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dump valve noise

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Old Jul 10, 2022 | 09:18 PM
  #1  
ray barker's Avatar
ray barker
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From: west cornwall
Default dump valve noise

i removed my dump valve of my 2wd saff red top i dont like the noise anymore from the top of the charge cooler. its almost a standered car running a stg one chip i pluged the short hose with a bung thinking this would be the end of the noise. i dont have the standerd air box instead a big k&n with the pipes that would of gone into the std one going into the k&n. i still have the noise ive got waste gate chatter when i ease of which is pleasing to the ear but got air pressure build up noise or it could be boost pressure escaping its deffenatly boost pressure as im on exseleration its quite loud. it gets louder the faster i exselerate. all the boost hoses and pipes look good and a new waste gate actuator. i didnt fit the the dump valve twenty years ago so i dont no what it was when standered. the dump valve was connected to a short hose on the top left hand side of the standered charge cooler ass if you were standing in front of the car looking at the engine. does this short hose have to be plumbed in some where els now or just left blanked of where the dump valve was. thanks in advance
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Old Jul 11, 2022 | 12:40 PM
  #2  
Caddyshack's Avatar
Caddyshack
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From: Guildford
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The small hose is a vacuum pipe to pull the dump valve open…it must be blocked off.

the chatter noise is the compressor wheel stalling against the built up,pressure when you close the throttle.

you may need a smoke test to rule out any leaks. You will hear turbo whistle though as that is the boost pressure building, they will always do that.

Do you have a boost gauge to check it is creating the required pressure and not venting somewhere like a split intercooler.
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Old Jul 11, 2022 | 07:27 PM
  #3  
ray barker's Avatar
ray barker
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From: west cornwall
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Originally Posted by Caddyshack
The small hose is a vacuum pipe to pull the dump valve open…it must be blocked off.

the chatter noise is the compressor wheel stalling against the built up,pressure when you close the throttle.

you may need a smoke test to rule out any leaks. You will hear turbo whistle though as that is the boost pressure building, they will always do that.

Do you have a boost gauge to check it is creating the required pressure and not venting somewhere like a split intercooler.
ive not checked the boost pressure i need to get a gauge and a t peice. the smoke test would be a good one. the waste gate actuator is set up right with the right base lift. ive got everything blanked of that should be. it does hesitate a bit under acceleration but in general it pulls hard and well. i called autodynamix at newtonabot they said the indution noise is alot louder as i have a big k&n air filter and a 4x4 bonnet. i could fit the std re circ valve it wouldnt make the induction slightly quieter but it would stop the waste gate chatter which i like so everything is how it should be. so there going to source me a std saff air box which will quieten it down just enough. basically im an old fart now. ive made my own stainless three inch exhaust with stainless wool inside its so much quieter than the mongoose but still breaths well. its so much more pleasurable to drive. i have lost a bit of performance but you cant really notice unless you get it in to the rev limiter i dont want to do that anymore
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