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Discussion Starter #1 (Edited)
OK, for those of us that may have been following NemesisEnforcer's thread for his TB upgrade nightmare, I have been looking carefully at my stock TB that was removed for a CFM 67mm upgrade.

I came up with an idea to "invert" the throttle plate on a stock unit, to get the 2 restrictive features of the stock design into the same 1/2 of the throttle bore, so the other side becomes 100% unrestricted like after market units.

This will not improve WOT, or dyno figures, but should produce a moderate improvment to throttle response without the extremely negative aspects of a touchy throttle some of us with larger TB's have learned to "love".

I have produced a collection of images and instructions to show how I reworked my stock throttle. I put this back on my car and was able to get a great idle, and the throttle felt pretty responsive. But my perceptions may be distorted since I was going from a 67MM to the modified stock unit, and I am working from my memories of how my car felt over 18 months ago before the 67MM Upgrade.

So IF there are any adventurous souls out there, here's the procedure to try for yourself and comment on.

NEMESIS ENFORCER - I Have the modded stock unit from these pics sitting on my desk with your name on it. PM me with a shipping address and it's yours. If works for you and you want to keep it, it's all yours! [thumb]
 

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Discussion Starter #3 (Edited)
disassemble TB

Step-By-Step.

You will need the following.

Torx Bit screwdrivers, or sockets. Sizes T-10, T-15, And T-20

Some throttle plate cleaning solvent, AKA carb cleaner type stuff, and a scotch brite pad.

Some blue Loc-Tite thread locker or equivalent

a 1/2" wood boring drill bit (or equivalent, see instructions in pics)

Remove the stock TB and get it onto a clean workbench. Then follow the pics, instructions below.
 

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Discussion Starter #4 (Edited)
Clean throttle plate, and bore

Clean the throttle plate and bore......
 

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Discussion Starter #5 (Edited)
Remove factory epoxy to free-up throttle stop screw

These pics show how I carefully removed this epoxy without butchering the screw, or threads etc. Alternate tools and/or methods will work here, you just need to be able to adjust the throttle stop screw easily when you are done.
 

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Discussion Starter #6 (Edited)
Remove factory epoxy -final touches

Here's where a little finesse will go a long way.....
 

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Discussion Starter #7 (Edited)
Begin the reassembly.....

Now we are ready to reassemble the TB
 
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Discussion Starter #9 (Edited)
Centering the throttle plate...

This is a critical step, and you will need to use some judgement and finess to get this right. If you are not comfortable making semi-precise adjustments to mechanical assemblies, you might want to ask a buddy with a little more patience for some help with this step.[?|]
 

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Discussion Starter #10 (Edited)
Wrapping up the bench work.....

After you are happy with how the throttle is centered, continue with the following steps to complete the bench work. The throttle may feel like its sticking in the bore right now, but we will adjust that throttle stop in a few minutes.......
 

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Discussion Starter #11 (Edited)
Final checks, and on-car set-up.

Before bolting your TB back onto the manifold, just go over the throttle to ensure you are comfortable with the feel of the throttle motion. If you have correctly installed and centered the throttle, and made the base throttle stop adjustment, the throttle should operate as smoothly as any TB sold. If not something went wrong, tear it down, review the instructions and start over.

When adjusting the min RPM with the IAC disconnected, it's expected that the vehicle will stall at first, and you will need to open the throttle slightly with the stop screw.

IF the RPMs are too high before starting these on car adjustments, then either the engine, intake, throttle gasket has a vacuum leak, or something went wrong with your bench work. Also make sure the throttle and CC cables are not holding the throttle open. If unsure, try making these adjustments with these cables disconected.

After making your final "stop screw" adjustments, recheck the throttle action to be sure you did not back off the screw too far causing the throttle to stick in the bore. If this happens you probably have a vaccum leak or bad reassembly. If you can't get this adjustment right, something is wrong.

After the throttle stop had been adjusted with the IAC disconnected, re-apply some epoxy into the throttle stop screw head/sleeve as it was from the factory.

Reconect the IAC and clear fault codes. (or discoonnect the battery one last time)
 

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Discussion Starter #12
CFM = 67MM - Focus Central = 65MM

i thought the stock one was 65mm and the CFM one was 67mm??
Yes you are right, I just edited the post.

WE were discussing the Focus Central 65MM TB in another thread, and I just had a brain fart......
[duh]

CFM and Cossie are 67MM.
 
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Discussion Starter #13
Stock TB = 61MM +/- 1MM?

Yes you are right, I just edited the post.

WE were discussing the Focus Central 65MM TB in another thread, and I just had a brain fart......
[duh]

CFM and Cossie are 67MM.
From what I saw during the disassembly of the TB, the stock throttle plate measures 2 7/16 inches which is just a hair over 60MM, the bore near the throttle plate is no bigger than 61-62MM MAX, but the inlet ID is 2 9/16 or 65MM.

So since the stock unit smaller at the throttle plate than then inlet, I would not consider it to be a 65MM unit. All the aftermarket unit's I have seen have the same size inlet, and throttle plate and the throttle bore is not reduced in the middle.
 

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Discussion Starter #15
Wow dude! This is the best write up ever! Rep to you.

I may have to give this a try and see what happens.
If you do, please update this post with comments on the instructions/diffculty to complete, time taken etc, as well as your driving impressions, and benefit versus effort. [dunno]

If we happen to get enough success stories using this rework I'll ask one of our moderators to make it a sticky....
 

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Force-Powered Focus
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wow, thanks TB. i replied to your PM. if my latest situation doesnt work out, i will have to hit you up on that lol.
 

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BodyKits=PantiesDrop
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excellent job bro, i'm definitely going to try this...maybe tomorrow!

rep to you and if it works i will put it up in the stickie area!
 

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Are you in any kind of manufacturing....this looks like what we call an S.O.P (standard operating procedure). Looks good +1 rep for you I think I might have to try this out.
 
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