CBV vs BOV

[rumsawatti]

Whats better and why? I know they do pretty much the same thing but are there any big differences, CBV is probably more environmental friendly, lol but what would you rather run? it may seem like a noob question, but i am a noob and i dont know much about turbo systems :)

[epson1]

the fuck is a cbv

[colombianbryan]

circulated bypass valve???

[The_Creeper]

Run the cbv.
not entirely sure if thats the same as what im thinking, but I'm assuming you mean a recirculating release system?

[sleeper108]

I think he's talking about the cars that are boosted without a BOV, which as I understand is possible, but not without a ton of tuning. PBM shop people seem to know a bit about it, so I would ask them for specifics. I'll be sticking with a BOV

[The_Creeper]

Well i just prefer recirculating systems. and its a little more sleeper style if your not going **ka-chew* when your beside someone you wanna race.

[!Zar!]

No bov at all.

Awesome response, and sounds like a million virgin sluts singing.

[ch1873857]

No bov at all.

Awesome response, and sounds like a million virgin sluts singing.

:ddog: yessssssss

[rumsawatti]

circulated bypass valve???

Almost, compressor bypass valve..it releases the pressure into the intake instead of the atmosphere, i dont think it makes the sexy blow off sound but it does the same job...

[Pandapants]

Compressor bypass valve (CBV) / Blow off valve (BOV) (http://people.physics.anu.edu.au/~amh110/blow_off_valve.htm)

[Kingtal0n]

If you do not run a blow-off valve, you risk damaging the turbocharger.

On a MAF based car, it is always a good idea to run a re-circulated bypass, especially on a push-type bypass valve (such as greddy type-s).

[rumsawatti]

^this is info im looking for, thanks man.

[90240sx07]

^^^ what about on a map based system?

[revat619]

^^^ what about on a map based system?

on a map system you can run atmospheric without any adverse affects.

[NoPistons!]

If you do not run a blow-off valve, you risk damaging the turbocharger.

On a MAF based car, it is always a good idea to run a re-circulated bypass, especially on a push-type bypass valve (such as greddy type-s).

Sounds like dsm 101 from 10 years ago.....



1. There is no hard evidence that on a well maintained turbo damage will occur if a bov is not used. They can break with or without. Thrust/shaft bearing failure can occur from a multitude of factors PLUS flutter but flutter alone isn't going to kill it.

2. blow through maf. It even works on 4g63 eprom ecus with stock turbo and maf location. =D Blow off all you want.
No bov at all.

Awesome response, and sounds like a million virgin sluts singing.

......and it doesn't fuck up your turbo as bad as historical regurgitated "information" claims. Response is good. That and short route piping is pretty much the only way i'd design a turbo system. Simple and effective.


I bet if you ziptied a juicy steak halfway to a bov you could make it sound like a queef.

CBV is a bypass. Not a vent. SOOOOOO if you're paranoid about flutter causing damage yet want to be kinda stealth and not run a boost leak (blow off valve) that'd be the way to go.

[Kingtal0n]

Sounds like dsm 101 from 10 years ago.....


1. There is no hard evidence that on a well maintained turbo damage will occur if a bov is not used. They can break with or without. Thrust/shaft bearing failure can occur from a multitude of factors PLUS flutter but flutter alone isn't going to kill it.

When the factory installs Bypass valves on all turbocharger equipped vehicles they are just wasting money right? because engineers design useless things to spend extra $$ on.
no offense intended sir, but please do not post information like that when you personally have done no testing and have no proof. If the factory recommends oil changes every 2,500 miles do not come on here and say you can drive 6,000 miles instead, and that there is no hard proof going longer wont damage anything. Bypass valves are there for a reason.


2. blow through maf. It even works on 4g63 eprom ecus with stock turbo and maf location. =D Blow off all you want.


A blow through maf is not a high quality solution, and again, there is a reason the factory puts the maf sensor before the turbocharger. Besides issues where turbulence and bends give intermittent signals at various throttle positions, a blow through maf also presents an intricate plumbing issue and is rarely installed with a correct orientation. It is out of the scope of most DIY's.

[Kingtal0n]

on a map system you can run atmospheric without any adverse affects.

This is good information. If you want an atmospheric bypass you can run a MAP sensor and the computer will have no idea that any air is entering or leaving the system, since tuning is based on air pressure instead of mass.
Of course, you will generally need a stand-alone computer to acquire such a device.
And finally, map sensors are not as good as MAF sensors when it comes to fuel efficiency. A map will generally be much more dependent on the oxygen sensor when it comes to finite air/fuel adjustments.

[LayNLow]

When the factory installs Bypass valves on all turbocharger equipped vehicles they are just wasting money right? because engineers design useless things to spend extra $$ on.
no offense intended sir, but please do not post information like that when you personally have done no testing and have no proof. If the factory recommends oil changes every 2,500 miles do not come on here and say you can drive 6,000 miles instead, and that there is no hard proof going longer wont damage anything. Bypass valves are there for a reason.
.

I have run without a bov for about 2 years now on the same turbo with no problems whatsoever. As have many other people

[jonsparrow]

i run a greddy type s that vents to atmosphere an iv never had a single problem with it. loud and proud.

[!Zar!]

When the factory installs Bypass valves on all turbocharger equipped vehicles they are just wasting money right? because engineers design useless things to spend extra $$ on.
no offense intended sir, but please do not post information like that when you personally have done no testing and have no proof. If the factory recommends oil changes every 2,500 miles do not come on here and say you can drive 6,000 miles instead, and that there is no hard proof going longer wont damage anything. Bypass valves are there for a reason.

Hey Florida, CA18det never came from the factory with any sort of BOV.

So suck it.

[Corey121]

I run a none circulated blow off on ka-t, and as for not running one it pushing air back into the turbo when the throttle body shuts seemes dumb to me, its doing the opposite of spooling the turbo, its trying to spin the turbine backwards making the turbine and bearings work harder.

[jonsparrow]

certain cars like VW GTI's an shit like that have to have recirculating BOV's cause they will stall every time it vents to atmosphere. personally i love BOV's and loud spooling turbos. an i love the flutter sound.
off topic but to those who think the flutter is bad i direct you to the titan supra. iv seen this car in person an it is serious. now i dont think the would be running that kind of BOV on a car like that if it was bad.

534LGpaueZ4

[rumsawatti]

^i seen this car a bunch of times, actually titan motorsports isnt far from where i live, awesome supra...

when was this video taken? cause last time a saw this car they had taken the spoiler off...
http://i854.photobucket.com/albums/ab106/smokescreen91/STP62395.jpg

sorry for off topic :o

[codyace]

No BOV vs BOV debate is old. I can't say I've ever heard of a car not running one chuck a turbo any faster than one with. Maybe in 100.000 miles, but not in the 10,000 that most POS sr swapped 240's see.

With that all said, I do not like the way a non BOV turbo setup runs. It's easy to confuse 'response' with a sudden rush/jerky response (similar to the big turbo coming into boost feeling to me).

Gotta think when that throttle blade is closed, it's filling the system, and stalling out the turbo...so while some argue that the system is ready to go and is fine, the truth is you need to respool the turbo in order to get it spooling again (as you technically loose boost pressure when this happens). Not to mention the fact that you've loost exhaust velocity too...again this causes that 'response' feel, that is realty respooling the turbo.

How 'different' are they really? Meh hard to say...I'm sure you could measure. I just don't like the way they react (not to mention they are harder to control the throttle with mid corner).

And anyone that supports blow through MAF either has
1. Lucked out in placement and all the variables with the system (doubtful)
2. Has no clue how a proper running draw through setup runs, thus thinks their setup works better because it runs better than their crappy draw through tune.

(And I have way to many DSM friends that have gone back to draw through that would support me statement there)

Edit: Like anything with cars, there are the two sides of this: 'Works' and 'Works Well'. Some are fine with it working, others are not. Tomatoes Potatos

certain cars like VW GTI's an shit like that have to have recirculating BOV's cause they will stall every time it vents to atmosphere. personally i love BOV's and loud spooling turbos. an i love the flutter sound.
off topic but to those who think the flutter is bad i direct you to the titan supra. iv seen this car in person an it is serious. now i dont think the would be running that kind of BOV on a car like that if it was bad.


That's surge, not flutter.

[cotbu]

Actually, sounds like both. Crossing surge line and flutter dump.

Sent from My Highly Tuned Vibrant!

[jonsparrow]

its an old video. i didnt take it. but its been online for ever.

[s14unimog]

I have run without a bov for about 2 years now on the same turbo with no problems whatsoever. As have many other people

years don't matter, miles do; as Cody stated. OEM's are looking for high mileage reliability. That's why most OE BOV's remain open under the least bit of vacuum.

And anyone that supports blow through MAF either has
1. Lucked out in placement and all the variables with the system (doubtful)
2. Has no clue how a proper running draw through setup runs, thus thinks their setup works better because it runs better than their crappy draw through tune.


Cody, I agree with everything I deleted from your post, but wanted to add to your list. Another problem with a blow-thru setup is that the MAFS ends up rereading metered air. It's the same reason you can't/shouldn't run a MAFS right off the compressor inlet; there is too much back and forth air movement.

I really think a recirculated BOV is the best setup since you reduce the surge & stall symptoms, reduce the restriction the turbo must over come to fill the charge system, and keep track of metered air (MAFS only). Surely this is why 99% of OEM's assemble their charge systems as they do.

Edit: it seems from the link above describes a CBV as merely a recirculated BOV. So same difference. I've never heard the CBV acronym

[!Zar!]

I have my blow off valve tight enough to surge at low boost, and blow off at higher boost.

Get the awesome surge sound, and blow off sound.

SHIT IS SO RAD

[s14unimog]

^Sick.


msglth

[codyace]

I have my blow off valve tight enough to surge at low boost, and blow off at higher boost.

Get the awesome surge sound, and blow off sound.

SHIT IS SO RAD

I'll be the first to admit that a turbo surging does sound awesome, especially after a nice hard dyno run and throwing the brake on quick CHA CHA CHA