Yes, Dennis has provided some up-close photos of the intake.  It’s clear that both the primary and secondary runners are connected together through the Variable Induction Valve (VIV) when the VIV is open above 5750 rpm (according to the Mazda literature).  That is rather interesting because on the six port the value is opened like around 7250 rpm – but then the “red line” on the 4 port is only 7500 rpm in the auto application, so I guess it would need to open before red line {:>).

 

Low rpm mode

 

It appears that IF  the 4 port is using the DIE effect at Low rpm (<5750),  it would use the “end of the tube” reflection of the FAW pulse below 5750 rpm to bounce the pulse back to the same rotor that generated it (since the VIV is closed  and prevents cross over)  – which means it would have to arrive back in less that 60 deg of rotation if it were going to aid the intake port that generated it OR if aiding a later port closing event then some multiple of 60 – probably 2x60 = 120 deg of rotation.  That would require a tube approx 72 inches long (depending on what rpm below 5750 you assume the “low rpm” mode peaked at) from port to “end of tube” or first large cross sectional increase.  But, on the other hand they simply may not use the DIE effect below 5750 rpm.

 

 

High rpm mode

 

AT  5750 rpm the VIV opens and the runners are then connected together and you get the pulse being generated at one port traveling through the intake through the VIV to the second rotor in time to assist it in retaining its charge near the closing time of the second rotors intake  port.  Based on the intake port timing spec I found for the 4 port,  it looks like the primary pulse has approx 117 deg of rotation time  to get to its destination and the secondary pulse has approx 93 deg of rotation time.  This is due to the different opening and closing times of the primary and secondary ports.   Interestingly the secondary opens later and closes sooner – I suspect to catch the inflowing air stream at its highest velocity. 

 

Based on this data it looks like a 36” (port to port) would give DIE boosts at the rpm shown.  The boost effect the effect would peak at those rpm and fall off on each side of those peaks.  This is based on the port opening and closing timing specs for the 4 port engine to arrive at the angular (Angle in the chart) rotational time required for to travel from one port to the port on the second rotor. 

	Exhaust Pulse/ First port Closing as target for HIGH RPM Mode
	RPM	RPS	Period	Rate deg/sec	Angle	Time Sec	Ft/sec	inch/sec	Distance		Dennis Measured Distance
HIGH	5650	94.16667	0.010619	33900	93	0.002743	1100	13200	36.2		36"		Secondary
RPM	5750
	7100	118.3333	0.008451	42600	117	0.002746	1100	13200	36.3		36"		primary

 

If you assume it takes some time to generate the pulse and it needs to get to the second port before it closes, I figure 5-10 deg of rotation is required for this activity, in which case I reduce the amount of travel time by – 10 deg giving the following results for 93-10 = 83 and 117 – 10 = 107 degrees travel time for the pulse

			Minus 10 deg
	Exhaust Pulse/ First port Closing as target for HIGH RPM Mode
	RPM	RPS	Period	Rate deg/sec	Angle	Time Sec	Ft/sec	inch/sec	Distance		Dennis Measured Distance
HIGH	5050	84.16667	0.011881	30300	83	0.002739	1100	13200	36.2		36"		Secondary
RPM	5750
	6525	108.75	0.009195	39150	107	0.002733	1100	13200	36.1		36"		primary

 

The time delay could be as - 5 deg (I don’t think much lower than that) which gives

 

 

The 4 port Renesis does have the high speed barrel valve.  Don't recall the distance from memory but just a guess is considerably less than the 18" Dennis got.   That must have been the distance to the low speed chamber in the nylon portion of the manifold.

Tracy