Tunnel shortening

[couch]

How short is too short? Have seen various lengths but any consensus?
Figure on room for bca tunnel bag and seat bag ...first guess is cut 10" ....

Figuring less tunnel equals less stucks so is 10" off enough?
More - diminishing returns?
Less - not worth the effort?
Whats the magic number?

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[Sheetmetalfab]

I’m happy with 8” off.

narrow bm fab bumper also.

 

[Teth-Air]

At what length cut will you start seeing over-heating problems. It has to have some effect?

 

[couch]

Thinking of adding a tunnel cooler in addition to or in place of stock ...

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[pepperhouse]

8-9” is the sweet spot.
I went shorter then 9” and then you start getting hit with your own roost. Added a snow flap back on to stop it.
Definitely increases trail temps.
Added a mtntk cooler to remedy this.

 

[Teth-Air]

Did you guys both weld it up or use the glue in kit?

 

[IceAge Performance]

We've played with a number of variations on shop builds and helping our athletes. One thing to consider is what rear bumper you are using. Just the swap from an OEM style rear bumper to a 2 piece BM Fab EXO bumper will move the handle in(forward) and up almost 3" also with tapered corners for less drag. This helps reduce the amount cut needed and helps retain more cooling area. On 155's 5" cut with the BM Fab bumper was an awesome combo and because of the 2 piece design could be shortened. For guys running OEM style rear bumpers 7-8 inches made more sense. This combo while also running a half length snow flap had very minimal heating issues but great gains for reduced drag and MUCH more capable sleds in tech terrain.

Note. All of these builds were done by cutting/welding so reduced length is exact overall amount shortened. Bumpers were installed with the same orientation to the end of the tunnel to keep before and after comparisons identical.

 

[TRS]

Just a reminder. When you cut and weld make sure you flush out the heat exchangers. Those tiny pieces of aluminum will plug your cooling system. Throttle body coolant line plugs first, causing your turbo to fail.

 

[pepperhouse]

Did you guys both weld it up or use the glue in kit?

I’ve cut two sleds now.

First one I did glue in kit.
Had a tiny leak at install pulled out piece and added way more rtv and been fine.
About 600km on it still working good.

The second I cut it and went with a 5’ mtntk tunnel cooler only. It’s ok but in setup spring snow or packed trail it runs hot. Prob going to add in glue kit or weld it to get stock cooling back as well as the mtntk cooler. I also don’t like the snow build up with just a middle cooler.

 

[Sheetmetalfab]

I’ve cut two sleds now.

First one I did glue in kit.
Had a tiny leak at install pulled out piece and added way more rtv and been fine.
About 600km on it still working good.

The second I cut it and went with a 5’ mtntk tunnel cooler only. It’s ok but in setup spring snow or packed trail it runs hot. Prob going to add in glue kit or weld it to get stock cooling back as well as the mtntk cooler. I also don’t like the snow build up with just a middle cooler.

What year sled? (Asking Because of the cooling system revisions)

 

[frntflp]

Trying to understand the differences between MtnTek (plastic manifold) vs welded and then vs cut length. Pros/Cons

Above talks of amt cut versus which bumper is used. Seems like welded is the best option in terms of the overall integrity of the system ?

???

TIA

 

[pepperhouse]

What year sled? (Asking Because of the cooling system revisions)

18 800 turbo with both a mtntk 5’ cooler and glue in kit cut 8” it’s better then stock for cooling.

19 850 cut 9.5” running just the 5’ mtntk cooler and it runs hot unless you’re in 2”
Plus fresh snow.