I'm not too found of most external engine sounds being heard in the cockpit, at all. In real life, even afterburners are inaudible from the 'pit. So, I've replaced the default cockpit "windloop" wav with one that I've christened, "jetpit".
As in the case of the default windloop, it is an airspeed-dependant sound effect. It is totally inaudible below 150 knots, and builds up in volume and crescendo above that speed. right on up to its 250-knot peak.
I'm of the opinion that it's a better (and possibly more realistic) sound effect, than the external engine wavs.
Watch and hear it in action in this video, HERE.
Should anyone want it, I'll upload it along with instructions as to how to enable it in both 3rd-party and default aircraft models.