Exhaust valve question

[Drnick]

Exhaust valve ; is it there for reducing noise,or is it there for performance ? .... if removed,(just the plate inside) how would that effect motor?

[kman0066]

Noise and mid-range torque supposedly. I'm guessing it accomplishes that by varying angles to increase velocity when rpm is lower. Lots of people remove them (including myself) on various bikes, never hurts it. Would probably be a little bit louder and the torque difference barely noticeable on a bike this powerful. When I swapped out my exhaust on the H2 SX I removed it completely, ran fine still.

[cOoTeR]

Kman was out a pain in the ass to remove on this bike or fairly simple?

[vcyclenut]

I did testing with it functioning normal and with it always open, I felt it lost a little power in the very bottom end with it always open and went back to it functioning normal

as a side note if you just disable it in the woolich software with out unplugging the servo it will be half open and run like shit

to remove the whole thing is a bit of an ass pain, to unplg the servo that's in the tail section is pretty easy

[THOR]

if you just remove the servo cables will it throw a fault code?

[vcyclenut]

if you just remove the servo cables will it throw a fault code?

.


I did not test this on the SX but any other exhaust valve if you leave the servo plugged in and remove the actual cables it does not throw a code

[FJR919]

I did testing with it functioning normal and with it always open, I felt it lost a little power in the very bottom end with it always open and went back to it functioning normal

as a side note if you just disable it in the woolich software with out unplugging the servo it will be half open and run like shit

to remove the whole thing is a bit of an ass pain, to unplg the servo that's in the tail section is pretty easy

Any speculation as to whether the Vandemon exhaust will have the same loss of low end due to the valve removal? How much power was lost with the valve removed and at what rpm range?

[kman0066]

Some bikes (like older Ducatis) will throw a code removing the cables as the motor does a sweep check on power-up. The SX does not appear to have this problem.

Theoretically yes, the vandemon exhaust should experience the same loss at lower RPMs. However, given that you will probably do a ECU tune with the exhaust, the net should be a gain overall. I didn't feel the difference on mine, but I also removed like 20lbs of stuff at the same time so there was a big transformation for the better at the same time.

[Drnick]

All u have to do is remove the actual plate that swivels on the shaft,from what I can see,it’s either screwed onto shaft,or maybe spot welded

[vcyclenut]

I did testing with it functioning normal and with it always open, I felt it lost a little power in the very bottom end with it always open and went back to it functioning normal

as a side note if you just disable it in the woolich software with out unplugging the servo it will be half open and run like shit

to remove the whole thing is a bit of an ass pain, to unplg the servo that's in the tail section is pretty easy

Any speculation as to whether the Vandemon exhaust will have the same loss of low end due to the valve removal? How much power was lost with the valve removed and at what rpm range?

it was very small loss, I had to switch back and forth a couple time to be sure. it was only just off idle. Totally not a big deal
it was barely noticeable

I don't want to speculate. The different header design and pipe diameter will mean it will in no way compare to the stock exhaust

it was not measurable it was just seat of the pants. Dyno runs looked identical with it open all the time.