El Andrew Gold Donating Members 2,039 Member For: 10y 1m 9d Gender: Male Location: Canberra ACT Posted 12/04/20 11:29 AM Share Posted 12/04/20 11:29 AM Might be hard to answer, but what size hose do you reckon is needed on the BOV plumb back to effectively vent boost pressure on throttle close? Outlet size on factory BOV and on my Turbosmart Compact Dual Port is 25mm. But the TS valve can presumably handle scenarios with much more boost than my 14psi. Reason I ask is I've chucked in a turbo side intake that has a fitting for a 13mm hose for the breather. I can eventually get a fitting welded in for the plumb back, but thinking as an interim I'll just step down the BOV to 13mm and T into the hose for the breather just before it hits the intake pipe. Ultimately I guess it doesn't matter too much, as plenty of people run no BOV at all. Link to comment https://www.fordxr6turbo.com/forum/topic/95624-hose-size-required-for-plumb-back-bov/ Share on other sites More sharing options...
k31th less WHY; more WOT Site Developer 29,522 Member For: 17y 1m 21d Gender: Male Location: Melbourne Posted 12/04/20 11:36 AM Share Posted 12/04/20 11:36 AM seems like you answered your own question 25mm (or 1 inch) is the usual size of the BOV outlets Link to comment https://www.fordxr6turbo.com/forum/topic/95624-hose-size-required-for-plumb-back-bov/#findComment-1693677 Share on other sites More sharing options...
El Andrew Gold Donating Members 2,039 Member For: 10y 1m 9d Gender: Male Location: Canberra ACT Posted 12/04/20 11:37 AM Author Share Posted 12/04/20 11:37 AM I guess I'm wondering whether 13mm is enough to vent the pressure or not Link to comment https://www.fordxr6turbo.com/forum/topic/95624-hose-size-required-for-plumb-back-bov/#findComment-1693678 Share on other sites More sharing options...
k31th less WHY; more WOT Site Developer 29,522 Member For: 17y 1m 21d Gender: Male Location: Melbourne Posted 12/04/20 11:41 AM Share Posted 12/04/20 11:41 AM hard question to answer... more a physics question... but I'd assume it would be enough. Link to comment https://www.fordxr6turbo.com/forum/topic/95624-hose-size-required-for-plumb-back-bov/#findComment-1693679 Share on other sites More sharing options...
arronm Dropping a turd Gold Donating Members 9,520 Member For: 17y 7m 4d Gender: Male Location: Perth Posted 12/04/20 12:05 PM Share Posted 12/04/20 12:05 PM 13mm is way to small Link to comment https://www.fordxr6turbo.com/forum/topic/95624-hose-size-required-for-plumb-back-bov/#findComment-1693680 Share on other sites More sharing options...
gaz097 Bronze Donating Members 1,752 Member For: 13y 10m 10d Posted 12/04/20 11:19 PM Share Posted 12/04/20 11:19 PM If you want absolutely no dose at all even 25mm will be too small.Think you will have a 25mm tube a little over 1m long? Trying to dump the same air that was flowing through a 3" pipe? Link to comment https://www.fordxr6turbo.com/forum/topic/95624-hose-size-required-for-plumb-back-bov/#findComment-1693683 Share on other sites More sharing options...
El Andrew Gold Donating Members 2,039 Member For: 10y 1m 9d Gender: Male Location: Canberra ACT Posted 13/04/20 05:31 AM Author Share Posted 13/04/20 05:31 AM Yeah the air will take the path of least resistance. So I guess it is going to depend a bit too on intake system volume and pressure. So hose needs to be big enough that the ease of exiting the pipe is more than the ease of stalling the compressor wheel.I reckon I'll just get a 25mm fitting welded in to the intake pipe pre turbo and do it properly. 1 Link to comment https://www.fordxr6turbo.com/forum/topic/95624-hose-size-required-for-plumb-back-bov/#findComment-1693688 Share on other sites More sharing options...
bloodycrashboy Feeling the Love :-) Bronze Donating Members 4,421 Member For: 12y 2m Gender: Male Location: Not in Cairns anymore Posted 13/04/20 05:40 AM Share Posted 13/04/20 05:40 AM BOV outlet is 25 mm can't put on a larger diameter hose even if you wanted to Link to comment https://www.fordxr6turbo.com/forum/topic/95624-hose-size-required-for-plumb-back-bov/#findComment-1693689 Share on other sites More sharing options...
OZYWALKER XR50T Gold Donating Members 2,795 Member For: 12y 30d Gender: Male Location: Western Sydney Posted 13/04/20 07:09 AM Share Posted 13/04/20 07:09 AM Youd want at least a 25mm internal hose for it. But I think it's more to do with the design of the BOV.Factory/bosche units have all rubber/plastic seats that seem to smoothly open and close.Any aftermarket valve has a metal piston and I think it's the sharper edges of the piston that adds to the noise alot as it opens more abruptly. Once upon a time I went from stock to a turbosmart direct fit (25mm).Massive noise increase and it was plumbed back with a process west kit. Now I've got 2 50mm turbosmart race ports (Because race yoot). At cruising speeds and light backing off the throttle it's quieter than the 25mm. Full throttle and back off quickly and it's a different story. I know it was ages ago but there was a guy on here (kruzin I think) who used two stock BOVs with good results. 1 Link to comment https://www.fordxr6turbo.com/forum/topic/95624-hose-size-required-for-plumb-back-bov/#findComment-1693692 Share on other sites More sharing options...
bloodycrashboy Feeling the Love :-) Bronze Donating Members 4,421 Member For: 12y 2m Gender: Male Location: Not in Cairns anymore Posted 13/04/20 07:26 AM Share Posted 13/04/20 07:26 AM I have a 25mm (internal) from standard BOV to intakeIf I close the throttle abruptly from WOT the noise is enough to scare those in the car beside me Some even get so upset that they give me the bird 1 1 Link to comment https://www.fordxr6turbo.com/forum/topic/95624-hose-size-required-for-plumb-back-bov/#findComment-1693693 Share on other sites More sharing options...
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