A hole in throttle plate?
Thread Starter
Safety Car
Joined: Nov 2002
Posts: 4,394
Likes: 6
From: Melbourne FL
A hole in throttle plate?
Would someone explain under what circumstances there would be a need to drill a hole in the throttle plate?
I thought it was a cure for idle surging for those with a cam that didn't have the car tuned.
Yet, I pulled my TB today and found a large hole has been drilled through my throttle plate.
:mad
Am I totally out in left field with my thinking as to the purpose of the hole?
I thought it was a cure for idle surging for those with a cam that didn't have the car tuned.
Yet, I pulled my TB today and found a large hole has been drilled through my throttle plate.
:mad Am I totally out in left field with my thinking as to the purpose of the hole?
Melting Slicks
Joined: Mar 2003
Posts: 2,744
Likes: 9
From: FL
Cruise-In VI Veteran
Re: A hole in throttle plate? (Z06ufgrad2002)
The hole helps the car idle, lets more air in. You increase the diameter if you are having idle issues. There are other ways to fix idle issues though. I know my Fbody had it, and I made it larger to lower my IAC counts. I'm pretty sure my FRC has it too, although I never really paid much attention. The vette does not have an IAC motor on the TB, due to the electronic throttle control. Kinda accomplishes the same thing.
Safety Car
Joined: Mar 2002
Posts: 4,928
Likes: 1
Cruise-In V Veteran
St. Jude Donor '09
Re: A hole in throttle plate? (Steve92LT1)
All C5s are Elect Throttle Control (ETC). They do not have IAC motors - the idle air function is controlled by the PCM via the TB blade motor. The TB blade does not need to be drilled unless you need more air than the maximum setting in the PCM ( i.e. Very Big cams). FWIW.
Thread Starter
Safety Car
Joined: Nov 2002
Posts: 4,394
Likes: 6
From: Melbourne FL
Re: A hole in throttle plate? (Bink)
I am running a big cam but, I was under the impression that it can be tuned without drilling a hole in the throttle plate. So I was a bit suprised when I pulled the TB out and found a hole in the plate.
I will have to go through my LSedit file and see if I can track down that setting and see if it is Maxed out.
Does anyone know which setting controls the throttle plate idle position and where it's located in LS1edit?
I will have to go through my LSedit file and see if I can track down that setting and see if it is Maxed out.
Does anyone know which setting controls the throttle plate idle position and where it's located in LS1edit?
Safety Car
Joined: Mar 2002
Posts: 4,928
Likes: 1
Cruise-In V Veteran
St. Jude Donor '09
Re: A hole in throttle plate? (Z06ufgrad2002)
Edit -> Eng Cal->Idle and Limiters-> IAC Park Position.
The only way to tell if it's maxed is to close the TB hole and set IAC Park to 63.99 (max value). If it will idle at the max value then you don't need the hole, per se. But, with a Big cam it may be a bit difficult getting the IAC, RAF and Throttle Follower tables in synchrony. FWIW.
The only way to tell if it's maxed is to close the TB hole and set IAC Park to 63.99 (max value). If it will idle at the max value then you don't need the hole, per se. But, with a Big cam it may be a bit difficult getting the IAC, RAF and Throttle Follower tables in synchrony. FWIW.
Race Director
Joined: Aug 1999
Posts: 15,466
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From: GARDENA Ca, State Of Konfusion
St. Jude Donor '05
Re: A hole in throttle plate? (Z06ufgrad2002)
I also had to have a hole drilled in the throttle body after the cam installation. The car would die at every light and a hole was necessary to get it home. Tuning was someting that was in the future. The M6 can get away with it, but the A4 definatley needs the hole or tuning to run properly.
Thread Starter
Safety Car
Joined: Nov 2002
Posts: 4,394
Likes: 6
From: Melbourne FL
Re: A hole in throttle plate? (wallstAL)
I also had to have a hole drilled in the throttle body after the cam installation. The car would die at every light and a hole was necessary to get it home. Tuning was someting that was in the future. The M6 can get away with it, but the A4 definatley needs the hole or tuning to run properly.
I will have to review my Edit file and see if the hole was really needed.
I have heard other shops managed to tune this cam without drilling a hole so my edit file should be able to give me some clues as to what exactly my tuner was trying to do OR not able to do with my car.
[Modified by Z06ufgrad2002, 7:28 PM 7/5/2004]
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