Low or High Compression?

[meatball]

If I may, and please Weston and those in the know, tell me if I am off ........

You need to understand static and dynamic compression ratios. Static being whats listed, lets say what? 17.0:1 on an HO?
Now dynamic....... you take your expected boost. Your boost divided by 2 is your dynamic, plus your static.

So,
35psi of boost 17+17.5=34.5:1
With twins making 70psi 17+35= 52:1

My point/questions would be this -
How is the engine used? Where would there be a binefit/drawback to this?
What turbo configuration? The turbo has a huge effect on the uliltimate output of the engine.....

So, would an increase in static compression work well on a mild built daily driven/tow engine with moderate rpms? My thoughts are yes.
Why are huge power makers lowering compression? My thoughts are these engines are typically making huge boost numbers at higher rpms. Dynamically, the block/head gasket will support only so much.

So my thought/question to those that know and lay awake at night thinking about this stuff is where is the line drawn? If a guy were to build a 400hp tow rig not expecting to spin 4k in hills that want good spool and mileage is there a legitimate advantage to increasing static compression?
Yes there are timing and injector and cam choices to be considered. I am asking purely from an efficiency point of view. Can/could an increase in static compression yield a reasonable gain?
On the high rpm high boost side I see why boost is reduced. Its in the math. The engine will only hold so much cylinder pressure, and using boost to make up for static compression seems to be the deal, unless I totally missed something. And even there, seriously high cylinder pressure. For arguments sake 14.0 pistons + 200psi = 114:1 dynamic compression. Just math, not specifics.

So, I'm just curious if in the lower hp range (400hp or less) would there be a benefit in HP, fuel economy, and turbo spool if a guy were to increase static compression.......

Thoughts?

BTW not specifically VP directed........

I think timing plays a huge part in this as well , as far as its effect on cyl pressure . The end purpose has to be considered when making that decision . On a static timed 12v at 21* , stock compression with 90 psi and 425's I see no head lift . My good friends common rail at 75 psi with 425's would lift the head .
His timing at full tilt is way more than mine , more cyl pressure . Less compression is a way to gain more in a performance aspect with a reduction in other areas . I don't know where the happy medium lies . Boost adds a lot to the equation but timing is often overlooked when it's directly related as well.

 

[Smokem]

So, I'm just curious if in the lower hp range (400hp or less) would there be a benefit in HP, fuel economy, and turbo spool if a guy were to increase static compression.......

If there were, would the OEM's not be doing so? I think people in general very much underestimate how much time and effort has been spent on the implementation of higher static compression.