So I changed my SC pulley on my '06 MCS a couple of weeks ago. I installed a Minspeed 15% pulley with JCW belt... I'd like to know if is necessary to reprogram the ECU by doing this mod in the car . If so, would it affect the warranty by reprogramming it? I have 16k on the car right now.

Thanks

 

IMO you do not need to do that. If you have the ECU reflashed yes that could effect the warranty. Another thing that happens is you bring your car in for service & they reflash the ECU to the latest version. Psst gone goes your dyno tune. I know 3 people that has happened to.

 

Not absolutely necessary, but certainly beneficial. Tuning ties everything together in the best possible way. At your level of mods, you are probably OK without an ECU tune. If you go further, def. look into it.
Warranty depends (as always) on your dealer.

Edit: Crashton, be sure to tell your dealer not to touch the ECU. I had mine add a note to my file saying just that. And then I taped the OBD port shut, just for good measure.

 

I had a 15% sc pulley plus a 2% crank pulley installed the first week of July by Randy Webb and he indicated no ECU change was needed.
I drove the car 800 miles to home in MO and have had 0 problems and a whole lot more fun. Gas mileage has NOT changed. Just motor and have fun.

 

ECU is not needed, but a colder spark plug is not a bad idea to help prevent detonation.

 

People keep saying that colder plugs are needed & I don't get it. My car has a 15% pulley an intake & exhaust. About 20,000 miles on those mods with stock plugs with zero issues. No detectable detonation by me.

 

I'm with you on this one.
I'm running on stock plugs with head work, exhaust header, cam, injectors, etc and I don't have any problem with detonation or knock. That's even with crappy ethanol blend gas in the winter.

 

This makes me even more confused. Comming from a WRX, you had to tune for everything or else boom... Even the 04-05 WRXs had to reflash before doing exhaust work or the car just wouldnt run right. After adding a downpipe and up-pipe to make my full 3in turboback it was highly recomended that I reflash before doing the mods.
I guess the cooper can just handle it differently like the 4g63. Im just used to getting a tune every time you do something different to the car to correct AFR's and ignition timing to keep everything running right.

 

Nah the MINI's are fine...it seems that the ECU adapts very well to changes... I'm running on the stock plugs and ECU with my mods, no problems.

-Cody