Recently, Larry Dighera posted:

On Wed, 25 Jul 2007 14:51:12 -0500, "Neil Gould"
wrote in
:

Compared to what?

I am rewarded with an immediate increase in power when advancing the
throttle of an IO-360 or O-540; there is no significant delay between
opening the throttle and an increase in power.

The original statement was the the Merlin would go from idle to _full
power_ in 1 to 1-1/2 seconds. I seriously doubt that your IO-360 or O-540
will do better, especially considering what the "full power" of a P-51 is.
;-)

But perhaps I was misinterpreting what was said. Of course there is
some delay before a burst-throttle and the engine reaching full power
due to the necessity of accelerating the mass of the moving parts
involved.

Absolutely.

Neil