Newly released STIC Super X2 carb review

TDC wrote:

This unit is based on a more advanced version of the STIC metering insert block. This design has more tune-ability and brings a more significant power...

This unit is based on a more advanced version of the STIC metering insert block. This design has more tune-ability and brings a more significant power level to the lower thru extended top range. The bore is 40mm/38. The body casting quality is at a high standard and design is based on the PWK AS series. Short Body and Screw Top versions are available. No bulky and heavy billet with potential leakage. Out of the gate, the functionality was to the Keihin standard and with a very low steady idle.

Good to see it is priced well against other brands, which do not provide high level performance gains.
I'll leave the performance gains at this. Based on my KTM 200SX STIC gains and tune, I predicted correctly in ordering a G2 throttle system and installing the #400(mud) cam at the get go. For MX riding! Yup, but also total control on a tight hard pack trail. Not the case with the MX tuned STIC block/Keihin with std throttle turn. Off/On throttle recovery is exceptional. And compared to the STIC insert, I was more consistently clearing short run-up jumps from slower turns, with less drama in 'the huck'. I go 200lbs on an otherwise stock 200SX, BTW. Nearly 20 yo bike and I'm definitely mixing it up now with faster young bucks on new 4t's. 

A few of the design attributes. The design has introduced a jet tunable air correction passage at the intake bell. Making high velocity air/fuel vapor available to the pilot circuit. The pilot circuit is sealed off from the float bowl! It instead draws fuel from just above the main jet at lower RPM signal, via a passage. Once increased RPM creates a pressure drop in the needle jet tube, the pilot reverses flow and then pulls vapor accumulating at the intake bell area. Be aware that the available vapor and pressure increases along with higher and higher RPM. This recycling is untapped with std carbs or FI.
With your air jet selection, you can control the amount of power you wish to introduce into the already intense acceleration of the vapor mixture created from the unique STIC needle jet tube.

For those unfamiliar with the STIC, here is my loose interpretation.
The key factor is its cooled vapor creation coming from lifting fuel supply rapidly with the aid of venturi sourced air. This air is routed thru. a series of passages and chambers. A vortex affect is created within the isolated and perforated needle jet tube. The central vortex flow is cooled. There is also a reduction in back pressure into the carb venturi. Thus, freeing up flow where otherwise recurring BP hinders flow. Keep in mind that a cooler charge increases power and vapor also travels faster than a coarser atomized charge. Hopefully this summary will suffice.
Side note, 98 octane spec heads can be run on 93 octane fuel, not sure about 91 octane pump.

I had two alternate tunes in less than 2 hours after delivered to my door. Had to turn the AS out .6 turns to clean up one of them going into the mid range. This signals needing a larger air correction jet. No changes required at track day! 

I returned to the track with some new brass bits. I went from a 50 pilot jet to an 80! BTW, 45 is stock. I increased the air correction jet size from an 85 to a 100. Providing more vapor to the huge pilot and circuit when it feeds the main needle jet tube. The main jet, needle, idle and response went unchanged. But the power increase across the powerband stepped up my speed and ease in clearing jumps. A couple buddies asked me if I had some 'T' injections, cuz they saw me repassing faster dudes and one buddy on a 250F said I'd drop him on the straights, but my outside lines helped him keep up.

Cheers