I think its the exhaust back pressure at high rpm, cam timing and cams...a little bit of everything. The RB20 actually makes more power as the new engine falls over after 6,500rpm
So will try new turbo with bigger housing, going for the 12cm2, cam gears, cams etc and I am pretty sure will find a bucket load of top end. Will throw the 20G back on to compare to see if the billet turbo is any better. I think the 20G could be a good thing if we can get it breathing up top and get it to hold onto power. A solid 4,000rpm range of 300 odd rwkws would be pretty solid result
The 12cm housing shall at least enable me to flow plenty and see what the compressors will flow
Yes, the character of the 2L is more fun. Will be interesting to see how is goes for traction at the track when driving in anger