The dyno has a speed restriction of 200kph, I have no idea what revs its at when it hits that. Seeing we run the same diffs can you let me know? Are our gearboxes the same ratio?
Boost in first is absolutely useless, especially in rear drive. (It will light up second in the dry) Usually around 5k I would say at a guess. Remember though, I have a 4k stall converter once boost ramps so once the initial second of nothing has passed it is always on boost, whatever gear i'm in.
It was interesting going up a hill on the freeway in the wet the other day, just leaning on the throttle, and as boost ramps the car stepped out at 100kph in 4th. I need the front diff in soon, before winter hits.