A strange thing happens around old hot rods and race cars.
Sometimes you’ll hear an engine sitting there at idle and it almost sounds alive. The RPM drifts up, then down, then up again. It isn’t a miss. It isn’t a tuning problem. And sometimes the owner will tell you, “That’s just how these things run.”
While recording the next Ask Ed episode, a viewer asked why some supercharged engines seem to hunt and surge at idle. As usual, Ed’s answer went far beyond the simple explanation.
Ed Smith and Superchargers in “Ask Ed Episode 60”
What makes the topic interesting is that many of the things enthusiasts assume are problems can actually be side effects of the way performance engines are designed. Camshaft timing, airflow demands, fuel distribution, vacuum signals, and supercharger behavior all interact in ways that don’t always produce the smooth, steady idle modern drivers are used to.
It’s one of those topics where race-engine reality doesn’t always match garage folklore.
We also spent some time discussing torque converter stall speeds, why certain racing engines actually like operating temperatures that would make street-car owners nervous, and several other technical questions sent in by viewers.
The next Ask Ed is currently in editing, and there are some good nuggets of old-school engine knowledge in this one.
As Ed often reminds us, understanding why something happens is usually more valuable than simply memorizing what to do.
See you soon!
Barry T