Originally Posted By: nleksan
It's Las Vegas, even the cold starts aren't really all that cold!
While a taxi sees far less than ideal driving circumstances, I'd be willing to bet that they still see better than the vast, VAST majority of engines. Taxi companies have a very vested interest in keeping the car on the road as long as possible, and consequently the maintenance schedules for the cars are typically extremely strict, so much so that I'd be willing to bet that on average they're better maintained than the average persons car to the point that the taxi with 350k miles will have the same or less wear than the avg car at 35k.
Still, it's advertising. I have done plenty of teardowns, and the only time I've been truly impressed was with my 2.8L I6 that had zero carbon buildup aside from minor varnish, completely clean valves, perfect compression, and not even a single visible mark on any of the cam lobes.... After 7x,xxx miles of which a few K were track miles, and a good deal were with a (at the time stock) Lysholm 2.3L twin-screw supercharger pushing 9psi of boost into the engine, one running a compression ratio of 10.8:1 static!
The only fluids it had seen was Redline and some Royal Purple (SL, high ZDDP), with the filters being Mahle, Mann, K&N, and AFE for the oil, and either Mahle (OEM) panel or AFE ProDryS cone air filters.
Additives? Redline SI-1, Redline Water Wetter, Seafoam in gas rarely, and Techron.
Since then, I have seen very clean engines and very dirty engines, but the only ones I've seen with almost no visible wear have been using RL with short-ish OCI's. Everything else, from M1 5w40 to AMSOIL, has always had visible wear, even with fewer miles.
Oh, and I know this is anecdotal, and the majority of these motors see a fair bit of track time, but I am just sharing my actual experience...
Whether in Vegas or the Yukon if the metal parts are cold enough to shrink its a cold start.
Only when the engines internals and the oils temps have levelled off are we looking at optimum operating conditions.
So until an engine achieves operating temps is wear minimalized.
