Which is what I was about to mention, the beautiful 55mm MAF. Have you tried to do your terminal velocity test on petrol? Generally, the gas mixer is no more a restriction than the standard MAF given their similar sizes. I'll have to chuck mine on the dyno and test it with and without the gas mixer and see how it goes to what ever km/h(dyno) my engine makes max power at.

funny my v8 has 310k,stock,lpg and runs over 220ks with lpg-----has gra gas system,3 stage.powers all the way-----soon to have heads lifted,wear.i think your running out of gas over 100ks.

I just took mine for a run out to Jabiru this week. I have an auto stock 5L with 3.23 gears i think. Pulls the same all the way to 140 then the wind kicks in and it goes a bit slower - it will keep going though. I don't know what it will do I've had it to 200 but it jumps around too much to go any faster. Not sure if this helps you

*lo* Barnicus- terminal Velocity Test... I dunno if I should kick her in the guts on petrol mate coz she has that timing noise come from it on petrol as soon as u expect any torque from the engine...know what I mean???