I found an old archived thread that showed a schematic of how to build an rpm switch to activate the 5th/6th ports, but the pic was down. Does anyone have this (or a similar) schematic diagram?

I know there's one for sale on summit racing, but I want to see if it's cheaper to build my own first.

Thanks- Terrence

 

Well, I have always used MSD switches with good results. I used one Summit switch and will never go back to summit. Those switches seemed to ramp up voltage.

 

well, all that is is just a frequency choke... or maybe just a high pass filter. Either way, it needs a positive biased opamp comparator at the end to actually "switch" when it hits the right rpm.

I just need the schematic with the right resistor/capacitor values to build it.

 

DIY frequency switch kit: http://autospeed.drive.com.au/cms/A_2810/article.html

 

That's pretty cool as well. Cheaper than MSD or Summit, but with shipping it'll still come out over 50 bucks. I'm sure I'll be able to do better than that. I guess I'll just have to do trial and error until I figure something out

Thanks for that site though. I found a link to the original manufacturer of that frequency switch, and they have some really cool, inexpensive kits, like turbo timers and boost controllers.

 

US$42 shipped.

I've built a few of Jaycar's kit, including the digital injector duty cycle display I've got mounted in the instrument cluster. Great products.

 

do the air solenoids for 5th/6th require a PWM signal, or do you just allow 12V to hit them so they let the pressure through to move the air actuators throughout the duration that you want them open? does any care need to be taken to then allow this pressure to fall off after the 5th/6th are supposed to close? or will this happen on its own due to imperfect sealing?

same questions for VDI system (though i would imagine these are the same ANSWERS as well)

thanks,
Max

 

The ECU just puts a Ground on the solenoid and that feeds air to them to open them. The Ground is removed from the solenoid and the air is bleed off at the solenoid to close them. Series five. Stock series five.

 

you could do it even cheaper, buy a cheap ebay adjustable shiftlight and use that to throw a relay connected to the solenoid. http://cgi.ebay.com/ebaymotors/Shift...spagenameZWDVW

25 dollars shipped, and if you use it to throw a relay which activates the solenoid then it doesn't matter if it ramps voltage up