camshaftsbp
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camshaftsbp [2022/01/02 21:51] – [Camshaft Theory BP] imakeyoufast | camshaftsbp [2022/01/03 09:41] (current) – [Quotes] imakeyoufast | ||
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We had never too much lift ([[https:// | We had never too much lift ([[https:// | ||
- DBilas | - DBilas | ||
+ | |||
+ | **IVC, IC intake valve closes (at)** | ||
+ | |||
+ | * The significant value to estimate the target power rpm of the camshaft | ||
+ | * Later IVC -> More time to overcome the pressure differential, | ||
+ | * Too late IVC -> Cylinder pressure > Manifold pressure, loss of power (but efficiency gain through better expansion (reverse Flow Atkinson Cycle [[https:// | ||
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+ | **OL, O/L overlap (OL duration = IVO + EVC)** | ||
+ | |||
+ | * Overlap can be used to evacuate the remaining intert gas out of the cylinder | ||
+ | * Free Flow Exaust -> Inertia of the exhaust gas helps via scavenging effect | ||
+ | * Positive Pressure Intake -> Inertia of the intake charge pushes the remaining inert gas out | ||
+ | |||
+ | If air or intake charge is pushed into the exhaust, NOx / HC emission increase. Also precious charge is wasted, resulting in higher BSFC. | ||
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+ | **EVO exhaust valve opens (at)** | ||
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+ | * Too early -> Gas goes through the exhaust valve and doesn' | ||
===== Rotrex Specific ===== | ===== Rotrex Specific ===== | ||
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- k24madness | - k24madness | ||
+ | ---- | ||
+ | The BP powerband shape is very sensitive to duration @.003. The few degree increase from a 4W to a 5A shifts peak torque a few hundred rpm. We found that an Integral stage 1 NB2 cam with a bit more lift but 10° more duration at .003 was no faster on track than the stock cams even though it made a bit more peak. If it is a 5 speed or driven on street with a stock longblock, we prefer stock cams for best driveability. Breathe on the longblock or do a full I/H/E +ECU and you can afford a little more duration as the low end improvements from the other stuff over up the losses from cams. For instance, the Tomei' | ||
+ | Add I/H/E + ECU with the Tomei' | ||
+ | - emilio700 | ||
+ | |||
+ | ---- |
camshaftsbp.1641156673.txt.gz · Last modified: 2022/01/02 21:51 by imakeyoufast