I've seen some pics of some NA-T set ups using a blow through with the Karmen sensor and an AFC. My question is how far can you push it? At what point does the sensor peg? With low goals of say 280 wheels is this doable?

 

280 RWHP is doable with a good tune. Anything beyond 300 rwhp will require upgraded injectors, a AFC/VPC or a AFC/ V8 MAF or a Map-ecu. Map-ecu has a hardtime controlling the karmen though.

 

Please do enlighten me: what are you talking about?

Kaiser (Chris?): There isn't really a solid answer for your question.
Your best bet is to mount the sensor in such a way that there is at least 6 inches of straight pipe before entering the sensor.
If you have a bend right before the sensor, the Vortexes will be all messed up, and the readings will be off.
It's trial and error here. Get a wideband sensor and start slowly increasing the boost, using the AFC to add gas where needed.
When you add gas via the AFC but the AFR at that point doesn't change at all, you know you've hit your sensor's MAX. Back off a little from that critical point, and you should be good.

Cheers,
~Alan