28-01-2014, 10:28 PM
Not read rest of the thread, but I know it'll be blamed on them - this is NOTHING to do with Hydraulic Lifters before anyone blames it on that.
This is a valve spring problem - the valves are floating from too much backpressure - that's because the turbo simply cannot move enough gas and/or the wastegate isn't opening.
Either the valve springs need uprating or you need to monitor exhaust manifold pressure along with inlet manifold pressure. The tuning process will affect both, adding in lots of fuel at mid RPMs will increase drive pressure insanely, IMO with a hybrid turbo with relatively small hotside, you need to monitor exhaust pressure.
This is a valve spring problem - the valves are floating from too much backpressure - that's because the turbo simply cannot move enough gas and/or the wastegate isn't opening.
Either the valve springs need uprating or you need to monitor exhaust manifold pressure along with inlet manifold pressure. The tuning process will affect both, adding in lots of fuel at mid RPMs will increase drive pressure insanely, IMO with a hybrid turbo with relatively small hotside, you need to monitor exhaust pressure.
