WetJet Pipe Mod and Jetting

I've got a pipe from a WetJet 300zx that I intend to flip the outlet on and run on my SN SJ. There is a water spray at the end of the stinger. Is it necessary to move the barbed inlet to the other side when flipping the outlet, or is there clearance next to the hull to run the water line on that side?

I've found that the stock jetting on the WetJet (61x w/ single SBN44 and standard 61x intake manifold) is 120 low, 130 main, 1.5 N&S w/ 115g spring.

Besides the pipe, the only other modification to my motor is an ADA head (35cc domes). I'd be comfortable running the stock WetJet tuning, but I pulled the pipe off of a grenaded motor so it doesn't inspire much confidence. On top of that, OEM jetting for a single carb Superjet 61x has a 135main. Why would Mastercraft drop the main to 130 on the WetJets when adding the pipe?

To be clear, this is NOT a Kraze pipe or Kraze carb/mani. I essentially have an stock WetJet setup.

Any advice on the pipe mod and carb tuning is much appreciated. Will post plenty of pics as things come along.
 
I was running a wetjet pipe on my SN, didn`t have it on there long enough to figure out jetting. It was too heavy for how much I beat on it, between that and the previous owner trimming the mount I ended up cracking the mount. I made a new mount out of steel but it never fit well and I ended up picking up a coffman sizzler within a couple weeks of breaking the mount. Anyway here`s some pics. The nipple on the stinger did not have to be moved but it did rub my hull at some point. I also had to grind the back side of the casting to clear the rear hood seal lip and move the e-box over.
 

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RMBC Freeride

Vintage
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Location
Pueblo, CO
I picked up a couple of these pipes really cheap to try on a SN for my kids and one to sell. One had been modded already and the other was stock.

I test fitted them on a SN and IMO the stinger hose barb needs to be moved to prevent rubbing. The one that had been modified also rubbed in a couple other areas. So when I cut the stock one, it took a couple tries to get it all to line up with no interference.

As for jetting, I have not run these yet, you might want to try Factory Pipes 701 SN B-pipe jetting as a starting point. It seems to work well for most cast pipes with a stock 44. I do remember reading that the Kraze 46 jetting has a very big main jet. Not sure if a 44 would need a bigger jet as well so be careful first time out...
 
Thanks for the responses guys. I just finished welding up the stinger last night. I ended up adding another bung for the lower water injection and putting a plug in the original. I also took down the entire ridge on the top of the jacketed casting for clearance and aesthetics. It is out for powder coat right now (wrinkle black) and blue ano for the mounting bracket. I will get some pics up once it is all put together.

I plan to start with a 120 low, 130 main, ~35psi popoff and go from there. As far as I can tell, that is the stock wetjet tuning with the exception of the popoff. Will report back with results. I imagine I'll end up at a 135 or 140 main but we'll see.
 

Roseand

Ready to RIP
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Location
Wisconsin
Thanks for the responses guys. I just finished welding up the stinger last night. I ended up adding another bung for the lower water injection and putting a plug in the original. I also took down the entire ridge on the top of the jacketed casting for clearance and aesthetics. It is out for powder coat right now (wrinkle black) and blue ano for the mounting bracket. I will get some pics up once it is all put together.

I plan to start with a 120 low, 130 main, ~35psi popoff and go from there. As far as I can tell, that is the stock wetjet tuning with the exception of the popoff. Will report back with results. I imagine I'll end up at a 135 or 140 main but we'll see.
That's a very very small main, I would go up just to be careful. Otherwise take it easy...

Sent from my SM-G920V using Tapatalk
 
I was thinking the same thing, especially considering oem superjet is a 135 main. But WetJet Parts sent me this spec sheet, and I'm essentially running a stock WetJet setup save for the head. Page two has stock tuning.
 

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RMBC Freeride

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Keep in mind that the hull type and pump type will affect jetting. A heavy sitdown hull loads differently than a SJ hull, generally a heavier load on acceleration, but a lighter load at full speed due to the lifting of a v-hull with strakes. A superjet, while lighter, is essentially flat and keeps a pretty high load on the engine at high speed. Higher load at WOT generally requires a bigger main to prevent detonation. Also the pump they use in a Wetjet is VERY different from a SJ pump.

So many variables... Impeller pitch, different waterbox design, etc... you can't just assume that what works on a wetjet will work on a SJ.

Bottom line: start with the bigger main jet and be safe! You can always work down. Number one rule of tuning is start rich.
 
All installed! I am starting with Factory Pipe jetting and going from there.

Will report back with changes once it's dialed in.
 

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I bead blasted the bracket and anodized it blue. The back rib of the pipe had to come down in order to clear the hull. OCD got the best of me and I smoothed out a few other parts. Black wrinkle powdercoat on the pipe.

In case anybody is looking to use one of these pipes in the future...

The E-box had to be moved over about two inches. I just put silicone and some stainless fasteners in the existing holes in case I ditch the pipe some time. WetJetParts.com has the copper crush gaskets needed for the V-band joints (I used a very thin layer of ultra copper as well. Mastercraft does this from the factory, I figured it couldn't hurt). Gates part number 21115 radiator hose fits the 2.5" outlet of the pipe and is just barely long enough to reach the waterbox - some trimming necessary after the 90. This is too big for the waterbox elbow but it seems to seal fine with the hose clamp. It also rubs on the tank some. I just used some turf between. I'm running an ADA head and MSD plug boots. The OEM water line routing sort of pushes on the plug boots to begin with. It seems like my head/plug/plug boot combination sits higher though. This landed the boot right in the way of the first stinger water inlet. The bracket is designed so that you can't use anything but a straight fitting. I just used a coupler then screwed a shaved 90 degree barb fitting on after the pipe was installed, as I didn't like the way the water line would be pushing on the plug boot continuously. With an A/M head, the two water outlets rob water from the pipe. I like the idea of drying the pipe out a bit, but I'm not sure how it will affect performance and heat, so I'm running an adjustable water restrictor on my second outlet in order to adjust pressure to the pipe if need be. There's a million other ways to do this.

Hoping to ride this week. Will report back.
 
Pulls smooth from top to bottom. Tons of midrange and topend, relative to stock atleast. The bottom end leaves a bit to be desired. I think I will tinker with it once the weather warms up, but for now, anybody considering running one of these pipes should start with FP settings as it seems to be happy with those, if not on the richer side.
 
Pilot 120
Main 145
1.5 N/S 115g spring (I was around 53 psi popoff)
Low Screw 2-1/2
High Screw 1-1/2
Stock wetjet F/A (similar in flow to SJ stock F/A)

For now I'm happy with this. Pretty sure its rich and safe all around. Will try to pull more power out of it when the weather warms up.
 
Pilot 120
Main 145
1.5 N/S 115g spring (I was around 53 psi popoff)
Low Screw 2-1/2
High Screw 1-1/2
Stock wetjet F/A (similar in flow to SJ stock F/A)

For now I'm happy with this. Pretty sure its rich and safe all around. Will try to pull more power out of it when the weather warms up.



How did the 145 main work out for you?
 
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