OK guys, remember this is the 471 housing that has the smoothed out mid bore constriction and was having trouble seeing/reporting enough air.

Made a larger "mini" velocity stack for the sensor bore (1" OD and .234 ID) to replace the .75 x .234 stack I had. It works OK, but could be perfected...

Now getting steady just richer than stoich at WOT above 4K RPM and stoich dither with WOT atlower RPM. MAF sensor POT set by "eye" and probably near correct, but not exact. Good enough for now.

Power is similar to that with 2.4" MAF, stock hose and plenum on S3 TB. (Now have 3" MAF with Manc's VS & S3 hose kit.) Conclusion: either S3 TB or manifold/heads is now the "choke" point.

Have XTB on it's way.

Sadly, the 2.4" mod to the small MAF is a LOT more work, and requires a lathe... The 471 mod can be done with a hacksaw blade and a file, though it's easier with a SawsAll and Foredom. It also requires the (at least) Stage 2 hose kit and a mini VS, but before we are done you will be able to buy those.

I am still planning to make one more 471 mod, along the lines Mance suggested and develop the mini VS for it. That one should be producable by someone (not me) at reasonable cost. It will be about 2 to 2.5 inches of nylon rod turned down to slide into the sampling bore and reamed out to make a VS.

I have to admit that I'm already scheming to do something with the 2002 A4 3.0 Avant I have. I'm sure I'll be doing some Abnormally Aspirated mods to that car as well. But I plan to document each step and test in between. (It's a tiptronic, so I'll record 0-60 times from a dead stop and simply planting my foot.)

UrS4... you may be getting an order from me soon for another Velocity Stack! I'll putz around this weekend to check inlet diameter. I also think your S3 hose kit will work on the 3.0 motor too! (The plenum is very similar to what we have on our 12v motors.)

Bob