Originally Posted by Spooler

I wish I would have drilled/tapped the exhaust manifolds so I could check drive pressures on each turbo. I feel like I am flying blind trying to figure out where the turbo's are maxing out and if backpressure is becoming an issue. One mistake in this area can cost me a headgasket. Ideally you want no more than a 1:1 ratio. 30psi of boost/30 psi of drive pressure. This will tell you where the turbo's exhaust side is becoming a restriction. The only problem is this may cause the exhaust manifold to crack unless they were cast with a bung area to install it.