Tunnel Dump on MCX Nytro - Stock Tunnel

B

Brutis20

Member

Lifetime Membership

Nov 30, 2007

138

22

18

Canada

• Dec 2, 2010

• #1

I have got a plan to use my current muffler and tunnel dump it on my stock tunnel. The plan is to install the muffler under the rear of the tunnel and have it exit out the back just above the sno flap (cut hole in tail piece). I have talked to MCX and no problem, also talked to a muffler shop and all I got to do is mount the muffler and they will run the 2.5" muffler extension from the Turbo to the muffler for a good price.

My question is if I mount the muffler (4.5" OD) under the tunnel in the back, is there risk of the track hitting it if bottoming out? the bottom of the muffler would be ~ 5.5" down from the tunnel. I know for normal riding this will be fine but if I bottom out I don't know har far the skid/track will come up. I was going to remove the shock and try this. Anybody have any experience with this?

As per below the muffler would sit about here but under the tunnel.

[/IMG]

[/IMG]

 

C

canucklehead

Well-known member

Aug 30, 2002

513

78

28

Southern AB

• Dec 2, 2010

• #2

Mine was like that, bought it that way so it will work. You can let the air out of the shocks and cycle the skid and see what you need for clearance. That's a lot of cutting and welding if your having it done by somebody. We ripped all of that off and made a short tunnel dump (no muffler) out the front, by the small cooler. It's not that loud, buddy has been running like that for years.

 

S

SWE_Mike

Free Member

Sep 22, 2010

16

10

3

North of Sweden

• Dec 2, 2010

• #3

Me and my buddy was planing for the exact same thing but we came to the conclusion that it wouldnt work if you bottoming out or you have a failuring suspension. im looking forward to if you got it to work.Keep us updated whit pics.

 

R

ridehard1212

Active member

Nov 26, 2007

606

26

28

39

LANGLEY BC

• Dec 2, 2010

• #4

does anyone have pics on tunnel dump to front of tunnel? (no muffler.)

 

B

bigbird

Well-known member

Nov 26, 2007

546

86

28

51

edmonton area

www.rushmotorsports.ca

• Dec 2, 2010

• #5

ridehard1212 said:

does anyone have pics on tunnel dump to front of tunnel? (no muffler.)

Click to expand...

I ran chad's (Cr racing) tunnel dump kit on my stock tunnel last year. Had to take out my tunnel cooler and have it shortened 2.5 inches. Cost me 50 bucks and works fine.

 

L

Linc

Active member

Nov 17, 2002

843

43

28

Pemberton

www.visionms.ca

• Dec 2, 2010

• #6

Take your sled, put it on a milk crate at the back part of the track and push down, that will tell you how much room you will have.

 

B

Brutis20

Member

Lifetime Membership

Nov 30, 2007

138

22

18

Canada

• Dec 3, 2010

• #7

Just might work...

So I let the air out of the rear shock as per pic. There is ~ 5" worst case scenario. I think I am going to go a head and try this. Right now I am just debating on running the exhaust out the back of tunnel or keeping it in this may eat up my snow flap but will look cleaner. Will mount it up and take i to the muffler guy. He quoted me earlier under $170 to tie this in. I would do it myself but I am not that good with welding light suff yet. There will be ~ 1" of room, I think this is OK for a worst case scenario as I would probably fab something up anyway (widdle a stick) if my suspension would completely fail.

Let me know what you guys think. Ignore the haywire for now...

 

Last edited: Dec 3, 2010

Thistledoo

Well-known member

Lifetime Membership

Aug 8, 2001

2,378

402

83

Lethbridge Alberta

www.babybeadtreasures.com

• Dec 3, 2010

• #8

you need to elevate the front of the sled.....and check again. Or did you put the milk crate under the very back to simulate going thru a creek?

 

ruffryder

Well-known member

Lifetime Membership

Aug 14, 2002

8,468

1,258

113

• Dec 3, 2010

• #9

Thistledoo said:

you need to elevate the front of the sled.....and check again. Or did you put the milk crate under the very back to simulate going thru a creek?

Click to expand...

Agreed, though remember the TS skid is coupled, so the rear of the skid will not be able to compress a large amount without the front of the skid also compressing. TS vid is embedded, check out section at 6:30 in video.



A coupled skid is a benefit in this instance. I know that with my gen 1 Kmod that isn't coupled, it is possible to compress the rear suspension ONLY at the back and have the track hit the muffler. My muffler is pretty small (height wise) as well.

To gain some more clearance, you can straighten your rails too. This will bring the rear wheels down a little bit in comparison to the rest of the suspension.

Just some thoughts.

 

Last edited: Dec 3, 2010

B

Brutis20

Member

Lifetime Membership

Nov 30, 2007

138

22

18

Canada

• Dec 3, 2010

• #10

So I checked it out with the shock depressured and put the back on the crate. Sure enough there is only about 2" of room. I still don't know which way I will go now, as the chances of this happening are slim. I may just dump the exhaust straight off the turbo down and to the rear about 8" long. It may be a bit loud but may try it. If not I may just weld on a turnout to the ehaust pipe how it is now and see if that helps. I don't feel like pulling my skid out and modifying my cooler. Anyone see any issues with these two ways of going?

 

0

0007

Free Member

Nov 28, 2007

510

49

28

Vernon

• Dec 3, 2010

• #11

Are you doing it just so you can haul fuel?
I think leipheimer makes a tunnel dump with a muffler

 

B

Brutis20

Member

Lifetime Membership

Nov 30, 2007

138

22

18

Canada

• Dec 4, 2010

• #12

Yes, to haul fuel and also keep the intake from freezing. I cut a straight pipe and will see how it will sound, may be too loud.

 

B

boostedballz

Free Member

Dec 18, 2007

295

97

28

• Dec 4, 2010

• #13

Rode with a straight pipe tunnel dump was louder than a normal MCX but not bad. Never been in snow conditions where the difference was so noticable but the tunnel dump was defintly less prone to icing. I was pulling less than 8 psi on my 270 then after a good de ice was back up to 17.

 

0

0007

Free Member

Nov 28, 2007

510

49

28

Vernon

• Dec 4, 2010

• #14

I fixed the filter on mine
I wrapped the aluminum filter in a humidifier filter and wrapped that in Flo rite material
The circumference is double and what little snow sticks just brushes off, never ices up
I like the sound with the muffler, there must be a way to pack 10 liters of fuel and leave it alone

 

B

Brutis20

Member

Lifetime Membership

Nov 30, 2007

138

22

18

Canada

• Dec 5, 2010

• #15

Here is what I fabbed up. Not the prettiest but hopefully it will work. Everything is just bolt on incase it doesn't. I am probably going to still weld a turnout on the exhaust to try that for the quieter option.

I am still unsure if this exhaust will plug or not?? I may make a deflector shield facing forwards but not sure yet.

Onething I noticed is that it is less bobbly on the idle and bottom end w/o the muffler, but this could be just me...

Also loking for a smaller muffler I can put underneath.

Let me know what you guys think?

Won't be able to try it in deep snow until next weekend.

 

C

canucklehead

Well-known member

Aug 30, 2002

513

78

28

Southern AB

• Dec 5, 2010

• #16

Nice work. It may plug with snow though facing back like that. You could cut the outlet some more on the forward edge to try and prevent it from catching snow.