An ECU tune can unlock more power, boost torque, and sharpen throttle response, but the performance gains come with potential ...

Duvernay has the highest stock output production Quad 4: the 190-hp 1991 to 1992 RPO W41. The 1993 W41 lost 10 hp due to smaller exhaust ports. I have a 1992 Olds Achieva SCX with a W41 Quad 4 engine ...

The Advance CurveAll engines require an ignition curve based both on the requirements of engine rpm and cylinder filling (volumetric efficiency). This means that at 3,000 rpm with the throttle open ...

Ignition timing is like seasoning: some is good, but too much ruins the results. Bumping up the ignition timing on pushrod 5.0s is a time-honored trick to wake up the under-hood lump. The EFI system ...

Turbocharging a naturally aspirated engine raises big questions about compression, tuning, and heat. Here's what every project car owner should know.

You are riding a vintage Harley, and the engine, which started normally until yesterday, suddenly won't start.No matter how ...