Biscayne Ep. 35 Throttle body modification to stop the whistle

Let's fix this throttle body noise and at least make it bearable.
With a IAC from a dodge truck and some dremel work it seem like the throttle body will be manageable.
I think the stock throttle body was around 72 mm and this one is 92 mm. Not sure why by they decided to make the idle air port tiny and the air velocity going through that tiny port causes a loud whistling noise. by carefully using some aluminum cutting bits I enlarge the hole as far as I could safely. this reduced the noise by at least 50% and installing an IAC from a dodge 5.9 V8 the noise was reduced even more. Once we have the air filter installed it should be hardly noticeable.

[@georgeperez4324]

adding the hole did help a lot on mine. still a little loud fast idle and with ac on, but when warm cant hear at all.

[@andrewk778]

Don’t you just love having a hobby car to play with. Thank you for sharing.

[@harperjmichael]

Even my 102mm Holley is like this. Might have to try opening the IAC port inlet like you did.

[@johnreese7352]

Huh? You have to port match the larger throttle body to intake... Port matching

[@aarontovar8769]

Did you ever fix the issue?

[@JOne0442]

I've got the 90mm Holley Sniper and it does the same thing !! It's kinda cool at first, then after a few days it makes you want to pull your hair out lol. I might try your mod, I want to go in small increments until it's bearable. Right now with the filter on and hood closed it's loud as #$%&. Thanks for your video bro.

[@ThePracticalMechanic]

No problem. For the price of these things they should be quieter. The intake hiss shouldn’t be louder than the exhaust. I’m no engineer and I was able to make it quieter so why couldn’t they? Probably because it was cheaper to drill a small hole than to perform the porting we did. I can’t believe how much material I had to remove to open up that port. I have also seen people drill a hole in the throttle blade to reduce the amount of air going through the IAC but many still have a whistling noise after.

[@chrisgore2849]

I have the same TB 90mm Holley sniper and it whistles from the IAC port, I’ve changed everything ever since the tbss swap. I’ve bought twice. I’m now looking this up on my day off. Cause I’m sick and tired of this noise.

[@aarontovar8769]

@@chrisgore2849 did you ever solve the problem? Got the same issue not sure what to do

[@MeanGreenGT19]

The throttle body on my 4.6 mod engine makes the most satisfying whistle 👌

[@joseb1700]

Great vid min sheet metal intake is insane . U just solved my problem . N smaller Tb wont stop it .. . Man great vid … thnx thnx

[@markbaldwin9425]

Same problem with stock 5.3 ls with bigger injectors...edelbrock intake with 102mm throttle body...startup ccold...howls like bearing out in alternator behind airfilter...reverse 180 degrees on airfilter with tube...to passenger side was all intake noise. 2003 5.3 ls from Tahoe in 69 elcomino...

[@hoosierboy69er]

I am just now researching this as I to have that loud sound coming out of my air cleaner but I got the Holley 92 mm throttle body and in their forums it says the pentyl on there motor is different from the original 5.3 pintle motor but thanks for sharing because now my suspicions that I wasn’t hearing things is correct I will know buy there iac ,Thanks for sharing again that goes to my throttlebody

[@ThePracticalMechanic]

Let me know how yours turns out. I thought it was just because I bought a cheaper unit that I had issues. I was very nervous machining out the ports but in the end it is much quieter.

[@hoosierboy69er]

ThePracticalMechanic I did what you did I didn’t order the original iac , I will let you know as soon arrives in the mail,The original for that Holley throttlebody they want 60 bucks I ordered a cheap one hopefully it doesn’t bite me in the ass for being cheap ha ha

[@hoosierboy69er]

A week later quick update look into getting an iac From an early 2000 3100 American engine anyone will work,Totally got rid of the loud hissing sound it is totally quiet now with no modifications,I got mine out of a junkyard out of a early 2000’s Monte Carlo with a 3100 engine

[@ThePracticalMechanic]

Great news. Junk yard parts saves the day. I’ll try a 3.1 IAC next time for sure.

[@chrisgore2849]

I just bought their IAC for my 90mm Holley sniper, the noise is worse on my 5.3

[@amydaudier3327]

If u mimic the stock tb and drill a hole then those Chinese tb will work just fine

[@deraculandrac917]

Thank you for the vid I have a 6.0 with a 92mm throttle body. Same noise before your porting I will try that & check if quiets down. Again thank you!!!!

[@ThePracticalMechanic]

Did it work?

[@deraculandrac917]

@@ThePracticalMechanic it worked a huge improvement. My son thought it was a belt squeak. Until I unplug the IAC & started the motor nothing. Pulled the throttle body ported the holes 1/4" inlet/outlet. Squeak noise is gone only the air noise remains. My customer is happy. The engine is in a 72 Olds. Cutlass. with a TH350 runs great, thanks again!!!

[@adamjaramillo2110]

Awesome man. Thank you.

[@willygarcia4764]

102 mm or 92 u must be tune in order to work properly mine does the same it sucks alot of air it idles high and no its not the idle valve or intake leaks

[@NaztyNate]

any tuning required after this? or can the dodge sensor plug right in and work?

[@Russell_Duncan]

If you decided to drill a hole in the throttle plate, could you solder it closed again later if necessary?

[@ThePracticalMechanic]

Russell Duncan yes you could solder it up. I even consider a rivet to plug the hole if the hole didn’t help or if It had undesirable results.

[@smithjo4152]

I'm experiencing the very same thing with my 92mm throttle body. By my question is with you just swapping out the idle air module, how much did the sound reduce? By boring out the ports, how much more difference did that make? Thank you in advance for your help.

[@jboxjohnny1176]

Thank You, Worked great on the Sniper. Some of the others might of been Chinese but even the Holley is made the same way. I blame it on the manufacture, sloppy design. I can slightly hear it at 100% and I mean slightly.

[@PreciousSandayan]

may iacv doesn't work anymore if i close that hole?

[@ThePracticalMechanic]

If you plugged that port the IAC will not operate.

[@ss8512]

Will this procedure you does it help with idle hanging?

[@haydencarlson2861]

You need to adjust throttle follower in the tune

[@LaXedLiFe]

Do I have to put my stock intake back on to stop the whistle on my rs Camaro ?

[@diymisfit_Mechanic_UDX404]

Pros and and cons, gotta pay to play

[@ls1_cammeroh]

Did the idle stick before this for a few seconds

[@ThePracticalMechanic]

They all seem to hang at fast idle for the first 10 seconds or so. If the throttle blades are actually sticking in the bore you probably need to adjust the throttle stop in a little more to keep the blade from sticking in the bore.

[@daryldavis4074]

Did you ever get rid of that noise mine is making a load noise don’t know if I should just get rid of it or try to fix it I cannot deal with the whistle

[@aarontovar8769]

Ever figure it out?

[@chadgrove3786]

Did you have to do any tuning after porting the iac opening?

[@ThePracticalMechanic]

no tuning was performed to idle settings. I adjusted the throttle opening and watched iac command. you want to make sure the IAC is at 0 steps. If it is at 0 steps you may need to close the throttle plate slightly. 15-20 steps on a hot engine with AC off is a good starting point.

[@johnreese7352]

In order to remove the whistle you need to port match

[@aarontovar8769]

I’m not to experienced on cars but what does port match mean?

[@paulvelez6824]

@@aarontovar8769 when the throttle body matches the diameter of the intake manifold

[@haydencarlson2861]

@@paulvelez6824i have a 92mm tb on a 92mm intake and it does the same thing

[@hansford2006]

Which iac did you use to fix the issue

[@ThePracticalMechanic]

It was off a dodge 5.2l engine I believe.

[@isaiah-lava5.086]

What brand is this throttle body?

[@ThePracticalMechanic]

It came from muscle rods but it is used on most Chinese intake kits and even on the holly intake.

[@gabriellsx9303]

That's stuped to ovoid the whistle....its a lovely sound

[@Turbochapman]

Lol Dude use spell check before you call someone stupid for avoiding a annoying sound his customer may not want to listen to.

[@gabriellsx9303]

@@Turbochapman lol but u still understand right ...

[@haydencarlson2861]

@@gabriellsx9303no