larger idle air bypass hole for a 383 TPI?
10-26-2011, 09:49 AM
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Car: '86 IROC-Z/'94 Z28
Engine: 350 LT1/382 LT1
Transmission: 4L60-E/T-56
Axle/Gears: 3.45/3.42 (soon 4.10)
larger idle air bypass hole for a 383 TPI?
Didn't see anything directly related to this so I figured I would post.
My vortec 383 runs a little rich at idle. Surges a little bit, and stalls at idle on occasion. The IAC is set correctly, though I have to open it a bit more for minimum idle air rate compared to the 350 (obviously).
Naturally, the idle air bypass hole in the throttle body should be sized for a 305 (as the intake is). I'm assuming that the jump from a LTR 350 to 383 is causing my instability at idle, considering I'm using a stock ported throttle body.
Cammed LS1 cars often use this as a mod to smooth out idle instability issues.
Has anyone enlarged their idle air bypass hole to smooth out the idle for a larger engine, and if so, what size did you punch it out to?
My vortec 383 runs a little rich at idle. Surges a little bit, and stalls at idle on occasion. The IAC is set correctly, though I have to open it a bit more for minimum idle air rate compared to the 350 (obviously).
Naturally, the idle air bypass hole in the throttle body should be sized for a 305 (as the intake is). I'm assuming that the jump from a LTR 350 to 383 is causing my instability at idle, considering I'm using a stock ported throttle body.
Cammed LS1 cars often use this as a mod to smooth out idle instability issues.
Has anyone enlarged their idle air bypass hole to smooth out the idle for a larger engine, and if so, what size did you punch it out to?
10-28-2011, 01:50 AM
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Car: 89 GTA
Engine: 5.7L Supercharged
Transmission: T-56
Axle/Gears: Moser 9" 3.70
Re: larger idle air bypass hole for a 383 TPI?
Ever thought of just opening the throttle blades more with the set screw? What is your IAC counts at idle?
(Woops you have a totally different computer setup then I thought, don't think it would apply)
(Woops you have a totally different computer setup then I thought, don't think it would apply)
Last edited by Tony89GTA; 10-28-2011 at 01:54 AM.
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