Most people use pump fuel most of the time and quality can be a problem. For that reason, pump gas maps from JMT Calibration come with multiple revisions or multimaps as standard to counter the bad fuel and give you options.

Dealing with timing corrections is a fact of life for tuning with pump fuel. Nonetheless, a good custom tune can deal with the problem effectively.

It is overlooked, but timing corrections are often a problem at lower RPM and when the turbo is spooling.

Why is this? When airflow changes rapidly during spool up, the fueling also changes rapidly, which can lead to variations in the fuel mixture. This can trigger defensive timing corrections from the DME’s knock protection system.

In the first picture, before a tuning change, notice how the turbo is not yet fully spooled but the car is pulling timing aggressively. By the time it has decided to advance timing again, we are nearly at redline. At lot of power has been wasted because the timing was not set correctly at the start.

By adjusting the timing during spool, we can achieve two things.

• Lower the chance of timing corrections
• Spool the turbo quicker

The second and third logs below were captured after our tuning change. They show the car’s target timing value (zwstat) plus the actual timing and corrections.

Notice the absence of any corrections at low RPM and how this allows the car to meet it’s target timing through the entire rev range.

JMT Calibration, offers tunes that are adapted to the fuel available to you plus a no-hassle approach to making map variations that you can flash for better or worse fuel at no extra cost.