power valves.... block or not?
- Thread starter Clarke673
- Start date
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skotertoken
Member
I did try, and it made a HUGE difference. All I can say is DO IT! You will have to get the clutching fixed after they are blocked, or else you will start experience DET by over rev.
So your saying the sled made more power with them blocked? Cuz u were over revving? So you added some weight?
From my understanding the valves are fully open at full throttle anyways, so I can't see where more power is coming from? ( atleast this is how it was on my 10 800..
X2 on more info! How many rpms did you pick up blocking them?
Cheers
H
highmark289
Well-known member
a few pictures of how you did the mod please
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gman086
Well-known member
Well that's not the point, they open SOONER so you get power quicker and that actually can lead to retaining more track speed and may need to add more weight to clutches. Haven't done it to the Pro but certainly works for the 800R and there's no downside other than losing some fuel mileage.
Have FUN!
G MAN
So this doesn't lead to a bogey or less low end?
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skotertoken
Member
I just made 2 small hoses that where blocked in one end and put them on the ves valves. It probably don't do anything on top end but it builds power so much quicker then stock! Thats why you probably should run the poo 11-weights.
ride report tomorrow?
thats the plan.
Ride report??
M
modsledr
Well-known member
The main reason for doing this mod is to allow the power valves to open earlier, which in turn prevents heat retention in the engine.
The power valve solenoid is an emmissions device that artificially keeps the power valves closed until a higher rpm than they would open on their own (by combustion pressure overcoming spring pressure).
I'm not sure how allowing the valves to open normally would gain any low end, since they are actually opening earlier...but I could maybe see some mid range gains.
Then again, it may all be a placebo effect.
The power valve solenoid is an emmissions device that artificially keeps the power valves closed until a higher rpm than they would open on their own (by combustion pressure overcoming spring pressure).
I'm not sure how allowing the valves to open normally would gain any low end, since they are actually opening earlier...but I could maybe see some mid range gains.
Then again, it may all be a placebo effect.
However, (and I would caution this), at the time the valves open, the engine actually suffers a momentary DROP in airflow, then a steady increase in airflow. While the ECU is controlling the solenoid which in turn controls when the valves open, the ECU also matches the drop in airflow with a reduction in fuel delivered to the cylinders. IF you take away the ECU's ability to control the valves (by blocking the lines) then you also run the risk of a momentary lean condition when the ECU signals the valves to open and cuts fuel...if the valves are already open, you'll have increased airflow with a drop in fuel delivery....lean condition!!
It worked on the earlier VES models that were carb'd because the carbs handled the fuel delivery in an "on demand" manner....the problems with EFI in this case (because this is not a closed loop EFI system) the computer only does what it's told to do (fuel curve) and is oblivious to actual "demand".....
It worked on the earlier VES models that were carb'd because the carbs handled the fuel delivery in an "on demand" manner....the problems with EFI in this case (because this is not a closed loop EFI system) the computer only does what it's told to do (fuel curve) and is oblivious to actual "demand".....
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gman086
Well-known member
So this would explain the very brief stutter when I hammer the throttle from a dead stop?! This is on my ECM controlled Rev and I can add fuel by upping the pilots, unlike on the injected Pro.
Have FUN!
G
So the computer is activating the solenoid and bleeding pressure to the valves at peak rpm?? It must be if peak rpms increase...maybe the reason peak hp #'s are low??
