Post by AutotestAddict on May 4, 2016 16:38:05 GMT
As per the title, I'm pulling my hair out. A recent supercharger swap has caused a loud whistle, worst at 1000 - 2000rpm. This isn't a general 'charger whine, its like sitting with a referee in the passenger seat. Its undriveable, though I keep trying.
I have narrowed it down to the throttle body to intake (doesn't happen with intake open to the air, still happens with air pipe upstream of the TB disconnected)
When swapping the 'charger I cut the flange off the intake pipe, I took the TB apart to fit mountings to the bulkhead, and I changed the pulley ratios (faster spin). Nothing else has changed.
I have tried running with no TB, too noisy (either recirc noise or dump valve noise)
I have tried running with the TB held open (quieter, but still present)
I have polished the internals of the intake pipe, particularly where I had cut it and left rough edges (no change in pitch or volume).
I have replaced the gasket in the TB and tightened it all up (no change in pitch or volume).
I have cleaned the internal surface on which the butterfly seals (no change in pitch or volume)
I have adjusted the idle valve on the TB (no change in pitch or volume).
I have had my hands all over the intake pipework trying to find/block the source of the leak (no change in pitch or volume).
I have attached the intake to the charger inlet with silicon pipe and clamps, each time ensuring a very secure fit, each time no change in pitch or volume.
Please tell me if I have missed something obvious here? It's driving me absolutely mad. I have only changed a couple of things, and in every other way the charger is working great. I just can't drive the thing because of embarrassment and headaches
I have narrowed it down to the throttle body to intake (doesn't happen with intake open to the air, still happens with air pipe upstream of the TB disconnected)
- It is loudest when the TB is fully closed (resting on the stop), and quieter when the TB is fully open.
- Opening the recirc and sticking my hand over the intake part makes it much louder.
- On the road, sticking my foot down changes the pitch of the note but not the volume, the note then gets higher and louder as you go up the rev range. On the overrun the reverse happens with the note coming down with rev range.
Suggests to me that it is a vacuum leak between TB and inlet?
When swapping the 'charger I cut the flange off the intake pipe, I took the TB apart to fit mountings to the bulkhead, and I changed the pulley ratios (faster spin). Nothing else has changed.
I have tried running with no TB, too noisy (either recirc noise or dump valve noise)
I have tried running with the TB held open (quieter, but still present)
I have polished the internals of the intake pipe, particularly where I had cut it and left rough edges (no change in pitch or volume).
I have replaced the gasket in the TB and tightened it all up (no change in pitch or volume).
I have cleaned the internal surface on which the butterfly seals (no change in pitch or volume)
I have adjusted the idle valve on the TB (no change in pitch or volume).
I have had my hands all over the intake pipework trying to find/block the source of the leak (no change in pitch or volume).
I have attached the intake to the charger inlet with silicon pipe and clamps, each time ensuring a very secure fit, each time no change in pitch or volume.
Please tell me if I have missed something obvious here? It's driving me absolutely mad. I have only changed a couple of things, and in every other way the charger is working great. I just can't drive the thing because of embarrassment and headaches