WISTLE OR NO WISTLE?

[Crazyhorse88]

HI GUYS, MY BUDDY HAS A STOCK SN-92 UNIT IT IS FAIRLY HARD TO TURN THE PULLEY, IT MAKES 5#OF BOOST @ 5K AND IT IS COMPLETLY SILENT AT IDEL BUT AS IT BUILDS BOOST IT MAKES A SOFT WISTLE BUT IS FAR FROM BEING LOUD! I JUST GOT AN SN-93 WITH A UPGRADED IMPELLER AND FRESH REBUILD, IT IS MUCH HARDER TO TURN THAN THE SN-92 UNIT, IT ONLY MAKES 5# @ 5K, IT IS COMPLETLY SILENT FROM IDEL TO 5K! THERE IS NO WISTLE AT ALL! SHOULD THERE BE A WISTLE? CAN ANYONE EXPLAIN THIS? THESE UNITS WERE INSTALLED ON THE SAME CAR 15 MIN APART AND DRIVEN BACK TO BACK! HOPE SOMEONE CAN SHINE LIGHT ON THIS I WAS TOLD THE SN-93 WITH NEW IMPELLER SHOULD MAKE MORE BOOST! IS THE SN-92 JUST A STRONGER BLOWER? THANKS FRANK

[speedytang]

They will perform the same since they are really the same internals. Does you impeller look different because the pitch of the blade will of course change the sound of the unit since no gears to make all that noise.

[Crazyhorse88]

YES THE PITCH OF THE BLADE IS SLANTED ON THE 93 BUT THAT IS THE ONE WITH NO WISTLE, IT IS ALSO THE TIGHTER ONE THAT I WAS TOLD WOULD MAKE MORE BOOST, BUT THEY BOTH MAKE THE SAME THANKS FRANK.

[speedytang]

When the units are first rebuilt it takes a few miles to loosen up but it will.