The Myth of Octane Adjusting Tunes and Why You Should Care
 

Hello everyone!

I wanted to chime in with a type of PSA on something we have seen being touted as a benefit by other tuning devices that are in competition with the Accessport. This notion of a tune which can somehow adjust for octane has been floating around the Porsche world for as long as I can remember but it is simply not true. In actuality what most of these "octane adjusting tunes" are doing is running a map designed for 93, or in really conniving cases, 100 octane, and relying on the knock sensor for the proper timing corrections when lower octane fuels are used, but doing so induces knock into the system. You wouldn't run 87 octane in your car on a map that is designed for 91, why would you run 91 octane on a map designed for 93 or 100?

What are timing corrections and knock and why should you care?

Knock causes severe spikes in cylinder pressure which if sustained will damage pistons, break ground straps off the spark plugs, bend rods, blow head gaskets, and wear engine bearings. If knock is excessive enough or if knock control has been dulled down it can cause instant catastrophic engine failure. It is one of the nastier ways for an engine to die and most certainly would warrant a closer look if a warranty claim is made.

Knock creates a distinct frequency depending on the block material, displacement, bore size, etc...The knock sensor is essentially a microphone and listens for this frequency and will pull timing to save the motor from damage. However Porsche doesn't have a proactive knock system in place to pull timing before knock occurs based off of prior knock events. Any timing correction seen is the direct result of what the knock sensor observes to be knock.

This is all assuming you can monitor knock corrections and to my knowledge the Accessport is the only flashing utility on the market which allows (and encourages) you to monitor your engine health.

COBB didn't make OTS maps for different gases because we wanted to, we did it because we had to. It is the only way to safely optimize power for all the varying octanes throughout the world. It would have been much easier(and cheaper) for COBB to make one file for all fuels but it would result in one of two outcomes; under powered cars or cars with knock. Both are unacceptable to COBB and are morally objectionable practices in our opinion.

COBB has grown to the company we are today because we take huge pride in customer satisfaction and make our practices completely transparent. We encourage people to monitor their own motors through datalogging and ask questions, not because we didn't test thoroughly, but because we want to educate all of our customers. We are all here because we love Porsche and whatever knowledge we can supply we gladly will.

Thank you all for reading, if there are any questions or things that you may need clarification on please don't hesitate to chime in or PM us.

-Jon