maxnix wrote:One of the points is, if you don't have your engine designed from the begining for a turbo application, in adding one you you will seriously erode its life expectancy. Maybe to minutes!
Slap-on turbos and superchargers are a recipe for a bomb.
I am not speaking of a "slap-on" application of forced induction here. First off, the only mechanical differences of consequence between the VG30DETT and the NA version are the pistons, the way the oil squirters are pointed, and the inconel exhaust valves on the TT. Of course, the cams are different as well. The limiting factor in applying boost to the NA VGDE engine will probably end up being the stainless steel exhaust valves.
Detonation is always an issue, but a well thought-out application of timing changes and intercooling can help enough to make it viable. Of course, bigger injectors are a necessity, as well as a nearly completely remapped set of EPROM maps.
Just recently it has been proven that 340 HP can be made on an NA engine that has only TT injectors, OEM TT turbochargers, and a remapped ECU. This was accomplished with no detonation, mind you. Detonation being the biggest worry by far in applying boost to a NA engine with a high CR, reliability might very well be decent.
Several NA Z32's have been running with supercharger with 7psi for several years now, at least one of them without an intercooler at all! As far as i know theyre still puttering along, with no failures. It should be noted that these Z32s had ECu maps designed for the stock twin turbos, which have completely different flow characteristics than the supercharger. This is a testament to the robustness of the block and its ability to survive adverse conditions, even with possible detonation due to incorrect mapping.
If a supercharger can be found that can provide the necessary CFM at 11 psi, an excellent supercharger system is entirely possible. Both powerdyne and vortech make units with promising flow characteristics, both of which i am currently researching.
Add to that an efficent 1 or 2 core intercooler, possibly air-to-water, and you have a very reliable system producing an excess of 300HP, reliably, on the NA VG block.
I agree that a poorly designed application is doomed to premature failure, and even a well-engineered application is doomed to a more distant failure. Of course, every engine has a finite possible lifespan right out of the factory.
so putting mederate-boost forced induction on a NA engine is no more detrimental than expecting 550RWHP out of a VG30DETT with stock internals. plenty have done it, and reliability is reasonable. long term reliability is definitely questionable, but thats not the point. anyone considering any of these torque-enhansers should very well realize that there is always a trade-off with reliability.
melted pistons? definitley a long-term possibility. perfect opportunity to get inconel valves and better forged, lower CR pistons.