Bored, align-milled and polished 30V Throttle body ("before" pic)
06-21-2004, 07:45 AM
#1
AudiWorld Super User
Thread Starter
Bored, align-milled and polished 30V Throttle body ("before" pic)
<center><img src="http://pictureposter.audiworld.com/711/30vtbi1.jpg"></center><p>
For those that missed the post yesterday you can find the pics in my pic poster here. They are listed there as follows:
Outlet before: 30vtbo1 (o1=outlet/before)
Outlet after: 30vtbo2 (o2=outlet/after)
These pics will be listed there the same way except with "i" for "inlet" side.
I stayed up and made the inlet side fixture last night and started turning it on the lathe this morning. Stock throttle body has a cast-in deflector walls 180 degrees apart on both top/bottom sides of the butterfly that for the life of me I can't understand their purpose. They are restrictive and turbulence creating. The stock throttle body flows 294CFM measured at 38" H2O. The 12V throttle body conversely flows 312CFM at the same settings.
Removing the outlet side deflector yesterday resulted in a net CFM increase of 20% causing the TB to flow 350+ CFM. Todays inlet side numbers are somewhat less but still proportionate to material removal. I was able today to remove only 3.2mm off the inlet wall deflector and increased the flow to 388.2CFM for a net 32% increase over stock.
Additionally the bore is now perfectly aligned with the butterfly shaft with no deflectors remaining. Those deflectors required air to make an abrupt last-minute turn just the top of the butterfly plate then an immediate 180 degree opposite turn after the butterfly plate. Only thing I can think of is they used that to slow velocity and help off-idle throttle modulation to get the car rolling from a dead stop. And admittedly what I've done may compromise that or cause some initial re-learning of how to use the gas/clutch on pulling away from a stop. Truth is no one will know until this throttle body finds it's way on to a car and can be tested.
One thing I do know or am able to predict from the work I've done is that acceleration should be dramatically increased by sheer flow increase as well as a far smoother pull under power due to the bore now being a straight-thru shot instead of the previous straight-right-left-right transition. The inlet velocity will also be increased due to a more aggressive inlet taper machined in. This is the same angle/degree I use on the 12V throttle bodies and the 12V/30V velocity stacks I make.<ul><li><a href="https://forums.audiworld.com/12v/msgs/29506.phtml">link to previous post</a></li></ul>
For those that missed the post yesterday you can find the pics in my pic poster here. They are listed there as follows:
Outlet before: 30vtbo1 (o1=outlet/before)
Outlet after: 30vtbo2 (o2=outlet/after)
These pics will be listed there the same way except with "i" for "inlet" side.
I stayed up and made the inlet side fixture last night and started turning it on the lathe this morning. Stock throttle body has a cast-in deflector walls 180 degrees apart on both top/bottom sides of the butterfly that for the life of me I can't understand their purpose. They are restrictive and turbulence creating. The stock throttle body flows 294CFM measured at 38" H2O. The 12V throttle body conversely flows 312CFM at the same settings.
Removing the outlet side deflector yesterday resulted in a net CFM increase of 20% causing the TB to flow 350+ CFM. Todays inlet side numbers are somewhat less but still proportionate to material removal. I was able today to remove only 3.2mm off the inlet wall deflector and increased the flow to 388.2CFM for a net 32% increase over stock.
Additionally the bore is now perfectly aligned with the butterfly shaft with no deflectors remaining. Those deflectors required air to make an abrupt last-minute turn just the top of the butterfly plate then an immediate 180 degree opposite turn after the butterfly plate. Only thing I can think of is they used that to slow velocity and help off-idle throttle modulation to get the car rolling from a dead stop. And admittedly what I've done may compromise that or cause some initial re-learning of how to use the gas/clutch on pulling away from a stop. Truth is no one will know until this throttle body finds it's way on to a car and can be tested.
One thing I do know or am able to predict from the work I've done is that acceleration should be dramatically increased by sheer flow increase as well as a far smoother pull under power due to the bore now being a straight-thru shot instead of the previous straight-right-left-right transition. The inlet velocity will also be increased due to a more aggressive inlet taper machined in. This is the same angle/degree I use on the 12V throttle bodies and the 12V/30V velocity stacks I make.<ul><li><a href="https://forums.audiworld.com/12v/msgs/29506.phtml">link to previous post</a></li></ul>
06-21-2004, 08:48 AM
#4
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I'll try it on my 30v if you want me to.
Just send it to me here in chicago. send me an email, I know you're in the denver area so it might not be convienient for you but I'll give anything a whirl if it makes the 30v faster
06-21-2004, 08:53 AM
#6
AudiWorld Super User
Thread Starter
this is a "brand new" never-mounted TB and it already has a 30V owner
He and I will be in close communication and I would guess he will also report his findings here.
