My D1SC has been acting kinda funny. Every once in a while, I will get an increase in blower whine (would say probably 2x as loud as normal) What I noticed is that it happens above 5500 rpm, but it doesnt do it all the time. Just every once in a while...

So i inspected the turbines and everything looks ok, but I'm stumped! Has anyone ever had this happen? It must be something inside the blower.

On a side note...i am at 5,500 feet above sea level, and ive got the 3.4 inch blower pulley and 7.65 crank pulley and the blower is maxed out at 11 psi..ive also got a 3.5 inch aluminum intake.

 

on 3.2 and 7,65 i made 18psi with no intake through stock twins

 

Belt Slip??

 

Belt is tight! My blower leaks oil, and I did find it really low on oil once, but i topped it off and have been watching the level ever since. Could that period of time that it was low on oil possibly be the cause of this?

Am I spinning the blower past max rpm?

 

We would need to know your max engine rpm to know for sure, but at 5500 rpm where the problem first occurs you shouldn't be anywhere neer overspinning it.

D1-SC has a max RPM of 62,000. With a 7.65 crank and a 3.4 blower pulley and the 4.10 step up ratio, at 5500 rpm you should be spinning at about 50,738 rpm on the blower. At 6000 rpm the blower would be at about 55,350 and at 6500 rpm it would be about 59,960.

 

I only spin the motor to 6000 rpm...I called Bob at Exotic performance plus today and he thinks its my idler pulley on the blower bracket. It seems to be a smidge loose, which he said will cause the high pitched scream.