Intake Manifold Runner Cross Section and Runner Length Simulation 1D Modelling

In last article we have fixed Plenum volume and Runner Cross Section on basis of 1D simulation.

2.8 Li Plenum volume gives smooth torque consequently now Runner Cross Section variation will be simulated for this proposed 2.8 Liter plenum volume.

Question - We should fix cross section first and then go for iteration of runner length? or vice versa. 
Answer - Best way is little complicated and time consuming. As we have fixed plenum volume -

1- First simulate cross section and get some best value for it.  

2- Now optimization  runner length

3- Go to step 1. 

Do this until unless uniform torque and uniform power curve is not obtained.  

Conclusion from Above Graph: - If we can eliminate torque dip near 9000RPM then we will have consistent Torque above 60Nm from 7500 rpm to 11,500 rpm. 

Conclusion from Above Graph - At D40373733 we get maximum torque 70.32Nm, but it is not smooth so it is better to have lower but constant torque from D35353535; So now will optimize Runner Length with D353533535 ( that is runner Dia = 35 mm constant throughout).  

Conclusion From Above Graph: - Considering low RPM torque response, we opted for L 260 (i.e. runner length 260 mm) consequently now we will further refine runner length near 260 mm. 

  

Conclusion from Above Graph: - L265 will only increase weight by adding 5mm in each runner as performance of 260mm and 265 mm is similar. L255 is not smooth so discarded.

Final Configuration of Intake Manifold:-

Plenum Volume	Runner Length	Runner Cross section
2.8 Liter	260 mm	35 mm throughout

Performance Indicators with Final Proposed In-Mani:–

Not only torque, but other parameters have been analyzed to validate proposed manifold performance. Go to next article for detailed design of intake manifold.