I've had my L67 TB off for a while because I wanted to hook up my charcoal canister. And the only way to make that work was with the original 95 TB because it has 2 vac ports on the side.
On the 99 L67 TB, I port matched the exit to the L36 UIM and grinded down the MAF hump. But I never did much more than that.
I've been messing with it a little bit at a time and heres where I'm at now:


I'm
-Filling in the coolant ports w/ epoxy
-Filling in a couple spots in the TB where I broke through (bolt holes etc.)
-Smoothing out the change in bore from the MAF area to the TB plate area
-Cleaning up the MAF screen area
-Filling in the area before the MAF
-Cutting the TB post
-Adding another port of the evap system
---still gotta cut it down and grind it leaving a lip similar to the original
-Once I'm finished smoothing it all out everything will be polished
So whatcha think?
Heres how my car is sitting right now: :(

Had to take it apart so I could give the rotors to a friend so he can spin em.

You dedication to your car never seizes to amaze me. Please post more as you progress. Just to also let you know Your making me want a series 2 again :P

Mike, you're going to have major problems if my experience with removing the MAF support is any indication. I have a S2 TB sitting right here. I know from experience that the MAF support and aperture is specifcally designed to capture a percentage of the airflow for the MAF to detect. You've removed that capability. You went way beyond what I did, but I still had major problems.

The little hole that captures the air for the MAF sensor is designed to be a percentage of the total area, and the small metal plate behind it is critical. Not only can you not modify it, but you can't remove it either or your MAF gets all screwy.

I predict bad results on your end.

Bill, you realize this is a 99+ TB right? There was no post, just a hump. And I have had this TB on my car for at least a year before I took it off. No problems. I just used the mini-afc to get the fueling right.

I predict you will fight it for eternity with no final tune. The AFC is a tuning aid for a final burn, not a band-aid for long-term use.

You will never get an accurate reading for that MAF sensor. My prediction based on my experiences with TB porting and mating different TB'* to my own car.

From my experience with it on my car, watching the fuel trims, adjusting the afc accordingly, having the long term fuel trims within 1 or 2 of 128, and having the short term fuel trims always hover around there as well, I think I'll do just fine. It never gave me any trouble.
This maf is very different from the maf in your 93 or 95.
It was designed & calibrated with that hump that I grinded out. But now it'* just a matter of re calibrating it. People have been running TBs like this for a while.
I do understand why you dislike the afc but I was able to get my fueling very close with out much trouble. With that, it'* just a matter of burning a new chip to bring my afc values to 100%.

Can you outflow your stock TB? What'* your TB velocity doing with the stock TB as compared to this one? Is there even any power to be had?

(not picking you apart here, seriously asking questions based on the L27/L67 TB game we've played).

I have no concrete data to answer those questions with.
My goal at first (when I bought it) was to flow more.
Now I'm actually trying to increase velocity. I'm trying to make the MAF section of the TB more of a gradual change in bore from the tip of the TB opening to the TB plate. More like a velocity stack. Then from the TB plate back, more of a gradual transition from the TB to the UIM. More gradual the a stock L36 TB. I can see this TB being much less turbulent than the huge MAF post, pre '99 L36 TB.
The butt dyno seemed yieild results but that can and should be deceiving since it will be flowing more when the TB plate is first opened. It could just feel snappier.

It should feel snappier on throttle response simply because you get more opening in a shorter time, but my concern is the top-end.

Have any other L36'* done this yet? The velocity stack idea has merit, but only if your primary opening isn't too large to support the flow in the first place. What that limit is, I have no idea (at least on the L36).

My top end is 6400 rpms right now.
What I'm doing is very compareable to the ZZP Stage 2 L36 TB.
That TB is on the quickest n/a L36.
Others (L36ers) have done this to L67 TBs but there was never a before/after dyno.