Nyper build thread

[Nikolai]

Took 3/16” off each side of the front arm. I took off more than I had originally planned so I could use a bushing with a flange to keep the arm from possibly rubbing the frame tube.

Had some steel bushings laying around I made work for now. Eventually I’ll make aluminum ones for final assembly.

And for the first time since starting this project I bolted the rear suspension in. There was a period in the last couple years I thought I’d never see the day. Feels good.

I want to shorten the tunnel about 5” more and taper in the sides. Mostly for looks as I don’t like how it’s squared off and I want to end it right after the cooler. First I’m going to install the track, drivetrain, front suspension, steering and get it sitting on the ground so I can get a better idea of what it looks like and see if I want to change anything before sandblasting it.

 

[Nikolai]

Now that I have a chance to see it with the suspension in I wish I would have tapered the lower 1” tube up more and just did a straight tube basically following the orange string line.

The tunnel weight from the bulkhead (vertical 3/4” tube) back is 14.73 lbs. Here’s the breakdown if anyone is curious.

3.54 lbs - 72” of 1 x .058 round
3.45 lbs - 122” of 1x1/2 x .035 rectangle
3.81 lbs - 169” of 3/4 x .035 round
1.17 lbs - 81” of 1/2x1/2 x .035 square
2.03 lbs - running boards
.47 lbs - front suspension mounts
.25 lbs - rear suspension mounts

If I did a straight tunnel with 1 x .035 for the lower tube(instead of .058) and used 3/4 x .035 for all the remaining tube and did more of the traditional truss style frame I figured I could do it for about 13.5 lbs, didn’t save as much as I thought it would. Only way to really drop weight would be a carbon fiber tunnel with some tube to pick up the suspension mounts.

 

[Brotherdan]

Now that I have a chance to see it with the suspension in I wish I would have tapered the lower 1” tube up more and just did a straight tube basically following the orange string line.
View attachment 177878

The tunnel weight from the bulkhead (vertical 3/4” tube) back is 14.73 lbs. Here’s the breakdown if anyone is curious.

3.54 lbs - 72” of 1 x .058 round
3.45 lbs - 122” of 1x1/2 x .035 rectangle
3.81 lbs - 169” of 3/4 x .035 round
1.17 lbs - 81” of 1/2x1/2 x .035 square
2.03 lbs - running boards
.47 lbs - front suspension mounts
.25 lbs - rear suspension mounts

If I did a straight tunnel with 1 x .035 for the lower tube(instead of .058) and used 3/4 x .035 for all the remaining tube and did more of the traditional truss style frame I figured I could do it for about 13.5 lbs, didn’t save as much as I thought it would. Only way to really drop weight would be a carbon fiber tunnel with some tube to pick up the suspension mounts.

Im so happy to see you working on this build again,I don’t see many custom builds that are documented,the rear frame looks good to me but im not an engineer.Im sure you have to be careful to not lighten it so much that you sacrifice strength,thanks for keeping us updated on your progress

 

[zx4ever]

Ya you might as well cut some off the tunnel as that’s what the trend is nowadays. And a few less pounds won’t hurt your goal. My turbo viper I bought with a shorter tunnel and it seems fine just have to watch wheeling as it can come over backwards. The first time it happened to me was a bit shocking as I was use to the bumper acting as a wheely bar

 

[Dan Lance]

Angle looks fine to me. Adblock plus takes care of the popups. Keep up the good work

 

[kinger]

I would question why you have any tunnel beyond the rear suspension mount. Make it a disposal part made from carbon sheet or even cheaper like poly just to keep snow off your back. A thin piece of bent aluminum with no structure would be strong enough. I was going to use the Patrick's custom carbon tunnel extension that weighs 3 lbs in my 151 size. Don't tow, carry a backpack on your back not the tunnel, it would work for a project like this.

 

[Nikolai]

I would question why you have any tunnel beyond the rear suspension mount. Make it a disposal part made from carbon sheet or even cheaper like poly just to keep snow off your back. A thin piece of bent aluminum with no structure would be strong enough. I was going to use the Patrick's custom carbon tunnel extension that weighs 3 lbs in my 151 size. Don't tow, carry a backpack on your back not the tunnel, it would work for a project like this.

Only because I have to put my u-cooler back there, it will be a double pass cooler about 21” long.

If there wasn’t a cooler than I think a carbon piece would be the way to go.

 

[zx4ever]

I wonder what a small rad and fan would weigh compared to the rear cooler. Reason I ask is my viper has no rear cooler just bulkhead cooler and rad and it does not overheat on the trail with the 3” track even. Also the lack of ice build up is sure nice as my old nytro and yamalaris ice up like crazy with rear cooler.

 

[Nikolai]

I wonder what a small rad and fan would weigh compared to the rear cooler. Reason I ask is my viper has no rear cooler just bulkhead cooler and rad and it does not overheat on the trail with the 3” track even. Also the lack of ice build up is sure nice as my old nytro and yamalaris ice up like crazy with rear cooler.

I estimated my u-cooler to be 7-8 lbs based on the extrusion I have. This is for a 21”-22” double pass cooler.

I have no bulkhead cooler. I was only going to run a rear cooler plus the coolant through the frame tubes.

Since I planned on running the coolant through the tubes, and used thicker .058 wall tubing for that reason, I’d like to keep the cooling system on the back. I am also trying hard to keep as much weight off the front as possible. That being said, if there’s a better rear mounted cooling option available than a u-cooler I’m open to any ideas. I have not welded up the extrusion yet and was honestly going to probably just have CR Racing weld one up for me.

I could maybe fit a radiator and fan in front of the fuel tank? I’m trying hard to not have any parts stick outside of the front spars, I want the body work to be small as a possible.

Fans dont weigh hardly anything. I have an extra 6” SPAL waterproof fan from my RZR heater and it’s probably under a coupe lbs, I can weight it tonight. Radiator will be the weight gain.

I’m open to any ideas on the cooling system. It would certainly make the rear tunnel less complex.

 

[Dan Lance]

With a rad you'll need a source of cold air and somewhere for the hot to go. If you go that route could look at automotive heater cores. Super efficient and light weight. Smaller inlet and outlet pipes but that can be fixed

 

[zx4ever]

I forgot you were not going with a bulkhead cooler. I’m not sure about deleting that cooler as that is where the snow has to go thru and I think would provide more cooling than the tunnel cooler. Just my thoughts. I think I have a nytro rad kicking around if I can find it I will fill with water and weight it just to see. Cooling systems can weigh a lot and it’s tough to design the lightest but efficient enough system to get the job done.

 

[Nikolai]

I did away with the front cooler for track clearance and to try and clean up the plumbing. With the coolant in the frame tubing there is very little external plumbing. I was trying to go for a “clean” look.

Got the front suspension installed. Biggest lesson building a tube chassis is do all the suspension mounting absolutely last. Welding on other areas of the frame moves the tubing and it only a takes a tiny bit of movement for the holes to not line up. I had to egg out the front 12mm a-arm holes a bit to get the bolts to go in easy.

This was my plan for the cooling a couple years ago when I cut up the extrusion.

 

[Nikolai]

My much younger stubborn self butchered my last set of gripper skis cutting the plastic knobs off and other stuff trying to get them below 5 lbs. I still have them but they were super ugly and I couldn’t get myself to use them on this build so I stopped by the dealer today and picked up a new set. I do have a bunch of lightweight hardware on my old ones I’ll post about when I get it swapped over, I need to tweak some of it first.

 

[kinger]

Will the U cooler not clear the track if its right under the bars and goes back to the rear suspension mount part of the tunnel? I see your tubes sticking out for what I assume is the connection, just make those a 180 degree bend and face the cooler forward vs to the rear?

 

[Nikolai]

Will the U cooler not clear the track if it’s right under the bars and goes back to the rear suspension mount part of the tunnel? I see your tubes sticking out for what I assume is the connection, just make those a 180 degree bend and face the cooler forward vs to the rear?

No, I am doing a rear mount turbo. Header and turbo take up that space.