The Truth About Compressor Surge
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- Опубліковано 2 жов 2024
- A quick guide on understanding different turbo sounds and what they mean.
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Credits:
Huge thanks to:
SRD Tuning
Christian Serpico
Nick Stonawski
Tom Barnard
Vinny Rattan
Dakota Parker
Kasper Stuckenschniede
Justin Hopgood
Paul Ayoub
Paddy Fox
Hussein Ali Haidar
So without a blow out valve, the car will laugh. With the blowout valve, the car will sneeze??
fuck this comment i love it
I like it when it laughs
I wil remember this comment for a long time
Hahaha dude
Yes.
Finally someone who actually understands how this works. Thank you CT.
ali p how does he understand it? He just explained it’s ok. He showed no examples or reasoning as to why. Having 20+ years in machine and car shops and understanding tolerances and bearings back pressure under load or not is still pressure. Which is going to put force on the bearings which will wear one direction more than another. This wearing the bearings to premature failure.
The whole it wears under WOT but not when it’s no makes no sense. Either way it’s back pressure on the turbine and bearings. So either it does or doesn’t at all.
Manufacturers understand better. And they put valves to protect from surge. Thank you manufacturers.
Dan Slotea not true, they are mainly in place to prevent the noise and due to they fact that many standard hot wire/thin film air flow meters could not measure the direction of air flow, and as surge when surge occurred the air flow meter incorrectly measured more air than was being consumed by the engine, causing a temporarily rich tune and emissions problems.
The Anti surge was just a happy coincidence, many early turbo cars of the 80s had no bov.
@@renners9636 Many 80s cars also had Brown interiors, solid rear axles and were absolutely terrible. It doesn't make them correct.
Also that was like 37 years ago, technology changes.
Look at Borg Warner.
No Grip can you be more specific in your argument against me?
My statement was very simple and only covered one aspect, that the main reason cars were initially fitted with blow off valves was not to protect against *damage* from compressor surge itself but to stop incorrect fuel readings under surge conditions and to stop annoying noises that most drivers would not expect from a normal car.
I made absolutely no claim of anything being better, the implication of me mentioning some 80s gasoline cars not having blow off valves was to validate the 100s of thousands of turbochargers that have lived and live without being destroyed by compressor surge, I never advocated it as correct, but simply noted in the case of many oem cars that it is was a design that did not doom the turbocharger to early mechanical failure.
Manufacturers are more worried about possible emissions and noise issues than a few turbos failing sometime after warranty is up.
Maybe turbos running 30+psi are more susceptible to wear I couldn’t say.
Thank you so much for this, please do keep making these types of videos where you explain common misconceptions. Superb guys
Wow! So like half of us thought flutter was just a fancy sounding blow-off valve haha.
James Russo that’s what has made me so pissed! All these “tuner” 600whp subies talking bout “it’s a BOV”
maybe 10% its clearly not bov. BUT some of the turbo cars that makes flutter noises does have bov but it only realeases part of the boost so the sound is kinda mixed
some people wind there blow off valves up tightly so it surges on low boost and opens the blow off valve on high boost
Yep my car flutters when I roll off in normal driving and chirps when I'm getting into it. Just depend on much boost there is before lifting.
GlassTopRX7 how tight is your bov set?
Been running no BOV on my single turbo 1JZ for near on 3 years now. Makes 20+psi on e85 reliably all day every day without issue. Why fix something if it isn't broken?!
You'll be fixing it a lot sooner than someone with a BOV.
Archer
old turbo buicks with blow thru system didnt have bovs and you can still find perfectly working ones with the same old turbo.
so after 25+ years and thousands of miles and still no broken turbo...
Also to note, WRC cars don't use BOVs either because (believe it or not) they slow the impeller speed down more than without one causing more lag ;)
as far as i know the bmw m6 GT3 don´t use a bov either and you can hear the flutter when they let off the gas ^^
andrenegwer says the guy parroting what he saw in a video from a very respectable, but less experienced member of the community. They are much more experienced experts who will tell you the opposite. What he covers is is mostly true but you still cause premature wear without a valve regardless.
Wait so thath means we can have sututututu ?
Stoteliu Siaubas that’s what I’m hearing.. throwing out BOV now..
BRAABABABA STUTUTUTUTU
Been saying this for years and no one would believe me
only low boost
@@randiey95 define low boost because im thinking if 15 psi qualifies🤔
Thanks! I was so worried with my quad turbo charged & dual supercharged Civic Si, with stock internals, would break all my turbos.
ErwinSchrodinger64
i wish this was trye and you had mad vids about it bruh
This is an automatic message to notify anyone that ErwinSchrodinger's quad turbo charged & dual supercharged Civic Si, with stock internals, had so much horsepower and so fast, it became a time machine and he went back in time.
ErwinSchrodinger64
all that was possible due not using bov
🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣🤣
A civic can handle 1000 hp on stock internals easily, fax
UK:CarThrottle = USA: DonutMedia
Bitvh who do you love?
Who you calling a bitch?! bitch
LMFAO the yg reference is great
Both
of course there's a VL commodore...
why wouldn't there be?
aka. Dose Mobile :D
Up the Vl and Rb30.
haha love my vl and I was surprised it made it into what I assume is an american made video but almost all turbo vls are bound to be flutter machines. Mines soon to join the turbo charged crew ;)
VL most over rated car in Australia pisses me off but I love the rb but just so over rated compared to batta
That R33 at the end was purely demonic
agreed
Thanks for making this video because people that never owned a turbo car comment and try to act li,e they know their shit.
my first turbo car was a -99 saab 93 2.0t and i tuned it from 150 to 270 without a bov, and its still fine and it has 320000 km on the clock!
@@garren3498 hows ur saab holding lol
I actually like the flutter sound much more than the blow off one. It just sounds more epic :)
Yeah but it sounds really good...
No im not 12
(Edit: changed profile pic)
Gordon I'm 13
Did you actually watch the video
Yet you have a GTR badge as your profile picture as do a lot of 12 year olds.
SSSSSSSUTUTUTUTU
Looks really shady with that gtr logo lol
After about 20-30 minutes of google searching and a bit of independant thinking led me to the conclusion that this video is plain wrong. Turbo surge of any kind is bad for the bearings in the turbo. If you were coming off a 7k rpm pull, and lift the pedal all the way, the throttle plate closes, but the engine does not wind down in an instant, so the exhaust is still spinning the turbine and air returning from the throttle body is pushing against that spin, via the impeller, in the opposite direction. This opposing force creates a lateral load in the turbine-impeller shaft and hurts bearings. Why else would anyone making big power buy a BOV? just to waste money and add weight?
20-30 minutes of google searching is better then people with 20+ years of experience not running blow off valves.
The reason google told you that is because forums are full of people spreading a myth they don't understand. They just read something and believe it. Plenty of people making HUGE power don't run BOV's. People used to always say "goldfish only have a 3 second memory" for decades, only to be told they're actually full of shit. I've seen plenty of pistons go through blocks, plenty of transmissions give out, but I have never seen someone need to replace a turbo due to running no bov.
Then why do companies like Canam who make turbo engines for side by sides not run a BOV at all or high revving high performance engines?
@@strider5119 it’s the equivalent of a placebo fir example Europe cars are unreliable or parts are expensive when the counter is actually more expensive majority of the time
Could you do a video about blower idle surge? I never fully understood the concept behind it. Thanks!
same concept. to much air is being pumpd, vs what is being used.
I get the best of both worlds with the Tial Q on my ms3. Spring in it is a -12 psi spring, and the vacuum in the intake manifold takes about a quarter to a half second to go from positive boost to -12 vacuum, and therefore it takes that long before the valve opens after boost. I get this lovely "stutu-schhhhh" noise from it and I absolutely cannot wait until I have a Garrett GTX2867R gen II on it and can hear the noise a 9 blade compressor makes vs the k04 6 blade.
If you're running the correct sized turbo, intercooler and piping for your setup, a BoV isn't necessary, the only thing a BoV MIGHT, and I stress the might, help with is eliminating lag (if you even have any) between gear changes as the turbine of the turbo won't slow down as much with the surge of pressure when the throttle blade is closed. As for the increased wear on the turbo when not using a BoV, for every study I've seen saying that it wears the turbo quicker, there's another that says it won't! :/ From my own experience, the only benefit I've noticed from a BoV has been reducing lag between gear changes. I put something like 15000 miles on a mk3 Supra 2.8 single turbo I built back in 1999 without a BoV then after some advice from a mk4 Supra owner, I fitted a BoV and it did help to eliminate the lag I was getting between gear changes. I ran the car for 2 years after that (must've been at least another 20000 miles) without any noticable signs of wear on the turbo, I sold the car to a friend who ran it just over a year before smashing it and one of the few things that was ok to salvage was the turbo!
Yeah, hear changes and when you close the throttle before reopening, I have noticed slight differences in lag reduction with a well placed BOV, as for longevity... I don’t think it’s that dramatic of a difference with our without as long as your system in balanced like you said
yes
good fix for this is flat foot shifting 😂
I'm under the impression you're mistaking the purpose of a blowoff valve and a wastegate. The boost control solenoid in conjunction with the wastegate and recirculation valve is what should maintain boost pressure between shifts, a blow off valve in theory is only there to blow off air pressure when you come off throttle
@@theposerhoser No he's correct. A wastegate is only there to prevent overspeeding of the turbo. A recirculation valve has a very similar job as a bov, a bov vents to atmosphere and a recirculation valve vents back to the inlet of the turbo. Not sure why you added the wastegate to the mix.
Time to block my blov of my Subaru :)
tubejorrit - Unless you have a open/atmospheric bov, it's not a great idea. Basically all turbo cars come with recirculating bov's from factory because they measure air through a MAF. If you change it to an open bov or block it off, you'll need a MAP based tune. COBB makes great devices for tuning Subarus
Do the bov mod and block the little pressure tube with a 6mm grub screw and then drill a 1.5 - 3mm hole in the tube after the screw. You now have a reference pressure of atmosphere for the bov spring instead of intercooler pressure. That gets you a bov that holds as much pressure as you want and causes a surge flutter before it then vents as normal. You do however loose the backup safety feature of the bov opening automatically at about 18psi boost pressure.
You still need some form of venting on a subaru with a maf as it doesn't like air reversed back through the maf sensor.
If you go vent to atmosphere all that will happen is that when you go off throttle it'll run rich for a second. That's it. You then need a speed density tune to fix that.
hope your on a speed density tune
MV60 is right
@@JolleBoiii No you don't. Recirculating bov's vent back before the turbo and that then goes to atmosphere via the filter. Vent to atmosphere bypasses the filter. Neither of them will do fucking anything to your cars tuning.
Its scary to me that people don't actually get this as it's the most BASIC understanding of how a turbo works. Think about that for a while. these are the same people that yell ''RICER'' if you made a modification they don't approve of.
StreatBeatsAudio Subwoofers basically people who call themselves car guys but have no clue at all
It sounds to me like you're just band-wagoning, because you aren't really providing reasoning behind your argument. You're simply persecuting. Compressor surge fundamentals are not the most basic understanding of how a turbo works. That's usually stage 2 or stage 3 in understanding a turbine's mechanics. An inexperienced person who has just finished their build wouldn't likely be aware that their blow-off valve serves purpose outside of alleviating pressure in charge pipes and intercooler piping/intercooler. If they heard open throttle compressor surge for the first time, they might just assume it's cool turbo noises and functioning as normal. Once they've blown the seals and bearings out of the turbo, then it might be something they learn. Also, some of your statements don't even correlate. You're a bit all over the place, which is what leads me to the conclusion that you're simply here to make others feel bad to make yourself feel better about your own ignorance. I'm not attacking you, but I would ask that you not attack others. If you think you have such a complete grasp on turbo-charging, perhaps you should do some research into intake harmonics and then come back and comment. You still have a lot to learn as well. Everyone starts somewhere. Learning is a process. I've spent years of my life building turbo'd cars and still learn things every day through trial and error, other people providing me information and tips, and research and equations. If you assume compressor surge is a fundamental pillar in understanding turbo-chargers, you've never seen a 16 year old driving a boosted Civic with no blow-off valve, no intercooler, no waste-gate, and no BCM or piggy-back. Turbo-charging is more complex than you are for probably prepared.
@@bestleesinna7702 lol
@@bestleesinna7702 turbo flutter does not wear the turbo out due to simple fluid dynamic laws
@@the_modfied_car4903 do you understand how bearings, friction, impact and directional force work? Cause what you said makes me think you don't. Turbo flutter is puts force on the fins in one direction, abruptly ceases that energy, which causes secondary forces to commence. This is a back and forth motion that wears down bearings and shafts. A smoother change in pressure results in less violent motion and reduced wear. You don't know what you're talking about. Fluid dynamics are all fine and dandy in theory but mechanical elements are your point of wear. Anything that moves, wears. You combine the immense heat and rpm a turbo operates at and you get accelerated wear. Not to mention the difference between double-sleeve, sleeve-bearing, and dual-ball-bearing turbos. Turbo flutter causes wear. Arguing against that isn't ignorance now, because you should know better. Arguing against it is stupidity because you're arguing against physics. This kind of wear is demonstrated by the price-hike of dual-ball-bearing turbos despite them being cheaper to manufacture than other varieties. It's because those forces don't wear them AS much, but still do. I just...I can't even talk to you right now. If you don't know something, ask. But don't try to teach people incorrectly.
The mental disability of anyone who thinks compressor surge is ok...it's a bit depressing to see this many.
Hands down the clearest explanation for this. Thanks guys.
It's never turning backwards, but think outside of the cold side of the system. Your exhaust gases still drive the turbine (not as fast as at work but still enough), while your turbo flutters, (example) your hot turbine is turned to left side and with closed throttle while fluttering the turbine is being slowed down at the cold side, putting immense torsion forces at the turbine shaft. I also love the flutter, it's one of the best sounds of this planet for me, but it's bad for your turbo, thinking otherwise is physically incorrect, so this whole video is Shit
The first problem I see with this video is while yes, you're right in your explanation dispelling this myth - but "Oh you're wrong because 'Car Throttle Extra' said so" is most likely not going to cut it.
Maybe you could cite your sources behind the logic explained in this video?
Does it means if no blow off valve in the system there will be more turbo lag because the turbine had slowed down so much when throttle valve closed?
Anas Takiyudin it's really not that bad at all
I'd say it depends. If you're letting off the throttle for a brief moment (like changing gear) residual pressure that haven't gotten out through the turbo yet will help to build the target pressure faster, but if you let off and leave it for a longer time (so the pressure can completely escape), then yes, rotor will take more time to spool up. Nevertheless, in both cases, the differences are barely noticeable.
Surge is better for response as the intercooler still has a charge in it that it otherwise has not dumped all out through a bov.
Lag is actually the time it takes for the pressurised air from the turbo to make it to the manifold. A top mount will have less lag than a front mount typically.
Ok, the hot side is the turbine, the cold side is the compressor. They spin at the same time being linked with a solid shaft. Ok moving on, what you're probably trying to describe is boost threshold where there is enough exhaust gas to spin the turbo to the point it produces positive pressure. Turbo lag as I said above is what happens above that boost threshold.
Turbos are great.
2:37 the subtitles say "Music" when there is the BOV sound 😂
Guten Tschüss my favorite genre of music😂😂
They are not wrong
Didnt know u could get compressor surge on a centif blower. 😮
ill risk my own turbo just to make my e46 laugh
Had my own turbo spin the nut off the compressor due to closed throttle surge and seen others do it too. It is all good if your turbo runs a left hand threaded shaft but the ones i have seen undo are right hand threaded. The turbines inertia due to weight is greater than the compressor wheel so it tends to back off the nut on the compressor wheel when there is a differential of forces applied. Cheers.
knock off garrett and BW moment
Got proof that it was specifically compressor surge that caused that? Cause I have never heard of that happening, ever lol
This is only half right. It puts pressure of the turbine face and force against the shaft back and forth.
That’s what the common complaint issue is. Not that it stops the compressor from spinning or goes backwards. That came up randomly and got regurgitated ever since.
And it’s more towards older turbos who already have wear and play. It makes the play and shaft wear/damage worse by adding unnecessary pressure.
Also just because it’s no longer under load doesn’t mean it doesn’t still have a small amount of load on the turbo or still have force by spinning.
I like the video, but this isn’t an end all just because some random kid on UA-cam “says so” lol
Of course, there is still a load while closed, but like you said, probably directed towards older turbos, any half decent non badly worn turbo won’t have the shaft effected by closed surge, I’ve never seen any example of that either to be fair and I’ve worked with turbos all my life, not on good working turbos anyway
Car Throttle THANK YOU!! At fucking last somebody got it right!!
Seriously: Utmost respect to you for actually RESEARCHING this subject and not just repeating what every forum / back of BOV box said.
Mumbo jumbo?
Lol
If the manufacturer installed a valve, then it means it should be there and surge is bad for the turbocharger. It might be that manufacturers know better than any "internet expert". I'll keep my valve, thanks, no need for flutter.
Dan Slotea It’s not actually about damage to the turbo, it’s about boost response. Like the video stated, the air (not the turbo) will momentarily stall, and the turbo will slow down a little. Then when you get back on the gas, the air has to organise itself back in the right flow direction, and the turbo has to spin back up to speed, meaning there might be a small loss of response. The valve keeps it all moving a little more freely in that situation.
On a car with an automatic trans, or a quick shifting trans like a dog box or sequential, it makes no difference since there is very little or no closed throttle time during shifts, making a bypass valve just another part to make room for or leak/fail etc, so it can safely be removed for simplicity in those situations.
Another often forgotten side of the argument is the effect of using/not using the bypass valve on the MAP or MAF sensor. I won’t go into too much detail, but you can imaging that depending on the vehicle or setup, a sudden spike in pressure as the throttle plate shuts may have an effect on the ECU via the MAP sensor, and turbulent/stalling air in the intake tract may have an effect on the MAF or AFM.
So basically, what you say is quite sensible, if the engine came with a bypass valve, and you are still using the factory ECU settings and factory engine sensor arrangement, it’s likely a good idea to continue using a bypass valve so as not to upset anything electronic.
However, removing the plumb-back hose and letting the valve vent to atmosphere can give you some mean af exhaust pops and crackles and maybe even a wicked exhaust flame on a car with a MAF, it’l momentarily go mega rich when that valve opens and really put on a show (and blow your cats out if you’re unlucky 😂)
@@KingOath I understand your point of view, however I am not interested in response time, but mechanical shocks to the turbo bearings. They add up and decrease the lifetime of the bearings. Or isn't it so?
From an engineering perspective, 'off-boost' surge is still a problem. Categorized as partial flow reversal due to air stall, the sound that you hear are large vibrations being experienced at the compressor blades and subsequently high stresses. Over a certain period of time, these stresses (or stress cycles) can and will cause fatigue cracks to occur, and eventually either the blade tips or entire blades can become heavily damaged. Anyone who says that off-boost surge is fine is.. well, wrong. :)
You're wrong
@@BAYAREAMX well I'm not, but believe whatever makes you happy!
Agree!!
Shouldn't a waste gate fix open throttle surge.
Should and will
Yes but a blow off valve won’t
Waste gate is on the turbine hot side, limits the amount of exhaust gases flowing through the turbine,slowing it down or speeding up.Does not in any way stop surge, that is what a blow off valve or diverter valve is for on the compressor side when throttle plate closes. Only time it will help is on a diesel, most are now VNT so its irrelevant.
This is WRONG. What they are talking about here is compressor STALL not surge. The true technical definition for compressor surge is when The turbocharger is moving a larger volume of air than the engine can in-take at a given RPM at wide open throttle. A symptom, of unstable air in the intake manifold itself. Also It is (or was) a far more common issue on turbocharged engines that use an individual throttle body assembly running large amounts of boost. I.e RB25/26. Synapse Engineering has a video demonstrating compressor surge.
No, there is open throttle compressor surge and closed throttle compressor surge. Open throttle is when the turbo is moving more air than the engine can take and the excess air escapes back through the turbo, as you said. Closed throttle surge is when the throttle body is closed and the air escapes back through the turbo.
It can’t surge if it has no load
No load no surge
Just pretty pretty noises
Tbh the only advantage a BOV is in a manual car so the turbo doesn’t slow between shifts.
The only thing a bov does is stop back flow when throttle is closed. To keep the turbo spinning in between shifts you need a recirculating valve that reintroduces the air into the turbo intake
Great video thanks ... might be worth doing one to explain why BOVs are pointless on turbo diesels ;-)
Well going on my car engine - it has no throttle plate. and is a deisel turbo, still get some nice flutters though when off thy gas!
I just blocked off the BOV on my speed3🤤
The choppy conflicting airflow can put stress on the compressor and shaft. i dont see why there is a debate, its physics. 100% your turbo will last longer with no surge. Now how much longer? who knows....It also depends on how much boost one is running over that time. Obviously 30psi will out more stress on the system compared to 10psi.
This right here. I agree. 100%
Ran no BOV on 240sx KA-T
it felt like a better turbo response not to have a BOV, because when I'm off throttle the would turbo flutter for around 2 second. So I guess for those 2 sec, it's like I have reservoir of boost ready to use. So If I opened the throttle within 2 seconds after closing the throttle the boost would just shoot back up to the boost limit almost instantly.
can't talk, busy fucking up my turbo.
so without a BOV is okay like on a 2JZ-GTE like on a supra without it okay if I throttle and I don't hear it when I throttle and when I do it bad is that correct
if you hear it while accelerating it's bad. If you hear it when you lift your foot off, its fine
Pushing 24psi no bov/dv for atleast 6 months daily driven. No issues yet. It makes sense that the free spinning turbo can chop the air with reverse pressure with minimal wear to the bearings/shaft because of its free spinning state.( whatever exhaust flow from the engine while shifting wouldnt be nearly the pressure returning through the intercooler) I don’t understand why so many others preach its pre detonation of the turbo?
Ive been running my Big turbo A4 for a few years without a BOV. zero shaft play.
I had seen some comments about that and I never did understand how it could spin the compressor backwards, turbochargers are essentially non-postive displacement pumps and a fluid pushed backwards through one would be extremely inefficient at causing any movement of the compressor wheel.
Wait but I thought flutter is better the a bov bc it can retain some of the compressed air creating less turbo lag where as the bov removes all of the air leaving with more turbo lag.
No bov will slow the speed of the turbine between shifting. A bov will cause the turbo to spin higher rpm between shifts helping with lag but you wont really notice a difference enough to feel it imo
Dont forget about Anti surge compressor housings.
Heads up for those that run a Maf sensor on the turbo inlet, subaru guys I'm talking to you. Doing this mod will cause problems with your tune. The air moving out of the turbos inlet on closed throttle is being metered and telling the computer it needs more fuel to go into the cylinders on closed throttle.
Thank you for equipping me with this God Level Power. I shall use this new found ability to do this to my car and not give a fuck about anyone’s bitching. I shall drown them out with me TUTUTUTUTU. Namaste sensay
Saabs, the pioneers to mainstream turbocharging, never used dump valves until 1985. And the compressor surging didnt do any harm to the earlier models.
I can imagine one reason being lower boost turbos of early times, closed surge would probably be more wearing on higher pressure systems but honestly, I think its a negligible difference, especially how everyone is always debating it and it’s so contradictory, like it’s never been such a significant different that people in general just haven’t come to a definitive answer.
the first clip is in lebanon the village is called taybe i am from there
I will get a volkswagen Touran,look for the bov,and get Rid of IT
Clorox Bleach dude I see you everwhere
2:13 - 2:19
Surely if the BOV is set to 20 psi and the turbo is making 21psi at wide open Throttle, surely the BOV will open
unless it’s computer run and the BOV opens at close throttle
Help!
You are thinking about the waste gate, now that is on the exhaust side not the intake side. The BOV has a vacuum line that connects to the intake manifold somewhere after the throttle body, this is how it opens to dump excess air when you back off the throttle. As the throttle body closes a vacuum (Between the engine and throttle body) causes the valve to pull open and dump excess pressure or recirculate it (Between the Turbo and throttle body). The BOV should not be opening under boost.
The waste gate will bypass the turbo (exhaust manifold to downpipe) and this will drop boost pressure, can be set statically or computer controlled
Sean Cockrell
Thanks, I knew about the wastegate exhaust side but I thought that the BOV was set to a certain psi too but now I know it’s the intake manifold vacuum. Cheers bud
Lloydy___ I have a mk4 golf 1.8t which makes fluttering noises under full throttle, it has been chipped a few years ago and now that i have watched this vid I'm becoming a bit worried. Should I undo the chipping or make the bov open later? Please help ;_;
@@mezzosplash change your diverter valve, diaphragm splits internally.RS6 710P or 710N version are the best.
so basically it will not damage your turbo but it will reduce performance since every time you slow down turbo on gear shift it will have to build up boost again when you open the throttle
thats why WRX recycle the air, so they dont have to wait again
@@DaytonaRoadster That's not the reason why... The length of the intake pipe is so absolutely negligible compared to the mass of air coming into that engine, not even superman would notice a difference between a BPV or BOV "response time" ...
Two main reason that I can think of atm is that, most people who buy a new vehicle want it to be quiet. Believe it or not, not everyone with a turbocharged vehicle (there are TONS of them out there if you think about it ), wants to hear "PSSSSSHHHHHH!!!" every time they let off the gas.
However, an even more important reason is this: If the vehicle has a MAF sensor setup (which most newer cars do), and you install a BOV, it's going to cause a huge unmetered air leak every time the valve is open, which can make the engine sputter, stall, throw a CEL, etc...
If you take ages to shift gear, maybe. Otherwise, no. The difference between bov and not having one is minimal. Flutter happens because there is compressed air between the turbo and throttlebody and it escapes. BOV's vent when the air between those same points reaches the amount its set to and will flutter for the rest anyway. You just don't really hear it at that point.
So compressor surge is making my truck slow
So how do you correct open throttle surge (ie turbo is too spooled for motor at a lower rpm)?? It's not to fix the turbo lol you definitely need a valve somewhere to correct it 🤔
I could be wrong but having a bov does make for much quicker boost response if you are going to be on and off the throttle frequently as in road racing,time attack,off road rallying and auto cross.
So the take-away from this video then, is that turbo flutter is ok, and doesn't hurt the lifespan or longevity of the turbo? Cuz if thats the case, I'm buying a BPV for my WRX haha
EGC_Warlock im also looking for that answer
So there's the believers and the haters. Some will swear closed throttle compressor surge will damage your turbo, some say it won't. Without factual data, testing and analysis, it all comes to experience. So far, it's pretty much story telling, rather than numbers and facts. I wouldn't add a BOV just for the simple fact it would add more complexity to the system, thus more points of possible failures. Conclusion? Just don't fuckin' overboost your thang.
you need to make sure the intake pipe was secured cause mine does come off after the flutter.....yeah the air seek the weakest way out
Thanks for this now I can run no bov on my new project
You’ve just convinced me to put a cover plate on my blow off valve. Congrats.
Thank you for posting this , god damn do I get sick of morons thinking OFF THROTTLE “compressor surge” , aka flutter, is doing any real damaging effect
Ironically I’ve been having a problem with my S15 under WOT where it’s been spluttering about at around 5000rpm, turned out to be the spring tension in the BOV set too tight . Once I had loosened it off, the problem is now non existent 🤦♂️😂
You're loosing boost at high rpm by loosening the bov spring, the flutter at wot should normally be regulated by the Wastegate
I don't have "turbo problems"... but I wish I did.
i feel you bruh
Buy a no name Chinese turbo from eBay and rebuild it a legitimate rebuild kit. Its a little more work but buy a oil and watercooled turbo, they are more reliable.
£100-169 for a new turbo bigger than you need with a 90’ angle air intake tube, to create big flutter sounds that folk will Balt in their pants. And your still driving at the speed limits. Or hammer the engine and get a little psst sound and uses shit loads of fuel. Which do you choice 🎉🎉🎉🎉😊 also bigger intercooler for cooler air means even more turbo flutter as it’s pushing out cooler air.
If you ain't making at min 400 hp you're good without a bov. Surge happens in high powered vehicles. Under load. Those race teams can afford to throw on a new turbo ever 1k miles
Use a ssqv and you'll have both worlds
combine it with a misfire anti-lag system
Blowoff valve not opening during wide open throttle is not entirely accurate. There are systems out there that have a constant vacuum line (held in vacuum with a check valve) and an electronic BOV control solenoid. These cars can open the blowoff valve whenever they want, even at wide open throttle. They can even use the blowoff valve as part of the boost control strategy in cases where open throttle compressor surge is completely unavoidable. The excess air can be recirculated into the intake or just vent with a consistently cracked open BOV.
Yet ALL Flutter is bad for journal Bearing Turbo's
they not meant to take the thrust loadings like that.
It really doesn’t effect the longevity of the turbo in most applications, maybe the most considerable is in highly tuned bearing turbos without a BOV but even then still lasting a long time, and it is still debatably negligible.
The amount that they slow down under load while the system is closed really isn’t going to do any harm overall, it’s not enough pressure to hurt those bearings, plus those bearing are made to spin at unreal speeds. They can handle a slight reduction in speed, it isn’t abrupt or dramatic enough to do anything notable, especially with how fast they run.
@@DoktrDub The issue is not the speed reduction The issue is the sudden and violent movement of the turbo impeller.
Under full boost Air is entering your intake at near Mach 1. This pushes the impeller against cold side housing away from hotside housing with play limits of the bearing tho small still present.
Journal bearings have no design in them for Thrust Loads Forward and Backward Only Rotational loads even spaced out..
So when they Flutter or stall they turbo impeller is suddenly no longer acting like a PROPELLER
This sends hot side slamming back into housing and pushing cold side away.
Then slamming back n forth at the speed you hear the flutter as the airflow stalls and the start stall n starts.
its like a electric motor with Journal Bearing its fine but move it back and forward fast in direction perpendicular to rotation and very fast bearing will die.
Hence why you never shake a coffee or herb grinder as they blow bearings fast.
Or if a skateboard had Journal bearings only a few sideways slides with side loading and they would fail.
can someone pls explain to me surge on turbo diesels, since there's no throttle plate usually, what would cause the surge? letting off throttle, less fuel going into engine, engine doesn't need as much air, air being thrown back towards compressor = surge? Someone enlighten me i'm confused lol, looking online has only made me much more confused.
That's a load of bull shit, a turbo is constantly spinning even at idle!
How would the car survive if both the TB and turbo shut and stopped completely, meaning no intake of air..
This doesn’t make any sense.. It’s technically the same exact thing just open versus closed throttle.. The principal is the same. Yeah close throttle might not be as bad. But over time you’re doing the exact same thing.
Am I the only one that got kinda scared by the GTR? I mean I was only expecting some revs not a fucking godzilla sounding thin to come out...
Dude knows fuck all, running no bov for over 6 years now the GTX3582R is a fresh as fuck..This "Car Guy" ...
As a Machinist/Welder/Fabricator/Mechanical Engineer, in 2004 or there about's, I got to work on a diesel semi-tractor that was attempting a Bonneville world speed record for that class. The diesel engine was turbocharged and producing 75+ psi. The turbo stall was discovered with a high-speed camera aimed at the fan. This wheel was coming to near complete stop and re-spooling. The solution was to add a Roots Blower to the mix to positively insure that the flow from the turbo was moving forward. This semi was geared so tall that it needed another tractor to push it to 75 mph just to get going in first gear.
Well, this is the coolest thing I've read all day. Funny enough a day that someone was trying to tell me how bad compressor surge is, which is why UA-cam suggested this video to me.
Do you happen to remember who or what company that was? It wasn't Cat with the race C10, was it?
@@wallcouldtalk Search UA-cam for "Ye Old Dragon".
How was the turbo coming to a near complete stop?
Got a link to a video of that? cause it sounds bullshit to me. Turbos spins at tens of thousands of rpms, it's not going to stall and come anywhere near a complete stop in between gears. That's an outrageous claim
I have spent the last hour on a Ford Fusion Facebook trying to explain the differences between flutter and surge to a guy. However, he is a "mechanic" so he won't hear any of it.
If you’re getting flutter while driving and not releasing the pedal, you have other issues lol, only time you should have flutter is when you take your foot off the pedal
I like blow of valve sounds more than stututu of fuckin surge
it's obvious that anyone who says that hasn't driven or even heard a turbo car IRL.. good vid man.
My 12 valve cummins has a non waste gated hx35 run 30 psi no problem no surge at all cuz of lack of a throttle blade
Never had a turbo issue due to closed throttle surge, both cars for over 5 years now. Good video, easy enough for all keyboard warriors to hopefully understand...
Unfortunately, this isn’t correct. Can 100% destroy the turbo
Lol 1:30 I only have one question!
What are you talking about?
Go on admit it you have no idea what your talking about do you.
Opinion piece with no facts. Turbo is under extreme load on the compressor side when surge occurs the impeller is not under load.
Is deleting my Electronic bov will b a problem? Audi a3 tfsi 1.8
BRB going to install a heavy ass spring on my N54 Blow-off Valve because I love that flutter sound.
What bov you using on your n54?
You are leaving out a huge segment of turbo vehicles. Diesel engines don't have throttle blades.
So surge is the name of the phenomenon, not the name of a modification like BOV, right?
this video presented claims good, but it did not prove anything.
The only type of compressor surge that is really a problem is when you are ON throttle, not off
This finally answerd my questions. Thanks guys. Subscribed.
I have replaced enough compressor wheels with bent inducer tips to say that you are wrong. But who listens to people who actually work with turbochargers if they could hear it from some youtube channel.
What's he so wrong about? The turbo isn't under load at closed throttle. It just spins freely.
Ok, Keep thinking that
Wanna tell us which specific cars and which specific turbos?
Actually the term flutter is also wrong, because it usually refers to aero-elastic instability
I'm not too familiar with the more intricate characteristics of turbo cars, but I'd imaging that turbo flutter is not good for keeping the turbo spooled.
You are correct, while turbo flutter with closed throttle sounds awsome and does not do any damage, it does slightly decrease preformance.
@@MatthewKrebs_BlackBrave8 tell that to all the people who have snapped hx40s running htem off their map... you guys crack me up. some idiot says on the internet its not bad so you take it as religous law.. plenty of videos of people breaking turbos by barkign them aka surge.
@@g__wizz Yeah people don't come to the internet for the right answer, they come to find reassurance of what they want, that's how they justify it. It's just about convincing themselves.
@@g__wizz I mean people think it's smart not to vaccinate their kids because of internet "knowledge" and "research". Its legitimately sad and scary.
@@g__wizz link me to these videos? Cause I spent plenty of time around high HP cars when I was younger, none ran bov's, all turbos were fine. The only time I had heard of people swapping out turbos is when they wanted to get more boost than the turbo could put out. Never heard of one breaking because of surge lmao
then how come I lost all my chu chu noises when upgrading to a larger turbo? recirculate blow off valve is also installed before and after the upgrade.
i love how you know your stuff man! but it sounds so damn good so i kinda dont care lol
So the flutter isn’t bad for the turbo as long as it only happens off throttle??
I have to be one of the few people that does not find the flutter sound to be cool in any argument.
So basically to get wastegate chatter just remove the recirc valve ? Noice