GT4
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- 8 Nov 2008
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ACHTUNG said:An interesting subject but a few other things to think about-
You are both assuming that a normally asperated engine runs at 1 bar induction pressure at the cylinders. Actually it runs at a vacuum. This will have a large effect on your calculations.
I wasn't:
Admittedly, this will be at slightly less than atmospheric pressure thanks to negative pressure. This is caused by restriction and non-laminar flow at the throttle body aperture. This equates to, say 95% efficiency.
The negative pressure I refered to is your "vacuum". The disputed 95% was a suggested partial pressure ratio.
If anything, Wattie was right and this reduction coefficient is lower and hence bodes worse for potential benefits of this kit.
As for the Laws you refer to, are simply the complementary partial equations constituting "The Combined Gas Laws" (not forgeting the Gay-Lussac equation forming the final rearrangement). In any case, any complicatication/refinement to the calculation further diminishes the possible benefits of the system.
You can consider the scenarios calculated to be best-case rules of thumb.
Same for Reynolds factors, any additional turbulence, pressure and flow density adversely affects possible benefits.
Finally, I did suggest that for genuine benefit the system would require mechanical lowering of intrinsic compression ratio (all FI installations should run at what would be a lower NA ratio)
technically in-cylinder compression ration should be mechanically reduced within the engine on the addition of any form of forced induction, but we'll ignore that finesse, as eCharger have
In addition, this would normally include, as you suggest, a redesigned piston faces and/or cylinder heads for optimised swirl