Rossier Engineering
5241 Hardin Avenue Suite B
Plover, Wisconsin 54467
(715) 341-9919
http://www.rossiereng.com

Renowned watercraft engine builders, Rossier Engineering, turns attention to ATV performance! Having designed and built engines for World Title winning watercraft teams, they bring considerable experience and expertise to the ATV arena! Rossier Engineering offers performance exhaust systems for four-stroke sport quads, including Honda TRX-450R, Yamaha Raptor & YFZ, and the Suzuki LTZ-400.

Suzuki LTZ-400 link:
http://www.rossiereng.com/z400_atv.html



I volunteered to test one of their exhaust systems for the Suzuki LTZ-400, write a ride report, and perform a dynamometer comparison with my Yoshimura RS-3.



Installed the “Short” 12-inch silencer Rossier Exhaust System on the wife’s 2003 LTZ400 quad and took it to Lil Sahara, Waynoka, Oklahoma with paddles mounted.


Installation Observations:
The RE head-pipe has a short bend from head, well clear of radiator fan and hoses, nice radius to “straight” section. Larger than stock “stepped header design”, it looks good inside (smooth transitions) and the stainless steel looks nice too! The “straight mid-pipe” section sits atop of the transmission, tucked inwards and away from your leg.

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This is a serious MX race set-up exhaust system with a twelve-inch long “aluminum can” whose end-cap stops about six inches in front of the grab bar, no worries about exhaust damage from being rear-ended!


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Engine modifications prior to testing Rossier Exhaust:
Quad Works air filter (K&N) with “home-made outerwear-type lid”: Stock carb, 140 Mikuni main jet, 25 pilot jet, DJ needle-3rd clip, 2.5 turns: Intake HotCam: Stock header with modified stock muffler (2-inch glass-pack): Thirteen tooth front sprocket.

I performed jetting recommendations per included instruction sheet:
Dynojet 155 main jet (an increase of roughly 5.7 Dynojet sizes)
Needle on 3rd clip (no change)
25 pilot jet and 2.5 turns on air/fuel screw (no change)
Air lid removed (kept modified lid -> no change)


Wife reports from Lil’ Sahara, Waynoka, OK:
Quicker response, pulls harder, more top-end, able to “cruise” in fourth gear where she previously cruised in third gear. Sound is a deep throaty growl.

I noticed more “grunt” from rolling and dead starts, the quad revs out further between shifts, nice improvement over my “hack-job” on the stock muffler! Noticeable improvement when drag racing too!

Back in Broken Arrow, OK:
To compare it to my Yoshi RS-3, I mounted it on my quad. Test rides with stock knobbies were impressive! The Rossier has a deeper growl than the Yoshi RS-3. Very nice response, I could not tell a performance difference from the Yoshi!

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Performed a compression check the night of 4 March 2005 and registered approximately 180 psi (cheap $15 tester, so I say approximately).


Took my quad to Lonnie @ SandTrax, Tulsa, OK (918) 445-4153 http://www.sandtrax.com/ to test it on his “Dynojet” dynamometer on March 5, 2005. We mounted his flat-track tires and he checked the air pressure (15 psi).


With the “air/fuel probe” installed, Lonnie performed three “5 pull runs” with the Rossier pipe; waiting between each “run” to allow the engine to cool. Normally, he discards the first 3 “pulls” of each “run”… I included pulls #3, #4, #5 to show how consistent this pipe/engine combination performs.



Intake mods: Spectre' Air Filter, 400EX Airboot
Stock carb with 155 Mikuni mj, 25 PJ, 4th clip, ~2.5 Turns:
DRZE gaskets,springs
Both HotCams
Procom CDI
Mild head clean-up port job

91 Octane Premium Pump Gas


Rossier "12-inch can" MX Exhaust System:
First pull with “Outerwears” ™ air box lid and seat on.
(The real Outerwears material.)

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Rossier "12-inch can" MX Exhaust System:
Removed air box lid @ Lonnie's suggestion.

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Rossier "12-inch can" MX Exhaust System:
Lonnie thought the seat was too close to the air box, so, with lid and seat off.


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Of course, he was right!



Allowed quad to cool, swapped on the Yoshi RS-3, and installed the A/F probe.

Yoshimura RS-3 with lid and seat off.


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Yoshimura RS-3 with lid off and seat on.

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Rossier 12-inch –vs- Yoshi RS-3 no lid.


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Rossier 12-inch –vs- Yoshi RS-3 no lid, no seat.

Now that both pipes can "breathe" better...


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VERY nice review straw! Thanks for all that info! Looks like the RE takes low end honors will the top end goes to the Yoshi! Two very nice pipes, both for different riders. Thanks for posting all of that for us to see! Very good info ...

My pleasure,



I cannot say enough good things about Lonnie @ SandTrax, of Tulsa, OK.

He prioritizes “Customer Service”, coaching/teaching performance theory to any customer who needs a little help. So, if he is running a little late, do not be discouraged, his interest in your particular circumstance is genuine. :D

NICE :)

What i see by looking at the A/F graphs, is that the Yoshi was rich between 5K & 6K and this is the same spot the Roisser did better. After 6K they were about the same on the A/F graph and the Yoshi had a slight advantage on top.

It would be nice to see what a STD Roisser pipe would do up against it, for that Yoshi is a STD series pipe.

Sweet post
Daniel

Nice review man, thanks for the time you put into it! Good job Joe Benner and crew @ Rossier, you guys have excellent products! :)