Throttle Body Porting 101
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From: Citrus Heights, CA
Throttle Body Porting 101 I ported my throttle body, did the bump stop mod and ground down the bolts on the butterfly valve. What I don't know how to do is shave down the post the butterfly valve slides in between. In the pictures of other ported tb's I've seen, it looks like the post is gone and there are just the two bolts left in. How is this possible? How can you get rid of the post and still open the butterfly?
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From: Citrus Heights, CA
Thanks for the help! I would guess you would have to remove the post to cut it. If so, what is the best way to do this. I removed the tps sensor and tapped on the post lightly and it did not budge. Is there a secret to getting the post out? Do you remove the front side of the post the the throttle body margins, or all the way to the end of the post? Does this make sense?
You can use a cut off wheel on a Dremel tool and just carefully cut the front half of the shaft out that is not threaded, the back half of the shaft is the part thats threaded for the screws to go in. After you cut the front half out I would recommend gettin two 4mm flat washers to go under the screws to reinforce the clamping ability of them since they are tapered and the blade is flat- this is what I do 
Use a piece of brass rod as a drift punch and the throttle
shaft will come out. It's just sticky.
I wonder just how much cutting half of the shaft off, is
worth. I didn't bother when I did mine.
Be sure to either stake or Loctite the screws when you
put them back, depending on whether you expect to ever
take the blade off again.
shaft will come out. It's just sticky.
I wonder just how much cutting half of the shaft off, is
worth. I didn't bother when I did mine.
Be sure to either stake or Loctite the screws when you
put them back, depending on whether you expect to ever
take the blade off again.
Do you have to replace that lock ring if you take the shaft out?
I was told that there is some sort of retaining washer that needs to be replaced if you take the shaft out.
What about the spring? will it un-coil itself ?
What is a deadblow?
I was told that there is some sort of retaining washer that needs to be replaced if you take the shaft out.
What about the spring? will it un-coil itself ?
What is a deadblow?
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A deadblow is a plastic hammer(most are orange) with media in it that is loose like sand- which I think most use sand in them. The ring is what I am talkin about and you do not have to replace it, just leave it off- there is no side load on the shaft itself to warrant puttin one back on.
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Originally Posted by Redneck Z
I ported my throttle body, did the bump stop mod and ground down the bolts on the butterfly valve. What I don't know how to do is shave down the post the butterfly valve slides in between. In the pictures of other ported tb's I've seen, it looks like the post is gone and there are just the two bolts left in. How is this possible? How can you get rid of the post and still open the butterfly?
remove the TPS sensor.
smack the shaft with somthing... it will resist a little, but it comes out.
the only thing holding it in is that little ring.
with it out, you'll see how to cut it easily.
when you goto reassemble it, make sure the spring is on correctly and the throttle cam is between the throttle stops, then using a socket, tap the ring back onto the shaft....
and you're done.
my friend Jay_99z showed me how to do mine.. hes ported a few of them now for the guys in the local club... personally i think the shaft mod alone is worth more CFM then all of the other "porting" and smoothing work combined......
Originally Posted by MrDude_1
personally i think the shaft mod alone is worth more CFM then all of the other "porting" and smoothing work combined......
[QUOTE=MrDude_1]
when you goto reassemble it, make sure the spring is on correctly and the throttle cam is between the throttle stops, then using a socket, tap the ring back onto the shaft....
and you're done.
QUOTE]
So what you are saying is that the retainer ring is reuseable?
when you goto reassemble it, make sure the spring is on correctly and the throttle cam is between the throttle stops, then using a socket, tap the ring back onto the shaft....
and you're done.
QUOTE]
So what you are saying is that the retainer ring is reuseable?
The main thing about porting the TBs is you are makin it a true 75mm. The TB from the factory may be a 75mm blade but the opening is restricted down to about a 72mm size until someone ports it(ehhimm ). Yes, the ring can be reused if you want to put it back.
). Yes, the ring can be reused if you want to put it back. Thread Starter
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From: Citrus Heights, CA
Thanks for the help guys. I popped the post out and cut it with my dremel wheel on my lunch break. BTW Bo, your tb's look sick. Now my next question is...Is there a rule of thumb on knife edging the plate? I did this on my old tb and it worked out well, only I think I could have taken it further. I know you can take off too much and cause an idle problem. What do you guys do?
I do not knife edge personally but have seen it done and you can do it just so you know that EVERYTHING that can be possibly done to a production TB has been done. Be sure to keep enough margin on it so that you do not have any idle issues, probably around .030" would be min. 
Voltage is the tail end of it. First you want to get
the blade stop set up so mechanical max travel
gives you a dead center, 90 degree opening at
the one end, and one RCH away from binding to
casting when closed. Closed is your stop screw
(may want to flip that so the Allen hole is top side
accessible) and open is the stop-tang which you
may (will) have to grind.
I found it easier / less error prone to hog back all
but a small nub in the stop-tang seating area and
then fine-file the remaining bit alone. Use a ruler to
find when the blade is dead center.
Then when you are all done install the TPS and read
idle position voltage with the throttle cables still off,
be sure the blade is seated minus a hair, if the TPS is
reading much more than 0.5V you may want to go and
elongate the mounting holes so you can rotate the
sensor and get a proper-range idle TPS voltage.
Adjusting to mechanically sub-par position at WOT just
to get idle TPS voltage right, is ***-backwards.
Be sure to recheck blade pull from the pedal, after it
is all set up TB-internally because a lot of cars do not
fully draw the cable, you may need more than just the
snap-adjusters to take out all the slack in the chain.
the blade stop set up so mechanical max travel
gives you a dead center, 90 degree opening at
the one end, and one RCH away from binding to
casting when closed. Closed is your stop screw
(may want to flip that so the Allen hole is top side
accessible) and open is the stop-tang which you
may (will) have to grind.
I found it easier / less error prone to hog back all
but a small nub in the stop-tang seating area and
then fine-file the remaining bit alone. Use a ruler to
find when the blade is dead center.
Then when you are all done install the TPS and read
idle position voltage with the throttle cables still off,
be sure the blade is seated minus a hair, if the TPS is
reading much more than 0.5V you may want to go and
elongate the mounting holes so you can rotate the
sensor and get a proper-range idle TPS voltage.
Adjusting to mechanically sub-par position at WOT just
to get idle TPS voltage right, is ***-backwards.
Be sure to recheck blade pull from the pedal, after it
is all set up TB-internally because a lot of cars do not
fully draw the cable, you may need more than just the
snap-adjusters to take out all the slack in the chain.
Originally Posted by Bad Blue WS6
that just lost me...
when the throttle body shaft turns, it turns the throttle position sensor.
if the sensor turns too far, its "out of range" for what the computer expects.
make sense?
ok, so you modify the throttlebody, and now it turns wide open... it turns a little more then before.
if the throttle position sensor is now being turned too far at wide open, you can rotate it some... now its not being turned too far. and everyone is happy.
got it?