| with lower compression, granted all things are equal other than this factor. The non turbo VG30DE and VG30DETT are great comparison platforms for this discussion. If you were to take a TTZ's turbos off, you would find the engine makes only about 160HP. If you want to test this a little, put your TT in 5th gear on the interstate and only push the gas pedal enough to make 0psi. You'll top out around 95-100MPH and by my DAQ setup I calculate a rolling and air frictional resistance of about 160HP. This is only a ballpark figure and I am not claiming this to be 100% accurate. However, what it does tell us is that the lower compression engine of same design/displacement makes less power. However, when boosting, the higher compression equates to a 'ceiling'. In Todd's car, the higher compression engine made 340RWHP at 11.5psi of boost. We simply could not make more power with higher boost because it required less ignition timing to keep it from detonating. Moving to the TT engine, if you were to drop the compression even more, say to 7:1, you could run ridiculous amounts of boost without detonation. Only drawback will be a big lack of power in the engine when it was not under boost. So then it all becomes a process of trading off. If you want to build an engine with MEGA power, but only over a small range of RPM, go with 7:1 compression ratio and run 40psi of boost. If you want ridiculous low end power, but can sacrifice peak power, go high compression. Everything else falls into the middle. There is a lot more theory behind why this is the case, but I'm not going to get into that right now - I'm hungry.
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