[vector]

I have a Whipple nonintercooled kit. Mild tune,6lb pulley, cat back exhaust.When I get under boost approximately at 2lbs to 4lbs I get a shrieking noise from somewhere. The noise goes away once I get under full throttle but I don't seem to be getting full power. This car has been checked for vacuum leaks,vacuum gauge reads 20.I have installed a new bypass valve actuator but that wasn't the problem.Does anybody know any tests or how to clean the butterfly in the valve? My car has run pretty erratic at times in the past so I'm thinking the valve might be full of gunk.I would like to try a few ideas before taking it apart.Any help is appreciated.-Daryl

[Dana W]

I am far far from an expert but I have had a couple of weird air noises develop from time to time. (No, not me, My cars)

Could be that your throttle door is acting like a whistle when it is partially open. That single butterfly with the long straight edges could do it.

Are all the joints in your intake tube solid? Maybe one of them has a tiny gap.

Those double screws will whine very noticably even though the whipple is supposed to be one of the quiet ones. Maybe they quiet down under full pressure? I've never been near one thats working hard, they're always in somebody else's car and pretty far ahead by that time.

Dunno what the cause may be for your shriek but I've had them originate from the passenger seat, when it's occupied.

[mell0]

might also be belt slip/ a pulley shrieking. might be the idler pulley. i would check your belt and make sure it's at 100% and if you were to take it off spin some pulleys by hand to see if they make any noises. just a thought...

[2000blown]

ya i have the same issue a have to get an 8 rib pulley kit . i can only make 12 pounds before i get belt slip my motor was built for 16lbs boost (SHM sean hyland motorsports ) long block and a vortech v-2

[2oo5GT]

Originally Posted by mell0

might also be belt slip/ a pulley shrieking. might be the idler pulley. i would check your belt and make sure it's at 100% and if you were to take it off spin some pulleys by hand to see if they make any noises. just a thought...

+1. Look for black dust on your idlers or other places, that will be the belt slipping. Def could be an idler too.

[BRENSTANG03]

mine slips at 6psi,only fully floored though sometimes,just check everything over

[mell0]

if it is indeed belt slip it might be from a faulty/failing belt tensioner too.

[vector]

New tensioner will be going on Wednesday.Thats 2nd on the checklist.1st was a bypass actuator.