The tray of my ski is currently ripped out and figured now would be the time to make any adjustments. Was thinking about buying the Rad dudes squarenose exhaust tube to make it the same as the RN superjet. I could see how this would create less restriction in the exhaust, just not sure if it is worth my time or not.
Increasing SNSJ exhaust diameter - Worth doing?
- Thread starter Jhucke
- Start date
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
Do it.
only worth it if youve updated the waterbox to 2-1/4 and the exhaust hoses as well
Planning on going RN oem box and the long tube of course.
Myself
manic mechanic
- Location
- Twin Lakes AR
Somebody has already proven the oem size is fine, even for a pretty healthy 783 with Lamey cylinder.......good enough for me.
Big Kahuna
Administrator
- Location
- Tuscaloosa, AL
Weird, 96 SJ came with the larger outlet......... Same Motor and Exhaust, only difference was the cases and carbs.......... Wonder why then changed then.
Appears to be @MTRHEAD superjet build. 8mil stroker in that thing, 60mph WOW. Pump is awesome in that build, would try to do something similar if I had a lathe or mill to work with.
With an untuned exhaust, any amount of back pressure will cause a loss of power. All things considered, Yamaha probably made it larger to lower the pitch of the exhaust sound.
Just for the record I am not intending on running stock exhaust.
My square goes in the 60’s and accelerates with the best of them. Unless your tray is full water I wouldn’t bother.
i also used the bigger hose from the stock 96+ Aluminum box to the back stock 93 tube. Had to splice it a couple inches longer but it just squeezes down to fit on the 90-95 exit tube size. No issues at all since installing
those of us that remember we used stock hose cut for speedwerx pipe. It allowed ease of installation and you just cranked the hose clamp down.
i also used the bigger hose from the stock 96+ Aluminum box to the back stock 93 tube. Had to splice it a couple inches longer but it just squeezes down to fit on the 90-95 exit tube size. No issues at all since installing
those of us that remember we used stock hose cut for speedwerx pipe. It allowed ease of installation and you just cranked the hose clamp down.
If you’re only looking for a performance increase, assuming you’re using a race style modified Yamaha 62t based twin, I wouldn’t bother because you won’t notice.
This discussion is similar to guys changing to aftermarket water boxes in skis that really need the oem waterbox back pressure to perform optimum. 90%+ of people putting in the free flowing waterbox do not sleeve the stinger down to compensate for what they did.
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