Blow Off Valve Boost Leak Explained [GO FAST BRETT]
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- เผยแพร่เมื่อ 12 ก.ย. 2016
- When is a boost leak not a boost leak? In this episode we look at how air can move around the side of the piston during a blow off valve boost test...
In this brand new series created by Mighty Car Mods, Go Fast Brett explains all things turbo, blow off valve and choo choo.
This series is proudly brought to you by Mighty Car Mods and GFB
www.gfb.com.au
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I love this series, I learn so much from Brett. Keep them coming please!
I am learning sooo much from these videos!
Why has it taken so long for this kind of simple explanation to be available?
(Probably because it has been available but I didn't even know what questions to ask!)
Damn I so happy this was uploaded at the right time because of a shit day.
Hey Brett, can you please make a video about wheel trim and housing A/R ratios? I think I might finally understand them if I had a video to go along with the explanation
Great video as awlays, loving this series! Have a GFB DV+ on my GTI and it holds boost like a beast! Also fixed that annoying whine you get with the stock DV while at WOT. Great vids and great products!
good series, informative content - 10 leaks that dont occur in daily use out of 10!
Do these leak under vacuum though? or only when you put pressure on it?
Excellent! I learned something today!
Awesome very useful video, thanks very much!
Lol this series is turning into "Please stop bothering our tech support for stupid shit" or "Yes I know it leaks a bit when you apply air to the wrong side but it doesn't matter, its not why your stupid car still runs 16s, learn to drive and stop bothering us"
lol
Thanks for these
A dual port BOV will then create a vacuum leak if the air can be sucked througt the atmosphere port?
What about when it leaks at the mounting flange where the gasket is? Mine is mounted on the intercooler piping with 2 bolts right before the throttle body and soapy water revealed a leak. Is that still considered a Boost leak or no? Im on recirc w stock bpv.
so can we clean our turbos? especially us diesel drivers. Should we even try to clean them? is there any point? cheers GFB.
Does that mean it's safe to slightly sand away some pitting inside the wall of the bov that the piston travels through?
but doesnt the engine vacuum allow unmetered air to get sucked from the recirculation side through the bov and suck air from the atmospheric side,this being said wouldnt we see lean mix at idle but not a wot since idle draws the most vacuum and wot pretty much equalizes vacuum?
also could i apply a little bit of thick grease to help seal this more?
TURBO TROUBLE: so I have a volvo with the T5, it boosts well most of the time but lately it has been feeling sluggish sometimes, it will get all grumbly and feel like it's chugging along till 5k or so them starts boosting properly, any ideas??
Is this video about back paddling for those who tested their GFB bov's and found them to leak??
It really looks like that..
I had my cobb xle BPV leak, got it replaced and all fixed now.
Looks like ill be installing my stock one to find my leak then. The TL RFL I'm using now keep leaking during my test.
this is quality
Ok I don't mess around to much with turbos, only really on diesel trucks, I'm more of a blower, super charger guy......so how would you properly check for boost leaks ? Love the series and keep up the good work.
I think the last video showed how you can check for boost leaks. Grab a condom.
Would that fit on my Honda?
So that means that the vacuum going to leak as well right?
I hate myself for watching this. lol! keep them coming.
What about the Boomba BPV?
the main point i got was...theres a lotta people that think they know everything and try to sound smart when talking about boost leaks....but then brett comes in and says yall are stupid. lol
Can you move this series to the main channel so this knowledge is shared with more people
I need a less tight spring on mine it doesn't open under vacuum at idle
How would i test a greddy FV?
that means that the recirc is pulling vacuum through the trumpet no ? causing a vacuum leak
These videos are very concise and well made, it's just a shame that it's such basic information
So basically don’t do a Boost leak test from the intake pipe, do it directly from the turbo inlet?
i think my bov is stuck partially open... i hear air hissing from it when boost is building. occasionally with the ac on full blast it'll close and the car will reach max boost. but normally the blow off valve doesn't pop up normally and air is hissing. Is my bov defective or just needs cleaning?
Did you figure this out? My splitter valve is making the sound noise and wondering if i need to adjust spring pressure or if its broken
Tip: If you suspect you have air leakage, buy start gas and spray on the airways with the car running car on in idle. If you hear the engine start to go up in revs, you found a leak.
carb cleaner works well too. except it will cause the car to stumble
I'll just nod and pretend I understood
I need help. I installed a valve but now my car has 12 codes plus my rpms at idle are high
Renaldo Simpson 𝐯𝐚𝐜𝐮𝐮𝐦 𝐥𝐞𝐚𝐤
@@renaldosimpson8755 god damn
I've got a vauxhall corsa vxr 1.6t .. just wondering what the best blow off valve to use ..or just stick to stock wastegate?? I have no idea ..help me plz
wastgate and blowoff do not do the same thing. blow off, removes the excess pressure from the intake side so it dosnt surge, a west gate gets rid of exhaus gasses, so it dosen't overspin the turbo
you can get a bov for the sound,but if your car has a maf and is tuned for a recirculatory valve, it will not work right, you will be having a/f mixture problems, and will need to get it maped for a bov.
so make sure of what you are dealing with before "upgrading" your curent setup, because the upgrade can be more than 1 part
Robi Flego thx man .. a friend said the same thing the other day .. thinking it sounds fine the way it is for now :)
+chebly no problem mate. you got a sweet little car :P your first car?
3rd... the first 2 car are nothing to shout about :) .. this is my first toy
cool
Would it be possible to use a piston-ring type seal inside of the Blow Off Valve to get rid of that .02mm gap?
It wouldn't as you would still bypass it going between the two outlets of the BOV. That would only help with leak down from the top to the bottom of the BOV
Piston rings actually have gaps in them.All the rings on a piston are rotated away from each other to help with leakage, but it is not a perfect seal however. Nice idea though.
.02 is nothing though. I machine parts to that kind of tolerance every day and when you press a shaft into a blind hole with that clearance, you can push the shaft down and it will spring back up to the same place because the amount of air displaced is minuscule.
Daniel Way
Thank you for the technical breakdown, I appreciate that! I'm trying to learn more about engineering, and your comment really explained why my idea wouldn't work.
Thanks again man, it's appreciated!
could you use a onboard air tank/compressor to turbo your car effectively ?
possibly but a car could empty any decent size air compressor tank in less then a feasible time on a reasonable amount of boost.
+scootbmx01 but u could have a air compressor keep constant pressure in the tank even if it's only 20 to 30 psi
+garret angle, you would need such a big air compressor it would be way too big
you could just mainline it from the compressor in the trunk and not even have a tank
scootbmx01 you could just mainline it from the compressor in the trunk and not even have a tank
If there is a leak post MAF pre turbo, even a small one, it is a leak. There's no "it's just a small one" non-sense. Granted, if you are tuned with said leak you may not have issues, especially on speed density. But if you have a MAF and plan on running the GFB Response, or whatever, you may run into hunting idle and or drivability issues under light load (going down a hill while applying light throttle or costing with light throttle input). Ran into this several times during my build with the exact BOV in the video and have since switched to a different manufacturers recirc with no issues.
Adam LZ needs to watch this video!
His wasn't the actual BOV leaking, but the flange that attached the BOV to the charge pipe coming off the turbo outlet
Overdrive Media Oh right
On a dual port BOV can it draw un-metered air in? How big of an issue can that be for tuning?
Yes, it can if the BOV is malfunctioning, has a dirty seat/valve or has a damaged valve or valve seat.
With a good BOV, no, the way the BOV valve piston seats with a positive seal it will not normally leak.
It would also matter where the BOV was located in the charge air piping as to whether or not the un-metered air leak would effect proper operation.
It's not (yet) in the "GO FAST BRETT" playlist. :P
I recently found out that most Tuners or so called Tuners in the USA wont even allow GFB valves as they think they all leak badly.
as they bench test them with only pressure on 1 side and think its broken.
(hence why i said so called "tuners" as they can't be very good at their job if they dont know how a GFB BOV works.)
#strongchinbrett
That's why when I leak test I go from the turbo outlet connection to the throttle body. There is no reason to pressurize a turbo or engine like that, but plenty of reasons why you should not.
It's not the pressure side you need to worry about, I mean if there's a boost leak then yah is an issue but if it seals then you need to pay attention to the the vac side, if there's a leak post MAF/pre turbo you will have a vac leak. Even if it's a small leak, a vac leak is a vac leak, and small post MAF vac leaks lead to issues aka: "lean conditions"
my wife likes your purple spray bottle... where did you get it? (the bottle, not...)
Rumour has it when you comment early enough you get a free MCM Lanyard, pretty please?
"How many videos can we make on blow off valves and wastegates?!"
I need to get another turbo car...
next time plug the recirculating part for the leak test :(
#2
Now add negative pressure and you’ll see it sucks air through there also which the mass air flow sensor doesn’t account of which makes the car run lean, this gfb valves ar good for the first few months and then they become trash, I just reinstalled the OEM recirculating valve on my Subaru because it was leaking vacuum and made the car run like shit Eve the ecu detected the problem,
I think the same way.
hey guys
This is a bad test as you didnt put any pressure inside the piston port of the valve to simulate how well it will hold under boost.
From my understanding you’re supposed to leak test the turbo
this was kind of irrelevant as you would never pressurise the outlet of a dump valve. if the leak was from the inlet side of the dv to the outlet, while the valve is still closed, then its a boost leak and therefore could be a problem. but a leak from 1 outlet of a dual port dv to another outlet isnt a problem is it?
can't have any leaks if you don't run a bov ;)
and you will have a God level ssssstu tu tu tu!
Only if this was actually true.. :D No bov=no boost leaks
kinda is, no bov = no leaks coming from the bov like in the video
there wasnt a leak in this video...
Unrelated to vid. But recently the BPV hose ripped off of my BPV, this caused something I can only describe as compressor surge or turbo flutter. My guess is because it couldnt ventthe pressure so it just wentback into the turbo. Its fixed now, but big question is..... what COULD be damaged by this event? And how can I tell? How would I even know if anything internal like seals or o rings or what the fuck ever are damaged by fords shitty workmanship?
boooooooooooooooooost
1st
I Didn't understand
me either. that's why I like na
Blow off valve vents boost pressure when the throttle plate is closed, that is where it shines. Under full throttle the engine can take the boost, and very minor blow off valve leaks are really of no concern. That was my take on it.
so you like going slow? :p
No, just what I understood from the video.
am i the only one that can't see the actual video? it's just a black screen
nvm, it's on my end
Honestly, im gonna bash this video. I dont see the point in showing how there is clearance between the piston and the cylinder. And why are you showing this test when its irrelevant to actual performance? This guy is spraying soapy water into a leak that he created. I dont get it. Why show me that? These BPVs when operating, do not even operate in that manner in which he applied that test so its irrelevant testing. Is that what you are trying to point out? That people shouldn't be testing BPVs like this?? Please explain. Am i missing something?
Yes, you're definitely missing something.
Really terrible camera work. For fs, let's stay focused on what he has to say rather than his hands
Why is this the third video on blow off valves I'm sure he knows more than this about cars wtf how boring
the main point i got was...theres a lotta people that think they know everything and try to sound smart when talking about boost leaks....but then brett comes in and says yall are stupid. lol