I picked up a 03 mini s about a year ago. Blew the engine on the drive home lol just put a used engine in it from a parts car i bought and i have a few questions for you guys. My mini has 15% reduction sc pully and 450cc seamens injectors, when i looked them up it said there for a ls7 Corvette and r53 mini. When i first put it back together i put the stock injectors from the parts mini in my car and it didnt run good. Low power rpm fluctuates and so on. Put the 450cc injectors in and it wow does it move, this is my first mini so idk if its fast for a mini but my question is i want to know if my car has the ecu tuned. From everything i read to run injectors that big and run well with them it would need a tune, is that true?

 

Probably tuned for the larger injectors. Most of is wait to do tune/injectors/cam (if aggressive) together to not have to tune multiple times.

 

Yep.....your ECU is tuned for the 450cc injectors. Anything other than that, and the motor's going to be running rich or lean. If the car is running with the 450cc injectors in it....it's already got a tune, or it would run like crap.