Port matching TB and intake

**kannon** · March 27th, 2001, 08:55 PM

One upon a search... I found Larry mention the following in a discussion about safely running 10 psi on a B16:

"Do not, under any circumstances, use one that tapers smaller as it approaches the throttle body. I don't care what anyone says, throttle
bodies like slow moving air to draw from, and to do them right, the tube should actually grow larger as it nears the throttle body."

If Larry is suggesting using a 3" induction tube, is he actually port matching the throttle body to 3"? A 762mm throttle body?

Im currently using a 3" Injen intake hooked to a stock throttle body. The intake includes a cone shaped rubber coupler to hook to the throttle body... this.. is exactly what Larry says NOT to do.

Even if the TB were matched, it would get drawn into a smalled intake manifold opening.

What is the right thing to do here?

**Sonnyballs** · March 27th, 2001, 10:46 PM

I think Larry is referring to the use of an intake pipe that tapers down as it approaches the throttle body. Ie, you could have the opening at the air filter be 3" and then slowly taper the pipe down to 2.5". This will effectively increase the air speed as you get closer to the TB since the same amount of air has to pass through a smaller opening.

If you look at the Thompson tube that TOO is a big fan of, you'll see that it does the opposite. The air filter opening starts out small, but the pipe gets larger as you approach the TB.

6 6517 Tubes06 2000

Sonny

**SC HYBRID** · March 27th, 2001, 11:03 PM

what if i take my throttle body off and bore out the opening a little bigger with a dremmel, will this help at all or does the actual opening at the butterfly make the biggest amount of difference.i know the butterfly would still be the same size,but would the ported flange more or less help with the air flow ?

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SC HYBRID 94-GSR
JRSC @ 12 psi
12.7 @ 109

**Sonnyballs** · March 28th, 2001, 12:41 AM

<BLOCKQUOTE>quote:<HR>Originally posted by SC HYBRID:
what if i take my throttle body off and bore out the opening a little bigger with a dremmel, will this help at all or does the actual opening at the butterfly make the biggest amount of difference.i know the butterfly would still be the same size,but would the ported flange more or less help with the air flow ?
<HR></BLOCKQUOTE>

If you expand the flange, you are basically doing what Larry said not to do. My RC Engineering throttle body does have a tapered flange. The opening is 68mm and it tapers down to 64mm. I am not an expert on this, but apparently this is a good thing for an NA motor, but not for an SC motor.

tb2

Sonny

[This message has been edited by Sonnyballs (edited March 27, 2001).]

**SC HYBRID** · March 28th, 2001, 01:52 AM

damn , that throttle body opening looks like its taking some abuse.

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SC HYBRID 94-GSR
JRSC @ 12 psi
12.7 @ 109

**Team Hostboard** · March 28th, 2001, 03:03 AM

Zip recently was doing a port match with his TB and manifold. Maybe he will chime in as I have not heard from him in awhile frown

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...Steven
"Have you clicked on a banner today?"

**Sonnyballs** · March 28th, 2001, 04:43 PM

<BLOCKQUOTE>quote:<HR>Originally posted by 1QuickSI:
Zip recently was doing a port match with his TB and manifold. Maybe he will chime in as I have not heard from him in awhile
<HR></BLOCKQUOTE>

The porting of his inlet neck has been done, but he's still waiting on the TB. Seems Holley and BBK are on infinite backorder. frown

SC: The throttle plate looks a little chewed up, but it's actually fine. I think RC sands it down to get it to the right thickness. Here is a pic of the backside:

tb1

Sonny

Sonny

[This message has been edited by Sonnyballs (edited March 28, 2001).]

**5 Liter Eater** · March 28th, 2001, 07:56 PM

What Larry is talking about is to have an intake that tapers out before the throttle body so the velocity slows down which cuts down on turbulance at the throttle body. Kind of like creating a waiting room for the air to hang out in until the TB wants to suck it in.

Of course the air speed will need to speed up again to enter the smaller throttle body but that is preferred method.

[This message has been edited by 5 Liter Eater (edited March 28, 2001).]

**zip** · March 28th, 2001, 09:31 PM

<BLOCKQUOTE>quote:<HR>Originally posted by 1QuickSI:
Zip recently was doing a port match with his TB and manifold. Maybe he will chime in as I have not heard from him in awhile

<HR></BLOCKQUOTE>

Still waiting for my overbore TB's to arrive. rolleyes