I just installed the KP Technologies VDC module that memorizes the ON/OFF position of the switch. It was fairly easy to install with the only challenge being exposing the black/red wire in the harness going to the ignition switch (to which you connect the module's yellow wire). Basically, there are three wires to solder in--two to the VDC switch (module's black to switch's black, and module's orange to switch's blue-black) and one to the harness. The only interior parts that need removal are the plastic kick panel above the driver's legs and the metal flange covering the underside of the steering column underneath that kick panel--a total of three bolts and two snap connectors. Now that I've done it once, I could easily do the install in about 30-45 minutes--although it took me about 2 hours figuring out the wiring, etc. The instructions, unfortunately, could be clearer about which wires in the switch connect to which wires on the module--but I've explained it above. If I knew what I just wrote, it would have been a piece of cake.

The module, so far, works great. After turning off the VDC switch, it stays off no matter how many times you turn off and restart the car. Works the same way if you turn the switch back on. For under $50, I think it worth it to avoid the hassle of trying to remember turning off VDC with every start and risking forgetting to do it. Unlike pulling the VDC fuse, this lets me turn VDC on for bad weather, etc. without any difficulty and instantly while I'm driving down the road.

According to Avalon Racing, it's critical to turn off VDC every time you drive if you intend to operated under boost with a heavy throttle. If you don't, VDC could momentarily cut fuel to the engine during wheel-slip resulting in detonation and engine failure. This happened to one of the 350Zs in which they installed a Vortech SC--the only car out of dozens that suffered a catastrophic engine failure. The other reason to turn VDC off is to save your poor brakes that get automatically applied to individual wheels as needed to prevent skidding.

 

I like the idea of this, but I believe that the VDC actually pulls timing and activates the brakes and does not cut fuel. It just makes the car slow down. Can someone confirm this?

 

From the service manual regarding traction control system. See the info about fuel being cut to the engine.

TCS Function AFS001KY

The wheel spin of the drive wheels is detected by the VDC/TCS/ABS control unit from the wheel speed
signals from the four wheels, so if wheel spin occurs, the rear wheel right and left brake fluid pressure
control and engine fuel cut are conducted while the throttle value is restricted to reduce the engine torque
and decrease the amount of wheel spin. In addition, the degree the throttle is opened is controlled to
achieve the optimum engine torque.

Depending on road circumstances, the driver may have a sluggish feel. This is normal, because the optimum
traction has the highest priority under TCS operation.

TCS may be activated any time the vehicle suddenly accelerates, suddenly downshifts, or is driven on a
road with a varying surface friction coefficient.

During TCS operation, it informs a driver of system operation by flashing SLIP indicator lamp.[B]

 

Deja vu?

gersteinp and I had this conversation in the Vortech problem thread here in the FI section.

I agree that the fuel is 'cut,' but I disagree with saying that ALL fuel is cut. THe service manual indicates that the throttle body is set to the positon to provide the most torque for the engine. Well, without fuel, you can't have torque. It is my belief (no facts to back this up) that upon detection of serious 'slip' the throttle body is closed (ECU utilizing the drive by wire system, and this is also verified by my car losing boost IMMEDIATELY upon slip), the duty cycle of the injectors is lowered, and timing is left unchanged.

I rarely ever shut off VDC in my car because I'm not totally used to a RWD car yet and I'm definatly not used to having 350 horses at the wheels.

 

Kevin-- I'm going to make a new post on this and describe my understanding of why FI and leaving VDC on is a toxic combination for the engine when driving aggressively.

 

Can you post a link to the memory module, where to get it and such please

 

here you go!

n1cK!

 

Could you post a pic of the ignition wire. I assume this is the 12 volt on off that is activated by rotating the key forward? I need to tap it for my boost gauge.

 

I don't have a pic of the wire. You need to take out the underpanel of the driver side dash (one left lower corner 10mm brass bolt and then pull straight towards you--two snap connectors--one on each side). Then, take out the two bolts holding on the metal bar under the steering column and remove it.
Find the harness leading to the ignition switch. It's a tightly wrapped bundle of wiring about 1/2-3/4" in diam. You'll need to use a utility knife to carefully slice open the plastic sheath. Then fish out the red/black wire. That's the one you want (12v power switched by the ignition key). Use a high quality wire-stripper to expose the copper wire without cutting the entire wire (it's too short to cut and then reconnect). You'll probably have to start it by cutting gently through the thick insulation. The wire stripper will then spread the insulation apart exposing the wire. Then you can solder right onto the exposed wire--electrical tape and you're done.

 

yeah thats what I was planning on doing. I jut could never find a good pic of the wire... I plan to do a full write up pics included when I install my gauges as I have yet to see one. Plan to install
Autometer CF boost, EGt, water temp, oil temp, and fuel pressure gauge.

 

Thank you!

 

n1cK!

 

its easier to use a fuse tap.. don't remmeber which fuse position i used.. but makes the install alot cleaner.. use the service manual to get the fuse location

 

I've now used the VDC memory module for about a week and it's been flawless. Helpful to be able to leave VDC on during yesterday's snowstorm but turn it off 'permanently' again today with the roads clear.