Your input on transitioning to 73mm UIM inlet

[Pole120]

Now that i've gotten my SVT's UIM back from extrude hone, i have a 73mm inlet and a ~63mm outlet on my SVT TB. Now to smooth out the airflow i've been considdering options for making the transition in diameters.

Here were my thoughts, please provide your input

1) Chanfer TB behind plate to 70mm and use a 70mm mustang gasket

-the isue i'm seeing here is i don't think you can chamfer the back of the TB that much without running into the TB shaft's bearings.

2) Chanfer TB behind plate to ~65mm (should be possible without bearing interference) and make a plate with a beveled ID to go behind the TB to take up the remaining diameter difference. Then use a mustang 65mm gasket on one side and the 70mm on the other.

 

[morbid]

Weird... my UIM from extrudehone came back with a 67.54mm TB opening. Also, the SVT TB exit is ~61.13mm. (The mustang 65mm TB's exit is ~66.93, FWIW)

Now... when flowing a smaller area into a larger area, I always thought it was best to leave the edges straight to retain velocity (not reverse port match). Anyone can feel free to correct that statement.

 

[Y2KSVT]

65mm Mustang GT throttle body. DO IT!!!

Mark

 

[Pole120]

65mm Mustang GT throttle body. DO IT!!!

Mark

On my 2.5???

~Josh

 

[Pole120]

Where are you guys getting the 70mm gaskets.....are they available from ford and if so, what should i ask for (model)

~Josh

 

[morbid]

You can't just use a larger gasket because the EGR part of the UIM will be exposed... since the larger TB's are rectangular, and our TB's are circular. For my 65mm, I first enlarged the 60mm gasket and sealed the top portion with gasket maker (since there wasn't anything holding the top of the gasket to the UIM).

Since then, I've made my own gasket out of 1/8" teflon. It's very rigid and doesn't leak. Also kind of acts as a phenolic spacer.

 

[Pole120]

I was at the dealer anyway last night getting parts so i figured i'ld ask for a tb gasket for a mustang GT 4.6 (65mm) and all he had was teh paper style we use on out IAC...do they not make graphite gaskets for the 4.6?

edit: Did some looking around and i can get a 1ft. sq. sheet of graphite gasket material with type 316 stainless steel wire insert for $13...that's enought to make 4 gaskets any size/shape i want.

~Josh

 

[Barge]

Having a expansion behind the TB really isn't that terrible of a thing although with the contour manifold design it probably really isn't necessary.

If a single plenum intake design with a port near the TB you actually want a large expansion of the plenum vs. TB so you don't kill flow to the first port.

But.... with the contour manifold I'd probably go with the mustang TB... i mean.. you can always go back if you don't like it. Then just chamfer the back of the TB to match the opening.

Oh.. and I should say even with the above mentioned large chamber expansion after the TB you should always have round edges.

 

[BlackE1]

By creating a chamfer on the exit side of the TB you will be in turn creating a diffuser type of set up, where your D,in is smaller then your D,out. The flow pattern this will create is a high velocity, low pressure at the center but a stalled ( backflow ) around the perimeter.

My guess is that it will help the flow pattern more then a sudden expansion in diameter, which would cause a disorganized flow pattern. But ideally I think having the diameters all the same size or as close as possible is what you really want.

 

[Pole120]

Well, my 65mm was at my door and I've had some time to play around and i think i should be able to transition from the 65mm outlet to the 73mm UIM with a lot of time and JB weld. I'll post some pictures as i go...

I find it totally ridiculous that my TB opening has apparently been opened up far beyond the size of many others. It's now becoming a complete PITA to deal with...

As stated, I'll post some pictures up of everything most likely tomorrow night for you to give your feedback on.

~Josh

 

[Rara]

Josh,

I would still consider making a plate to move the TB further out giving you more room for a more gradual transition.

 

[Pole120]

Josh,

I would still consider making a plate to move the TB further out giving you more room for a more gradual transition.

I planned on a 1/4" - 1/2" Aluminum plate to ease the transition and also to serve as the portion of the assembly that stops the SVT TB cam lobe in the correct 100% open position...unless someone can let me in on how to use the stock mustang linkage.

 

[95pgt-t]

hmm not sure on how to use the stock linkage..when i had my 65mm tb the stock pre98 linkage was welded to it:shrug:
here's what i'm talking about

 

[GTO Pete]

Well, my 65mm was at my door and I've had some time to play around and i think i should be able to transition from the 65mm outlet to the 73mm UIM with a lot of time and JB weld. I'll post some pictures as i go...

I find it totally ridiculous that my TB opening has apparently been opened up far beyond the size of many others. It's now becoming a complete PITA to deal with...

As stated, I'll post some pictures up of everything most likely tomorrow night for you to give your feedback on.

~Josh

Josh,
My EH'd UIM outlet was larger than yours which was ok on a 3L. I went to a 65mm Mustang TB and optimized it. There's a decent amount of metal on there to expand several millimeters which helps with the transition from TB -> UIM.

HTH

 

[Pole120]

Thanks for the input. I've got the 65MM in hand and I'm having the outlet machine tapered out to about 68mm. Behind that will be a 3/8" aluminum adapter plate with a transition machined into it to match the UIM, should be a nice transition with an included angle of under 35 degrees so flow should be nice and smooth.

Thanks,

~Josh