Have an 01 C4 3.4L. We can only purchase 92 octane unlead. To bring to the octane level to about 96 by mixing 1/3 100 LL avgas with 2/3's 92 octane unleaded, would this cause any harm to the motor?

Thanks

 

Where are you ? I also have an 01 C4. What about Ethanol free gas ? do you have that in your area?

 

AvGas has lead in it (LL = "low lead") and that will ruin your cats. 92 octane is fine for your car.

 

Mark the L L in this type of avgas stands for low lead. Even in a diluted form this amount of lead will kill your cats. Unless you’re running the engine very hard (extended use on the track etc) 92 is enough. The largest number of Porsches in the US reside in California, mostly surviving well into old age on only 91 Octane.
What is the temperature and altitude where you reside? The need for higher octane diminishes at lower barometric pressure.

 

ARE YOU SNIFFING GLUE!!!!!

NEVER PUT ANYTHING OTHER THAN UNLEADED IN

If you have put in LL already, you may have damaged your cats already and they are big $$

92 octane is more than fine and most places in the USA the highest normal gas is 91. In any case the ECU will adapt even if you put in 87.

Putting in higher than 93 is a waste of $$ as it does nothing unless the car has been tuned for it, no matter if you are on the street or even long track sessions or driving hard

Do yourself a favor and do a search here before trying such things

Also, might be nice to introduce yourself on a first post, Pics too as without pics, it ain't real

 

Hey now, ease up on the guy. At least he asked BEFORE flaming chunks of catalyst made their way from the exhaust...

 

I like this response! LOL

 

Jay the task-master, always hard at work to help out a n00b.

 

If you aren't running 110 leaded in your 996 you're leaving tons of performance features on the table.

 

Doesn't that only help when they are upside down?

 

I can't run 110 octane because I need that room for more spare tires. Much safety.

 

You're thinking of pianos.

 

I personally find 110 octane is perfect for when my car is loaded up with my three spare tires for a trip to the local grocery store where I make sure to jack up the car and check for any oil leaks, small mammals, and stone chips, before entering said grocery store. Safety first fellas!

 

You are all doing it wrong. Proper way to travel is to have AAA Van follow you everywhere, with a set of wheels/tires, spare engine, spare tranny, and trained crew of expert race drivers/mechanics/engine builders manning the whole operation.

When JI goes out for a leisurely drive up to Oceanside.

 

Lakota ND. We have 92