BOVs?

[Rupewrecht]

thread split as requested!

[zappy65]

Does anyone know of any Techs/ Workshops that have any major knowledge on the BP/ BPT platforms, im talking tuning and mechanical knowledge of turbo setups etc?

[project.r.racing]

Yes my old room mate:-

Company: Cox Automotive Services / Redline Garage.
Contact Person: Dave Cox.
Location/Address: 3/5 Service Rd, Maroochydore 4558.
Contact Number: 07 5443 3507.

He did his apprentiship in the mid 90s at a Mazda dealer, knows all there is to know about Mazdas engines from that era. Know everything about my car! He has done multiple GTX and GTR set ups on TX3s and built a MX5 racecar with quads. Knows all there is regards turbo applications into motorsports, mainly drag and drift. If he cannot answer your questions, then no one can...

Ryan

[zappy65]

Ryan you are a god sent, thanks mate....ill give him a bell after Christmas...

[project.r.racing]

Ryan you are a god sent, thanks mate....ill give him a bell after Christmas...
No worries John, I'll let him know you'll be contacting him. Oh and btw - the pic of the engine bay in your GTX plans thread was his work...

[zappy65]

Mate that is awesome, after seeing that plumb back method, i want it...one question though, why did he weld it so the air flow from the BOV was facing toward the pod and not toward the turbo?

[project.r.racing]

Since the purpose of a BOV is to release pressure from building up and destroying a turbo. Having the plumbing venting back directly into the turbo would defeat the purpose I think. Plus it sounds awesome when the BOV goes off inside the airbox/filter. Much like a rally car. But ask Dave, because most likely I am totally wrong as usual.

[zappy65]

I thought the purpose of the plumb back was to send the extra air into the turbine to keep it spinning when under boost...?

[DavoAust]

i thought a plumb back was a legal way of releasing the extra pressure as atmospheric ones aren't legal. i guess if you plumbed it into the manifold you could possibly use it to keep the turbo spooling, although i doubt big sudden pressure increases would be good for the system long-term. Also would you want your turbo to suddenly spool for a sec every time you shifted before dying off?

[zappy65]

A plumb back is a legal way but it has its advantages....the whole point of plumb back is to keep the air circulating, it does have proven effects on FI cars, this is why im opting for this option, plus i want to be sleeper...the air that the BOV does put back is not necessarily strong...just enough to keep it spooling whiile you are below the torque range of the turbo...meaning the turbo will spool up quicker and stronger....

[Rupewrecht]

A plumb back is a legal way but it has its advantages....the whole point of plumb back is to keep the air circulating, it does have proven effects on FI cars, this is why im opting for this option, plus i want to be sleeper...the air that the BOV does put back is not necessarily strong...just enough to keep it spooling whiile you are below the torque range of the turbo...meaning the turbo will spool up quicker and stronger....

...do you have any proof to back this up?

The point of a plumb back is for emissions and noise purposes, not to keep the air circulating. There will be virtually no difference between the performance of an atmosphere venting BOV and a recirculating one

[project.r.racing]

^Agreed^

[zappy65]

...do you have any proof to back this up?

The point of a plumb back is for emissions and noise purposes, not to keep the air circulating. There will be virtually no difference between the performance of an atmosphere venting BOV and a recirculating one

No, i dont have any evidence but word of mouth and unfortunately these days that aint very reliable...ahhahaha, this is what ive been told by other turbo enthusiasts...

[project.r.racing]

This is what ive been told by other turbo enthusiasts...Ricers that drive S13s or R33s right? lol jk/z

The point a a BOV/PRV is to vent the compressed air out of the system. When a driver jumps of the go pedal, the throttle closes, cause the compressed air to find another way out. the only direction is back thru the turbo. Compressed air being pumped back into the turbo's blades causes them to become brittle and damage after a while. It's called compressor surge, it sounds awesome but kills turbos within 12-18 months. Blades break, go places the souldn't, you know the rest...

But as natural air goes thru a turbo, it gains oily, exhaust,fuel gasses and there for under EPA rules for environmentally friend emmisions, the compressed gases are vented back into the intake system, where they are sucked back into the turbo afterwards as per normal turbo operations.

All gases must go thru the cat convertor, so all gases and recycled back thru the system, etc.

normal air flow:-
airbox - turbo - ic - throttle - cylinders - turbo - cat - exhaust

vented air flow:-
airbox - turbo - ic - bov/prv - turbo (again) - ic (again) -throttle - cylinders - turbo - cat - exhaust

Did I make sense?

Ryan

[LordWorm]

Since the purpose of a BOV is to release pressure from building up and destroying a turbo. Having the plumbing venting back directly into the turbo would defeat the purpose I think. Plus it sounds awesome when the BOV goes off inside the airbox/filter. Much like a rally car. But ask Dave, because most likely I am totally wrong as usual.

you plumb back to before the turbo.... (i.e. you plumb back from the charge pipe, to the intake pipe before the compressor)

does the job well, but higher boost applications would obviously benefit from an atmo setup.

I don't really understand the "emmissions" side of it, the air isn't mixed with fuel at the point it is "blown off" - and a near instantanious return to vacuum conditions in the engine would cause any unburnt fuel in the manifold to be sucked through the engine as per normal.

I think its more a case of throwing fancy words at the legislation to make it carry more weight....but its primarilly a noise thing from what i can tell.

for a street car, i can't see why there would be any appreciable difference between a plumback and an atmo bov, all else being equal. However, there can be issues if you are running an atmo bov with a MAF sensor, as, depending on the location of the BOV, you can vent already metered air (this is an issue alot of the mazdaspeed protege guys in the states have)...it all comes down to placement of the bov at the end of the day, but most like to keep the stock location and so plumb back is the way they have to go unless they delete the MAF by going to a stand alone.

Of course, i could be wrong too.....but thats my understanding of it.

[zappy65]

Ricers that drive S13s or R33s right? lol jk/z



Ryan

They probably say the same things about Astina's....lol and no actually the person/s who fed me that was actually off this forum, i dont wish to casue fuss so i wont disclose furthur info....i understand how they work, i jst think its stupid, im with Lordworm, i think its all a whole heap of Cr@p and noise pollution...is the main reason behind it all...but without saying i do want it to be legal...and i dont care much about the WWWHHHOOOSSSHHH sound...+ im going to have a FMIC so anyone who knows what to look for will know..hahahaha DONT MESS WITH JOHNNY!!!

[bourbon]

can this please be talked about in another topic...back on track..this is a reccomendations thread not a general smack talk on BOV...

[Aaron]

Compressed air being pumped back into the turbo's blades causes them to become brittle and damage after a while. It's called compressor surge, it sounds awesome but kills turbos within 12-18 months. Blades break, go places the souldn't, you know the rest...


Not quite. Many early factory turbo cars didn't run BOVs and didn't have those failures. They are linked to boost pressure and driving style.

However once you start to fiddle with things it does become more of an issue. You can basically end up witha compressor stall situation where the intake (compressor) side of the turbo stops spinning, while the exhaust side still has "drive" from the exhaust gases. It's not unheard of to have the shaft snap under that condition.

However the biggest and worst part of having a lack of BOV is that you get a significant drop in performance on/after gear shifts as the compressor is being slowed or stalled whne the throttle is lifted and then needs to "spool" back up again to an efficient speed for the gas flow. This takes time and energy. With a BOV the compressor doesn't generally get that significant forced slow down so when the throttle is opened again (and BOV closed) it's pretty much immediately at the same boost generating capability as when the throttle was closed.

Anti-lag systems work off this same principle, except using a lot more smarts they essentially run the turbo as a gas turbine to maintain turbine speed whenever the wastegate or BOV would normally be reducing the speed of the turbo. There's all sorts of bypass and tricks involved but in simple terms the turbo is always kept at an optimum boost generating speed.

A.

[project.r.racing]

You can basically end up witha compressor stall situation where the intake (compressor) side of the turbo stops spinning, while the exhaust side still has "drive" from the exhaust gases. It's not unheard of to have the shaft snap under that condition.

However the biggest and worst part of having a lack of BOV is that you get a significant drop in performance on/after gear shifts as the compressor is being slowed or stalled whne the throttle is lifted and then needs to "spool" back up again to an efficient speed for the gas flow.Well now I know, I was close, didn't realise about the proformance side of thing, but if you think about it, it make complete sense...

Ryan

[rodhog]

You want the truth

lets go back

way back

Original turob cars- they dind't have them.

Theyu had true BLOW off valves- Et - turob's Vl turobs' FJ20's had a nice mounted one 626 /capella turbo's

Most all throttle body injection and all only used the main valve as a pressure release.

All cars had some form of turbo surge on backing off.
It did not fail them.

In fact if you look at the most comon turbo failure, of then and back then?
Bearing oil seals. Now look at the most comon failure to day - of a turbo charger Bearing oil seals.
Nothing has changed.
It was in alot of cases lack of - water cooling.
Most comon fialure with the Vl's was it but notice how even the early mazda 626 and tx-5's didn't suffer it. depending on year they ran a water cooling section and added a oil cooler. Same goes for the toyota's and Rx-7's

Note the early Tx-5's beofre unleaded ran around 9psi boost. limited in the unleaded era to 6psi. Ford's cheap way of saving the motor. instead of chaning the timming in the dizzy.

Bpass valves arrived during the same time - As Noise emisson went up in 1988 - Note it was 1990 it was effective in Australia along with the rear 3rd main stop light.
You will note how all the Mazda 626's in 1987 had a rear 3rd top light along with 323's and I think Bg's etc
but the telstars did not - They were not sold in Europe - So they did not complie untill the law came here.
That year brought in tougher noise dampening, and emissions.

Now why is it they bypass it and then put it back in.
Factory cars have two reason one - for Airflow meters.

The other is Plain EPA.

There is a rule. for cars And you must obey it under all states etc blah blah blah. I went through this. QLD your right - I love your mod plate.
in NSW it's easy to get around but hard to get it approved. BLah blah
Vic - Your screwed - it's jsut plain expensive and pain full . The rest I have not dealt with.

Effectivley - One air has entered past the AIR FILTER - which must not contrain contamints - like oil - again a little law that is nothing really.
But once it past by the airfilter all that air must be consumed by the engine. OR out via the carbon canister eg filtration system.
Note how all oyur little solenoids have little proberly mitsubihis symboled filters ontop of the out let.
Once air enters it is considered dirty and must be expeled correctly.

This is why for- example PCV is run the way it is. some of you may remember a 187's in a only EH or even HQ with a 202 with just breathers.
in 1975/76 the first of the carrbon emisson laws came in to play here.
This is effectivley the same law that applies to the BOV.

Now you might say but it's only compressed air. That's right but your factory air intake is also a factory Recycle air intake.
So your not just compressing air.
but how come some cars come from EPA and are allowed I've seen 200sx's leave etc.
Simple the turbo is only compressing air.

but how come the BOv is still plumb can't it go open.
but when they do a drive by noise test, it pecks and it fails.


I hope that explains BOV's too you all.

Also just because I know in NSW it's going to get tighter. I'm in one of thme positions where I might be asked to sit on report again to try and defend owners. I tryed to get a mod plate system here but engineerrs here are well - trying not too. Some of you may or may of not heard but year the trail has ended and not too well either.

but The added bit is alot of you don't realise those nice fancy BODY Kit's Add noise to the driveby sound levels. especially on newer nicer cars as. I understand it effects post 93 models moslty.

So try and keep your body work tight and alot of the extra plasti underneath helps keep it quite alone with under bonnet dampening

[dave0r]

in NZ its "GAY" to have the BOV plumbd back.

Vent to Atmo is so legal here its a crime not too :)

[project.r.racing]

in OZ its "GAY" to be from NZ. lol

We couldn't get John Howard to sign the Kyoto Agreement, but they fine us for venting into the atmosphere, go figure???

[rodhog]

that's because when the laws came in

Australia was no nuclear in our back yard - We hate the French.
Back then australia was we will lead the way with recycling.

It's amazing how under a long 11 year of No progress for the future we have been left behind.


As for NZ - I have to say they have there own problems.
If they ain't complaining about overstayers or - how saying how wonderful the place is. I would not have a reason to tell them to leave Bondi.

It's funny how the lot living here think NZ is the greatest But they Won't go back. LOL Mind you I'd rather swap them for some of our own overstayers here LOL

[dave0r]

in OZ its "GAY" to be from NZ. lol

We couldn't get John Howard to sign the Kyoto Agreement, but they fine us for venting into the atmosphere, go figure???


LOL , i was waiting for a post like that

There are good points to both our countries,, but also bad points...we'll leave that outa this thread

i like that fact we get almost every jap import made and that there isnt a law yet about BOV's

[zappy65]

NZ is the best place to import cars...FULL STOP...my cousin can import almost any car he likes, which also doesnt help the new car market...BUT WHO CARES....anyway, since Plumb Back is legal and doesnt get as much attention im opting for this well...option...Ive been harassed enough by cops who think my elec oil pressure gauge is mechanical instead....i got a defect for this the other week but i fought it and won ...in like an afternoon...hahaha

[rodhog]

a lot of people say using no bov can cause dammage to the fins of a turbo compressor, but i don't think there is any actual research to prove this as yet.

.


You want to know how to do that. Leave a car stock run whole thing stock replace stock jap intercooler might be small but use one XR6 turbo intercooler = bent fin on turbo compressor.

[hitokiwi]

put simply...

atmo - goes 'psht' loud and is illegal as it dammaged the environment with deadly emmissions!


Heres what i dont understand and i've never gotten an answer to this question. I thought the idea of a blow off valve was to relieve the pressure when the throttle butterfly vavle(s) are closed? If this is the case it would be mounted on the intake side and there shouldn't be any damaging emmisions as its just compressed air?

Feel free to have a go at me, but i'd really like to have an answer to that question.

[dave0r]

Having NO blow-off valve can cause some damage to the compressor wheel if going WOT with more than a few PSI;
Shock wave can bounch back and damage fins.
the compressor wheel will stop so fast that it spins backwards as the rest of the turbo spins forwards ( think about this one)


compression surge is a good for you to g00gle newman!

Edit; by having a plumbback setup you can lessen the "lag time" between fast gear changes as the air already there, HP wise, dont think it makes a differecne

[zappy65]

Edit; by having a plumbback setup you can lessen the "lag time" between fast gear changes as the air already there, HP wise, dont think it makes a differecne

I think this is what my friend meant ay?

[dave0r]

put simply...
a lot of people say using no bov can cause dammage to the fins of a turbo compressor, but i don't think there is any actual research to prove this as yet.
.

I was talking about the "but i dont think there is any actual research to prove this as yet"
Been covered many times on turbo related materials, ie books, internet etc..Hence the "g00gle" comment

edit; its like saying "theres not real evidence to show that he anti frezze helps protect ya car when its all Ali block/head" its just asking for a internet bash

[project.r.racing]

a lot of people say using no bov can cause dammage to the fins of a turbo compressor, but i don't think there is any actual research to prove this as yet.no? only about 10 years of rallying in europe and japan in the 80s, when turbos where 1st introduce to rallying, they kept breaking blades and shafts from compressor surge.

there does not need to be any research done for this, it simply happened in motorsports and the manufacturors devised ways around it. i idea was a pressure release valve. developements of this in todays world are know as blow off valves.

ryan

[rodhog]

no? only about 10 years of rallying in europe and japan in the 80s, when turbos where 1st introduce to rallying, they kept breaking blades and shafts from compressor surge.

there does not need to be any research done for this, it simply happened in motorsports and the manufacturors devised ways around it. i idea was a pressure release valve. developements of this in todays world are know as blow off valves.

ryan


ONe does have to remember how much boost they were running back then - think of the Group B rally cars. Alos turbo technology was still in it's early ot mid days of being really reliable.

but the fact is, it have JOB to do. Stop compressor surge.

Why plumb back, it's quite obvious to most that 90% of cars that used turbos when realsed had early EFI. 90% based on ? Bosch desgin systems Deltronic and simialr. You know that airflow meter made by denso is just Registered desgin copy. In fact alot of stuff is. Either made by denso or Mitsubishi.
Now being air flow metered. I'm sure they would have realised early on any leak would have lead to a bad reading or air. As when oyu remove air that has been read by the airflow meter it has to be replaced. only one place to do it. It goes on. Backfire ETc I think most know about the overfuel

By why no Atmosphere. It's not just compressed air. Every factory air intake is more then just a intake it's a recycle centre. Even todays cars have some of the Carbon canister going in this way and not the manifold like of old.
all these things can't be going anywhere but through the cat converter.

These are nto issues for people to question because they are desgin rules which in turns makes them LAW. Meaning you can't Fight it.
It's like if EPA test a Brand new factory off the floor FORD or Holden with say 30,000kms on it. by now like alot of them one or more of the Cat converters has proberly died. They don't last. But if you got finded and said to the maker at the dealership I wanti t replaced under warrenty - they can take out the warrenty clause and - claim - WEAR AND TEAR PART.

Most might if it's rattleing just replace it for being nice.
But if you said you got defected fined by EPA and say everyone had to replace there cats when they fail - Well .................................................. ................

I don't think I have to go into the politics of it all but leave it at this.

A factory bypass - is Factory it's legal.

NO BOV bypass factory - is legal

Adding BOV to non bypass or BOV fitted car - is not legal

Adding BOV period is not legal, becuase it's not test and it's not passed a ADR law.

Because the law in it's palinest form wants your car to be as the manufactuer desgined and built it to be for Desgins which by definition are the LAWS.

This is why CAPPA CSV and I think AVO turbo world spend extra on getting there kits ADR approved so that they don't get suded.
Everyone else claims "This is off road or Racing use only item" This clause/line SAVES them.
Theorecitcally it means also if you add it you use it in any other situation - You are breaking the law.

[sik astina]

I heard the same thing too with the F1 cars like zappy65 said before in the thread.

My Bro did my setup in my astina. With the plumback BOV aiming right into the turbo blades, keeping the air circulating white shifting gears. You can really hear my BOV even tho its plumback :)

Best to stay legal and keep the police off ya back :)

[reshiek]

Hey guys, did not think it was appropriate to open another thread, when there was one for BOV.
anyways, i would like one for my BA Astina 97, i do not have any engine mods in the car what so ever. is this legal?i seen in many rx7 1988 models:)
is there a particular one i need to look for?any places to buy them?
thanks in advance

[project.r.racing]

um? you need a turbo 1st dude...

[derb]

um? you need a turbo 1st dude...

you can hook up a BOV to any car. :p

you can also buy this kit that is a little box and speaker under the bonnet and it makes a PSCHTT noise every time you lift off the throttle.

[reshiek]

um? you need a turbo 1st dude...

haha i cant afford that at the moment.but project R-why do i need one?like why can i get one, with stock engine??i never understood that part. maybe you can elaborate on that a bit??thanks heaps

you can hook up a BOV to any car. :p

you can also buy this kit that is a little box and speaker under the bonnet and it makes a PSCHTT noise every time you lift off the throttle.

are you being sarcastic?
do you mean a fake blow off valve??

[bourbon]

hey bud, with blow of valves you can install them to any car...as long as it turbo'ed youll be able to do it...

in a naturually asperated car it wont work


and yes you can get fake blow off valves...you can get them to put in your exhaust and it will make the sound :p a bit dicky but some like it...

[70NYD]

haha i cant afford that at the moment.but project R-why do i need one?like why can i get one, with stock engine??i never understood that part. maybe you can elaborate on that a bit??thanks heaps



are you being sarcastic?
do you mean a fake blow off valve??

a blow of valve is a little device that releives manifold pressure due to the compressor (turbo) when throttle is released to help with throttle off deceleration. without one venting to the atmosphere or recerculating it back around to the front of the compressor you would not slow down when you let go of gas to quickly, and it might place unnecesary straines on the turbo as the exaust gasses might not be sufficient to spin the turbine and drive the charger against all that pressure that is there. so what ryan said is right, to make the sound you need the turbo. u can put one on there but it will not do nothing as the pressure in the manifold will never get above atmosphere :)

Welcome to AGT :D


edit


damn my slow typing

what bourbon said :)
those little ones that go in the exhaust can be obtained from ebay. IMO a lot more that just little dicky

[reshiek]

Thanks for your help guys.

http://cgi.ebay.com.au/Fake-Turbo-Whistler-Whistle-Blow-Off-Valve-BOV-Sound_W0QQitemZ250315404532QQcmdZViewItem?hash=ite m250315404532&_trkparms=39%3A1|66%3A2|65%3A1|240%3A1318&_trksid=p3286.c0.m14

is this what you meant 7onyd?

bourbon why cant you do it??and is there further damage if you do it on a normal car?

[bourbon]

it just wont work with out a turbo...you wont have enough pressure build up for it to even make a noise...

[Rupewrecht]

bourbon why cant you do it??and is there further damage if you do it on a normal car?

Because, as said above, an NA car does not produce the manifold pressure to set off a BOV when you back off. It's useless to even put one on as it just wont work. It wont do any damage though.

[project.r.racing]

bourbon why cant you do it??and is there further damage if you do it on a normal car?well after spending $200 for a metal fabrucated intake pipe and welded a $300 BOV to it. all it will do it nothing. as no air will flow thru it - as not enough air pressure it built up to pass through it.

[reshiek]

allright i will follow your advice, specially from rupe, bourb and project.
been reading some of your previous posts from the other threads and you KNOW what your talking about:)
*sigh* i wish i could make my car sound cool.
oh well

[bourbon]

http://cgi.ebay.com.au/Fake-Turbo-Whistler-Whistle-Blow-Off-Valve-BOV-Sound_W0QQitemZ250315404532QQcmdZViewItem?hash=ite m250315404532&_trkparms=39%3A1|66%3A2|65%3A1|240%3A1318&_trksid=p3286.c0.m14

is this what you meant 7onyd?


thats the type bud!!!

[reshiek]

thats the type bud!!!

i don't think i was to disgrace the astinagt forums, if i ever get a astinagt sticker. so i shall give up on this project. i just wish i can speak to some in sydney(someone who has a astina)ask them what they recommend i do.
thanks anyways bourb

[bourbon]

you dont need to talk to some one in sydney...thats what the forums are here for to ask and get information...for a starter what model do you have???

[reshiek]

BA Astina 97, which i love.
i have a sound which i am proud of.
pioneer 5650
front 5x7 some cheap brand
pioneer 6x9 260 watts
rockford fosgate sub 12 inch 300 max(do not like much bass)
rockford forsgate amp to support sub
rockford 4 channel 56 watts x 4 @ 4 ohms RMS
sound is done for me. do not need anymore.

bourb, i said wanted to meet up with people in sydney. cause i see the qld guys which is many of you just asking advice and doing stuff.

[project.r.racing]

nice big sounds set up.

fake BOVs do not make a car sounds good.

a nsw astina is the same as a qld astina.

if you cannot make it sound good, make it look good instead, rims, lowered, chin lip. :)

[reshiek]

nice big sounds set up.

fake BOVs do not make a car sounds good.

a nsw astina is the same as a qld astina.

if you cannot make it sound good, make it look good instead, rims, lowered, chin lip. :)

Thank you
haha i know what you mean, but i am very much a noob when it comes to my car and what i can do.
I been trying to make sense, by reading one of the sticky thread. for putting lights for the interior like the stencil of the dash. the instruments to be white ( i hope that makes sense)
hope to get a HID kit for my lights.
and the rims, personally do not like chromes. hence why if you saw the pics on the other thread (BA Astina Tyres).
sorry project what is a chin lip:o

[70NYD]

BA Astina 97, which i love.
i have a sound which i am proud of.
pioneer 5650
front 5x7 some cheap brand
pioneer 6x9 260 watts
rockford fosgate sub 12 inch 300 max(do not like much bass)
rockford forsgate amp to support sub
rockford 4 channel 56 watts x 4 @ 4 ohms RMS
sound is done for me. do not need anymore.

bourb, i said wanted to meet up with people in sydney. cause i see the qld guys which is many of you just asking advice and doing stuff.

mmmm i like :D nice sound system man ;)

a chin lip is a small skirt that goes around the front bumper :)
have a look at my readers ride for a example