Whistle sound at part throttle

Hock

Registered User
I hear this whistle sound at part throttle, its not a vacuum leak. The only reason I say its not is that I have heard the sound while under the hood revving the engine. I can hear it at the air filter. Is it possible that the 70mm throttle body is too small since the blower upgrade?
 
funny thing is i still have the stock tb, upgraded to a late model blower, and i too have a whistle when at partial throttle.
 
Whistling means there is air getting in/out where it isn't suppose to. You've got a leak. The shaft seals on aftermarket TB's tend to be not so good :( and will leak.

Fraser
 
Whistling means there is air getting in/out where it isn't suppose to. You've got a leak. The shaft seals on aftermarket TB's tend to be not so good :( and will leak.

Fraser

The strange thing about it Fraser is that I hear the sound at the filter and no where else. Does that still apply in my case?

BTW, it is a 70mm BBK.
 
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I had a BBK on the 93 GT. Whistle. BBK is junk. You would thing that you can't screw up a throttle body but they put two SCREWS on the shaft of the butterfly plate that could go right past the TB! Pro M or ask these guys. Screws in the air stream makes me nervous. The whistle could be the screw is loose and plate isn't centered.
 
I had a BBK on the 93 GT. Whistle. BBK is junk. You would thing that you can't screw up a throttle body but they put two SCREWS on the shaft of the butterfly plate that could go right past the TB! Pro M or ask these guys. Screws in the air stream makes me nervous. The whistle could be the screw is loose and plate isn't centered.

I had a BBK for years and was a great product and had no leaks or issues with it, much better then some of the Professional Products TB's people have had problems with.

Ummm, Ford put screws on the throttle shafts to hold the throttle blade on the stockers, kinda an industry standard...:cool:

An upgraded blower will sound different at the filter since you are moving more air.
 
Unless you are 100% sure its the filter itself that is "whistling", you have a leak, which means if that is after the MAF you have unmetered air getting into the motor which leans it out because the computer doesn't know that air is going in.

Fraser
 
Unless you are 100% sure its the filter itself that is "whistling", you have a leak, which means if that is after the MAF you have unmetered air getting into the motor which leans it out because the computer doesn't know that air is going in.

Fraser

if you assumed it could be the filter its self i would just remove it and see.. unless its really dusty where you live.:rolleyes:
 
Unless you are 100% sure its the filter itself that is "whistling", you have a leak, which means if that is after the MAF you have unmetered air getting into the motor which leans it out because the computer doesn't know that air is going in.

Fraser

Fraser, I'm having trouble grasping what you said because I'm used to notion that where you hear the sound is where you find the leak. So I just don't understand how that would work. Not denying it, just not understanding it.

As far as the filter goes, its an old K&N but it has less than 1500 miles since I last cleaned and it seam to be in pretty good shape still. But I will take it off and listen for a change, also had a friend suggest doing the same thing.
 
Fraser, I'm having trouble grasping what you said because I'm used to notion that where you hear the sound is where you find the leak. So I just don't understand how that would work. Not denying it, just not understanding it.

As far as the filter goes, its an old K&N but it has less than 1500 miles since I last cleaned and it seam to be in pretty good shape still. But I will take it off and listen for a change, also had a friend suggest doing the same thing.

Every single "drop" of air that goes into the motor needs to be measured by the MAF so the computer knows how much fuel to deliver. If you have leaks anywhere then that will make the motor run lean because the computer doesn't know about that air that is going in.

If the whistling is happening anywhere after the MAF, that means air is getting in where it shouldn't be. One area that can do that and whistle is the throttle body, because the seals around the shaft generally are not that good, especially on after market stuff.

If its the air filter itself that is whistling, then cool, all is ok maybe, or the filter could be ripped.

Fraser
 
Fraser,

I know all of that. What I'm not understanding is why would I hear a leak (if that's what the noise is from) at the filter and not at the source of the leak?
 
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Fraser,

I know all of that. What I'm not understanding is why would I hear a leak (if that's what the noise is from) at the filter and not at the source of the leak?

Resonance through the pipes. Try another filter to rule it out. Sounds are very misleading in cars... how many times have people thought the noise was from the back of the car but in reality it was from the front :).

Fraser
 
Resonance through the pipes. Try another filter to rule it out. Sounds are very misleading in cars... how many times have people thought the noise was from the back of the car but in reality it was from the front :).

Fraser

Ok, well that makes sense.
 
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