Bonneville America Forums Forums Technical Forums Performance Mods Advanced Versus Retarded Timing (EFI) TOR TUNE

First there is no advantage to running premium gas, it is not better and in fact does not burn as easily as lower octane gas. Higher octane fuel is geared to higher compression engine as it has a higher resistance to pre-ignition. The ping you get with lower octane fuel is due to pre-ignition from the fuel igniting due to compression. It can also be from carbon deposits. The carbon gets hot and causes the ignition too soon. If the new map you have causes ignition too soon you will get a pinging sound so that new map could be your issue. What ever it is fix it before it causes damage. Try your old map and see if it goes away. You should actually run the lowest octane fuel you can without pinging. I agree that the timing should probably have been left alone and just adjust the a/f mix for the new pipes.