Effect of turbocharging on engine life

[MPowerA7X]

I have a '97 M3 and am interested in a turbo for it, but I would like to keep the car in good running condition for the rest of my life, considering the e36 is the best designed model. How will the turbo affect the longevity of the engine. How long can I expect the car to run well with a turbo kit installed? Thanks

[UrineMachine]

Depends - many will argue that a small, factory style turbo setup will last just as long as stock, due to modest power output resulting in minimum component stress and strain etc. You can probably consider a larger turbo w/ high output to be more strenuous because as the engine turns, there is a sudden increase in engine output, rather than a slowly ramped up output, which might suggest strain on rotating assemblies and causing shorter lifetime of components.

But, I have a very high mileage large turbo setup and I have nothing but an oil leak coming somewhere from the front of the engine. As long as you are not sacrificing engine reliability with tuning (tune it wet on fuel) and such, then it should be reliable.

[Highboosted]

Numbers I use for my 6G72, 400-500 HP, 17-23 psi boost, 8:1 compression, daily driver:

I fully expect 120K Mile between top end jobs, at least 150-200K between bottom ends if nothing breaks. Only reason I freshen up the top end early is because leaking valve stem seals can lead to knocking which will kill a bottom end. I check and replace main and rod bearings at 120K, because my oil pan is dropped then anyways. I don't cut cranks because mine if forged, too risky, I just replace them if the bearing surface is FUBAR'd.

That being said, on the race block I go by 100 hours for bearing check and cylinder borescope every 25 hours.

[MrBlonde]

45 months and 7 days.

[E30stain]

keep the boost low and dont rape the shit out of it and you will end up with just as much mileage as you can handle.