Wet shot Nitrous with S/C

[dpartinvr4]

hey guys, we got an Audi a4 1.8T in the shop I'm working on, and I'm going to pull the ZEX wetshot kit off of it and have been considering putting it on the taco, I'll be honest, It's mainly for the Purge to show off, but it's just a baby 25 shot, and I figure It will help the rotors seal and keep things cool. I havent' stripped it apart yet so I don't know what kit it is exactly, but there's a Big purple box and a couple solenoids. the bottle is MIA, but when you arm the system and hit the purge, the solenoid clicks at about 3 times a second. there is a WOT wire tapped into a line at the TB, so I imagine It's probably a basic kit. I'm new to the Nitrous world, and have been searching the inter webz and everybody says something different on where to mount the nozzle, from what I can conclude a small shot like that will be best post maf, pre throttle body. for any of you guys that have done this before, what all will I need, i.e. fuel rail adapter or can I just tap the rail with a Schroeder valve?


1. what parts are needed to hook up a wet shot system to the OE fuel system

2. WOT/ or window switch, or a combination of both

3. where should the nozzle be installed

 

[Torspd]

Gifter has a thread with a lengthy discussion with Shadowdeath. Shadowdeath is the one to talk to.

 

[Fiddich]

If it is a wet shot then you could use it as a 7th injector

 

[Whitebeauty]

Wet shot is liquid right. Why would that go before the maf? Wouldnt it ruin it or soak it. I always thought wet shots go in with the fuel.

 

[justin13703]

Wet shot is liquid right. Why would that go before the maf? Wouldnt it ruin it or soak it. I always thought wet shots go in with the fuel.

He said post maf not pre maf

 

[Whitebeauty]

Oops read to fast. ? Then it would b like a 7th just about.

 

[dpartinvr4]

I've PM'd shadowdeath to see if he can chime in, some of the questions have been answered in other places in older threads, but I'll post questions on here as I think of them to try and condense the information all into one thread, I'll see if he doesn't mind adding his thoughts on dry shots and with N/A applications as well.

Wet shot is liquid right. Why would that go before the maf? Wouldnt it ruin it or soak it. I always thought wet shots go in with the fuel.

Direct port goes in with the fuel, Wet shot has metered fuel and Nitrous injected at the same time through a common nozzle.

did some digging, here are some pictures of his setup and a wiring diagram.

I have more pictures somewhere but here are these.

Here is a wiring diagram he made specifically for the XR/customers for anyone who may want to use it:

 

[Bulldogger]

Wet shot nitrous systems add fuel. Dry shot systems just spray the nitrous no fuel. That is the difference between wet and dry systems

 

[donovanbedwell]

purging is just so badass lol my buddy used to purge his 50 shot in his SRT-4. just tell the cops it's C02 :top:

 

[5H4D0WD347H]

1. what parts are needed to hook up a wet shot system to the OE fuel system

2. WOT/ or window switch, or a combination of both

3. where should the nozzle be installed

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1. Just a fuel rail adapter with some kind of splitter of your choice (if you want to run fuel pressure sensors), URD I believe sells these still & some -4 fittings & hoses, (DO NOT USE TEFLON TAPE).

2. Both (sometimes one unit will do both functions), make sure you get good ones & test them prior to use (so you understand thoroughly how they work and set them up correctly) - you don't want some cheap shit faulty electronics here.

3. The nozzle placement varies based on a ton of things. With out getting crazy in depth on this topic (because there are many dif types of nozzles and many dif setup combos to incorporate them with) I will give it to you short and sweet.

With wet nozzles you want to minimize any kind of fuel drop out/puddling ANYWHERE in the intake tubing/manifolds (especially important with today's complex dry manifolds & intake tubing).

Your wet nozzle placement should primarily be where the nitrous and fuel mixture has the least obstacles to go through while preserving good distribution to each intake runner.

You essentially want the path between the intake ports & the injection nozzle point to be as unrestricted by gravity and obstacles (bends and other shapes/valleys) as possible while maintaining good even distribution to all of the intake runners.

To make an example out of my setup this is why the nozzle is just before the bend going into the TRD compressor housing. This nozzle placement cuts out two obstacles - the uphill travel of the intake tract and the first 90 degree turn in the blower assembly (had the nozzle been installed before the throttle body that is). By placing it in the last run before the compressor inlet (with some distance before the last bend and the nozzle) this allows the mixture to atomize as much as it can before entering the blower with out being restricted. The blower then sucks up a well atomized fuel/nitrous mixture into the housing to be further atomized & distributed on the other end.

When the nitrous/fuel exits the blower outlet it is very well distributed to each intake runner by the time it gets there.

This logic is more important with larger shots but should be adhered to no matter the size. There comes a time with single point wet injection systems that you need to move to a direct port setup (due to cylinder distribution and fuel drop out potential).

150-200 HP is probably as much as you want to run on a single point wet setup to insure good distribution with out too much nitrous going to one cylinder and excess fuel drop out.


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I will end by saying I am not a fan at all of Dry shots, they usually create extreme lean spikes that can trip off detonation that wouldn't have happened if it were a wet shot.

A wet shot also creates a quick (blink and its gone on a modern vehicle) lean spike but its not nearly as severe and a lot of it can be tuned out much more easily.

I am also not a fan of used Solenoids unless you damn well know the person you are buying them from took care of them and trust that nothing stupid was done with them. A set of new solenoids is to cheap IMO to even mess around with the possibility of one not sealing correctly or closing. At the very least id rebuild them.

 

[dpartinvr4]

Pre TB was suggested because it acts as a last line of defense in the event something catastrophic happens, What are your thoughts on that.

 

[5H4D0WD347H]

Pre TB was suggested because it acts as a last line of defense in the event something catastrophic happens, What are your thoughts on that.

I choose better nozzle position & nitrous/fuel atomization/distribution (less fuel drop out) over the small chance the TB would actually do anything to stop the motor from receiving nitrous you didnt want it to (a lot of throttle blades aren't completely closed at "0" throttle) - a hit of nitrous at idle/closed throttle is a no-no anyway. If a solenoid stuck open your better off being WOT and shutting the bottle off, at least this way you are adding fuel as well and in the proper rev range to use it.

If you want to safe guard against a nitrous solenoid sticking open run two nitrous solenoids plumbed together in series - this way if one fails to close the other one does.

If you want to safe gaurd against small leaks passed the nitrous solenoid into the intake while the vehicle is parked dont leave the system pressurized when you dont plan on using it. Just close the bottle and use your purge solenoid to empty the lines when not in use.

Its also good to wire up the fuel solenoid to a button of its own so you can test it prior to doing a run if you wish. Say you are on the highway and want to do a large run - you can energize JUST the fuel solenoid quickly and hear the click and see the AFR gauge plunge rich; this is a good confirmation to have.

 

[dpartinvr4]

ok, and i've seen the argument of fuel pooling on the intercooler fins being an issue, with a 25 shot, I don't really foresee that being an issue, but at which size would that be something to start thinking about.

 

[5H4D0WD347H]

ok, and i've seen the argument of fuel pooling on the intercooler fins being an issue, with a 25 shot, I don't really foresee that being an issue, but at which size would that be something to start thinking about.

By that time the mixture has been so well atomized & heated through the compressor it really shouldn't be a huge issue with reasonable sized shots. The nitrous/fuel mixture will increase the blower efficiency through multiple ways and you will actually see a small boost gain & more power per pound of boost because of the efficiency increase.

Ive run larger shots (6x what you will be running) through blowers similar to the TRD unit successfully before the intercooler. If you could fit a single nozzle after the intercooler and get better distribution on the outlet side of the intercooler then that would be the only better way to go other then direct port (as it would probably cool the charge air even more).

It is howeever doubtful that you would be able to achieve that aft intercooler single nozzle placement since you are so close to the runners at that point, you would need some kind of well made spray bar at which point it would probably be more economical & just as easy to go direct port.

 

[dpartinvr4]

slowly getting everything installed

its just chilling there for now, I'm working on a hard mount.

and a sticker I made when I got bored

 

[5H4D0WD347H]

Haha like the decal, looks good man. Glad to see that you are taking your time.

 

[Gadget]

 

[05xrunnerx]

slowly getting everything installed

its just chilling there for now, I'm working on a hard mount.

and a sticker I made when I got bored

its cleaner under the hood than the back seat :top:

 

[dpartinvr4]

better?

 

[dpartinvr4]

got everything hooked up, got this video and now it won't cloud out, pulled the bottle "freshly filled" and cracked it open.... nothing but warm air, not even a bad smell, i think they did something wrong and it's a 25lb bottle, so 10 lbs of nitrous, I would think it would last a little longer than one hit with -3AN lines. [ame]http://www.youtube.com/watch?v=KV3Q_UbJtrE[/ame]