How to: Port a V6 Throttle Body

**rwalshphoto** · 02-12-2009, 06:04 PM

Porting the 3.5L V6 Throttle Body

I started this project last week and got quite a bit of questions and lots of inquiring minds so here is my best shot at explaining the porting of the V6 throttle body.

The Intake Diameter at the entrance of the Upper Intake Plenum is 71mm. For the sake of this write up and assuming that the results are favorable to the theories presented the porting of the throttle body will be done in such a manner as to create a funnel or venturi effect into the manifold. I'm sure by now you are all aware of the physics behind this, after all the AirHammer is designed around these ideas as well as all other well-performing intakes.

Stock Throttle Body (Info):

* Cast Aluminum
* 67mm at the barrel entrance
* 65mm at its smallest point at the perimeter of the blade
* Exit diameter of 68mm tapered to 72mm
The Ported Throttle Body (the end result):

* approximately 71mm at the barrel entrance
* Tapered to 72mm, smoothed into perimeter of blade

Note: Diameter of TB at blade area will NOT be altered (see further instruction)

* Smooth tapering of the ridge on exit of throttle body
* Sand / Polish (optional)

Tools Needed:

* Pneumatic or Electric die grinder
* Carbide Cutting Bits (cylinder with round tip works best)
* Flap wheels or Sanding cones (80 grit, 120 grit)
* Caliper (for measuring diameters to check for accuracy and consistency)
* 500 grit, 1200 grit, polish compound, 2" cotton rag buffing wheel (for polishing....optional)

Illustrated Procedure:

70mm Intake Diameter of Upper Intake Plenum:

Stock Throttle Body (Unported):

Porting, In Process - Carbide Bit, Rough Surface

Taper Back of throttle body, smooth ledge, do not remove to much near blade:

Check for consistency:

Sanding, Flapwheels or Cones (80 grit, 120 grit)
** Smooth the ledge into the blade area but do not go to deep, remove as little material as possible near the blade.

Check for consistency last time before polishing:

POLISHING
* Sand with 500 grit until all major visible scratches are gone
* Sand again with 1200 grit until your fingers are numb
* Cover areas in polishing compound
* Use cotton rag buffing wheel on a drill or die grinder to polish to mirror finish

End Result:

**CHARGERTREV** · 02-12-2009, 06:06 PM

It feel any better?

**rwalshphoto** · 02-12-2009, 06:14 PM

Originally Posted by CHARGERTREV

It feel any better?

Dunno yet, car has only had 3 miles to learn it. Throttle response is definitely better, cant say yet for the rest of it.

**DaILLestWun** · 02-12-2009, 06:32 PM

You da man!!! Beans to you!!!

**fnkychkn** · 02-12-2009, 06:49 PM

great write up, Ryan. should have posted it in KB submission forum.

i can sorta see how this could improve airflow but i fail to see how this can improve throttle response. was battery disconnected or fuse 11 pulled to reset PCM?

**rwalshphoto** · 02-12-2009, 07:26 PM

Originally Posted by fnkychkn

great write up, Ryan. should have posted it in KB submission forum.

i can sorta see how this could improve airflow but i fail to see how this can improve throttle response. was battery disconnected or fuse 11 pulled to reset PCM?

Pulled fuse 11, yes but not the battery. In my previous thread when I initially started on this I didnt take anywhere near this much out, maybe brought it to about 72mm. But since Billet Tech is giving it a GO and I wanted to try this at max capacity. So its time to data log and send it to Mike Lafrad again and see what he can do.

As far as perceived gains, it just seems more responsive and "jumpy" if you will off the line. And testing the throttle ranges at different speeds 0-60 and transitions between coasting and WOT. Also hold the car against the stall converter seems to take more braking power now to hold the car back.

**fnkychkn** · 02-12-2009, 07:43 PM

just pulling the fuse is enough to reset the PCM and improve throttle response.
pretty sure i have a spare T-body somewhere. might have to try this.

**rwalshphoto** · 02-12-2009, 10:05 PM

Originally Posted by fnkychkn

just pulling the fuse is enough to reset the PCM and improve throttle response.
pretty sure i have a spare T-body somewhere. might have to try this.

Very true, however I've probably pulled Fuse 11 4-5 times in the past week or so between playing with this in different configurations (I started at 72mm and worked up to this 74mm where it is now) and it has got progressively better and the longer the car has to learn it the better it gets. I just sent some logs to Mike so we'll see what he thinks... poor guy is gonna kill me.

**rwalshphoto** · 02-14-2009, 01:39 AM

So here is what the schedule is looking like everyone:

I will be headed to Speedworld tomorrow night to do some track runs now that I am tuned for the cams and also the ported manifold and ported throttle body. If anyone local (cough cough) would like to tag along lets swap out a stock TB and see what the difference is.

I will be dyno testing this throttle body on BritishNate's car as soon as his tuning is squared away for the camshafts and he gets his post-cam dyno done and his JBA headers installed. We do a baseline run for the car with that current configuration which is:

Inertia Camshafts V1.1
Custom Tuning by Mike Lafrad
K&N Intake
Blastin Bobs 10db kit replaced suitcase with Magnaflow
JBA Shorty Headers

We will install the ported lower manifold and do a few runs with that and then a few more runs with the ported throttle body. We will probably try and put a few street miles in between testing for the manifold and TB as it takes time for the car to learn the mods without being specifically tuned for it.

**ChuckWagon** · 02-14-2009, 08:03 AM

Excellent work Ryan! Great pics! Beans to you!

BTW...them there are some new calipers huh? j/k

oh yeah.....subscribed

**shagmag07** · 02-19-2009, 02:12 PM

subscribed

**ToddStone** · 02-21-2009, 12:54 PM

So, just to go back to the grinding, you really don't want to touch the flap area at all, is that correct? How much space did you keep away from it?

You reshaped it so that from the 68mm to meet the 72mm (just making sure I read that right). Thanks for the write up. I'm very intrigued.

**rwalshphoto** · 02-21-2009, 01:26 PM

Originally Posted by ToddStone

So, just to go back to the grinding, you really don't want to touch the flap area at all, is that correct? How much space did you keep away from it?

You reshaped it so that from the 68mm to meet the 72mm (just making sure I read that right). Thanks for the write up. I'm very intrigued.

I used the 120 grit flap wheel at a low speed and took off just enough material to smooth that ledge down into the blade area. The goal is just to get rid of that lip and nothing more.