I've had a 997tt throttle body laying around for a while, but it doesn't bolt up to the 996 plenum, so I figured I'd break out the welder and play a bit.


Off to the lathe tomorrow to cut an o-ring grove into the flange for a proper seal. After that, assemble it, roll beads onto the edges and install it this weekend. I bet it will take more time to install this than it will to build it. As of now, I have about 40 minutes into it.

The 1/2 moon is for a splitter, I'll slice the back of the tubing and weld it into place. Ideally, I'd make a 'y' here, but I didn't have the 3.5" bends. Since I'm hopefully installing a 997 GT2 intake system onto the engine in the next month or two when I have the engine down, I figured I'd at least do the splitter.

This is what I came up with:




The irony is that I had all the bits on the shelf to put this together. Of course, it's stainless, which means it'll never rust right? My stainless welding is a bit off, guess I've been working in front of the computer too much. Since it's the cold side, I'm not worried about it.

For those of you who have done new plenums, what has been the solution for the 1 way valve in the top of the plenum? Based on where it's routed, I'd say it's a pcv valve type device.

 

Awesome! Looks like you got skills making custom fabbed pieces. Welding looks good to me =)

 

Thanks, it's been a while since I have really done any welding. The metal is burned a bit (gray areas) and the ring above it rises slightly higher. I can't decide if it's the well 'used' gas lens cup that has some splatter in it or my simple refusal to use the pulser. Either way, it's adequate for this project; it's not like this part is under heavy stress.

 

That looks great! You will need the three nipples on the drivers side, unless you make a single larger one and do two tees for the other lines. A simple check valve will keep you from pressurizing your case on the top passenger side take off. Unless your tolerances are very close I would do more then an o-ring as a gasket, I have a cayanne turbo TB and used a complete gasket around the t-plenum to TB join.

There are ramped "stops" on the plastic intakes that you have to join to. Make sure your couplers do not slid up on them or else you will never get a pressure seal.

You doing this engine in or out? I did mine with the engine just lowered and it was a pita.

gl

Tom

 

Stainless rust? Only if during welding you allow inner granular migration or carbide precipitation to occur. Your TIG welding looks very nice especially if you haven't done it often. A gas lens cup may help improve shielding gas color around the weld. How did the inside of the weld come out?

 

After talking with Kevin at UMW, he strongly urged me to not put the divider in this plenum. After his explanation, I agreed with him 100%. Thanks again for your time on the phone! (btw, is this a plenum or a splitter? I suppose it's kind both)

Tom: Development is on a spare engine that's going in the car in the next 30-45 days. (once I get all the bits done). I may or may not swap this onto the car prior to then, if so I'll just lower the engine as much as possible to make some extra space. I have the benefit of access to one so I can really 'see' what I'm getting into. I'll pressure test the o-ring before I mount it in the car. Thanks for the good advice. I may end up with a full gasket, but I'm going to try the o-ring first.

I'm pretty sure I have a crank-vent valve laying around that will work perfect for this application. I'm still not sure what I'm going to do for the nipples. I have some small stainless tubing here or may weld on a flange so I can drill/tap for brass fittings. Either way, the 'hard' part is done.

CJV: The rusty stainless was a joke.
Inside turned out decent. I didn't let the gas purge as long as I should have. I got in a hurry, what can I say. I got good penetration, so it was just a little clean up work. I'll radius the edges a bit more before I'm 'done'. I changed the gas lens and turned the argon flow down a bit, that seems to have cleaned up the turbulence I had. There were a couple of nice big splatters of something in the screen of the lens cup.


Today's small block of work; too much traffic and work today. However I did make some progress:

 

Hi Brad,
Enough already, you know the welds look great .( modesty modesty modesty .lol)
If I had done the welding it would have been with s/s mig wire & pure Argon and wouldnt have looked 1/4 as good as yours.

Well done.
Frank.

 

mmm, might be easier to start over. I wonder if a pipe expander could get the top and bottom of this and then all I fab is the left and right. Then all I'd need is some 3/4" wide flat. Thin tubing might be too hard to slice in 1/2 an roll around it.

 

Good work Brad.

 

Good work Brad and let us know the results when you put the plenum on your engine.

Rolando

 

I started over. Instead of trying to make a smooth transition to this part, it was easier for me to just start over.

To save it from the scrap pile. If someone wants the stainless one, as it sits; I'd take $75.00 for it. (shipped price to the lower 48) If you like, I'll finish it out with nipples for around 75.00 more. I have to go buy several pieces and fab a 'manifold' for all the nipples to tie into.


This is 'version 2' Started out with two 90 degree 3.5" aluminum bends. I don't have a flange that's been laser cut for this one, so I'll be on my own to hack out an aluminum one from 3/8" material. (band saw and hole saw will do just fine)

 

Wow, your fab work is pretty wicked.

 

Looking good Brad! Just a word of advice when welding stainless - the cooler the weld the better 90% of the time, welds should look golden. You have a great skill so keep it up bud! Not trying to knock you or anything, those welds would still hold a tremendous amount of pressure. Your aluminum looks pretty much flawless!

 

Thanks Neil! I'm happy with it. I wish I had thought about the transition 'prior' to welding it up. So to the 'use it for something else' pile it goes.

*nod* on the golden color. I always welcome constructive criticism. I'm a self-taught welder, meaning: I bought the welder, googled a bunch and started sticking metal together about 7 years ago. I welcome hearing anyone's advice, (good or bad) as it's almost always based on their experience and something can be learned from it.

The bulk of my problem with the stainless was a contaminated gas lens cup and argon flow was too high. The turbulence was causing oxygen to get into the mix. I was just trying to get a few more years out of a $3.00 part... A lesson I can't seem to learn.

 

I have looked into these for gas lenses about a year ago, still using the ceramic ones but these are made from pyrex and look very promising: