Thinking about plugging the exhaust valves has anybody done this on the Pro? Will this compromise reliabilty or have any downfall on the motor?
PLUGGING EXHAUST VALVES?
- Thread starter sledsnowco
- Start date
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mnescape
Active member
Im not talking about the hose in the bottom of the engine,im talking about the hoses directly on top of each exhaust valve. Some were along the line i heard there is performance gains by doing this.Does engine pressure open the exhaust valves, if so then what does the solenoid do? Thanks.
Blocking off the vent lines defeats the purpose of having PCM cntrol of the valves. Why would you want to do that? The PCM is programmed in 3D to adjust fuel, timing and exhaust valve position in concert to make the most torque possible for the throttle position.
Blocking off the vents would force the valves to open to early and limit low end torque which is achieved by keepint the top of the exhaust port lower in the cylinder.
Awhile back I remember some guys disconnecting the solenoid completely, plugging the hose and changing the exhaust valve springs to heavier ones. This made them function strictly mechanically like they use to.
The heavier springs hold the valves closed until enough exhaust pressure is created to open the valves.
They work strictly off exhaust back pressure instead of the computer telling them when to open.
Don’t remember what the results were?
Would have to get the right springs so the valves don’t open to early or late.
Older Ski doo exhaust valves have an adjustable cap on them so you can adjust the spring pre-load if needed. They work good.
Would be nice not to have the oily mess from the exhaust always bleeding out the vent tube, but as stated. The PCM is programed to time the Valve opening to maximise engine performance.
The heavier springs hold the valves closed until enough exhaust pressure is created to open the valves.
They work strictly off exhaust back pressure instead of the computer telling them when to open.
Don’t remember what the results were?
Would have to get the right springs so the valves don’t open to early or late.
Older Ski doo exhaust valves have an adjustable cap on them so you can adjust the spring pre-load if needed. They work good.
Would be nice not to have the oily mess from the exhaust always bleeding out the vent tube, but as stated. The PCM is programed to time the Valve opening to maximise engine performance.
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Some of the original thinking was the exhaust valves are being delayed with the ECM for EPA reasons, not purely performance goals. Along with deleting another system that may fail later.
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gman086
Well-known member
THIS! The other responses are just plain hilarious. Blocking them opens the valves sooner = more power sooner and less heat soak but you waste more gas (less efficiency) = bad EPA mojo. Blocking them is the ONLY way to go for performance enthusiasts IMHO. Just make sure you cap the intake for the solenoids so you trick them into thinking they are working all the time. Still would like to hear what spring works best if anyone has done side-by-side. I believe FTX was doing some tuning? And don't tell your friends... in fact, no this mod doesn't work at all.
Have FUN!
G MAN
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Disconnecting the electrical connector at the solenoid and running the sled with it unhooked will result in the check engine light coming on.
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allpowersports
Well-known member
Why?
Just plug 'em already!
When you're out on the snow next time, Take a simple set of mini-vice grips, and pinch the 1/4" black rubber line anywhere between the "T" and the electric solenoid, leaving the wires still plugged into the solenoid.
In a lot less time than it takes to read this thread, and no money wasted, you'll have your answer.
When you're out on the snow next time, Take a simple set of mini-vice grips, and pinch the 1/4" black rubber line anywhere between the "T" and the electric solenoid, leaving the wires still plugged into the solenoid.
In a lot less time than it takes to read this thread, and no money wasted, you'll have your answer.
I would just leave it the way it was made. There is probably a reason for how the sled is setup. Just add gas and oil and ride
Cheers!
Reason is E.P.A., not improved performance.
Same as the "old style" Edge's, no solenoid there............................
Improved response and bottom end performance, and not "holding back" the exhaust in the cylinder.
Thank you gman086 and kraven I will pinch it this weekend and report back.
