GR Yaris Vulcan Cut Head gasket & ARP bolts Upgrade

[@davindermanku8187]

So far 32 psi on the GT660, turbo speed 132krpm moving 580lb/min air for around 600hp on E75. Garret state a max speed of 135krpm so it’s pretty much maxed. Car needed 23% more fuel versus GT25-550 at similar boost. Coolant pressure rock solid after about 10 consecutive runs to 7500rpm redline in 4th. This HG and bolt set up is very good.