Setting Up Vct Switch On Rb25 (freq. Sw. From Jaycar)

[3LGODZILA]

ive bought a nistune board and an rb20 ecu to use in my r33 and ive got a frequency switch from jaycar to control the vct.

ive been told the range is around 1800rpm - 4700rpm. should i go straight off this or should i do dyno runs with and without the vct to get it exact?

from what ive read the vct solenoid has a constant ignition feed and a switched earth. so really all i have to do is run an earth to one side of the NO contact and run a wire to the vct solenoid from the other side of the NO contact on the switch and then adjust the switch so that it turns on and off at the desired rpm? and of course have a 12v ignition and earth going into the switch to give it power, and tap into the rpm signal and run that to the switch?

also when adjusting the the actual switch to turn on and off at the desired rpm can i be free revving the car in neutral?

[Crans]

Haha I was just about to post a similar post on how to wire it up, just purchased my kit and half way done soldering

[3LGODZILA]

haha awsome. let us know how it goes

[Crans]

All soldered up should be as easy as connecting power, ground, ting off rpm signal from ecu. cutting vct wire on loom connecting to board the connecting other end of board to ground.

[Crans]

Just saw your sig. Elec work on the side need my altinator tested only putting out just 12v when driving

[stricnynel0s]

i used a MSD RPM activated switch, it just adds a ground between s certain rpm range than than removes it after that point is reached, effectly turning on , than off the vct soleniod. the msd cost like 80 dollers and looks nice, it can also be used for nitrous and other things

[3LGODZILA]

i heard the msd ones were a couple of hundred bucks otherwise i would of got one of them.

crans just check that the battery is alrite 1st, even if u hook up a jumper pack or something then if its still not charging check the basic conections (main pos and neg from battery, and the connections on the starter and alternator) if thats all good then get someone to rev the engine while u got your meter on there if the voltage still isnt going up then its your alternator, most likely brushes or diodes

[Crans]

brand new battery. watching voltage levels while driving via nistune readouts

[KiwiRS4T]

ive bought a nistune board and an rb20 ecu to use in my r33 and ive got a frequency switch from jaycar to control the vct.

ive been told the range is around 1800rpm - 4700rpm. should i go straight off this or should i do dyno runs with and without the vct to get it exact?

The answer is yes. Since you have gone to so much trouble you may as well get the ideal settings from the dyno. Of course you can set it near enough beforehand and adjust it when you get the opportunity on a dyno.

[badhairdave]

The frequency switch will only switch it on or off at a set rpm. it isn't a window switch like the msd unit.

You could get it to work that way by playing with the hysterisis but that would only work in one direction (either increase or decrease in frequency) which makes it useless becasue your switch point would have to be at 1100 or so which you just don't see in regular driving unless you stop.

[Crans]

Dave has it right. Just got mine working(not tuned 100% tho) if you are driving revs hit 1200 vct activates you give it some throttle revs climb past 4700 vct turns off you quickly tap the breaks and revs drp below 4700 it dosn't re activate. you have to let the revs drop below 1200 fo it to be able to activate again.

How much for the msd unit and where can i order from?

[3LGODZILA]

so the jaycar switch is a fail then?

+1 about the msd unit

[Crans]

my home made unit was just tested looks promising just need to sort out a grounging issue which stops the tacho in the dash from working.

rpm counter is slightly off but that dosnt matter quick fix should be a capacitor on the rpm feed to filter out noise

[badhairdave]

you just set it so it switches the vct off at 4800 or so but it's on the rest of the time. Having it on at idle isn't ideal but doesn't hurt anything from what i've read, if anything it cleans up the idle if you have biggish cams as it reduces the overlap.

Thats how i'll be setting mine up anyway.

I would have liked to get a greddy mss which would have done it properly and is a compact nice looking unit but they are discontinued.

[Don Dada]

I used the Msd unit when i changed from auto to man and couldn't get the nvcs to work and u can't go wrong with this unit...

Simple to install and adjust to any rpm up to 10k if u wish

U don't want it on at idle bc it makes it idle like shit .... dont know how it will react with bidder cams tho

Ended up sellin it tho bc its difference was verrrrrrrrry minimal on my stock set up

http://cgi.ebay.com/ebaymotors/MSD-8969-DI...S-/300399015408

[3LGODZILA]

my home made unit was just tested looks promising just need to sort out a grounging issue which stops the tacho in the dash from working.

rpm counter is slightly off but that dosnt matter quick fix should be a capacitor on the rpm feed to filter out noise

r u talkin about the jaycar unit?

let us know how it goes n if theres any probs,

[Crans]

r u talkin about the jaycar unit?

let us know how it goes n if theres any probs,

nah i built and connected the jaycar unit and it useless it uses low high triggers not rpm window.

A friend is helping me build out own vtc controller using a amtel cpu

[stricnynel0s]

yeah, msd went up in price i got mine brand new from local dealer for 90 dealers delivered the next day heh. msd is simple though like 4 wires; pwr, grnd; rpm signal; and one that either adds or removes the ground to the item you wanted to use it on. its liek a gray wire if you want it to have power in the rpm range or a blue wire if you dont want it to have power in that rpm range, quick and easy

[Crans]

Where did you buy it from?

[Crans]

Just received my MSD RPM window switch. Good looking little unit. Still working on my home made unit but really need the car running properly.

Just reading that it can only ground 2.5amps will i need a relay connected or is the vct load 2.5amps or under?