so its a window switch,ignition box,timing retard all in one?

 

Yep, not a bad deal I would say.

 

alwayscode ~ A window switch is a secondary switch ( Think of it as a secondary power switch, that is RPM activated, that only works when the main switch it turned on ). You set it for the RPM's you want the nitrous to come on and off at. Without a window switch, if you went WOT from idle, with N20, its WAY harder on the motor than if the RPM's were higher, say at 3,000 RPM's.

Nitrous and extra fuel are injected at the same rate, say 100HP shot, and will inject the same amount of extra fuel/n20 at 1000RPM's as it does at redline. This is what makes N20 hard at low RPMs. Typical window switches are set, on a stock LT1/PCM to come on at 3000-3500 ( In an attempt to already have good traction too ) and turn off at 5800 RPMs ( To avoid the problems with the stock rev limiter). The stock rev limitier pulls fuel, not spark, and so if your spraying, and would hit the rev limiter, it kills injector pulse. No pulse means no fuel, no fuel leans it out big time, it gets super hot, detonates, and will, it not at first, eventually blow the motor. You want to basically set your window switch at just a hair (100-200)RPM's higher than where you shift at, and/or below the stock rev limiter. This way you are still spraying up until the point where you let off ( Or dont heheh) to shift.

Also, another reason so use a window switch, well, in a M6 car: What happens if you miss a shift ? It forces the motor to spin higher then it was ever designed to. This alone is hard on it. Then the PCM (If it was never programmed ) reads its past the rev limit, and cuts fuel. So now your revving high, and leaning out. To top matters off, you would still be spraying an extra 100-150HP on it, and that really is the icing on the cake, that will blow your motor.

From the last couple years reading on here, the number of guys W/O a window switch who missed a shift, and had their engine survive it, are very far and few between. Its bad lol.

Hope that helps some.

 

GREAT EXPLANATION RM125....I totally understand it now, thanks for your time ---

 

I missed a shift and the motor lived..but I let go of the button heh.

 

When hooking up the mallory 685 box. the window switch wire needs to go where? also with the Start retard wire? Any one have an answer?
Thanks Mike

 

The start timing retard is a built in feature of the box and is programmable by the controls. You don't want to play with its value, leave it at the default, which is .01 I believe. Some people who have messed with it could not get their cars to start. You need to be concerned with two wires, the violet wire, which is for the window switch, and the yellow wire, which will be for the timing retard when you are spraying. The violet wires provides a ground, therefore, you will want to disconnect the main ground of the nitrous relay and connect it to the violet wire of the Mallory. If you have a fuel pressure safety switch, then the ground wire of the fuel pressure switch will be connected to the violet wire of the Mallory instead. The yellow wire is connected to the 12v on the activation side of the ntirous relay. A wire tap would be the easiest way to achieve this. When the nitrous relay sends a 12V input to the solenoids, it will then initiate the timing retard.