SN Superjet fix and improve build

[lcgordon]

What you're finding out is that Tuning the Jet Pump is an ART, not an exact Science. The Perfect Impeller is usually found by Trial & Error or Field Testing.

At 5000 ft elevation, your Engine is losing about 15% of its Sea Level Horsepower.

With that Pipe, at Sea Level, you could expect 90 HP. Discount 15% and the Power is around 75 HP, very close close to a Stock Super Jet.

The Stock 701 Super Jets come with a 13/17 Pitch Impeller. That's what all 701 SJ's came with out of the Factory for ALL Elevations.

A Stock Pitch Stainless Impeller will do. Don't exceed 17 degrees Pitch. It will be plenty.

I would favor a Stainless 2008+ OEM Impeller, a Skat Trak 9/17 Impeller or the Solas equivalent.

But you should also be monitoring the RPMS with your current package. Install a Tachometer and report back with your Max RPM readings.

Plenty of Guys (Mtrhead and Kevbo) here that can help you find the best Impeller for your Setup using the actual RPM readings for reference.

Thanks for the information, I'm not looking for the "Perfect Impeller" just one that's decent and does not rob a crap ton on top.

I am a little bit confused on the different types of impellers. From what i read you cant compare pitches of different brands to other brands.

Is the top end pitch the same between props? Like an old 17 deg should run the same on the top as a new 17deg? Is it on the low end that the new fancy impellers are different? Right now my 17 runs plenty fine on top. Im not asking for anymore. I would also like to not loose a ton either.

I will get a tach and report back. It may be a bit. I'm debating on being done for the year and start my whole process or riding a couple more times. It is getting less enjoyable out there in the colder water although its not that bad really.

Thanks for the info you have already given me 50 times more information than the impros guy and you are not even trying to sell me something.

 

[lcgordon]

Couple of questions i have been reading other peoples builds but not quite sure.

I have an almost full quart of epoxy resin form UScomposites. Do you think another gallon would be enough to reglass the tray and build a tray bottom?

I see people cutting in various places from the rear of the ski in the tray. I know you dont want to cut so far back that you are behind the bond line but i would like to rebuild the most of my tray i can so what is kind of the max min distance from the rear i can cut?

I still have a decent amount of 1708 mat. I would think this is what i should build the bottom of the tray out of. Can i use if for everything though? Should i get something lighter for other things like mating the cuts back in areas. How many layers for the bottom of the tray? I think i saw somewhere somebody said they did 4 layers of 1708 but i cant find that.

I see a lot of people using the pink foam which i plan on using. A lot of people then pour a lot of 2 part foam into the cracks and stuff. Is this necessary? I would like to not do this.

I am eager to start the process, it is getting colder and colder here and I'm not super interested in getting back in the water.

Oh and last thing do i need to lower the exhaust tube? wondering if i should cut the foothold or lower the tube. I tried searching for somebody lowering the tube and how to do it but did not see much. I would guess you just cut a new hole in the firewall and patch the old one. But maybe thats not how its done.

Thanks

 

[smoofers]

I lowered my tube in my thread. The link is in my signature. Also, I'm running a 701 62t/61x with 185 psi, MSD enhancer, b-pipe and light weight flywheel. The Hooker 9/15 rips with my setup. Haven't tried the 10/16, but I worry it might be too steep.

 

[lcgordon]

I lowered my tube in my thread. The link is in my signature. Also, I'm running a 701 62t/61x with 185 psi, MSD enhancer, b-pipe and light weight flywheel. The Hooker 9/15 rips with my setup. Haven't tried the 10/16, but I worry it might be too steep.

Edit: Yours is the one i saw make the tray, love it! I am going to try to do the same thing but no mold. I will try the same 3 layers. Super excited to start this build.

Thanks I will look. I have been through your build it was good. I probably just missed the exhaust. Do you think it was needed?

My ski has a 17 now and it spins it just fine. I just don’t wanna loose a bunch on top. I really like going racing around the lake. For like 45 bucks you can do custom. Wonder if 9.5/15.5 would be the ticket. I need to get on the phone with them at some point and talk to them.

 

[smoofers]

Edit: Yours is the one i saw make the tray, love it! I am going to try to do the same thing but no mold. I will try the same 3 layers. Super excited to start this build.

Thanks I will look. I have been through your build it was good. I probably just missed the exhaust. Do you think it was needed?

My ski has a 17 now and it spins it just fine. I just don’t wanna loose a bunch on top. I really like going racing around the lake. For like 45 bucks you can do custom. Wonder if 9.5/15.5 would be the ticket. I need to get on the phone with them at some point and talk to them.

You don't have to lower the exhaust. Most modern foot holds will have a spot where the right hold ramps up to clear the tube. I didn't want that on my tray so I lowered the tube. It's really just personal preference.

 

[lcgordon]

You don't have to lower the exhaust. Most modern foot holds will have a spot where the right hold ramps up to clear the tube. I didn't want that on my tray so I lowered the tube. It's really just personal preference.

My foot holds I got I don’t think have the spot. I’ll have to check. They are more universal ones. The lowering looks easier than cutting the hold and rebuilding the front to have a bump so probably just lower it. Really just seems to be removing the tube, patching the hole, cutting the hole lower and seal. I have to seal it anyways, so much water leaks on the garage floor from the bottom of the exhaust outlet.

 

[lcgordon]

Anything in a new style will be better than that old school 4-7v imo.
Assuming you don’t have any boring done to your nozzles I would just go with the 10/16 and if it’s a little steep you can always tweak your setup to help the ski spin it up a little faster.
I would say with the package you’re running you’d be safe with a 10-16.
Unfortunately pump tuning is very tedious and expensive to figure out so you’ll be spending the money for someone who knows their stuff to size it for you or you’ll be spending the money to experiment. Most guys don’t really like giving away their hard earned knowledge unless they’re certain you’ll be doing business with them. It stops people from getting their advice and then buying their prop somewhere else cheaper.
I don’t have much experience dealing with Glen but Brian from torrent is awesome and if you decided to go that route he’s great for sizing props and doing business with.

I just ended up buying a 08+ oem prop. Seems like people like them. It was quite a bit cheaper than the hooker. Maybe it was a bad idea but i think it should work out okay.

 

[lcgordon]

Well im gonna go for the cut tomorrow. Cutting on the front line of all the tape. Would anybody change anything?

 

[smoofers]

Looks good. Don't be afraid. After you make that first cut the fear goes away. If you screw it up, it's nothing that can't be fixed with epoxy and fiberglass.

 

[lcgordon]

Thanks smoofers. I followed your cuts a bit. I am a little farther than the last pic shows. I took out the right side foam but still have the left to do. I did about 3 hours of foam removal today. My foam was soaked. All of it was wet besides the sides. I have about 1/4 inch of water in the bottom when the foam was removed.

 

[smoofers]

Looking good!!!! You already defoamed!!!! That's a huge chunk of work already behind you!

 

[lcgordon]

Looking good!!!! You already defoamed!!!! That's a huge chunk of work already behind you!

Yeah I’m not quite there. I need to do the left side part. Prob 30 min left. How clean do ppl get these things. It’s hard to get every last bit of foam. I think just making sure I get it really clean around where I need to seal.

 

[smoofers]

Yeah I’m not quite there. I need to do the left side part. Prob 30 min left. How clean do ppl get these things. It’s hard to get every last bit of foam. I think just making sure I get it really clean around where I need to seal.

that's pretty much the ticket. You can't get every last little bit. Do the best you can and make sure the areas you're going to epoxy or seal to are clean and bare glass. Keep up the good work. Looking forward to seeing your progress.

 

[lcgordon]

that's pretty much the ticket. You can't get every last little bit. Do the best you can and make sure the areas you're going to epoxy or seal to are clean and bare glass. Keep up the good work. Looking forward to seeing your progress.

Thanks. I will have the rest done soon. My goal is to get the ski done by March for some cold wetsuit riding and testing.

 

[lcgordon]

Got all the foam out. Pretty excited. I think it was about 4 hours work of work just for the defoam. I think the crow bar thing worked the best with a little bit of chisel and flat head work in the real right areas. I just need to use maybe some steel wool or sand paper to clean up around all the pipe mating areas so that I can caulk. Just bought a big tube of 5200.

Besides all the tubes , insert areas and exhaust what do ppl seal? Do you seal up all the bond line? Any areas around the pump?

 

[smoofers]

Got all the foam out. Pretty excited. I think it was about 4 hours work of work just for the defoam. I think the crow bar thing worked the best with a little bit of chisel and flat head work in the real right areas. I just need to use maybe some steel wool or sand paper to clean up around all the pipe mating areas so that I can caulk. Just bought a big tube of 5200.

Besides all the tubes , insert areas and exhaust what do ppl seal? Do you seal up all the bond line? Any areas around the pump?

The bond line definitely needs to be sealed.

 

[lcgordon]

The bond line definitely needs to be sealed.

Cool thanks so pretty much everything that has green glue stuff should be sealed up.

I am also planning on using the pink foam and drains in the back so when it leaks I have a plan.

 

[lcgordon]

Is there anything I can do about the peeling gel? Can I tape off and regel somehow. I’m not that interested in doing a bunch of work. I don’t wanna peel the graphics off and paint. I’ll leave it if it means that.

 

[tomski]

It's not gelcoat.

 

[lcgordon]

It's not gelcoat.

What is it then? Just paint? I was looking at some other posts and people said oem is gel. I have no clue. I have some small bad areas that will prob just get rattle can white. I may see how that hold ups there and do the same in the bigger areas.