Super Jet Basic SN build !Completed! *Tuning time*

Quinc

Quinc

Buy a Superjet
Location
California
CPT 771 with all the fixings going in the SJ! =) Thank you to @chucktor for getting me the plugs for a proper leak down test!
JE1mXO3.jpg
 
Quinc

Quinc

Buy a Superjet
Location
California
After neglecting her all summer. I finally gave her some updates:

Old Coffman dry pipe. I added a sprayer with 120 low jet after the coupler. (already a spot there so trying it first.)
62T cases
61x 83mm @Nuklear6 CPT ported cylinder
@#ZERO Flywheel
MSD enhancer
dual freshly rebuilt 38's (no choke, 1 screen)
75P
140H
34psi pop off (really not sure where to start here, have read from keeping it at the stock 55psi to as low as 24psi)

New midshaft, pump, bearings, etc
Trying a solas 14-18 impeller until I get my Solas 13/15(similar to hooker 9/15) back from impros.


pipe.JPG
 
Harbor

Harbor

Location
Stockton
Quinc said:
After neglecting her all summer. I finally gave her some updates:

Old Coffman dry pipe. I added a sprayer with 120 low jet after the coupler. (already a spot there so trying it first.)
62T cases
61x 83mm @Nuklear6 CPT ported cylinder
@#ZERO Flywheel
MSD enhancer
dual freshly rebuilt 38's (no choke, 1 screen)
75P
140H
34psi pop off (really not sure where to start here, have read from keeping it at the stock 55psi to as low as 24psi)

New midshaft, pump, bearings, etc
Trying a solas 14-18 impeller until I get my Solas 13/15(similar to hooker 9/15) back from impros.

THat pipe looks pretty cool !

View attachment 360864
Click to expand...
 
Req

Req

Location
SW Tenn
I love this square and plan to steal a few ideas for my winter project. I have a spare square I am widening, reinforcing and shortening. Riding is glass lakes and rough rivers, some boat chasing, basic tricks, and cruising.

How did shortening the rear affect the high speed stability? Does it still plane and carve ok? How much would you take off for a 200lb rider with a -9 pole setup?

I ride flat however have been known to be sort of stupid from time to time, how much 1708 would you throw in the engine bay and under the tray?

I have a gp760 short midshaft, would it be worth making a plate and moving the engine back an inch?

Would cutting a 3" deep foothold into the firewall above the midshaft be worth the time? It would give me more tray room in the dash area and double as a toe hold letting me shift more weight forward.

Some blaster guys set the entire pump back with an added wear ring and reglass the mounts. Would setting the pump back 2" or so have any tangible befit for a shortened superjet? Not a mag pump set back, just moving the entire assembly back 2".

Thanks for the tips man.
 
Quinc

Quinc

Buy a Superjet
Location
California
Req said:
I love this square and plan to steal a few ideas for my winter project. I have a spare square I am widening, reinforcing and shortening. Riding is glass lakes and rough rivers, some boat chasing, basic tricks, and cruising.

How did shortening the rear affect the high speed stability? Does it still plane and carve ok? How much would you take off for a 200lb rider with a -9 pole setup?

I ride flat however have been known to be sort of stupid from time to time, how much 1708 would you throw in the engine bay and under the tray?

I have a gp760 short midshaft, would it be worth making a plate and moving the engine back an inch?

Would cutting a 3" deep foothold into the firewall above the midshaft be worth the time? It would give me more tray room in the dash area and double as a toe hold letting me shift more weight forward.

Some blaster guys set the entire pump back with an added wear ring and reglass the mounts. Would setting the pump back 2" or so have any tangible befit for a shortened superjet? Not a mag pump set back, just moving the entire assembly back 2".

Thanks for the tips man.
Click to expand...

This is hands down the most fun ski I have ridden and I am at 220lbs. I put the foot holds above the pump and down an inch or so below the rest of the tray.

I am running -2.5" on the rear with a flush cut stock ride plate. It took a couple rides to get used to, but I have no problem going full speed and have gps'd her at 51mph.

1 layer of 17oz and 1 layer 12 is more then enough. Make sure and overlap the sides with the bottom etc.

I cant say on moving the engine back 1" also I do not have any first hand experience on those pump mods.

I use the fire extinguisher as a front foot hold when I ride in the surf. With the -9" pole I think you will be fine getting your weight forward enough.

*Pro-tip. Do not go overboard on the mods. While they seem great on paper; tackling the SN with a big project takes a lot and most people burn out before ever finishing. Or do it in sections. Maybe save the front foot hold and pump mods until the next winter.
 
Quinc

Quinc

Buy a Superjet
Location
California
Well, bottom end was not great, but mid-top was fantastic. I am running a 130 jet on the sprayer, so going to try a 85 or 90 next to see if that is the issue. (thanks for the tip @chucktor ) Then I will hopefully have my impeller back from impros and I am sure that will help as well.

She also vibrates like a mutha-fer until I get above half throttle. I ended up shoving some pool noodles between her and the hull. Going to re-check the engine and pump alignment. Or are these pipes known for vibrating? @Big Kahuna @waxhead



View attachment 360864
 
Big Kahuna

Big Kahuna

Administrator
Location
Tuscaloosa, AL
Electronic waterinjection may help with the bottom end. This was needed with the type 4 pipes. Speedworx was the only Dry Pipe that made good bottom as well. I noticed you said you added a sprayer, assuming just dumping water in, but no way to cut it off?
 
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