hd4mud

I put a TBSS intake on my LQ4 that has LS6 heads and cam. This was a low budget project (net cost was around $100 after I sold my stock intake, TB and the TBSS TB) I did not want to spend several hundred on a high-end TB from FAST or Nick Williams, so I put on a $100 eBay TB. I did have to sand the area the IAC goes in to get it to go in, but other than that it works pretty well.

The only problem I have with it is the plate seems to be so tight to the housing that it whistles when you first give it gas.

I thought maybe it was the PCV tube so I reinstalled that with some RTV around it, but nothing changed.

I though my home made fuel vapor line might be leaking so I build a new one from new replacement hose and connectors, but still the whistle.

My "custom" 4" intake tube was not quite lined up with the adapter at the MAF, so I ordered a 22 degree flexible boot and all that is sealed up tight for sure, probably tighter than it was before I swapped the intake.

When it still whistled after all that, I ran it with no intake tube at all and it still whistled when you first hit the throttle (could have done that before redoing the intake tube but the tube was less than aesthetically pleasing as it was so I really needed to straighten it out anyway).

I tried to adjust the minimum TB plate opening with the adjustment screw (with the intake tube connected), but even with the truck idling at 1200 RPM, there is still a bit of a whistle left.

Now I am thinking I should drill a 3/16 hole in bottom of the throttle plate (like the stock TB had), but I don't want to make things worse and I won't be able to undrill the hole once its there.

Has anyone had any experience with this?

What is the worse case scenario if I drill the hole in the throttle plate?

Could it be something besides a very tight throttle plate causing the whistle (when you blip the throttle it sure sounds like its coming right from the TB)?

Please don't tell me to buy a different TB as this is an off road toy and it will just have to whistle if the only fix is a $400 TB.

BTW, I originally bought a Pro Comp TB thinking that was a decent TB for under $200 and it was a total POS. The throttle plate looked like it was made by an 8 year old (visible gaps everywhere), so I was a bit stuck at that point since I wanted a TB for less than $200.

FFDP

iTrader: (2)

I've seen it where it's the air rushing past the IAC passage inside the throttle body that makes the sound.

It kinda like a shovel on concrete when it's started cold to me.

Pro52R

iTrader: (16)

Mine whistles too. It's stock. Has always done it.

hd4mud

Thanks for the feedback

hd4mud

I decided I would just change the TB and intake gaskets and this has made it so I can only hear a slight whistle when I am under the hood. I can no longer hear it from inside the cab.

Atomic

iTrader: (42)

My NW 90mm tb whistles loud as hell, pretty sure it is the IAC valve, just havent felt like messing with it. Its kinda funny actually.

hd4mud

I think I may look at that next.

smokeshow

iTrader: (16)

Razor had that 'issue' with the 102mm in front of his 2.3 whipple as well. Wasn't really a problem, just sort of a characteristic of the setup.