Originally Posted by agrazela

... a modded L67 TB is the cheap n' easy way to go to open up flow. What I found from scanning and graphing is that the larger L67 throat on an L36 gets you into higher MAP faster (i.e., at lower TPS%), and higher MAP faster = higher VE faster = more powah faster!

To put an L67 TB on an L36 UIM will require you to fill in the L67 TB mating flange with epoxy (and sand it flat), and to alter the three mounting holes a bit to raise the TB a scooch to better center it on the L36 UIM inlet...

...

ANY change to the TB anywhere between the MAF screen and the throttle plate will alter MAF readings, thus altering MAF calibration, thus requiring a tune.

...

I expect an L67 TB swapped onto your L36 would run very crappy without the correct MAF calibration burned to your PCM.

Originally Posted by agrazela

Rear of TB filled with epoxy and sanded flat, to mate with L36 UIM and L36 TB style of gasket:

http://momentoffame.com/photopost/da...L67_TB_002.jpg


But make sure you do NOT fill in the PCV intake hole (unless you are running some sort of exotic breather setup)

http://momentoffame.com/photopost/da...hole_on_TB.JPG


(Here I drilled the epoxy back out after realizing I was stupid )

http://momentoffame.com/photopost/da...L67_TB_016.jpg


It'* harder to see in a pic than in person, but the L67 TB sits just a little low on the L36 UIM, and some of the bottom ridge of the L36 UIM inlet juts above the L67 TB throat:

http://momentoffame.com/photopost/da...L67_TB_005.jpg


So what I did was to drill out the three mounting holes 7/16":

http://momentoffame.com/photopost/da...L67_TB_006.jpg


Notch the back edges of the holes a bit to anchor some epoxy:

http://momentoffame.com/photopost/da...L67_TB_009.jpg

http://momentoffame.com/photopost/da...L67_TB_010.jpg


Then re-drilled the 6mm (or 1/4") mounting holes just a scooch (maybe 1/8"?) lower than they originally were:

http://momentoffame.com/photopost/da...L67_TB_011.jpg

http://momentoffame.com/photopost/da...L67_TB_012.jpg


So that the L67 TB outlet was centered better on the L36 UIM inlet:

http://momentoffame.com/photopost/da...L67_TB_014.jpg


The L67 TB increased MAP vs TPS, especially at low-to-midrange:

http://momentoffame.com/photopost/data/523/MAP_v_TP.JPG


(May explain why L67 is programmed to go into PE at ~25-30% TPS, rather than the ~45-50% IIRC of the L36)

And, properly tuned, increased VE throughout the powerband:

http://momentoffame.com/photopost/da.../L67TBVE_3.JPG


(How much of that was due to this TB being ported and polished and how much was JUST due to it being a larger-throated L67 TB, that I do not know; also, I did NOT have a wideband when I collected that data, so it may not be 100% as accurate as I'd like)

Now then, proper tuning for this involves not only starting with a stock L67 MAF table then doing the standard VE, fuel and spark tune business, but also lowering onset of PE (as mentioned) and fiddling with (well, increasing, of course!) the table that puts a limiter on the rate of MAF Hz increase.

Originally Posted by agrazela

Yes, all that stuff will swap. You still need the L67 MAF calibration table in your PCM, though; the MAF sensor is the same, but the calibration is different because the TB around the sensor is different.