Boost Spike = Blown Head Gasket

[we4Mateo]

X3! Porting that hole is almost a requirement at this point in the new turbo/internally wastegated downpipes. Happened to me as soon as I bolted up my new turbo. Before the porting i was making 24 psi at part throttle now i can adjust it as low as 15 psi with the HD actuator and an RJC 3" dp.

x4...even my TE44 needed porting to get good boost control. I use an RJC style boost controller, and my non-ported turbo exhaust would make more boost with the dump open than shut, but it stays the same now, and I too can get down to low boost, 13psi or so, even with HD gate now that it's ported. And if your exhaust flows well, the boost should stay the same with dump open or shut. I just like the way it sounds at the track while spooling at the beam...I seem to pick up 2-3mph though with it open.