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Old Aug 23, 2007 | 09:18 PM
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Default Throttle Body hole

How big do you drill your TB hole out to on the NW90? Tune seems to be fine but the car will not idle right now and the IAC is maxed out. Does anyone know how big i should go?
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Old Aug 23, 2007 | 09:58 PM
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not an expert, but i don't think you should be drilling any holes in the tb.
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Old Aug 23, 2007 | 11:42 PM
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My tuner drilled mine out a little to get my 408 to idle better. I think it's mostly trial and error.
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Old Aug 24, 2007 | 01:58 AM
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Your going to have to drill it slightly bigger, check your IAC's if there still maxed repeat. Drilling is really the only way i know. If you crack the throttle blade your IAC will no longer control your idle, and you still risk it stalling on you.
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Old Aug 24, 2007 | 08:17 AM
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Originally Posted by Gimp98TNT
Your going to have to drill it slightly bigger, check your IAC's if there still maxed repeat. Drilling is really the only way i know.
There are two schools on weather or not you have to, and I think the argument can be fired up and rage forever, but IMO you will have to drill it.
I did, and I just have a 224 cam.

You can try maxing out the set screw but you will need to reset and monitor your TPS voltage after doing so. I tried that, but you have a small threshold to work with (>= .5 X <= .69 I think but don't quote me) and I didn't like mine lingering too high within that so it sits right in the middle.

I drilled a couple times to get my IAC proper at idle. I actually went up one bit size on the original hole, and then drilled another smaller hole on the top half.
My IAC is proper now and my idle trims are almost spot on.
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Old Aug 24, 2007 | 08:33 AM
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Originally Posted by Gimp98TNT
Your going to have to drill it slightly bigger, check your IAC's if there still maxed repeat. Drilling is really the only way i know. If you crack the throttle blade your IAC will no longer control your idle, and you still risk it stalling on you.
x2 Make sure you pull the TB off of the motor before drilling it!
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Old Aug 24, 2007 | 04:55 PM
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You can drill it as big as you need. Just keep in mind that as the drill size gets bigger, each step up makes a bigger difference than the last. Sometimes it is better to drill another small hole and just have two. Once you get the IAC counts down under 100, I usually just adjust the screw some to fine tune them.

Nick
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Old Aug 25, 2007 | 02:22 AM
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Originally Posted by Nick Williams
You can drill it as big as you need. Just keep in mind that as the drill size gets bigger, each step up makes a bigger difference than the last. Sometimes it is better to drill another small hole and just have two. Once you get the IAC counts down under 100, I usually just adjust the screw some to fine tune them.

Nick
Thank you sir, Finally someone with some knowledge... Thats what my buddy said that is tuning my car, But the only problem i see turning that adjuster screw in is that once the pcm reads and tps load its out of the idle table. The guy tuning my car said right around 100 is where i want to be so that you for the info.
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