break in first or dyno tune first?

[ruggiero06]

if you are rebuilding a motor what do u do first?
do your break-in period or take it to be dyno tuned, then broken in.

im know its a matter of mostly opinion/preference. but i want to see where this debate goes.

 

[riko666]

Every engine needs to be broken-in I don't think that's up for debate - you can have this done on the dyno though...

The majority of all bedding in between rings and cylinders occurs in the very first miles of running the engine from the rebuild, if you jump straight in and dyno-tune it you can risk not seating the rings properly, and if the dyno-tune is extensive, have lots of bits of metal from the bedding-in process circulate and embed themselves in the engine.

 

[finx]

the above advice is good.
dyno run in will be very expencive due to the time it will be on the machine to do this. best advice is if it is running an aftermarket ecu have a base map done with low boost pressure, follow the usual running in procedures (your engine builder will tell you how they want it done as there are numerous different methods) and do about 500km then take it for a mild dyno tune.

 

[Neal Gt]

I would say defo breake the car in first, get runnin for at least a few miles