Anyone ever try drilling air evacuation holes in tunnel?

[ReTodd]

It might be silly but it seems like the track spinning at 45mph creates a pretty significant air pump in the tight space of the upper tunnel. It then gets narrowed down to 1/2" where the track meets the drivers.

I wonder if drilling a few 1/2" holes along the upper portion of the tunnel would decrease back pressure and gain you a bit of track speed. Anyone ever try that?

Rt

 

[high time]

You might have a point, at least at high speed. Most of these guys arn't going to worry about it in deep snow mountain riding. I think I have encountered this air/ snow blockage at the finish line on Hill Drags. Especially a few years back when running an Attack-20 in hillclimb position. Gear ratio wise, I should have still been accelerating, but as it was, I was not.

Owen

 

[Wheel House Motorsports]

i guess i would have to say, yes, there is SOME air resistance from the track spinning, and at higher speeds, it has some affect and for the sake of argument .0000001hp loss is an affect, just not worth a chit or noticable. i would say you would see more results from the weight lost on the alumium before you notice any benefits from drilling holes

the effort it takes to compress air the maybe 1psi that is being generated inside the track is negligable in comparison to the strength in your tunnel you lose by drilling holes in it... if your that worried, drill your track, problem solved.

 

[89sandman]

sweet, ported tunnel. wheres my holesaw i think porting the track may produce the same results without taking a chance on weakening the structural integrity.

 

[snowmobiler]

maybe plumb a turbo down to the track?

 

[TEC800]

try it, then you could tell everyone you have a retodded tunnel!

 

[94fordguy]

A couple things to consider, drilling on the top of the tunnel would not work because of the seat, gas tank, etc... If you drill in the 'front' of the tunnel, then your just going to be shooting that air (and the snow that is with it) right into the engine bay... So aside from the extremely weakened tunnel, your now packing more snow and ice into your sled than you were before.

The one benefit I do see, if you are shooting snow at your engine cases, at least you wont have to worry about overheating as much

 

[jpxp154]

please let us all know how it turns out if you go with your idea

 

[LRD]

Its been done with oval water crossers, holes in the front sides of the tunnel
if I remember right.

Good Luck

 

[suitcase]

That is a real good point, For me I think I'll take the HP loss before drilling holes in my tunnel. If I did something like that I would mess my tunnel up and have to put a new one on my sled. For sure if you do, do this let use know the results very interested.

 

[polarblu]

isnt this what the drop and roll is for in the sleds that were effected?

 

[winter brew]

my .02.....the track does move some air, but there is no build up of pressure in the tunnel....no way. There is far too many escape routes....the gaps on either side of the track, all the drive windows in the track, the entire area above the track to the tunnel or snow packed in the tunnel. Even if all but 1 of these were somehow sealed off, there would still be enough area to eliminate a build up of pressure.
I have given this thought in the past, especially with the ported track craze and the D&R craze back in the late '90's.
I am fortunate enough to get to help build and conduct a varety of tests at my "regular" job that involve air, air pressure and ALOT of airflow. We get to use a variety of precise monitoring equipment and seeing what it takes to make and hold air pressure as we have had to do and then comparing that to a snowmobile I am of the opinion that there is nothing to gain in this area. Now snow resistance is another story. A fully heated tunnel to eliminate all buildup?? hmmm....

 

[H2SNOW]

if I were and that worried I would probably just go on a diet and loose 15 lbs ..lol

 

[Weekday Warrior]

retarded




air pump? lol

 

[1moretime]

I agree with WB. There can't be any real noticable air pressure under there. Think about how fast a turbo has to turn to generate a few pounds of pressure in a very confined and air tight enviroment. Now poke a small hole in the box and see what happens to the pressure. I do believe that there is hydraulics taking place by the amount of snow that is being thrown back into the tunnel. The snow build up will generate resistance and cause some track speed loss. This is why some minor track porting is not a bad thing......or adding more HP to overcome the resistance .

 

[XFIRE800]

my .02.....the track does move some air, but there is no build up of pressure in the tunnel....no way. There is far too many escape routes....the gaps on either side of the track, all the drive windows in the track, the entire area above the track to the tunnel or snow packed in the tunnel. Even if all but 1 of these were somehow sealed off, there would still be enough area to eliminate a build up of pressure.
I have given this thought in the past, especially with the ported track craze and the D&R craze back in the late '90's.
I am fortunate enough to get to help build and conduct a varety of tests at my "regular" job that involve air, air pressure and ALOT of airflow. We get to use a variety of precise monitoring equipment and seeing what it takes to make and hold air pressure as we have had to do and then comparing that to a snowmobile I am of the opinion that there is nothing to gain in this area. Now snow resistance is another story. A fully heated tunnel to eliminate all buildup?? hmmm....

Carbon Fiber tunnel...........

 

[svensdream]

isnt this what the drop and roll is for in the sleds that were effected?

evacuating snow and air is a secondary benafit of rolling the chaincase.

 

[turboal]

good questiion , it isnt the air that causes the problem , its the snow .
consider it in the terms of how much snow can the tunnel process with the length and depth of track designs today.
tunnel with as little as 1/2 inch of clearence versus the same sled and track with 3 inches of clearence.

the new tracks with the holes in them allow the pressure to drop and blow off into the middle of the track when room allows .ie depending on how deep and stiff the snow is .

adding powerto a track that has little clearence will build higher clutch temps , add enough ie a turbo and that gets you there but at a high expence .

basic difference in the doo rev platform and the new xp is basically all about the tunnel clearence .

if you run in conditions that isnt as deep as we regulairly seein our area you wont experience some of what were talking about

was haveing thoughts about installing snow extractors in the rear , before the top rear idler wheels , pull the snow out to the sides , only would work in the deep stuff to a point i supose .

 

[turboal]

built a tube chassi sled last for last seasons use . it has 4 inches above the track lugs and 8 inches in the front , motor was a stock 01 doo motor and riding with the new 09 sleds we found that we went antwere they would go , makeing similiar track speeds , useing the same 2.5 lug depth the new sleds have . tunnel clearence is important in our snow conditions .

 

[go high fast]

drilling "air evacuation holes" goes on the list with:

1.) drilling holes into a perfectly good track
2.) rolled chain cases
3.) belt drives
4.) tracks as long as a football field with paddles suited for ping pong
5.) extravert drivers
6.) TSS 04 LW being a big step forward over the TSS 98
7.) Teams newest clutch being a big step forward over the TSS 04
8.) 2 wheel rear axel being a big step forward over the 3 wheel axel
9.) expensive space-age 2 stoke oil
10.) light weight brake rotors, jackshafts and driveshafts

let us know if it works. also, for all the stuff besides the air that passes through the evacuation holes where does it go?

dont meant to imply that i haven't spent $$ on questionable stuff...........just look above next to Currently...enough said.