Originally Posted by bfellini

Avoid cruising or staying at a steady rpm as much as you can... there's less tension on the rings and can lead to glazing in the bores.

Try not to clutch in while slowing down.. The key is engine braking, decelerating in gear. This provides high vacuum and gives the rings tension... Same with accelerating quickly.

Everything is wearing in, coatings are being worn off, so there is lots of particulate in the oil... lots of sustained high rpms creates heat, and can bake particulate into rotation surfaces, creating gouging or scratches.. not good.

Originally Posted by bfellini

An inertia dyno is super helpful in breaking in obviously, as you can use the drum inertia for sustained engine braking between ramp ups... hub dyno's, and small roller dyno's don't help with engine braking so just focus on the ramp ups.. In my experience, a dyno is the safer choice, and quicker for break-in, as you have more control, with the added benefit that you can dial in your tune at the same time.

Personally, I try to stay away from high boost during initial break in, to ensure the fueling is spot on and not washing the bores from over-rich conditions.

Originally Posted by tb13

I'm sure there are a million and one different ways to break a motor in properly. What most ways all seem to agree on is varied load and frequent oil changes using non synthetic oil for at least the first thousand miles. Pretty much just enjoy the car, but don't beat the piss out of it. General consensus is that once you pass 1k miles the majority of the break in process is complete, with fresh oil you should be just fine to drive the car as you wish.



When I purchased my current daily driver, a 2017 WRX, I was told not to boost or pass 4k rpm for the first 1k miles. Within the first hour of having the car it had seen peak boost of 19psi and well over 4k rpm because warranty. I didn't avoid my normal freeway driving to and from work and always did a few pulls. I always let it hit operating temperature before I would get into boost and at 1700 miles the car was tuned on E54 laying down some of the best numbers the tuner had seen. Recently passed 3k miles and the car is still running perfectly.



Really what I am trying to get at is there is no real "right" way to break in a motor, but you should take care of your new motor and it will take care of you.