Goldilocks Zone for FI

[Irace86]

Maybe this is a well known fact, maybe not. I tried a search, so forgive me if I am ignorant to well established facts or if I am adding to many threads that already exist on this topic.

I am wondering if there is a Goldilocks zone for going FI. Obviously engines should have time to break in, but are they really broken in after 10k miles? There is a point too when higher mileage engines can tolerate longer mileage intervals between oil changes because of less grit in the oil because there is less honing left to the engine. If an engine gets too old some seals may be leaking, some parts have lost their tight tolerances and this could lead to failure, especially with the addition of FI.

So when is the break in truly complete? And what is the Goldilocks mileage for FI applications. I feel this is different if a car is built for FI versus adding FI to a NA engine.

On a related note, I know some like to buy their car brand new, so they know what it has been through, but I always felt a little more confident with a high mileage vehicle (60-100k miles) because I know it is likely not a lemon and everything is broken in well at that point.

Opinions?

[Xuningshen]

Bought the car brand new, boosted at around 9k. about to hit 25k. Unfortunately I didn't do any UOAs before i boosted. according to my UOAs I've done since then, my wear has been about the same each time, so "very steady wear levels" according to them. I imagine mine was pretty well broken in at 10k

[Gavmen]

I think these cars, like other modern cars need to beat on to be run-in. I think the 'manufacturer time' would be 6k miles (10k kilometers). However I think they could probably be charged straight from factory.'

gav

[Irace86]

@Gavmen so you think if it is spinning a bearing its likely a lemon or just a problem with oil pressure or quality of lube. Not breaking in the surfaces well enough with extra power or extra spirited driving?

[Gavmen]

Just judging by the failures of NA or FI'ed cars there's no trend for milage (bearings, cams, heads, slow oil leaks, gearbox, etc) i.e. leading me to believe that at either 100miles - 50,000miles there wouldn't be much of a difference if intending to go forced induction. (This includes the FA20DIT in the WRX, here a bang there a bang, everywhere a bang bang straight off the factory floor, and some running very well high boost +e85!)

Obviously there will be more issues on higher mileage cars but not related to the application of FI (e.g. wear and tear).

I think a lot of the issues are known and so if you have a good knowledgeable tuner/workshop, you'd find a lot of your issues are due to wear and tear or straight up bad engine vs catastrophic failure due to FI (assuming reputable and conservative tune and tuner, running the car on the raggedy edge obviously brings the onus back on the tune).

gav

[Irace86]

Thanks for the perspective. Sounds right. I'm sure failures happen because of high temps or just lemon issues than premature exposure to FI.