And frankly I can understand the confusion. So let me explain how the evolution has occured and why I'm using the terms I am today.

Yes there was a Stage 1 throttle body. But it was identical to the TB fodder being offered by Blau, TAP, MTM et al. No difference whatever. But the results were vague, ambiguous minimally perceptable and mostly placebo effect. How could anyone who paid $300 not feel something!?! Some felt improvement, some felt "something", some "thought" they "may" have felt something and others (including myself) didn't really feel much of anything. Certainly not enough to blow $300 for. Tho I think a car with an automatic tranny did/does benefit more with that TB than the manual tranny cars. Those were "knock-out" items offering me no more reward or challenge than driving nails. I was doing those for $100 as they only take about 50 minutes but I hated the work, the finished product and the net results obtained.

Stage 2 started the velocity stack era for me. But it didn't stop there. I also started offering flowed/contoured and modified butterfly shafts, ground screws, butterflies that opened a full 90 degrees to the throttle body primary & secondary bores and some other "secret sauce" items. And 4 or 5 other mods that were later dropped as being superfluous or unnecesary, ie: they didn't flow any more at a useable CFM than a TB without them. Keyword here is "useable"... yes they flowed much better at unattainable CFM's. In fact one such previously deleted item was re-applied after the advent of the airbox velocity stack as it did prove to be measurable at our flow rates when the VS was in-place.

Then came the airbox velocity stack. First ones were black ABS taken from several UrQ airboxes I had sitting around from yesteryear. When my source dried up I ventured out into the discount muffler shops for bell-flared 3" steel muffler tubing. Had the bell-flare but no taper in the inlet. Later I turned up my own swaging dies, sent them out for 'case-hardening' and bought a Dake 5 ton arbor press and started making my own, to my spec and in-house.

Then came bored MAF housings, silicone induction hose, cold air intakes for some models and a host of other research projects that continue and are on-going.

Today those progressively higher stage numbers, ie; 1, 2, 3 actually have a deeper more definitive meaning than purely sequential revision numbers. They are related to the products size. Any product today that has a "3" suffix is a 3" diamter (business area) piece (minimum) from beginning to end. There is no place in it's entire useable feature that is less than 3." Any product labeled "Stage 2" on the other hand is generally 2" or greater when compared to above. It's also the "entry-level" item for a piece that usually has a better-quality, higher power Stage 3 counter-part. And where there is no other size offered (as with the airbox velocity stack) adding "Stage 3" to it just feels unnecessary. Glad I didn't start with Stage 10 as we'd all be running some seriously large MAF housings and silicone hose today. There are also sixteen Stage 2 and Stage 2+ throttle bodies out there that are in fact "Stage 3" by definition today. I didn't adapt the Stage 3 designation until I found CNC'd velocity stacks. It was at that point I re-defined my "Stage" descriptions to describe more than just a revision upgrade and to reference some idea of it's size via the "stage" description.

I leave any item that came on the car to be perceived as Stage 1 in the evolution.

To that end the Stage 3 TB has a total swept inlet area of 3.15-3.20" (altitude dependent) Stage 3 silicone hose kit is 3" I.D. throughout it's entire length. Stage 3 MAF is 3.xx" minimum I.D.

Stage 2 MAF and hose kits are 2.xx" in their I.D.s. Could be 2.00" to 2.99". Tho they just happen to be 2.72" & 2.75" respectively at their smallest diameter. But the plenum inlet that hose kit connects to is closer to a 2.5" I.D.

And Stage 1 doesn't exist for my nomenclature purposes other than what came on your car originally.

Hope this helps

 

So is my Stage 2+ Throttle Body is now being called a Stage 3?

 

But they are virtually indistinguishable from each other as I still do all polishing/finishing on the CNC'd ones. And there's no longer the epoxy contours around the O.D. of the VS directing air into the secondary as that only starts to show a positive increase at 600+ CFM. But when you reach 350HP you'll be damn glad they're there ;-)