Toronto Integras - Torontos Acura Integra Club - My fully built B18C with a Garrett GT40 Turbo.

Haha, the break-in debate never ends...

The TUNE is the most important part of break-in. Whenever clearances are tight with fresh rings and bearings, an over-rich tune will f*ck things up faster than you can kill the motor at 8000RPM.

The first 10-15 mins of initial running is the most important, and the tune has to be good.. Not too lean, not too rich. Too rich will allow too much residual fuel inside the cylinders and wash down the thin layer of oil that coats on the cylinder bores when the pistons go up and down. On a fresh motor, this layer of oil is really thin due to tight clearances, and a few minutes of over-rich conditions will start scoring the walls and ruining the motor right from the get go.

I've had seen really fresh motors die due to this reason... The best practice is to run the fresh engine at idle and rev it up and down slightly, bleed the coolant system and let the engine go through one heat cycle and then do a quick oil change. This is a rebuilt motor and not a brand new motor on your 2009 Honda Civic. A rebuilt motor have high chances for small dirt and metal debris from machine work, and tons of them can be trapped inside the oil galleries and passages. A quick oil change prevents any of those debris from working its way to important areas when you start raping it.

Once its good, you can technically do whatever you want to the motor and it will usually be fine unless something really goes wrong (bad oil pump, overheating, etc). Again, tuning is key and you don't tune into boost regions that require running the engine rich say 11.5:1 AFR.. That means high boost tuning on pump gas is not suggested because pump gas big boost turbo cars want it rich. But you can go straight to race gas and tune for 800+ WHP if you wanted to, given the amount of needed octane and a good enough fuel to support that power under good AFR's (12.0-12.5:1).

Aside from me dealing with probably about 25-30 forged motor builds over the years (including my own builds), all of them went though the same process and then was broken-in on the dyno. That also includes my own Integra which only had about 20 mins of run time before I tuned it for boost. I only tuned for high boost though after about 1000kms because I would switch to synthetic after the engine has ran for a good while.

My forged Dart block motor on my Integra now is pretty old now with about 90000kms on it since '03 and the car was driven and raped like any turbo Honda. I am at the point that I have to rebuild my valve train because the titanium retainers are worn out from the mileage and only has about 20% life left. The motor still doesn't burn a drop of oil, and has the same compression since the day it was broken-in, and now I have just taken it to 658 WHP @ 30 PSI...lol

The amount of stages which this motor has gone through is quite awesome...

2003-2004 = GT28RS setup with 300 WHP for about 25000km (was daily driven)
2004-mid 2007 = GT2871R setup with 400-420 WHP for 55000 km (was daily driven)
2007-2008 = GT4088R setup with 560 WHP for about 10000km (weekend driven mostly)
2009 = GT4088R setup with 658 WHP (for about 3000km)

Aside from daily and weekend driving, it obviously was my track car too whenver I decide to hit the roadcourse or drag strip about 2-3 times a year.

Anyway, to add to this thread, I am a huge fan of a GT40 turbo as well :D Lovely topmount setup! Mine's only a ramhorn and the same turbo looks small all of a sudden in the engine bay..lol