Who is running dry shot nitrous? Curious about it

[CamP]

Originally Posted by 1991 Corvette ZR-1

I will need to figure out a 12 volt key on source easiest to tap into for the last wire on the window switch.

I heard that chevy added a couple of 12v spares in the console in 1991. One switched and one always hot, but I haven't confirmed that.

[Subfixer]

Originally Posted by CamP

I heard that chevy added a couple of 12v spares in the console in 1991. One switched and one always hot, but I haven't confirmed that.

Yes. I found them in my 92, under the seat adjuster buttons in the center console taped to the harness. 1 hot, 1 ignition, 1 ground.

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[1991 Corvette ZR-1]

Originally Posted by Subfixer

Yes. I found them in my 92, under the seat adjuster buttons in the center console taped to the harness. 1 hot, 1 ignition, 1 ground.

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Thank you for this. I may take a look under the console for these wires. I routed the wiring needed for the door switch and finished the door harness, including 10 amp fuse on the 12v keyed side of things, per the Nitrous Outlet diagrams. Not sure if this arrangement is going to work with the door panel going on, but guess I will find out. Seems like there is enough space behind the panel for the fit. The idea is to have enough slack that if the panel needs to come off, there is no stress on the connections. Always fun to bust out the terminal crimp tool.

[1991 Corvette ZR-1]

Alright, I found the group of wires. I remember seeing these before. The size of the pink w black tracer wire was smaller than I thought. I routed a 12 ga red wire visible in the picture because I have the four switch 12v sources terminated into a barrel crimp and the 12 ga is the supply side of that voltage for all switches, including window switch.

Connecting these it not the issue as I have the tools, it is the difference in gauge. Wonder if I should be tapping a larger gauge wire. Thoughts from any electrical experts? Everything is fused, including the 12v supply,so I am probably overthinking it.

[1991 Corvette ZR-1]

Looks like I may be all set to use that wire. With the key on, the arm switch powers on the window switch. Relays are clicking when using the switches and purge button, so I am not a total hack at this. I do not have the hot at all times wire connected at the battery, just the ground side for now. The terminal lug adapters I picked up actually worked out. I have a few more little things I want to sort with the wiring and appearance but not too bad so far.

[1991 Corvette ZR-1]

Well I hit a snag on this little project. The ECU does not like the window switch being connected to read TPS signal. Idle immediately pegs at 1500 and stays there. I thought it might be the distance from the ECU to the window switch. When I unplug the window switch connector, the idle settles back into normal.

Marc was helpful recommending the NOS 15982 switch which should have a built in high input resistance so as to not affect the voltage. But then again, I would think this Nitrous Outlet switch would also have that feature. I need to give them a call on it. Dead in the water until I can work this part out.

[1991 Corvette ZR-1]

Well I did not need to reach out to Nitrous Outlet, the problem was me. I did not have the window switch grounded to the battery while testing the TPS reference signal. With that done, no issues with idle and with that done, I was able to set my TPS percentage ON threshold. I used 95 as the threshold. The switch toggles between 99 and 100 readout when I press the accelerator pedal all the way down, so 95 seems like a safe bet for the reference setting.

RPM on for stage 1 is 4000 and off at 6000. Stage 2 is disabled. I figured that was a good range where the stock cams did their work already. I do not feel like coughing up money for a remote bottle opener and a bottle just yet. I do have a ZEX bottle already, I should probably just get a ZEX compatible opener. I also have a tuner nearby with a mother bottle and filling station.

I still have a bit of research and work to do before any possible spraying. Definitely want the wide band 02 and that will be the next purchase. Not sure why I pick the hottest times of the year to do projects. For anyone curious about what the switch looks like with the display settings, here are a few pictures.

[1991 Corvette ZR-1]

I received an inquiry about tapping for the rpm signal. I wanted to include pictures of this, but do not think that is possible in a PM, so I figured I would post it here. If you look in the engine bay, near the ECU, you will see a large bulk harness running from the ECU to the engine. On that harness should be a white or grayish plug that appears to have an empty male plug connection capping it off. You will want the F terminal cavity from the female plug to tap for the rpm signal.

It is a Metri pack series 150 male terminal crimped onto 16 gauge wire, which should be sufficient. Once it is crimped on just gently insert into the male connected empty F cavity. The terminal has a barb on it that clicks in place inside the connector and that is it. I attached some pictures. The crimp tool I use is an S&G tool for metri pack or weather pack terminals:

https://www.amazon.com/Tool-Aid-Term...67001003&psc=1


Terminals male and female:

https://www.amazon.com/18-16-Metri-P...35319378&psc=1


https://www.amazon.com/Female-Metri-...1F7S5LGC&psc=1

Seal that slides over the wire and lower arms of the terminals crimp around:

https://www.amazon.com/18-16-Metri-P...35319578&psc=1


I highly recommend one of these as well. Automatic wire stripper. If you ever have to tap into a wire without cutting it, this is the tool to have. Also if you are making your own connectors and terminating your own wiring, you need one of these. I love mine.

https://www.amazon.com/Stripper-Elec...49183348&psc=1


Hope this helps.

[JT ZR-Won]

Thanks for the pics and the diagram, that is great info!!

Jay

[1991 Corvette ZR-1]

Originally Posted by JT ZR-Won

Thanks for the pics and the diagram, that is great info!!

Jay

Glad I could help out, Jay. If that is one thing, if any that comes from this exercise in boredom, it is that I found some info to share and help out. I cleaned up some mounting brackets, wiring, routed the purge line and that is about it. I am at a stopping point for now, as the next thing I would like to do is the wide band O2 install, but August is not the month to try that here in sunny Florida. At least not in a garage without air conditioning.

I was iffy on the door mounted switch panel, but I like how it turned out. The wiring arrangement in the storage compartment bugged me, even though I will not see it with the door closed. And since I am using a basic 95% WOT and 4,000 rpm on / 6,000 rpm off, I really do not have a need to access the switch constantly like I originally intended. So I re-pinned all the wiring connectors so it looks a little cleaner inside. I will eventually have something a little more professional than scotch tape and marker to identify the relays.

I think some of the Florida ZR-1 guys need to have an intervention with me and take my tools away.