Nyper build thread

[Sportsterdanne]

Long time !
Just found your new build and its really nice !
I dont recomend steep running boards, i had quite step angle on my build and its not nice when standing up and riding.

 

[Nikolai]

Thanks. Good to know on the running boards, I’ll make them flatter and bend them up at the rear suspension mount.

 

[kinger]

My custom tunnel I had in my head but never built for my Apex modeled at viper 2 piece tunnel and I was going to make it thick side plates just to get back to front and rear suspension mounts with lots of water jet out cut outs that simulated gussets. Then the rear tunnel I was going to use the Carbon fiber rear tunnel from Patricks carbon. I was also going to skin the inside of the front part with CF plate. Basically a beefy 1/4" plate with lots of holes in it strategically placed to bear the loading, and everything else CF, even bonded together with CF adhesive that is stronger then rivets. sounded good in my head anyway LOL.

 

[Nikolai]

It would be nice if you could incorporate the chaincase and bearing mounts into the same alu plate so everything stayed aligned.

Here’s what a friends Pro chassis weighed. It had coolers but no running boards. Figure a couple pounds for boards and we’ll say 58 lbs total.

And my Nytro when I disassembled it. The rear cooler was 4.85 and the front cooler was 3.35 plus hoses and bottle, so probably 10 lbs total for the cooling system and the seat was 2 lbs. So my chassis without the cooling and seat would be 60 lbs.

I’d like to be about 20 lbs less than my Nytro was. Nytro has inner chaincase built in so Nyper would have to be weighed with the inner chaincase half on to be equal. This is going to be tough to do. I want the Nyper to be bulletproof so I’m using a little thicker tubing throughout.

I lowered the 1” alu tube to where I jigged the boards, and dropped the string line in the back a little so it better matched the header mount angle.

I calculated 15 sq ft for the tunnel if I were to do a complete aluminum tunnel with only chromoly boards.

.050 would be 10.5 lbs
.063 would be 13.2 lbs
.080 would be 16.8 lbs
.0625 UHMW is only .333 lbs/sq ft but offers zero additional strength. It would be good for nothing other than blocking snow.

Going back and forth, these are the pro’s I can see for using an aluminum tunnel.
- can bolt the header directly to it
- can bolt the gas tank directly to it
- can rivet the rear cooler to it and alu helps dissipate heat
- much less tubing and welding required
- adds strength to the overall structure
- cheaper than carbon and will last longer

Cons
- not very high tech
- weight
- needs to be coated to keep snow from sticking. Vinyl wrap is probably the lightest

I’m going to use 1” x .049 for the lower tubes (from tube below motor to rear bumper). Steering hoop will be 1” x .058, chaincase hoops 1” x .058 and the front spars probably 1” x .035. I think the tubing would be strong enough that I could get away with a .050 tunnel.

 

[kinger]

I have thought about and open tunnel. Think snow bike, why do you need a tunnel? Cantilever a seat out from main chassis. Put some foot pegs out where you mainly put your feet and let the rest stay open.

 

[Nikolai]

I would really like to do that, it’s just hard to envision the tube layout necessary to accomplish it. I started working on the front end again and I’m going to focus on building the front section while I keep brainstorming the back. I wish there was a way around having to run a big u-cooler but I can’t think of anything else that would be smaller in size, be of similar weight and cool the motor as well. Plus it’s more weight in the back.

My old single pass u-cooler had 86” of extrusion. I have just enough width to fit a double pass. If I shorten the tunnel 6” similar to the 2020 Skid Doo Mountain sleds, it leaves with me a 15.5” x 26” area for the u-cooler before I run into the compressor. Doing a double pass cooler, it’d be about 116” of extrusion, roughly 35% more than I have now which is good because I won’t be running a front cooler anymore.

I did have an idea to make two u-coolers half the size (15” x 13”) and put one on top of the other with a bout an inch gap in between. I have no idea how well it would cool though since only the bottom one would see snow. The top would mostly be air cooled. But if it did work, that’s another foot off the back of the sled that doesn’t need structure.

 

[Nikolai]

So here’s what I’m thinking on the cooler. Top and bottom coolers would be identical in size and layout. Inlet & outlets from/to the motor would both be on the Mag side making the plumbing to the motor easy. On the Pto side would be a fitting and hose connecting the two. Right now it’d be 104” of extrusion. I don’t know if that would be enough, increasing the length to 14” from 13” would make it 112”.

I don’t know if it would help, but I thought I could partially box in the coolers with some .030 aluminum sheet to try and trap snow kicked up by the track.

It would still have to go behind the turbo, but it would make the tube work considerably shorter and more like a snowbike.

Thoughts? Would it cool as efficiently as one single double bypass cooler? (Provided same length of extrusion used). Stupid? Worth trying? Any better ideas?

 

[kinger]

That doesn't seem like a bad idea at all. I think it would actually be sweet in my trail sled were I need more cooling and the only real estate is that back 15" of my BTX tunnel. A guy could add some duct work to get air in between the two units at speed. Might be cool!

That said how thick is the heat exchangers you using? Could you run them vertical as the sides of your tunnel with the fins pointing in and break them up where you need to mount the suspension and through bolt through the heat exchanger, maybe reinforce that spot but use bare minimum tube to connect the heat exchanger and carry say 50% of the load so you don't end up with cracked heat exchangers from flexing. You could do 4 runs, 2 on sides and 2 under seat with no tunnel skin, the cooler would be the skin and its heated so it would never have snow stick.

So your 'tunnel' would be exposed tube frame, foot pegs for boots, sides and top are back side of heat exchangers maybe even a gap in between the runs in the middle, the heat exhangers would be fastened to the tube. Literally just leave the rest open! Next hang a seat from the main structural support up front so you don't need a lot of structure support for the rear of the seat. I have even thought of using a tiny fox float and making a cantilevered 'air sprung' seat. Just for a little more give on those hard landings for my back. In trails this sounds horrible for spraying snow all over my back and soaking me, but your playing in the mountains your covered in snow anyway.

What do you think? I love it when you can combine functions and eliminate one of them (ie skin and heat exchanger, now getting rid of skin)

 

[Nikolai]

I’ll be too narrow to run them next to where the track goes. The extrusion is less than 1/2” tall but my chassis is only about 15-9/16 between the tubes. It would work on a factory width Nytro or Apex which are 16-3/4 I think.

I’m going to try it. If I make them 14” long it puts the back of the cooler 49” from the jackshaft, and about 18” shorter than a 153 Viper tunnel. My thought is to support the turbo and cooler with welded tubing(for strength), and then weld 4 tabs and have a rear bumper that bolts on(3/4 x .035 tube bolted with 4 bolts) so if it bends then I can replace just the bumper. This way I can use lighter tubing for the bumper and not have to worry as much since it will be replaceable.

 

[Nikolai]

Rough idea but the blue tape marks the back of a 14” cooler, the permanent marker line would be the front. Ignore the aluminum tube, I was just playing around with different running board ideas.

 

[kinger]

That looks cool! Make 1 for me too! Keep the tunnel cut out right inline with the gap between the stack so you could get air or shove snow in there if need be. I am digging this idea. What will the total height be? 2" Shouldn't interfere with the track I wouldn't think.

 

[SaskAttack]

I wonder if two coolers stacked would form a melted ice bridge and block off the upper cooler for the most part. Kind of like in certain conditions snow freezes into ice just a few millimeters from exchangers and sled heats up, takes specific conditions but does happen.

 

[Nikolai]

I don’t know but that’s a valid concern. I could raise the coolers a few inches out of the tunnel and then angle the fronts down 15-25 degrees, maybe it would help water run off and keep from forming into ice?


To change topics for a minute I’m going to recap on the upper a-arm. I’m making the center to center on the mounting points 5.5” to give me more of a pyramid with the tube and simplify the chassis. Did a rough check at the dealer awhile back to make sure it would clear the shock(I’m using regular air shocks w/o ressis).

Bought a straight shock mount off eBay for $26 so I could pull measurements to build a jig. The jig will be for building the upper L & R tubes which will each have 6 tabs for the shock and a-arm.

Also got the lower rear a-arm tabs made and tacked in place.

 

[kinger]

The suspension geometry is over my head, I think as long as your pattering after the OEM chassis that is a good thing. Sweet build, I wish I could but a new chassis for my beat down apex and swap everything over to it, I just don't have the time to build one from scratch. Do you have another sled you actually ride? Seems like its been a few years of building but no posts on riding

 

[Nikolai]

Geometry is unchanged.

I haven’t ridden in a long time. I just work on it in the evenings after our daughter goes to bed (2 yrs old) and #2(boy) is due May 31. I’m hoping to wrap up the tube work by June so I have the summer to figure out body panels and find a track.

I’m obviously not very good at keeping timelines though.