I am not sure if anyone has gone over this yet, I didnt see any thread covering this mod so I am posting one. I am not responsible if you damage anything attemping this mod!!
I have done this mod on other vehicals in the past such as Mustangs, rangers, etc, & did notice an improvement!!
I have not done this mod on my Tacoma yet but theoreticallt it should work without issues!
Thise mod is known as Halfshafting!
(Please note the photos I used are not of a Tacoma Throttle body)
FIRST; You will need to remove your entire intake setup & set aside.
NEXT; Unplug any connections to the throttble body & set aside.
Next; Remove the Throttle Body.
"THIS MOD CAN BE DONE WITH OR WITHOUT REMOVING THE THROTTLE SHAFT INSISDE THE THROTTLE BODY HOWEVER IF YOU LEAVE THE SHAFT INSIDE THE THROTTLE BODY YOU RUN THE RISK OF DAMAGING THE THROTTLE BODY ITSELF SO BE EXTREEMELY CAREFULL IF YOU DO SO!
IF YOU CHOOSE TO REMOVE THE THROTTLE BODY SHAFT (SAFER WAY) THEN YOU WILL NEED TO CUT OFF SOME RIVOTS OUTISDE THE THROTTLE BODY & RE-RIVITE THEM BACK ON WHEN YOU ARE FINISHED (REQUIRES A RIVITE GUN)"
EITHER WAY YOU MUST REMOVE THE THROTTLE BODY ITSELF!
NEXT; allow the throttle plate to close. Use a screwdriver to remove the two screws securing the butterfly plate to the throttle body shaft. (If the screws will not loosen, They can be drilled out using an electric drill & new threads can be made using a tap & die set)
See the two screws? those are the two you are removing!
NEXT; turn the throttle shaft to the open position and slide out the butterfly plate.
NEXT; counter sink the holes on the top side of the butterfly plate. and be carefull to NOT drill all the way through the soft aluminum plate. A drill press with depth control is preferred for this step.
Larger counter sunk holes in the throttle plate.
NEXT; With a dremil tool or small hacksaw, cut the top half of the throttle shaft. DO NOT remove the section that is threaded. Remove the side that is an open hole. Clean the cut with a file or grinding wheel.
There should only be a slight amount of material left on the top of the shaft, cut along the seem where the plate fit into place & make the top section of the shaft nice & even with the throttle bore.
You are cutting the top section so as to make it even with the bore of the throttle body!
NEXT; Make sure there is no metal shavings or debri before reassembly. I would reccomend using an air gun to thoroughly blow out all pieces.
NEXT; Holding the throttle shaft in the open position, slide the butterfly plate back onto the throttle shaft. Make sure the counter sink holes are facing up and align the screw holes of the shaft and plate. Secure the plate to the shaft using brass flat head screws (use phillip head screws but the kind that are not rounded/flat on top) If the screws heads do not fit flat against the plate, remove the screws and file the flat head until a flush match with the plate can be achieved.
NEXT; Check for proper fitment, There should be no gaps or daylight through the disc. Use locktight on the threads during final assembly.
You can see here this person actually made a slight mistake when cutting & missed about a quarter of an inch on each side.
Im sure by now you get the general idea.
This mod is good for at least a 5% increase in airflow.
If you wish you can use Emerny cloth to polish the throttle body & throttle body shaft & also the butterfly plate while evreything is apart.
Some people also prefer to taber/bore out the end of the throttle body while it is dissasembled.
To do this you would use a cylinder honing tool that is available at Sears and many Auto Parts stores. You would then attach it to a cordless drill and insert it into the throttle body using a gentle up and down & side to side motion to bore out the end of the throttle body. A Dremil tool can also asisst in boring the Throttle Body. DO not get near the disc seating area. If you enlarge this area you will have major idle problems on the vehicle. The goal is to enlarge the opening where the intake tube attaches and gradually taper this back down to oem size before the disc. Polish the bore afterward with emery cloth, & poloshing compound, etc.
Re-assemble all connections/wires & re-install your intake.
Idealy you want the finished project to look somthing like this;
Nice & smooth! obviously much higher flowing then the stock throttle body; Now the air wont have to jump the "speed bump" going past the throttle blade.
These are relatively simple mods & basically free!!
If anyone does this mod let us all know how much of a diference you noticed! I will be doing this myself pretty soon & will post more how-to pics when I do!