I just became the new owner of a 2006 MCS. I would like to put a 15% reduction pulley on the supercharger but the mechanic at the dealer said it would run lean and I would need to modify the fuel system too. Does anyone have any experience with this?

 

You can run it fine without fuel system modifications. Do a search on 15% and you'll see the happy customers. To get the most out of the bolt-on mods the current wisdom is to get a tune. (also a good search tune). I did a 15% with "bench tune" from LDG and have been very happy.

 

No need to due fuel system work. You can do that and/or some ECU tuning to perfect things, but it's not necessary. I've got to MCSs with 15% pulleys and both have over 20K miles with no issues and run great with nice power bump (one is an auto and one a stick).

 

Surprise, surprise!

The dealership doesn't approve, and they want to squeeze more labor money out of you, for no good reason.

Thousands of us have reduced pulleys, and we didn't have to do anything to the fuel delivery system.

Yes, larger injectors will help, but you're not doing any harm by running the stock injectors, and you're still able to reap huge rewards from the pulley only...

Ignore him.