Samps

I am going to eliminate all of the vacuum lines from my motor along with the OMP. I am going to keep my air-pump to control the 6th ports and the VDI. I need to know at which RPM both of the systems will work best at. I was thinking that about 4k would be the best for both, and it would be easier to keep them the same. Does anyone know the optimal RPM to activate these? I can just bleed off excess air for either one to make them open whenever I want, but I don't want them to open to early or to late.

Mr. Eccentric

Damn it here we go again... I posted something re: this topic awhile ago and it almost spurred a riot. There are so many schools of thought on this. Racing Beat says they dynoed a stock 2g and it actually lost power below where Mazda has 6pi set to open (about 5300rpm). A modded car may be different, but without extensive dyno time, there's no way of knowing. I say leave the actuators operating as they are now. Also the VDI is designed to have a supercharging effect via pulsation waves; again, if you jam the plate in a static position, you will lose benefit rather than gain.

Samps

I think the VDI pulsates on its own. I ran a vacuum line directly from the air-pump to the nipple on the VDI and it kinda bounces open and closed until a certain point then it just stays opened. If the stock system opens at 5300, then that is maybe where I will start at. I highly doubt that the simple solenoid valve has anything to do with the VDI pulsating, the internal workings of the VDI actuator is probably what makes it pulsate. Both systems need simple air pressure; at what RPM they get it is the question.

And I couldn't care less if a riot started due to this thread, as long as I get the info I need. Sometimes flame wars spark up the most info.

tmak26b

5300is the VDI, not 6 port. 6 port is 3800. Read the dyno chart

http://www.geocities.com/tmak26b/90dyno3a.jpg

pd_day

iTrader: (6)

Hmm....I thought hp = tq at 5252.
Anyone care to explain?

splking

HAILERS told me it was at 3800 rpm.

Samps

5300 = VDI

3800 = 6th ports

That's what I needed; thanks!

deadRX7Conv

HP = torque * RPM / 5252
torque = HP * 5252 / RPM
torque = HP at 5252 RPM

Interesting dyno curve. HP=T at 6400 rpm
Could this be caused by running in 3rd gear?

Samps

I think the chances of me getting the ports or the VDI to open at a specific number like 5252 is just about impossible. I will take anywhere from 5k to 5.5k and be happy.

tmak26b

They dont seem to cross at 5250 because if you look at the Y variable. It is different for torque and hp. So if u match that up to X (RPM), you would ave thte cross at 5252 rpm

SureShot

I'm looking for a small electric air pump, so I can remove the belt driven iron pump. The only writeup I've seen so far uses a Cadillac suspension pump.

tmak26b

THey dont draw up that much power,

HAILERS

Nothing to add to the above. Just thought some series five people might want to see what happens on each pin of the ECU at some given times. Might help in the future. So three jpg to follow.

HAILERS

Series five two:

HAILERS

Series five three:

Bambam7

Samps- were you looking for the stock RPM points or the "best" ones??

The Mazda engineers did a great job of coordinating these points perfectly. The VDI is perfect opening at 5200, regardless of engine mods.
The 6 ports are pretty much ideal too at 3800.

I hope you arent getting into the whole RPM activated switch stuff, since the ECU sends out +12v signals at each of those points- just use those....

A lot of people are saying that with mods, those points change, but they dont- not enough to make a difference anyways...

Liquid Anarchy

iTrader: (2)

Really? That's killer! Another $25 saved. BUT, the question is, I get how you can make an electric pump turn one of those on... but can you actuate BOTH of them, at different RPM's with 1 airpump?

Bambam7

Well, that depends on how fast the air pump spools up.

If the air pump spools up fast enough to turn on get full pressure 1/2 second later, then do this:
Run the air pump (using a relay of course) off of the +12v 6 port signal.
Since the air pump will always be on over 3800 , tee off of the pressureized line, and run a line to the VDI. Use the stock VDI solonoid, signalled by the stock signal inline to open and close that line at 5200 rpms. Cool? I think so...

If the air pump takes a second to spool up, it may hurt 1st gear performace. In which case you will want it on all the time, or switch activated (flip switch, or a full throttle gas pedal switch) Then you use both the stock solonoids... one to dump air to the 6 port actuators at 3800, and the other for the VDI.... essentially the ame as stock plumbing.

Have fun.... I love doing stuff like this!

Samps

I am not planning on using any switches at all. I am removing all un-needed underhood equipment. I am going to leave my airpump in and run two vacuum lines from it. One will go to the VDI and one will go to a "T" running to the 6th port actuators. I will then adjust air pressure via bleeds untill I get the correct opening points. I did a lil test last weekend and got it working at almost the desired points; but that was with the ACV still intact. Without the ACV and the end of the airpump hose plugged up it will create alot more pressure so I will have a lil more control. I had a hard time getting the 6th ports to open as early as 3800. They seemed to open at around 4500 with a direct line from the airpump to the actuators without any air bleeding at all. The VDI is simple; it will get pleanty of pressure. When it is done; I would be willing to bet that this is the best set-up if you want to keep the ports and the VDI working. An electric pump is more trouble than it is worth. We already have a source of air pressure, why mess with it. The air-pump is a lil heavy but only sucks up a small amount of power. And by keeping the air-pump you can always re-route it to the cat for your yearly inspection swap. I know this is going to work, and I know it is going to be easy. Hopefully this will eventualy end all of the dabates about removing the pump and wiring the ports and the VDI open.

Liquid Anarchy

iTrader: (2)

THX BamBam, I keep forgetting those Solinoids! Most likely, the pump will be on the entire time the car is. I think that's how they are in Caddys and Lincons anyway. As long as I don't hear it, and it doesn't produce a huge drag on the alternator, then I really don't care

tmak26b

Hmm some guy used the airpump off the vette, thatthign blew up because it is not suppose to run 24/7