Any one know of an RPM activated switch that will work with our cars? I hear the MSD one will work but it needs to be configured for a 4 cyl engine. And to do that, you might need to send it to MSD for them to do it. Or can you do it yourself?

 

You can do it yourself. Make sure you don't get one that requires a CDI box though, (if you don't have one)

 

Just get the Summit RPM Switch - Part # SUM-830449. It does not require any pill. The RPM's are selectable through DIP switches. This is what I use for my electronic 6-port.

 

whats the range the summit one can be adjusted through. Im going to use it to activate my 5th and 6th ports. I thought because its designed for v-8's its range is limited to 4000-19000. I guess that would be ok for the ports to open at 4000, but dont they open up at around 3800 stock?

 

http://homepage.mac.com/carldavis/intake/tune.html

 

I think that Is where Alcor Is getting his Info from

 

Thats the one I have and It works beautifully. I had to use the "fine tuning" screw for precise rpm activation for my auxilliary ports.

 

Sorry for asking this again, 5th and 6th ports should be opened at 3800 rpms, am I correct to assume that that is also when the secondary injectors come into play? And in your experience, when should VDI be opened with the RPM switch? I apologize for digging up this old thread.

 

I ended up tweaking my electric auxilliary port setup to exactly 4000 rpms from when the switch would activate to open the sleeves. I did this to stay away from secondaries coming on @ 3800 rpms.

Doesn't the factory set the VDI to open at 5000 rpms? I'm not sure...

 

The auxiliary ports do open at around the same time the secondary injectors come on, but the two aren't related. Mazda's info actually says the secondary injectors come on at 3,700prm and the S5 6PI solenoid is activated at 3,850rpm. If you open them about then you should be alright, but the optimum opening point will be affected by mods to the engine. The best way to determine that point is to do two dyno pulls, one with the ports open and one with the ports closed. The rpm where the two power curves cross is when the ports need to open for maximum benefit.

Factory opening point is 5,200rpm. This is determined by the tuned length of the manifold passages so this point is probably not affected as much by mods, but the optimum opening point can be determined in exactly the same way as above.

You can always start your own thread with a couple more lines of explanation. This would mean not having to wade through all the other posts before realizing it's four years old...

No point, the two things won't effect each other.

 

http://www1.jaycar.com.au/productView.asp?ID=KC5378

 

Actually, I needed to do this before I fixed the notorious 3800 rpm stumble. I didn't want the two of them to come on at the same time so all It took Is to seperate them by a mere 200 rpms. I left It this way even after fixing the 3800 rpm stumble. It worked great.

 

But why? Like I said, they have no effect on each other. How could they?

 

I bought this unit
http://www.performancepartsoutlet.co...s/MSD-8671.jpg (not from that site)

and I have the box that says activated switch on it
http://www.0-4factory.com/msd-rpmswitch.jpg

Will this work to open up my vdi or did I get stiffed?

 

B'c when the auxilliary ports opened up at 3800 rpms It amplified the hesitation I had experienced. When the switch activated It didn't plunge the actuators normally (as Is the case In stock format) It forced them openly aggresively on account of the high pressure air compressor I was using. When I replaced my engine harness with a brand new one I had no more problems. Further, my NA wasn't exactly stock at the time.

 

An APEXi V-AFC has an rpm activated output. Haven't seen anyone with that type of aux port control though.

 

Does not that switch need some type of module???? Made by MSD? I tried to check it out on the google but got tired of looking, what with no vested interest. You might try to write a thread of your own asking that question. I'm sure there are any number of folk on this forum that are knowledgable about that switch. Not me though.

And while here, I'd select that Jaycar rpm/frequency switch over the Summit one hands down. I own both and know what I'm a talkin 'bout. Not that the Summit isn't a good choice anyway if rigged right i.e. triggering a seperate relay for whatever device your wanting to operate. NOT using the Summit to operater the device by itself.