Quote:
Originally Posted by Westersund
Personally I'd go for E85 if you're not planning on opening the engine, if that's not an option due to availability of E85 I'd go with water and meth injection. Aiming for 400 WHP without opening the engine I'd stick to the centrifugal instead of a twin screw to get more linear boost instead of boost lower in the rev range. Mostly because it puts less stress on the engine if the boost comes higher up in the rev range, I'm not so sure the rods will remain in one piece with 400 WHP and full boost at low revs. 
Other then that the M54 is a really strong engine when it comes to boost. With new pistons, rods, copper ring gasket and ARP bolts it will be a tank of an engine. |
This will be a fully built engine. I'm not comfortable pushing much beyond 450 whp though, even with a built engine. Much of the drivetrain cannot handle it, as it's been proven on E46 cars. My goal isn't max power with a limitless budget. I'm looking to either upgrade what I have plus the built engine, or switch to a custom TS3-like setup.
Old thinking was that CR had to be lowered when running high boost, because inlet air temperature can be regulated (lowered) via an intercooler. Once it passes into the cylinder, you've got what you've got, and CR and fuel quality will dictate whether you will get detonation. New thinking is that high CR will work without detonation, but it's risky and up to the tuner. When asked about CR, my tuner said 11.5 for the Vortech. While he is very experienced and knowledgeable, I wanted to see for myself what this meant for the air coming into the engine (or intercooler). I was curious as to whether a Vortech running high boost could handle a higher CR than stock, and how inlet temperatures differed from a twin screw at the same peak boost.
The other questions I wanted answered were, just how much more power would a high boost twin screw make down low versus a centrifugal kit, and would a high compression centrifugal kit ultimately provide a faster car when going balls to the wall? It appears the answer to the first is question is "30-40%", and the second is "no".
The advantages and disadvantages of the various types of forced induction don't shine through very much when you are only running 6-8 psi. Yeah, a twin screw or turbo make power sooner, but that's about it. A properly sized turbo doesn't have much lag at 6-8 psi. The twin screw doesn't heat up the inlet air to the point of needing a lower compression ratio. And the engine naturally produces most of its power, rather than artificially with forced induction.
Once you crank up the boost, the true characteristics of each type of forced induction shine through.