I just got an Eaton Supercharger and an XCAL tuner installed. When I slow down to about 25 or 30 mph, I feel somewhat of a surge feeling that almost feels like it comes from the rear end. I'm not sure what it is, but it started as soon as I got everything installed. Does anyone have and ideas?

Thanks

 

I don't understand "surge-feeling" unless you feel the downshift more now?
The only thing I compare to your statement is when downshifting my semi, I get thrown forward physically whem I'm downshifting on the low side of the trans. do to the upsurge in rpm.
Maybe you can find a better adjective to describe it in more detail!