Install your stock BOV, recirculate it.
The varying timing is your ECU's idle control strategy, trying to maintain the correct idle by adjusting the timing & the idle control valve.
If you like whooshy whoosh noises, best to install an ECU that can do speed density.
Just saw this video on your YT channel, looks like the Garrett G35-900 is a great match for your setup!
Barely even making your way into the red in 3rd at PWC, looks like a touge like circuit.
I am going to buy a R33 upright, then will buy a set of those Z1 350Z to 370Z dog bones and see how much I need to mill off the dogbone to allow the Akebono caliper to fit on. Another option is to space out the dogbone, which might require more work.
I am not sure how thick the R34 GT-t upright caliper mounting tabs are, as this will influence how everything sits. The caliper essentially needs to sit at the same height as the original calipers.
(not my photo)
I'm assuming you're only upgrading the front?
If so, no issues.
When you bleed the brakes make sure part of your process involves going around the block and activating ABS then rebleeding again.
I find pulling up the handbrake abruptly, then slamming the brakes is enough to trigger the ABS at low/safe speeds as there's enough of a wheel speed indifference from front and rear.
I'm sure there's an easier way of cycling the pump but there's not much info on it.
Just get GT-R Brembos all round, convert the rears to drum hand brake too.
A true car enthusiast will appreciate the OEM+ approach, spend the left over money on a Nismo GT-Pro LSD. Enjoy life, then sell the car, profit and buy a M2 Comp.
When you're in Sydney next, come drive my shit box. It's not 450kW, but it's 437kW, we can make it 450kW if we drop the cat, and drop the plumb back lol...
Has VCT, has 8600rpm limiter, has twin scroll.
Reduced low down torque, so your turbo will come on later.
And if it's a single scroll setup, expect a later rpm for your turbo to come on song.
Removing VCT is silly on a mild car, especially if predominantly for street use.
The plan was to sell it just before warranty runs out.
However the car market is so cooked, cost of living is as bad as aids, mortgage repayments have nearly doubled so yeah nah, will keep it for now.
Also if we were to replace it with the same Tiguan, we will end up paying more and getting less safety features.
(personal opinion) I prefer to run a 1.0 to 1.1 bar radiator cap, FWIW with my 1st motor (stock), I had a 1.1bar radiator cap using an off the shelf 42mm PWR radiator and the car was thrashed and cooled down for a good 10 laps on a near 40 degree day at Wakefield Park.
Water temp never went past 120 C (from memory) and no coolant was gurgling, albeit it did have a 25 row Setrab oil cooler. I even used the A/C on cool down laps lol.