Originally Posted by
jediali
OK great, seems you have some nice ideas (thinking outside the box), and its funny we both want the same thing. we are narrowing down what should really be done on the V10.
Just to clean up the intake question, the plenum is treated more like a branch. for example if all 10 intake tracts lead back to a common branch then:
when intake valve opens expansion wave is created, it travels back up intake tract and reaches branch, at the branch the wave splits in 2, a compression wave travels down other 9 intake tracts towards cylinders(useful),a expansion wave travels back down the same tract (not so useful). i guess technically this is a plenum but it is small and exists in all intake systems.I like your IIM system, sounds great, i see them on racing engines.
i don't want a spec-monster (nice term) but a further extension to an engine such as the RS4 V8, superb low end torque but also high end capability.
The biggest reason you see IIMs on racing engines and not on normal cars is solely a question of space. IIMs will make the most power and will get the most out of shockwaves and if they are steplessly variable then they will optimise the whole rev range much better. However they require alot more space than a plenum design (any plenum design) This is the main reason that normal cars have plenum designs (they take up much less space) Also plenum chambers help to ensure that each cylinder gets an equal share of air and earlier in automotive history it helped ensure all cylinders got fuel even though you only had one carburetor or injecter. I say stick with steplessly variable IIM.
Also making an engine that has good low down power (through massive torque) and is also capable of revving high while maintaining suitable VE isn't too difficult if you think of these two extremes as seperate. The tricky bit is getting the transition from low down grunt to high rev screaming... What you want is a quick torque peak (at least before 2500rpm the earlier the better) that doesn't drop below 80% until really high revs. The torque line should be as flat as possible.
Do you know/understand/guess how IIMs use shockwaves?
Power, whether measured as HP, PS, or KW is what accelerates cars and gets it up to top speed. Power also determines how far you take a wall when you hit it
Engine torque is an illusion.