How to port a TB
heres one link. http://www.geocities.com/wilwaxu/throttlebody.html
Bumpstop, cut half of the throttle shaft out, Knife edging the leading and trailing edge of the throttle blade, and porting and blending out the ridge.
One thing I did different though was I left a little bit of the cut-out throttle shaft sticking into the opening. I didn't like the idea of those 2 screws taking all the torsional stress from the throttle blade opening and closing. Now there's just enough that the load is still primarily on the throttle shaft. I chamfered the edges of the shaft to minimize the turbulence.

















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heres one link. http://www.geocities.com/wilwaxu/throttlebody.html
https://ls1tech.com/forums/showpost....6&postcount=22
The Best V8 Stories One Small Block at Time
first off, this isnt hard at all, dont be to imtimidated,,,
DRAW YOUR LINES TO MARK YOUR BLADE AND SHAFT LOCATIONS FIRST!!!!!!
Look at your spring now, remember how it goes, or use the pics on here to get it back on when the time comes
remove the sensors with a T20 bit bit, the TB blade comes out with a T15 bit
Just hammer the shaft out as they say,,,it only takes a tap or two,,,grab the lil ring and place somewhere safe for now. When you go to put this very tight fitting ring back on, use the back side (where the square is) of a 3/8 deep socket,,also only takes a tap to get back on.
i used the sharpie lines as piced above,,helped to judge how much you've done,,,dont forget the lip,or outer edge too,,,those are important when your fine edgeing the very front of the TB
I used Dremel bits,,,
952 aluminum oxide griding stone,,,this is what i used to get the rough stuff done. IT TAKES A WHILE TO DO, BE PATIENT,,,it really does, takes some breaks so you dont burn up your tool. The bit will get heavily coated with aluminum,,,try to keep it clean as you go. The front lip of the wide opening of the TB is the hardest part,,take your time, and work in small areas, being aware of the outer edge, and how close you are to it,,,the two edges right next to the opening up top for the air flow are kinda tough, just work in small sections. Dont for get the restriction you can feel with your fingers back right in front of the TB blade,,kinda a hump there to get rid of. I used two of these bits as one of them fell apart during use
TB looks very thin on the bottom, and it was the easist part of the outer lip to get, so be careful down there when grinding
Be sure to work the very outer edge as you go, but dont worry about being perfect at this time,,just dont go beyond,or jimmy up the rim by cutting down into it,,stay at a nice angle working or feathering up into the TB main cavity
then i went to the sanding drums,,,i only found two kinds, one was 60 grit, the other was 120. 408 and 432 Using the 60, i went to town, it really makes light work of the more difficult areas when using the grinding stone,,wished i would of went to it sooner than i did (i did the entire inside with the stone before switching) I only used one 60 grit roll
Then,,the 120 to really clean things up,,used only one, went over everything inside. Take your time, do a nice work over in there.
then i hand sanded with a sheet of 220
THEN,,my lil kit came with a loofa lookin thing, small, Finish Abrasive Buff,,,511,,this thing was freakin awesome as a final clean up,,i also used it on the outside of my TB,,,made it extremlly shiney. Be fore warned though,,,the disk disinigrates as you use it, so be careful when you get down to a nub,,,,i coulda used two for the whole TB, inside and out
Assembly is just the opposite,,be sure your spring is on ther properly
i did'nt knife edge my blade, but i did cut the shaft frontoff to remove the restriction. I to left a edge on both sides just to keep an extra grab on the blade, though the screws feel that they hold pretty good. just use a file to make it nice and neat after you cut the shaft out with a reinforced cut off wheel, 426. The screws were placed with loctite upon reassembly, and i cut the extra screw sticking out the back side,,,also grinded down my cut marks.
A quick coat of polish to brighten things up made for a TB that i was bummed had to be hidden by all the other stuff.
All in all i spent about 4 hours on this
Now all i need to do is learn how to use my Multimeter for a bump stop mod, and will be doing the cable adjust if needed as well
Last edited by Bad Blue WS6; Oct 6, 2007 at 04:36 PM. Reason: spelling
machine down the lip a little at a time. set up a travel stop so you don't hit the blade-pin with the bit.
polish with some polishing paper.
if you want to pull the blade out...go for it, but most of the gains are from the TB housing work.
took me all of 15mins in my dad's machine shop.
make sure to use a lower speed setting, the TB is odd shapped so it doesn't balance well when spinning. although we were able to do it on a small lathe (maybe 8" radius max capacity), so any typical size machine would work.
call some machine shops...probably be about an hour's worth of labor.
i'll be home for Xmas...you could ship me the TB and i'll do it.
$60 and i'll pay for return shipping
holy crap!!
here is a pic of what 15-20 mins did....granted i didn't get a high polish on the inside, but it is a little polished.

and it's done on a lathe...but i guess if you think using a machine exact down to a couple thousandths of an inch is a rush job compared to grinding...so be it





