Who is running dry shot nitrous? Curious about it
 

I wanted to see about those running dry shots what your set up looked like, where you mounted your solenoid and your line routing. This is not a definite for me, just in the research / curiosity stage but let?s say I am staring at a pile of nitrous parts and wondering about another project.

What I have:

10lb Zex bottle with pressure gauge
lines
nitrous filter
solenoids
pills
evacuation tube and hose to outside of vehicle
Mini switch panel for arm, heater, opener and purge from C7
wiring and relays

Off the top of my head what I would still need:
Fogger nozzle not sure which brand, I guess Zex
bottle opener - Zex brand? not needed but I have a switch
WOT switch - brand unsure
Window switch - brand unsure

With this small of a dry shot, would a heater even be necessary? If so, what is a good safety switch to pair with it to prevent overheating? Also, where is the best nozzle placement? The factory accordion duct would have to be replaced for this. Post pics if you have them of your set up, I wouldn?t mind learning a thing or two. My secondaries are eliminated but throttle shafts are still in place and held in open position with brackets.

We all know about the now way defunct NOS kit custom made for ZR-1s, I guess it would be nice to piece a kit together of decent parts that replicates the built in safety of that old kit. 50 shot was the target?maybe 75 max and I am done if I go through with it.

Ported top end, stock heads minus secondaries, headers, exhaust, aluminum flywheel and 3.90 gears are what I have.

Re: Who is running dry shot nitrous? Curious about it
 

not too many nitrous warriors on the lt5 there was a nice safe NOS dry kit and other more aggressive direct port stuff that Julio and Kurt did on some 415s. Lots of wounded warriors and not too many folks has the fold to keep refreshing the high end engines.

Nitrous warehouse did some cool nozzles that would fit under the injectors that looked really cool as you could run stages and it made sure the nos and fuel went right down the port.

Re: Who is running dry shot nitrous? Curious about it
 

Usually if you Google the topic with zr1.net afterwards you will find some good information here

http://www.zr1.net/forum/showthread.php?t=25970

Good luck with your decision.

If replacing an LT5 was the same cost as an LS I would be spraying also.

I chose to stay naturally aspired.

FWIW a friend of mine was racing a turbo BMW in the later 90s or such and had a nitrous backfire.

Blew the plenum through the hood of the ZR-1 and destroy the motor.

Re: Who is running dry shot nitrous? Curious about it
 

I had a NOS dry kit back about 20 years ago and it worked very well. Made about 460rwhp and over 500rwtq on a bone stock ZR-1. Ran 11.74 @ 124mph in the 1/4.

The key to the system was the NOS relay that prevented the system from triggering until the secondaries were activated. Sold it to someone in Sweden, but I should have kept it.

Re: Who is running dry shot nitrous? Curious about it
 

You will notice that Nitrous is not discussed much here.
There's a pretty good reason why.
High compression and nitrous don't play well.
One little hiccup and you will be replacing your LT5.
If you're rich and don't learn fast, give it a shot or two.
But just don't make it a habit.
You have been forewarned.

Crabs

Re: Who is running dry shot nitrous? Curious about it
 

Good takeaways on this subject. Karl, I reviewed that thread prior to making this one. Lgaff has quite the talent for making things work on these LT5s. I was impressed by him jumping in with the wet shot. Is pooling in the intake still an issue with small dry shots? I understood this to be a primary concern with wet shots but WOT with a small dry shot would still allow this?

Re: Who is running dry shot nitrous? Curious about it
 

I ran over 1,000 pounds of nitrous through my engine, before I had a brain fart and burned a $15 exhaust valve. It was self inflicted. The rest of the engine components looked good. If done properly, a modest shot won't hurt anything.

The biggest issue I see is the price of nitrous has gone up 600%+ since I was using it.

Re: Who is running dry shot nitrous? Curious about it
 

I learned something from Graham a few months ago that probably would have prevented my burned valve. He said that disconnecting the MAT sensor results in a few degrees of timing retard. I'm pretty sure I never would have burned that valve had I known that in 2004.

Re: Who is running dry shot nitrous? Curious about it
 

No fuel puddling with a dry system.

Re: Who is running dry shot nitrous? Curious about it
 

That was my understanding. Liquid in the bottle, gas while decompressing to reach atmosphere pressure, impossible to puddle. I am sure the opportunity for a plenum backfire is probably still a thing even with a dry shot. My understanding is the nitrous is an oxidizer and therefore not explosive or combustible but aides in the combustion process. Have people popped their plenums on dry shots? If so, I am picturing them doing do on the ragged edge of what you should using for dry versus using a wet system.

Re: Who is running dry shot nitrous? Curious about it
 

I had one backfire on the freeway with my dry kit. It broke my air filter housing, but no other damage.

I was running a 140hp shot with no timing retard. For freeway use, I should have been running a smaller shot with some timing retard.

Re: Who is running dry shot nitrous? Curious about it
 

So something like a 50 shot would be on the easier end of the spectrum. This is a big fat disclaimer that I am not going to do anything anytime soon, if ever. However, I have ordered some things to keep me busy and get started. I think I could set everything up to the point where I could put a bottle in and run nitrous if I eventually wanted to.

Re: Who is running dry shot nitrous? Curious about it
 

Ask George about dry shot of nitrous. He had it on his 1990 ZR-1. I don't
think he had any trouble with it after Pete (ZR-1) helped with some ground
wiring I believe. I was told that I could run a 100 shot of nitrous even with
368 cu in 12.5 compression ratio setup.
John

Re: Who is running dry shot nitrous? Curious about it
 

As I mentioned before, I ran a 140 shot and used over 1000 pounds of nitrous. I have the original pistons/liners in my shed and you'd never know they ever saw nitrous. Almost no measurable wear whatsoever.

A 50 shot would be super safe as long as the system was properly installed, fuel pumps are healthy, and a/f ratios were good.

Just doing little things
 

Just passing time today. Installed the switch panel. Not hard wired in yet. All the wires connected to it are secured behind the panel until I get to that. I found a trim piece off eBay for about $35 shipped so I didn?t have to butcher the piece originally in the car. Decided to give this a try as I already had this C7 switch panel. I think Nitrous Outlet had a sale on them for $30 whereas they were normally $65 years ago and impulse buy I did.

Just listing this for my own future reference to come back to:

Purge is blue with white stripe
Heater is brown with pink stripe
Arm is orange
Bottle opener has brown with orange stripe & brown with green stripe

Power is red with white stripe for all switches
Ground is black


Not sure which wire off opener switch is open and close. Will have to double check Nitrous Outlets wiring diagrams.

Just killing time
 

I am still kicking this around as I research more. No rush at all here. I picked up a nitrous solenoid to go with a spare purge I already had in the parts bin. Just got an entry level unit. No bottom exit port, so I needed a manifold and some little connections to join the nitrous and purge.

Created a little bracket I need to clean up still. Plenty of clearance with the hood fully closed. It would be nice to see some other solenoid placements by other members, but I guess there are not too many messing with it. I planned to mount all the relays and fuses in the tray behind the driver seat. Power supply and ground will be 10 ga wire run to the battery for both. I had some spare 4AN line I used to check that the feed line can reach the manifold without interference as well as routing past the coolant outlet tube.

Lee was kind enough to offer his perspective on this should I decide to go all in.

Re: Who is running dry shot nitrous? Curious about it
 

You will likely find that you need a little larger fuel jet to keep it from going way lean

Re: Who is running dry shot nitrous? Curious about it
 

Hi, Lee. If I do anything, I will end up sticking to the dry side of this system.

Re: Who is running dry shot nitrous? Curious about it
 

I don't know how the zex dry system provides extra fuel, but the nos dry system uses a solenoid from the nitrous line to a pressure regulator that steps the nitrous pressure down before connecting to the fuel pressure regulator. This spikes the fuel pressure up when the system is activated.

Re: Who is running dry shot nitrous? Curious about it
 

Interesting, I would very much like to review that whole system. Wonder if Holley still has the PDF instructions or overview kicking around somewhere.

Re: Who is running dry shot nitrous? Curious about it
 

The NOS import kit is has a similar configuration as the old zr-1 kit, but without the zr-1 specific black box that triggers off the secondaries. The Z kit also had a inline fuel pump booster, but you wont need it at 75hp.

If you scroll down to "tech resources" you can download the installation instructions. The layout is on page 11.

https://www.holley.com/products/nitr...parts/05122NOS

Re: Who is running dry shot nitrous? Curious about it
 

Here's a dyno run from the NOS ZR-1 kit.

https://imgur.com/a/WPn0TVp

Re: Who is running dry shot nitrous? Curious about it
 

Doesn?t look like the image wants to populate.

Re: Who is running dry shot nitrous? Curious about it
 

Must be a forum issue. The link shows up when you hit the quote button.

https://imgur.com/a/WPn0TVp

Re: Who is running dry shot nitrous? Curious about it
 

Very nice. Was that a stock LT5? Looks like I may be picking your brain on this as well in a while. I picked up a window switch.

https://nitrousoutlet.com/i-30559958...YaAmq_EALw_wcB

I have had good experience so far with their products, I figured I would stick with them for as many parts as possible. I like that the conditions of rpm and TPS signal both need to be met before the switch allows nitrous activation. And talk about a rabbit hole because now I am eyeing this

https://www.innovatemotorsports.com/products/psn1.php

I like that it also includes PSI readout for bottle pressure. And I THINK it is possible to make a discrepancy in AFR trigger a kill to the nitrous activation as well with this. I am going for overkill on safety measures. Comes with a bung to weld onto the headers for the wide band. I guess I will have to figure out the best placement. The OBX headers have the stock O2 on top versus the original manifold location. I think wiring the new window switch in along with the micro switch panel and various bits should keep me busy for a while.

A fool and his money are soon parted.

Re: Who is running dry shot nitrous? Curious about it
 

Yes, it was bone stock at that time. I'll do my best to help, even though it was 20 years ago.

If you clone that dry system from NOS, and use your window switch, I don't think you'll ever have an issue with a 75hp shot.

Messing with wiring
 

This is where I ended up for the wiring so far. I will clean it up later. I liked the window switch?s compact size. Made it perfect for mounting in the tray as well. I terminated the wires into a Delphi connector and plan to leave enough slack in the wiring on the female plug side so the switch can be held from the driver seat for parameter set, or check and then put back.

Wiring
 

So I think I am in the neighborhood as far as the right wires to pull for tach rpm signal and TPS. The diagnostic plug F terminal has a white wire going to it that I can tap into thanks to this old thread dropped in the shift light thread.

http://www.zr1.net/forum/showthread....ighlight=shift

Big thanks to Jerry for the knowledge on that one. And sure enough, it matched up with the info in the 8A book. TPS throttle position input wire is dark blue and according to the diagram is in connector B in the number 3 spot. I remember connector A is yellow and you would think they would go in order. Anyone tapped into this wire before? It is the only dark blue wire in 3 on all the connections. I planned to tap into it a little further from the main bulk connector.

Re: Who is running dry shot nitrous? Curious about it
 

You're out of my element there

No worries, you have been a great help so far. I occupied myself with other things in the meantime. I redid the wiring and relay placement so it is a little neater. Crimped on a Delphi terminal to the tach wire going to the window switch so that it plugs into the factory diagnostic connector. I will need to figure out a 12 volt key on source easiest to tap into for the last wire on the window switch.

Re: Who is running dry shot nitrous? Curious about it
 

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.

Re: Who is running dry shot nitrous? Curious about it
 

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.

Sent from my Pixel 4a (5G) using ZR-1 Net Registry mobile app

Re: Who is running dry shot nitrous? Curious about it
 

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.

Wire size
 

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.

We have power
 

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.

Re: Who is running dry shot nitrous? Curious about it
 

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.

User error!
 

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.

Tapping for rpm signal
 

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.

Re: Who is running dry shot nitrous? Curious about it
 

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.