I know this is a really good thing for the n/a rotory engine. But does FI change this? Should a one way be placed on the line? Is there enough air to influence the a/f's?
Do FI engine even need this?
While I am at it do FI engines need the VDI? If not then is it better to permantly keep it open or shut?
olddragger

 

Well, the way I understand the SSV and the VDI(which is very little), is that they have a vacuum tank that stores the vacuum until it is needed to open the ports so that under boost the engine can still open the SSV and VDI.

Apparently you need them to open at where they open now in order to get drivabilty on a street car. If you block them open your power curve will be steeper yet come on sooner. So classic lag feeling. Good for race track where you want 6K+ power only, but perhaps not so good on the street.

The opening points can be tweaked a little bit depending on the capacity of your FI system but blocking them open all-to-gether would be a different story.

 

The flash tuning programs will allow you to open them whenever.
The vacuum tank holds enough reserve to keep them open for many minutes at a time, so having them slam shut during a race is unlikely.

I plumb the AWP to a charge pipe so that it always sees positive flow, rather than using a check valve.

 

Yeah, pretty much.
It just becomes a boost/vacuum leak everywhere else.

 

No check valve.
Its plumbed into the charge pipe so it always sees positive pressure.
That's why it isn't always a vacuum leak.

 

Just disconnect it. Rotaries have run for decades without them.

 

ok so plug it (will it hurt idle?), put positive pressure to it, or put a check valve on it? Which is best to do for the s/c engine? S/c may be a little different in that the awp is the most active at idle and the s/c (mine)is at boost from crank up?
olddragger

 

Plumb it to the MAF tube and put a check valve on it.

 

Yeah, you have to touch the gas pedal to get boost. heh.

 

No, actually quite the opposite.
That is why the Pettit doesn't idle very well.
The Lysholm blower always produces boost. That is when it needs a bypass.
OEMs usually clutch the blower pulley to prevent it from drawing too much air across the MAF at idle.

The plumbing of the JAB that I am talking about pulls the air from the MAF tube, where the air is always at atmo pressures.

 

How hard would it be to fab a clutch for the Lysholm??

 

Probably just grab one from a Millenia or a Mercedes.
I'll look into that at some point.
For now, the only easy solution is to jack the idle speed up.
In a way, the idle air bypass that Pettit puts in the system takes care of the idle for the MAP based engine management.

 

That may be a great "mad Max" type of mod.
olddragger

 

If you clutch the s/c, how does the tune compensate (or flash, hopfully)? or is the clutch controled by RPM?

 

This is how my AWP (a.k.a. Jet Air Bleed) is setup. My Oil Metering Nozzle Bleed is setup the same way. My Vacuum Chamber is plumbed to the UIM with a check valve in it. My Air Solenoid Valve on the Vacuum Chamber is capped off because I no longer use the Secondary Air Injection system. My Secondary Shutter Valve Solenoid is connected to the SSV actuator. My VDI Solenoid is connected to the VDI actuator. Anybody see any issue with this setup?

 

Rumor has it that that no longer used VFAD circuit could be used to operate the clutch mechanism through a reflash. This could be tied to the RPM and another variable. MazdaManiac would have to elaborate on this.

 

Hmm, so the AWP is the unlabeled middle vacuum hose from the intake accordion... interesting.

 

The tune would not have to compensate since the S/C being disconnected won't keep the idle from operating like stock.

The clutch would be engaged with a Hobbs switch or could be activated by the VFAD.