I wonder if this notion comes from the 80s, when engines with turbos had lower compression ratios for reliability. Today's turbocharged motors have higher compression ratios than in the malaise era, and the turbos have a lot less lag. Turbos no longer mean you have to sacrifice fuel economy for performance (unless you have a lead foot).

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salawat 2 days ago | parent | next [-]

>Turbos no longer mean you have to sacrifice fuel economy for performance (unless you have a lead foot).

That's incorrect. Virtually every turbo'd gas car runs slightly richer than stoich to use the unburnt fuel to manage temp/knock. Diesels, you actually get more efficiency out of with a turbo for free. With gas you're practically guaranteed to be throwing fuel out the pipe.

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Toutouxc 2 days ago | parent [-]

That isn't some turbo specialty, the effect is the same in both NA and turbo engines. And AFAIK it isn't really feasible anymore. I don't know about other manufacturers, but for example Volkswagen Group's EA211 EVO2 engines run pinned at lambda 1 no matter what.

	▲	salawat 2 days ago \| parent [-]
		All I know is my last turbo'd vehicle was always running at 13.8, and that was a 2013 Nissan with a turbo'd L4, and it annoyed the piss out of me. Pretty much guaranteed only getting 26 MPG at highway speeds. This was despite claims in the manual saying the AFR was fuel octane dependent & would automatically vary (which I found out through experimentation was full of shit). It just stayed pinned to 13.8 whether you ran 87 or 91.

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PunchyHamster 2 days ago | parent | prev [-]

Nope, just engineering to do not much more for warranty. Turbo engines arent inherently unreliable (tho you might need to replace the turbo itself every 100-200k so still more expensive to maintain), just need to build extra strong block and components if you want it to run for a long time.

And why would company do that if that would put it far over warranty period?