Interesting thread guys. Here are some of my Tilke circuit modifications:
Abu Dhabi:
http://www.gmap-pedometer.com/?r=5740128
I have used the second S bend in the first sector and have also got rid of the chicane and opened up the hairpin and brought it forward so there is enough run-off without the chicane. The chicane halfway down the straight has been opened up to improve the flow of the circuit, and I have cut out the chicane at the bottom of the circuit to increase the speed into the fast right handers to make them more challenging. I have also opened up the penultimate corner.
Bahrain:
http://www.gmap-pedometer.com/?r=5740144
I have diverted the cars down the outer circuit and missed out the chicane to create a high speed section for overtaking into a new hairpin which then brings the cars onto the inner circuit, which they then follow round to the tightening left hander. The only change in this section is the ninety degree left has been opened to make it more challenging. Behind the pits, the cars bear right onto the ‘oval’, where they rejoin the straight.
Shanghai:
http://www.gmap-pedometer.com/?r=5740151
I have slightly opened the turn 6 hairpin to increase speeds into the esses, after which I have replaced the two slow left handers with one medium speed corner, which adds to the esses and makes them tighten in succession. i have then changed the next hairpin into a left kink on to the long right hander which would be more steeply banked. I have then changed the hairpin into a more classically shaped one, and opened up the final corner a bit.
Istanbul:
http://www.gmap-pedometer.com/?r=5740157
the best Tilke circuit before COTA but I think some areas could be better. I have made the first corner quicker and opened up turns 3 and 4 to give a better flow. I have obviously left turn 8 alone but opened up the chicane afterwards so they enter the tightened kink on the back straight at higher speeds. I imagine this to be like the old 130R. This could then cause mistakes and allow for overtaking into the final few turns, which I have left alone as they provide good wheel to wheel dicing for position.