09-14-2011, 09:49 PM #1
- Join Date
- Sep 2011
BOV, surge kit why need a vacuum line
Im trying to understand the purpose of that vacuum line affect on the BOV,
There is negative pressure building up because off throttle, throttle valve closes ok so then the air pressure has no where to go so hence the BOV lets out the air pressure.
So why the vacuum line below the map sensor?
09-14-2011, 09:52 PM #2
The vacuum is what opens the valve on the BOV.
09-15-2011, 08:13 AM #3
09-15-2011, 08:40 AM #4
When the throttle is let off, the throttle body closes, but the super charger is still continuing to spin. Instead of that pressure building up as a back pressure against the supercharger, the BOV opens,releasing the excess pressure. Once the amount of pressure goes below the preset limit, the BOV closes. The vacuum line is how the valve knows the difference between boost and unwanted back pressure. If the vacuum line wasn't there, the valve would open any time boost was applied.
09-16-2011, 09:58 AM #5
09-16-2011, 09:59 AM #6
No. the valve is spring loaded and one direction
09-16-2011, 10:03 AM #7
09-16-2011, 11:54 AM #8
The dump valve has basically two operating conditions; throttle open, and throttle closed. When the throttle is open, the boost pressure coming into the valve from below the diaphragm is equalled by the pressure onto the top of the diaphragm that comes via the small hose from the engine plenim chamber. As the pressures are equal, the spring holds the diaphragm onto its seat, and prevents the pressure venting away. When the throttle is closed, the pressure coming into the top of the valve is significantly reduced, (often to a vacuum), and the pressure below the diaphram lifts it away from its seat, allowing the excess pressure to vent away. As the throttle is reopened, the pressures again equalise, the spring pushes the diaphragm onto its seat, and the boost pressure cannot vent away.
09-16-2011, 12:36 PM #9
Thanks for the help. I think I have it now.
09-18-2011, 04:20 PM #10
Greddy BOV adjustment
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By Jay in forum Yamaha PWC Performance (2-stroke)Replies: 3Last Post: 08-06-2011, 08:57 PM
By Rt-HemiBoY in forum Sea Doo ClassifiedsReplies: 16Last Post: 05-16-2011, 05:38 PM
By Rt-HemiBoY in forum Yamaha ClassifiedsReplies: 2Last Post: 04-28-2011, 01:51 PM
By blue_nova in forum Polaris How To & FAQsReplies: 1Last Post: 11-02-2008, 11:33 PM
By excess in forum 4-Tec PerformanceReplies: 4Last Post: 08-16-2006, 07:03 PM