SR20VE conversion w/ EFR7670 low dyno numbers - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

RalliartRsX · 06-14-2020, 04:25 PM

Flow rate is in terms of cubic feet per min. The cubic feet is a volume. A volume has a specific mass associated with it like a box of air has a certain associated mass that is occupying the specific volume

The cross sectional flow area between the DE vs VE has changed enough where the VE head can flow more mass of air for a specific volume as due to the flow rate being higher, it can fill a specific volume (cylinder) with more air for a specific time (intake stroke). Hence why I state that a DE does NOT have the exact same VE at a given RPM peak RPM or whatever. The VE can fill the specific 0.5 liter volume at a much faster rate, and hence mass, than a DE during an intake stroke, which is a fixed constant.

If you are pouring water into a 2 liter glass, and you pour one at 2 l/sec and one at .5 l/sec do the glasses fill the exact same amount for a 2 sec pour? Because that's exactly what you are saying above....
The calculation for VE is
VE = (cfm x 3,456) / (c.i.d. x rpm)
So let me ask you this, if a DE flows say 100cfm @ 4000 rpm, and a VE.120, can you explain to me how both engines have the exact same VE if we are assuming 4000 rpm is peak torque or cylinder fill or whatever you call it?

But hey, if I have to extrapolate that idea, then maybe I give you more credit than I should....

06-14-2020, 04:25 PM	#32
RalliartRsX Post Whore! Join Date: Apr 2006 Location: Maryland Posts: 4,793 Trader Rating: (32) Feedback Score: 32 reviews	Flow rate is in terms of cubic feet per min. The cubic feet is a volume. A volume has a specific mass associated with it like a box of air has a certain associated mass that is occupying the specific volume The cross sectional flow area between the DE vs VE has changed enough where the VE head can flow more mass of air for a specific volume as due to the flow rate being higher, it can fill a specific volume (cylinder) with more air for a specific time (intake stroke). Hence why I state that a DE does NOT have the exact same VE at a given RPM peak RPM or whatever. The VE can fill the specific 0.5 liter volume at a much faster rate, and hence mass, than a DE during an intake stroke, which is a fixed constant. If you are pouring water into a 2 liter glass, and you pour one at 2 l/sec and one at .5 l/sec do the glasses fill the exact same amount for a 2 sec pour? Because that's exactly what you are saying above.... The calculation for VE is VE = (cfm x 3,456) / (c.i.d. x rpm) So let me ask you this, if a DE flows say 100cfm @ 4000 rpm, and a VE.120, can you explain to me how both engines have the exact same VE if we are assuming 4000 rpm is peak torque or cylinder fill or whatever you call it? But hey, if I have to extrapolate that idea, then maybe I give you more credit than I should....