cure for throttle body whistle?

[RysRed96GT]

i installed a 75mm TB and i have two problems:

1. there's a varying-tone whistle when i start to give it throttle. it will fade as i give it more throttle.
2. also, my idle seems to hang at times. when i'm cruising at 2k, for example, and let off the gas and put it in neutral, the rpms will hang around 2k. if i blip the throttle, it will go back down to idle.

for the first one, i've read this can be common. someone mentioned drilling a 1mm hole (like the stock one has) and that'll cure whistling issues.

for the second one, could this be the iac? or could this be the TB itself? if the butterfly isnt sealing completely, would it cause these symptoms? i BELIEVE it is sealing fully though.

aside from that, i love it. but the idle issue is annoying as hell. and if i can cure the whistle too, that would be even better.

thanks!

 

[SLY GT]

aside from that, i love it. but the idle issue is annoying as hell. and if i can cure the whistle too, that would be even better.

thanks!

What exactly do you love about it. It seems a little much for your setup.Are you planning on adding a SC

 

[03ghoststang]

the rpm hang up i am more then likely sure it's the iac, as for the whistle noise personally i have gotten use to it and im even surprised when i hear it on my car every once in a while

 

[RysRed96GT]

i definatly feel a difference. pulls noticably harder. plus i got it cheap, so im not complaining.

 

[RysRed96GT]

UPDATE:

i took a look at it again. seems that the butterfly valve was getting stuck right before it fully closed. that explained the surging idle and explain why blipping the throttle made it go back down. once down, it idles perfect.

i modified my spring to have more tension. so now it feels stiffer on the throttle (which i like) and it closes fully, even right before.

as are the whistle, it's still there, but starting not to mind it. but is there a cure? is it just because the opening is much larger? i dont think i have a leak, i checked all the hoses over and over.

 

[robg860]

i installed a 75mm TB and i have two problems:

1. there's a varying-tone whistle when i start to give it throttle. it will fade as i give it more throttle.
2. also, my idle seems to hang at times. when i'm cruising at 2k, for example, and let off the gas and put it in neutral, the rpms will hang around 2k. if i blip the throttle, it will go back down to idle.

for the first one, i've read this can be common. someone mentioned drilling a 1mm hole (like the stock one has) and that'll cure whistling issues.

for the second one, could this be the iac? or could this be the TB itself? if the butterfly isnt sealing completely, would it cause these symptoms? i BELIEVE it is sealing fully though.

aside from that, i love it. but the idle issue is annoying as hell. and if i can cure the whistle too, that would be even better.

thanks!

I had the same thing.....its a rough spot somewhere in the machining process. The high air flow velocity causes the whistle when hitting the rough edge. I sent mine back to accufab for a new updated one. The late model accufab are quiet. Any other older ones can possibly whistle and sound like crap. I took mine off the next day.....it drove me crazy, thats just me. You can have 2 HP or a whistling sound when you hit the gas. Pros and cons......

 

[Serper3]

i also have the whistling but it occured after i installed my dragon plenum. i have the stock tb but the whistling is only in the mornings basically or when the car is cold... i kinda wanna get it fixed it gets annoying as hell.... any ideas or self fixes?

 

[Kilgore Trout]

UPDATE:

i took a look at it again. seems that the butterfly valve was getting stuck right before it fully closed. that explained the surging idle and explain why blipping the throttle made it go back down. once down, it idles perfect.

i modified my spring to have more tension. so now it feels stiffer on the throttle (which i like) and it closes fully, even right before.

as are the whistle, it's still there, but starting not to mind it. but is there a cure? is it just because the opening is much larger? i dont think i have a leak, i checked all the hoses over and over.

Good job nothing like the satisfaction one gets from tracking down and fixing a problem. Especially on one's Mustang...

 

[twogts4us]

i also have the whistling but it occured after i installed my dragon plenum. i have the stock tb but the whistling is only in the mornings basically or when the car is cold... i kinda wanna get it fixed it gets annoying as hell.... any ideas or self fixes?

I've heard that's a common issue on the Dragon elbow because of its design, which has a 'splitter' down the middle.

 

[MTShambles]

With my 96 Cobra I added a Big bore TB and my K&N whistles. I can hear it if I open the hood and put my ear next to the filter. Its nothing bad as far as i can tell, and after a while you just get used to it. My guess is that its whistling because I increased the cfm by about 200 or so.

 

[Newbie143]

Almost everyone who swapped their TB+plenum has that whistle sound your hearing.Most likely around 2300-2700rpms. And when you give it more throttle the sound will fade.Its perfectly normal.Its not a leak. If i said i know the cure i would be lying , but then again i never tried to find a cure for it.Some people actually like that slight whistle

 

[tomustang]

What exactly do you love about it. It seems a little much for your setup.Are you planning on adding a SC

I had 75mm TB on my PI swap GT, I'd say the the most noticable gain was the throttle response right off the line.

 

[mogs01gt]

You shouldnt have to mess with the spring. Most after market throttle bodies still have metal burrs around the throttle body blade. It is always a good idea to take some sand paper and clean up all of the metal or debri that is in the throttle body.