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Discussion Starter #1
For the stock throttle body- modified- did anyone shave down the lip on the throttle plate? It looks like it really holds back the airflow ?,?
 

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nope, I ported the top part very much but I left the part below the clapet intact... but it would be interesting to test a throttlebody raiser plate... should be very easy to make out of thick plastic block... (where to find plastic block now?)
 

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That lip is made on the butterfly to help when driving in city traffic. The lip restricts air flow during the initial opening of the throttle so the car has less of a tendency to lurch forward when your in starting out in stop and go traffic.
 

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I checked that out as well when I ported my throttle body. I decided not to shave down the throttle plate because it was too much trouble, but if you are going to go through with it BE SURE to reinforce the underside (when throttle body is removed, you will see a hollow spot on the back of the plate, where it is the thickest. You will have to fill this with epoxy, because in order to get the plate thin like the other side, you will have to grind the top of the plate, and without a backing, you will grind right through it. I didn't do this because I am worring that it might make the plate too flimsy, and if you snap the throttle shut abrubtly, the plate may break off and fall into the intake.
 

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I have it on good report that the lip is there to cause a positive type of turbulance in order to speed airflow through the unit.
I don't know for sure but I do know that who ever designed it had a reason for the lip. I wouldn't remove it unless I had a spare TB in case it is a required component.
 

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Discussion Starter #7
When I looked at the lip, and the way the body is shaped (matching contour) and wondered if it was actually there for a purpose - like intial roll-on for starting out smoothly. Thanks for the comments.

Has anyone shaved down the lip, and what was the result, i.e., - how did it work?
 

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Well I have 2 stock TB's (don't ask)so if it dosent work right I'll change it back to the one that I've not ported out. We have snow here now and the roads are crap but if it gets better Saturday I'll give it a try. In the mean time I'll to figure a way to smooth down the underside of the plate with out to much trouble.
 

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flattenin the rod that holds ur throttle plate in the bore is an old 'race-only' trick on high end carbs. people like barry grant do that on their high end pieces. not somethin 2 b done w/a dremel home-brew style. dont bother w/it here, 2 much 2 mess up 4 so lil gain.

remember that its just a single shaft on a small TB, when ur ready 4 that extra flow, go w/a bigger TB. this isnt like a good sized 2bbl or a performance 4bbl where there r multiple plates like a 4bbl that'll have 2 small primaries, then 2 big secondaries. when barry grant or holley etc do these perf carbs, all that stuff is mostly done cnc'd, not a dremel tool home brew style. not worth ur time, 2 much risk and time invested 4 not enuff gain (if any). hope this helps

-Ult

[ 12-05-2002, 07:02 PM: Message edited by: UltegraSTI ]
 

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Discussion Starter #10
Claplet? - I think you're talking about what I would call the butterfly - the round disk mounted in the slot of the pivot shaft. There is an angle, or lip (about 3/16") on the downside of the disk which has to be in the way of the airflow. I would think by grinding that off and making the disk flat, more air could get in and with less turbulance.

I don't know about a riser plate. Sounds like a good idea, but haven't really looked to see how much room is under the hood.
 

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Well, My FIRST thought would be, "Why is it there?"
Because it is a lip, and HAD to be molded that way, there MUST have been Some sort of reason.
If that reason is unimportant, grind away!
I'd want to figure out what purpose it served first.
 

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I've never had a chance to look at a FC TB up close.Do they have the same kind of set-up with a lip on the plate like a stock TB?
 

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well i'm undecided on whether 2 pick up a y2k manifold and use that stock, or clean up some of the bumpy spots in it, or 2 do the same 2the y2k1-present version. not sure at this pt. i just know i'm gonna port this 1 i have now 2 replace my ported 1 that gave away.

-Ult
 

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Discussion Starter #14
- Ok, it sounds like most people aren't going for trying to clean up the throttle plate. It still bugs me to see that lip on there though...

Another question on the same topic: What is the best epoxy to use to build up the outside of the TB? And when grinding, take off enough to made a fully round inlet ?

BTW, years back, we had a Triumph, and part of our mods included filing down the shaft and screws of the throttle plates to let in more air, plus tapered both sides of the plates to improve flow.
 

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dont do that, b/c the screws r 'mushed' on the extreme end 2 keep them from ever backin out and droppin (as possible the plate) in the manifold=not good. as far as the lip is concerned (after doin another 1 2nite, c post), its not worth ur time and 2 much risk 2 try and hit that, make it clean, and flush.

-Ult
 

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Discussion Starter #16
Forgot to ask about the Idle Control Intake Port? I understand it holds the idle up on deceleration. Anybody experiment with reducing the opening to get better cut-off?
Thanks,
 

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Originally posted by ZilverX:
Forgot to ask about the Idle Control Intake Port? I understand it holds the idle up on deceleration. Anybody experiment with reducing the opening to get better cut-off?
Thanks,
<font size="2" face="Verdana, Arial">hmm, i looked at it 2nite comtemplatin it. think i might try makin a 'blockplate' 2 cover say 1/2 or most of it, whateva worx if it worx. not that its super critical 2 me b/c i putt 'round all the time when i'm not blastin down the 1/4mi. i'll try some stuff over the next wk or so.

-Ult

[ 12-06-2002, 11:21 PM: Message edited by: UltegraSTI ]
 

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UltegraSTI. You are correct sir!
I found my spare TB and had a look at the plate, and it IS more trouble than it’s worth. However my question still stands. What is the plate on the FC TB like? Is it flat or does it have a lip like the stock one? Anybody got time to take some pictures of this part? I would love to have a look at the Idle Control Valve Intake Port on these things as well. Does the FC TB give you more engine braking, as well as more power?
 

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back from when i had 1 (returned it after it refused 2 open 100% b/c of b'g incorrectly machined, another story though)





i'll b portin another 1 out 4 myself this weekend in addition 2 some more manifold work.

-Ult

[ 12-06-2002, 12:18 PM: Message edited by: UltegraSTI ]
 

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thanks man. I have wanted one of those for a while but was waiting to see some better pictures.
 
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