane booster contain this stuff, personally I would not use octane boosters.

 

I agree with MartinJF. No need to use octane boost since this sounds like an interim problem with availability and the computer can handle the knocking.

 

thanks for the info, greatly appreciated

 

Your pcar will run fine on 89, it just won't be very perky.

If you want to up the octane, you can use Toluene from the hardware store as a safe octane boost additive. Google search for "octane calculator" to get info on proper mix ratios.

-I really wouldn't bother though, drive on 89 and wait it out.