Hey Guys
To Blow Off Valve or not to Blow Off Valve that's the question?
GReddy kit 11550021A
Motor D16Y1
Intercoolers upgrade
Pro?
Con?
Type?
Any advice would be great
Thanks Guys
Luke
Printable View
Hey Guys
To Blow Off Valve or not to Blow Off Valve that's the question?
GReddy kit 11550021A
Motor D16Y1
Intercoolers upgrade
Pro?
Con?
Type?
Any advice would be great
Thanks Guys
Luke
u might aswell, but plumb it back into the system, unless u get off on the 'PSSHHTTTT' noise. they help stop compressor surge, so it will help ur turbos longevity(sp?) turbo smart make good ones.
either way u like... having a plumb back BOV prolongs the life of your turbo but doesn't give as much sound as ones that vent to atmosphere.. so if you're asking whether you should have a BOV installed or just have a big hole on ur piping... i'd say bov... because u're gonna wave ur turbo byebye if u don't
OK
Is I'll get one
$85
http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA:IT&ih=002
$261
http://cgi.ebay.com.au/Go-Fast-Bits-...QQcmdZViewItem
Second hand Turbo Smart
http://cgi.ebay.com.au/TURBOSMART-BL...QQcmdZViewItem
So are BOV like turbos, never buy second hand?
Thanks Guys
Luke
My friend bought 2 2nd hand ones from ebay and they're both fine
his got a hks SSQV for cheap if ur interested PM me
Why does it need to be plumed back to stop surge?
Any Bov can eliminate surge.
Get one. Have one to atmosphere if you like the sound. Or plumb it back if you don't like the sound or to make it legal. :thumbsup:
So only plumb back's are legal in OZ?Quote:
Originally Posted by DLO01
Pretty sure in all states that an atmosphere Bov is a defect.Quote:
Originally Posted by Lukezen27
Maybe someone can confirm.
Thats what Ive heard.Quote:
Originally Posted by DLO01
It's not like a turboed Honda is legal anyways :p
What do you mean Klay, mines fully legit. :p
^^sounds right, in qld neway
its a 450 fine and 3 points for noise pollution aswell. mate got done in his 32.
My opinion is deffinately run a bov.
Bov both have asthetic and practical uses. Firstly they have a massive range of sounds which sound pretty cool as well as your basic stealth ones. (whatever floats your boat)
Practically they are designed to protect your turbo from backpressure when your throttle body shuts. This backpressure after time can reduce the life of your turbo to the point where is may even fail. (depends on running boost, driving style, turbo etc etc). also Bov reduce your boost lag inbetween gear changes, as your compresser wheel is still able to spin freely, if the air is going fowards and escapeing, but not if its compressed backwards thought the turbo (wording could be a bit off, make sense?) do to haveing nowhere else to go.
If your in it for the practicallity (not a fan of a wankish "cha ching" noise every time you change gears) i would think get a basic stealth bov (no big trumpet ends), mount it just after the cool side of your cooler in your front bar, in front of your wheels, that way its out of site and cannot be seen if you open your bonnet.
lol at people who think turbo hondas are illegal..
also has anyone ever though of putting a Breather style mini pod filter on the outlet of your bov? so then air would not be leaving your engine system unfiltered? possibly a way of gettting around legallities? (doubtfull though)
thats about it :)
Regards Lyle
I think the legal side of things is more, keeping it a Closed System, and Noise Polution.Quote:
Originally Posted by Sexc86
And emissions? Surely that's an extreme difficulty in making it legal.
So is this one a plumb back?Quote:
Originally Posted by DLO01
http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA:IT&ih=002
"Compatible to Turbo & N/A Cars"... lol
And no I don't think so. It will say it in the description if it is.
That picture is an Atmosphere valve.Quote:
Originally Posted by Lukezen27
Can you point me in the direction of the legal type?Quote:
Originally Posted by DLO01
mate, its not so much what bov "Type" is illegal and what isnt its how they are "installed" is what determines the legality of them.
Venting the compressed air strait to atmosphere - Illegal
Plumbing the compressed air back into your intake ( just after your air filter before your turbo) via a seal tube / pipe - Legal (this is how most if not all factory turbo cars are setup)
ps. lol good old ebay... a bov to suit n/a!
OKQuote:
Originally Posted by Sexc86
This is my fisrt turbo setup and I'm a noob
SO what one should I get and what other parts ie hose do I need?
thats allright mate, do you want this part as a purely functional accessorie to your setup? or do you want it for a bit of fun to ? make a cool noise? (although illegal)
CoolQuote:
Originally Posted by Sexc86
functional and legal :thumbsup:
But I like the cool noise but I'll take functional and legal over cool any day..
Shame though I was looking forward to that shzzzzzzzzzz sound :(
u can still hear the noise, but its not as loud as a atmospheric one, sounds more like induction noise, but its pretty good neway.
Run no blow off valve for the best sound and completely legal! Bring on the evidence of no blow off valve causing turbo damage...
hmmm, well if you want it plumbed back.... get a bov with a circular strait flat outlet... (not a bell mouth or trumpet). This way you can get a hose made up (similar to a radiator hose) to go from the outlet of the bov back to a inlet flanges on your intake pipe between your air filter and turbo.
here is my ghetto diagram
http://i12.tinypic.com/4u3kqvo.jpg
paint FTW, good explanation though.
how does it have the best sound??? and running a plumb back BOV is completely legal. and having one does prevent damage to the turbo, because every time u take ur foot off the gass, the air gets forced back onto the compressor wheels, which creates more stress, and some lag, as the air is forcing against the spin of the compressor wheels.Quote:
Run no blow off valve for the best sound and completely legal!
so BOV does have some fuctionality, instead of just sounding good.
IMO it's the best sound. I like the chattery sound. And that's not a proof of damage, that's called a theory. Here's another one. Bearings and compressor blades are quite strong. Intake charge air might have a mass of let's say, 100grams. Clearly you are completely correct in saying that there will be "more stress and some lag", but i'm looking for some evidence which says that this stress is more than completely negligible.Quote:
Originally Posted by Joel The Mole
Quote:
Originally Posted by string
mmm, running no bov what so ever, physically doesnt sound too bad but seriously does have long term repircussions. Dont really need to show evidence, just go ask any manufacture why then run a bov type device standard? because they are made to last. i mean i dont think most if not all leading car manufactures run a bov just for the hell of it? or because it sounds good ahah. feel free to rebut
I believe that manufacturers run a blow off valve (plumbed back) to avoid noise pollution, and in mass air flow systems, avoid the rich backfire on gearchange/throttle release.
If there was any actual physical evidence derived from a real test, every blow off valve manufacturer on the planet would be pimping it till their last breath. Though, i'll admit, I don't keep up to date, so there very well could be a test floating around somewhere, which is why I asked for 'evidence'.
yeah thats cool on the sound, everyone has there own opinion on it.Quote:
Originally Posted by string
can't really provide any evidence on damage, i can only base this on info i have read, and like sexc86 said, that manufacturors(sp?) fit these on stock cars. but in theory, it does seem completely logical that not having a BOV will cause more damage than having one fitted
OK guys I got the theory down!!
Its very easy to understand but what make/model is eazy to make legal buy running a hose back through the lop..
Just like my PC water kit :wave:
u want a plumb back BOV, try GFB or turbosmart, there pretty good brands
Hows this one?Quote:
Originally Posted by Joel The Mole
http://cgi.ebay.com.au/Go-Fast-Bits-...QQcmdZViewItem
This one looks like what I need
http://cgi.ebay.com.au/ws/eBayISAPI....tchlink:top:au
i'd go the second one, as the first one looks like an atmospheric one.
Quote:
Originally Posted by Sexc86
Dont get a BOV. If BOV are so good. Why dont race cars use them??
Ever watch the Bathurst 1000 back in the early 90's?
Those sierras ran 40 psi racing and 60 for quilifying. Dont hear them going PSSSSHT when they shift
Quote:
Originally Posted by aimre
I thought they would be setup with flat shift, so their throttle bodys would be alwayes open (even gear changes, ie dont have to remove foot from gas peddal) therefor they would never loose boost pressure inbetween gears nor need a way to vent it?... please correct me if i am wrong
Dude if u like the sound of it then get a atmo bov. when turboing a honda i realy dont think your thinking much about being legal. there wont be 1 part under the hood thats legal unless engerneered. So what ever you chose at the end of the day it is illegal on a honda.
So the whole idea is not to get pulled over, so imo id get the pump back so u dont get cop attention. it is tempting tho, they do sound mad and im trying to decide my self which way to ago 2 for my setup as well.
Mine will be completely legal for insurance cover and will be engineeredQuote:
Originally Posted by TEGZOTIC
i would beg to differ, in qld anyway it really isnt that hard to make it legal. Just put aside $80 to go to an engineer to get a blue mod plate pop riveted to your engine bay with the appropriate code for a forced induction conversion. As long as it looks relatively clean/ secure, maybe might need to pass an emmisions test. your fine ;) why spend thousands on a turbo conversion and then be stingy on $80 for a mod plate so you dont have to worry about legalities? it would be the same case for an engine conversion... would be just as illegal as a turbo converion if it wasnt mod plated... in qld anyway im not sure about anywhere else.
In sydney its over $400Quote:
Originally Posted by Sexc86
Quote:
Originally Posted by Sexc86
They still gotta let go to brake. They dont use bovs.
Another reason they put BOVs in factory cars is becoz normal ppl would buy a car from factory that sounds like a pigeon fluttering. They'll b like WTF?
Quote:
In Part 2 of our interview, we speak to a leading industry expert Simon Gishus about Nissan engines, Holden Gen 3 V8s, and directions for modifications...
What are some areas where people often make errors modifying their turbo car?
http://us1.webpublications.com.au/st...4/1457_2lo.jpg
"The classic blow-off valve.
"The blow-off valve is designed as an emissions control device for OE manufacturers. It came about when smaller engines made more and more power using larger turbochargers and bigger intercoolers. As you close the throttle, the build up of pressure and the larger volume inside the intake has to go somewhere; it can't go into the engine because the throttle is shut. Instead, it has to do a U-turn and it comes screaming out the airflow meter. That creates the 'gobble-goggle' sound.
"The gobble-gobble sound is something the public has grown to love.
"The airflow meter is not all that smart and does not realise the air is going in the wrong direction; it therefore measures the air twice (once going into the engine and again going out in the wrong direction). The computer now tips in twice as much fuel as what's required, making it run rich - making it not pass emissions.
http://us1.webpublications.com.au/st...4/1457_3lo.jpg
"Therefore, manufacturers fit a blow-off valve - or a recirculation valve as they are actually called. A recirculation valve opens when it senses manifold vacuum, returning the air trapped at the throttle body to between the airflow meter and the turbocharger. As such, the airflow meter does not take a double reading - the car now passes emissions.
"Unfortunately, we've had people ringing up and wanting the "audible gear change alarm".
""What audible gear change alarm?" we ask. "You know, when the Sierras were running around and just when they went to change gear it used to go whoda-whoda-whoda" they tell us.
""No pal, that is the dump valve..."
http://us1.webpublications.com.au/st...4/1457_4lo.jpg
"Some people do think that at the absolute upper extremes of boost levels - about 30-plus pounds - the blow-off valve does, somewhat, save the compressor wheel and shaft from trying to rotate backwards. It doesn't actually rotate backwards at all - all you're hearing is cavitation. What happens is, you've shut the throttle, the turbocharger is doing 100,000 rpm and now has a boost spike of 50 psi. Because it's working in a higher region than what it's designed for, it slips; it basically does a skid like a car tyre does when you dump the clutch. That's the noise you hear - the whoof-whoof-whoof is the air doing a skid."
Is there any performance gain to a blow-off valve?
http://us1.webpublications.com.au/st...4/1457_5lo.jpg
"We've tested one on a manual gearbox performance car run at Winton Raceway. I think it was running 1 minute 40s back then, but it would lose 2 seconds a lap putting the gobble-gobble valve on. When you look at data acquisition, what you find is - as you change gear - the blow-off valve dumps all the pressure built up through the intercooler and pipes. It then goes back to zero manifold vacuum when you get back on the throttle, you have to build all that boost back up.
"The fact that people think that they keep the turbo spinning is a problem. The people that suggest this have never had an engine on the dyno and never had a turbo tacho in their hands. What people don't realise is, when you shut off the throttle, you shut off the air supply to the engine - this shuts off the exhaust gasses coming out of the engine. When there is no exhaust flow, there is no energy to keep the turbine spinning - the turbo slows down at an alarming rate.
"If you change gears at quite a good speed, you can actually get a boost spike on changes; if you're trying to hold a constant 30 pounds, when you do a racing change you'll get 32-33 pounds when you crack the throttle open again. If everything's working well, you've got a full head of stream waiting to go into the throttle as soon as it's opened.
"I've done this on a rally car and it was quicker through every timed section without a dump valve. You'll never hear a World Rally Car going pssshhht because they don't use a dump valve - you get the woof-woof-woof noise instead."
who said they don't?Quote:
Originally Posted by aimre
lol.
well depends on what race car.
look at the japanese ones.
lol.
geeze you serious? that sux! spose $400 is better then an equally heavy fine/defect + pointsQuote:
Originally Posted by aimre
$400 is steep!..... ehheheh gobble gobble
There's always someone who'll do it cheaper, you just have to know the right people. I don't know the right people and I know a guy up the road from me who does engineering certificates for $250.
In Sydney?Quote:
Originally Posted by string
Bov are used on factory cars (plumbed back to meet adr) to eliminate lag between gears from the throttle being snapped shut and pressure being applied to the compessor blades .
It is for performance only ,it does not kill the turbo not to have one.
Factory turbo cars are set up so that you feel almost instant boost and grunt from the lower to mid rev range where most people do their driving.
That is why factory turbo cars such as the WRX feel grunty mainly from 0-120kmh but not much after due to turbo sizing etc .
The venting of excess gasses keeps the blades spinning between gearshifts therefore the turbo is ready to boost again next gear with minimal acceleration.
Think of this.The factory bov on a WRX is good for standard boost and not much more, telling you that the bov spring tension is good for stock boost so when it vents ,it vents most of the gasses.
Anything more than stock would see the bov leaking under load ,not being able to hold boost.
No i'm not from Sydney but I don't see why a capital city discounts the posibility of cheaper than arse raping prices.Quote:
Originally Posted by Lukezen27
aimre speaks from the heart about this matter it seems haha
wtf,, 80 to 400 buks for a turbo eng certificate, thats NOTHIN... if thats the case who wouldnt do that then. last time i looked into it, it was over 1000buks to get it engerneerd in melb.
Or to eliminate noise, or pass emissions.Quote:
Originally Posted by albii
There are a few reasons why they do it. Read what i posted before.
Also if u change fast enough, u can actually get a boost spike. Due to the throttle closing and the turbo still compressing for a second. When the throttle opens again, all the still compressed air in the piping rushed into the intake manifold, u can get like 2 psi spike, so u get no lag at all.
yeah ok, Lets look at a jap carQuote:
Originally Posted by destrukshn
http://youtube.com/watch?v=roLBHcw8eKA
:D
O look, here a concept car, so no ADR to adhere too
http://youtube.com/watch?v=bR96aWfpWN0
from TopGear, although jeremy incorectly describes whats going on
lol that S2000 got pwned
and that P2 is insane
400 is just to get it looked at once. If for some reason u dont pass, the price only goes up. So it might end up $1000Quote:
Originally Posted by TEGZOTIC
Hm now I've heard that sound I like it :thumbsup:Quote:
Originally Posted by aimre
Sounds mean
I asked a turbo manufaturer/repairs workshop some questions in regard to Bov's and thier effect on Turbos. Hope this clears up any misconceptions or myths that we may have. This is their response:
I asked **** here the same questions as you've asked me, and although he has seen no 100% positive sign of damage due to no BOV, he still recommends using one for over 10psi of boost pressure when using a Ball Bearing turbocharger.
As for the BOV helping keep the turbocharger spooling, I can definately say this works, as turbocharger reversion would definately cause the turbocharger to reduce spool speed quite rapidly. There may only be a small difference in response time, but there is definately a difference.
But im saying without a bov, u can get a spike between changes, so ull never actually fall out of boost.Quote:
Originally Posted by DLO01
Try it one day, remove ur bov, and eye ur boost gauge while changing gears
Thats ok, I was not targeting anyone. Would never do that. Everyone has thier own opinions.
Just wanted to ask questions to the people that actually repair turbos to see thier thoughts. :thumbsup:
Just wanted to share the info with everyone.
i no when my old bov was jammed i had major problems :) honestly why wouldnt u BOV it, its not like its expensive, and it can be done legally. at least then u dont have to be paranoid about it.
i just find it amazeing that different states have these outragous prices for mod plates i mean $1000!!!! wtf do they do?
but i guess we have to pay $2200 for prestige number plates where as in vic its only $400.00 go figure dam goverment and their "non profits"
Becos its another thing that can go wrong. I dun wanna be driving and the piston get stuck in the up position, or it simply just leaking.Quote:
Originally Posted by Aza
What major problems did u have. Ther are hundreds of cars running no BOV and they go fine
any plumback with a pod will make a noise
Hey guys,
So in a nutshell,
I would go BOV on a everyday car and no bov on a race car.
Plumback for legality, insuarance etc and
Vent to Atmosphere for the fully sick "Audible gear change" sound.
Gotta love that sound, I go past pedestrians and they pooh their pants, its hilarious.
Thats my summary of this, and that if you really need to worry about it their are some decent brands like GFB which make BOV's that make no noise and can be adjusted to vent to atmo.
For 100% increased performance and up to 300kw instant gain (proven!), just buy one of these bolt-on BOVs! Will work with N/A cars!
http://www.takakaira.co.jp/accessori...ightpager.html
:cool:HOW COOL!:cool:
Now that's just silly:eek:Quote:
Originally Posted by xenonkuraz
Those Japanese will never cease with their silly (but 100% LOL) products.
http://www.takakaira.co.jp/accessori...ager/type2.wav
LOL @ the sound.
check out the synapse BOV. supposed to have new technology in it and be the fastest bov on the market atm.
You may actually find that you get a raise in boost because as you take your foot off the accelerator, the throttle flap closes, and the air stuck between the turbo and the throttle body has nowhere to go (well, except for back through the turbo).Quote:
Originally Posted by aimre
Also, there are also a few problems when not running a blowoff valve. I have listed them below:
As the air has nowhere to go except through the turbo, it is in fact slowing the turbo down. This is counterproductive performance wise, as you want the turbo to be spinning as much as possible.
Pushing against the normal direction of airflow is bad. Why? Well, air going backwards through the turbo backwards is adding additional load on the turbo bearings (remember, it will be fighting against the air going through the exhaust turbine). Also, the air exiting the turbo is already hot from being pressurized, so the additional heat can cause unwanted expansion (even enough for the impeller to touch the housing sometimes!).
Air rushing back through an airflow meter will cause one of two things. It can either slow down any air already passing through it, causing the engine to run lean (not fun), or rush back though the airflow meter over a short time, causing the engine to run rich. In some cases, this can cause the airflow meter to 'max out' (too higher reading), causing the ECU to get grumpy, go into limp mode, etc. This is generally not an issue if your vehicle uses a map sensor to determine airflow.
As far as legalities are concerned, my understanding is (and I'm more than likely wrong, but anyways...) that vehicles with airflow meters require them to be vented back for emissions purposes (big puffs of black smoke and crackling from the exhaust are frowned upon by the RTA :)). Cars without airflow meters can have the bypass valve vent to atmosphere, but the noise must be under a certain level (which is near impossible). This would more than likely vary from state to state, too.
i would happily replace a turbo every year just to hear that dose.
TUUUUUUu, tuuuuuu tuuuu tuuu tuu tu
haha, yeah cant get enuf of the dose,Quote:
Originally Posted by Bludger
wif mine, i change it around every now n then, when i wanna dose sound, i just disconnect the BOV, but if i want to hear BOV, just re connect it, you can sorta feel a diff though when BOV is connected
Air flow meter?
that synapse thing is crazy.
and -
dose, gotta love dose, commonly refered to as cooler dose
I know why the spike happens, but if u open up the throttle quick enough, the air rushes back in your plenum, before its gone "back out" the turbo.Quote:
Originally Posted by strafe
Also, wtf airflow meter? Plz stop your copy/pasting mate
My opinion - If the 90% of turbo oem cars come with a recirculation valve, when the manurfactures are all focoused on keeping costs down, then theres obviously reason for them using one. They dont just go sticking random parts in there cars, they do testing and evaluating, if it was worthless it wouldnt be there.
Tons of top level race cars use a BOV, for example:Quote:
Originally Posted by Blue
http://i106.photobucket.com/albums/m...zz1987/jkm.jpg
If they didnt believe the benifits out weighed the extra weight, they wouldnt run one, simple.
Its a car by car basis, on some it may be basically completly pointless, while on others it plays an important part.
Heres a good read, seems unbiased, unlike alot of other BOV talk - http://hrc.s10.forumsplace.com/viewtopic.php?p=15
IMO this argument is completly and utterly pointless, unless youve studied fluid dynamics to a very high level, and you can actually understand how this surging air acts on the turbos mechanicals, which none of us have.
Aimre, you seem dead set trying to convince everyone theres no benifit, do you understand how the surging air effects the turbines mechanicals? Im guessing not, which really dosnt make what your saying any more than an uneducated opinion, the worst kind there is.
To run one, or not to run one, simple question.
Run one if you like the noise or you want your turbo to be working in the best possible conditions, and the extra cost dosnt bother you.
Dont run one, if you dont like the noise, are super paranoid about weight reduction, are scared of it malfunctioning, you like the dose sound, or your happy to risk maby reducing your turbos working life, to save some cash.
Quote:
Statement :- Compressor surge will not damage a turbocharger. It's only air being chopped by the compressor wheel!
Fact :- DEAD WRONG! People who state this fact should have their licences taken off them for being a danger to a perfectly good car. Compressor surge is one of the leading reasons for premature turbocharger failure. It runs a close second place to problems such as poor oil delivery to turbo bearings, high boost with ceramic coated wheels and hitting a turbocharger with a 9 pound hammer because it's too big for the space in the engine bay. But regardless of how many BOV companies put special notes on their turbo spec sheets and their websites, people who believe that the fluttering sound coming from their turbo when they back-off is only air being chopped by the compressor wheel, continually destroy turbochargers and then blame the turbo for being either too small or not built well enough to handle their engine. Believe me, I've seen stock standard CA18DET's with a bit more boost and no BOV destroy turbo bearings, shafts, wheels and in some extreme cases even the housings for one reason, COMPRESSOR SURGE.
That fluttering noise isn't just the excess pressurized air trying to rush back past the compressor wheel in the wrong direction. It does some horrible things that a lot of people aren't aware of. This is a tech article on BOV's not compressor surge so I will outline the other hazards here but leave the full explanation for the Compressor Surge article.
Hazards associated with compressor surge :-
1 - The air rushing back through the compressor wheel actually applies end load to the shaft. Although a turbocharger can handle some end load their primary direction of movement is spinning around. When this compressed air hits the wheel and creates the fluttering noise it actually pulses against the wheel. This pulsing at speeds reaching over 100,000 rpm causes the shaft to hammer backwards and forwards on the thrust plate. Eventually the plate wears out and the wheels hit the housings. How does it do this when th air is coming from one side of the wheel? Well providing the wheel dosn't completely stop it's still trying to push air into the inlet tract, the air trying to get out forces it's way around the front of the wheel pushing it back, onto the thrust plate.
2 - When a compressor wheel is being spun by the turbine wheel it has air being sucked into the smaller side of the wheel and being pushed out the larger side. Where it comes out of the comrpessor wheel it's at a tangent to the wheel itself, which means it's coming from one side of the wheel, not the middle. When this compressed air rushes back into the housing it hits the side of the wheel and creates a lot of side load against the wheel and shaft. This side load is what causes bush bearing turbos such as the T25 and T25G to destroy themselves rather quickly when subjected to compressor surge. The amount of side load on the shaft actually chews into the bush, regardless of how good the oil feed is. Ball bearings aren't as prone to this problem, but it does mean that eventually the bearing will have to be replaced, and a lot sooner than they realistically should be.
3 - When this air rushes back into the comrpessor wheel in the wrong direction it actually starts working the same as an exhaust brake on a truck. It puts pressurised load on the wheel and slows it down. Depending on the boost this slowing down effect can be very quick. There have even been instances where the compressor wheel has come to such a sudden stop with so much reverse pressure that it will try to spin backwards. Not a good thing to happen. It will result in a shattered wheel or snapped shaft and in the worst case an exploded turbo housing due to one of the previous two outcomes.
4 - When you back-off, if the car is fitted with a boost controller (be it electronic of mechanical) the wastegate will start to close. This means that the turbine wheel will begin to increase speed. Now knowing that the compressor when hit with this excessive back pressure of compressed air slows down rather quickly, we can clearly see that if one end of the shaft is trying to speed up and the other is slowing down, eventually something has to give. Normally after it does, it's the hip pocket that starts giving the most.
5 - This is a problem which isn't as big as the others, but it's a problem none the less. On Nissan's and some other vehicles fitted with "hot wire" AFMs, the air coming back through the compressor housing has sometimes reach the AFM. This can result in damage to the sensitive resistors which measure the air coming into the engine. AFMs are not really designed to handle pressurized air although some American cars do have "blow through" AFMs which are in the inlet tract after the turbocharger outlet. AFM's aren't a cheap item to replace if it does get damaged though. If it doesn't damage the AFM then you've come out of it not too bad, but now we see another problem involved in this as well. If air comes through the AFM the opposite way to the proper direction of air flow, then it can in some cases actually cancel out the incoming air flow. This will result in the AFM reading no flow what so ever and suddenly trying to shut down the injectors to stop the engine from over-fuelling. Due to safe guards such as knock sensors and O2 sensors the quick instanance of this happening won't normally damage an engine. So as I said, it's not a major problem, but still a problem you need to be aware of.
To Fit or Not To Fit, That is the question!
sorry, my brain doesn't function as well as your brain, i just love dose
LOL:)
Exactly my thoughts, i got a stock recirculation valve from an s15 with 25k on the clock for $9, for my future setup, cheap piece of mind.Quote:
Originally Posted by Aza
If somone were to get a nice new expensive turbo, i think its definatly worth the slight extra cost, to get a bov, so your not trying to surge air back through it. Treat it right and give it the best possible working conditions.
The only reasons i can see to skimp on this part, is because your doing a setup on the cheap, and are using a cheap 2nd hand turbo.
EDIT: Or cause you love dose^^^:p:thumbsup:
I'm going to buy one for these just to be on the safe side plus I want my setup completely legalQuote:
Originally Posted by Muzz
http://cgi.ebay.com.au/ws/eBayISAPI....ayphotohosting
Ok so does this guy you quoted have this super fluid dynamic knowledge u speak of?Quote:
Originally Posted by Muzz
How can u say im uneducated? i have also shown articles saying that the use of a BOV is pointless. You must know it all cos u quoted some guy off some forum, and i just quoted the guy that owns nizpro and is responisble for this.
http://youtube.com/watch?v=6RpGKP_FsTc
Im sorry
Btw, luke, if ur gonna buy a bov, dont buy them cheapies, they leak.
I don't so much care if they work or not but want my setup to pass whatever tests needed to make it legal?Quote:
Originally Posted by aimre
They are required are they not?
Man that's red hot
O, lets not forget the people on calaisturbo who have had their cars dosing for 4 years without rebuilding turbos.
Is it or is it not legal to run without a BOV?
Can anyone just answer that?