Disconnecting plumb back hose from stock BOV

[buzurk]

Hey guys,

tried to do a seach but the word BOV is too short

What i would like to know, are there any issues with running a non plumb back bov on the car, as in 100% atmo???

If not, then there should be no reason i cant pull the stock plumb back hose off, and block it, there for allowing my stock bov to vent to ATMO

Anyway as a play around we tried this and it seems to work well!! only issue on cold start the car is a lil rough for 10 secs

Can anyone see any real issues running this>

[Nepharius]

Umm off the top of my head

Every time you change gear (or step off the gas) you will run MEGA rich and probably backfire pretty badly if you rev it hard.

I believe running so rich may damage your cat and cause it to prematurely fail.

If it matters your car will be illegal (at least in Vic but probably in many other states)

If you are just doing this for the noise, may I reccomend a short ram intake? Most of the fun, none of the draw backs... that I know of.

[MPS2NV]

I tried it years ago, sounds great but the factory bov is poo and leaks under vacum, the occossional back fire at closed throttle lol

[TUFMPS]

It will sound better but it will drive terrible. Something about the STD bov makes the gear shifts smoother???? I tried full vta for awhile and put the stocker back on for something and the car was so much nicer to drive. Sold the bov straight away. I did miss the crackle and pop when driving hard- sounded tuff as! No damage caused and 3 years/100k of driving.


Also:: The stock valve blows very slowly and sounds stupid when venting. Grab a proper one if your going to do it. although just to prove my point go and test it lol. you wont do it again.

[Doug_MPS6]

Nepharius is dead right. Forget it, unless you have a piggy back that enables you to incorporate fuel cut. All you'll do in 100% VTA without this measure incorporated is wash your cylinder walls with raw fuel and dilute the cylinder wall lubricant. And have lots of backfires. And soot out your cats. And risk blowing out your exhaust prematurely. None of this is good.
Get a duel port BOV and run it 50:50 for the same sound but no disadvantage.

[Caffeine Fiend]

Hey guys,

tried to do a seach but the word BOV is too short

What i would like to know, are there any issues with running a non plumb back bov on the car, as in 100% atmo???

If not, then there should be no reason i cant pull the stock plumb back hose off, and block it, there for allowing my stock bov to vent to ATMO

Anyway as a play around we tried this and it seems to work well!! only issue on cold start the car is a lil rough for 10 secs

Can anyone see any real issues running this>

As per all the replies above. I wouldn't mess around with trying to get this working. If you want the BOV noise, grab a Turbosmart and VTA. Yes it costs money, but it's doing it properly

[Doug_MPS6]

CAFFIEND, I think you mean 50:50 with the Turbosmart, not 100% VTA. If so, I agree.

[MattMPS3]

A lot of guys in the states were running like this, short of the occasional pop on gear shifts I don't think it caused too many other issues, I think Doug may be over dramatising the issue a little, these engines are known for having fairly high levels of fuel dilution in their oil due to their DI nature.
The technical reasons as to why this occurs is that you are confusing the MAF sensor, you are allowing metered air to escape the system, which the ECU cant account for and adds fuel for air that isnt there.
Im not sure how technically minded you are, but I will try and explain, the MAF sensor calculates the amount of air coming into the engine for it to set the amount of fuel it needs to inject to maintain a stoichiometric afr, if you vent this air to the atmosphere the ECU has no record of it leaving the system, believes it is still there and adds the required amount of fuel, as the air is not in the system , the fuel added gives you a momentary rich environment, which doesnt completely burn, resulting in unburned fuel entering the exhaust manifold / turbine housing, the temperature....etc etc, pop out the exhaust.

Do you really need your bov to vta, its already pretty loud in full recirc with an after market intake anyway (pretty sure I read you had one somewhere), if you just have to have the loud pssshhh sounds, I recommend a 50/50 bov that will keep the ECU happy as part of the air is being recirculated.

[Caffeine Fiend]

CAFFIEND, I think you mean 50:50 with the Turbosmart, not 100% VTA. If so, I agree.

Yes mate, the dual port.

[rogwick]

I'm also inclined to recommend the Turbosmart Dual Port unit. Run it in 50/50 and set it correctly. I used to get the occasional backfire but in saying that I didn't get round to tensioning the spring correctly. I still maintain that most of my noise is intake (induction) related, the CAI is fairly loud when on boost, especially driving through Perth city

[Caffeine Fiend]

Rog, what's 'sdw' on your cai pipe mean?

BWAHAHAHAHAHAHAHAHAHA

[rogwick]

"Suck Da Wind" Thanks for asking!!

[SarcasticOne]

Rog, what's 'sdw' on your cai pipe mean?

BWAHAHAHAHAHAHAHAHAHA

"Suck Da Wind" Thanks for asking!!

thanks for the laughs guys.

[Grajy]

Jon = Not a fan of Atmo Vent.

-1
Atmo Vent = Buy a VL Commodore...

[TUFMPS]

even vl's dont do atmo vent. they do no bov at all.

[Doug_MPS6]

BUZURK, Hi. Back to your original query. Apart from all the prior comments including my own, I think just reefing the bypass pipe off the stock BOV and blocking the bypass extension to the turbo inlet would just look like a bodgy job. You would certainly VTA 100%, but with all the negative results already described.

The function of the bypass it to divert pressurized air back to the inlet side of the turbo when the throttle plate closes, rather than allowing a standing pressure wave to surge back from the closed throttle plate to the outlet side of the turbo and bringing on compressor stall. A 50:50 bypass still permits this turbo-protective process to happen, while also relieving some of the boosted air to atmosphere to give the classic BOV discharge sound. There is no other real benefit to having a noisy BOV, apart from to one's ego if one is that way inclined.

An adjustable BOV like the Turbosmart enables you to tune the BOV so that it dumps just enough air into bypass to keep the turbo happy, but also discharges the rest to atmosphere. I ran 50:50 for a while, but I have so much air dammed up in my long plumbing system that I was still getting compressor stall on throttle closure, so I have replaced the VTA blocking plate and converted the BOV to 100% bypass again. One problem I find with the Corksport bypass extension is that it is a significantly smaller diameter than the OEM one, and I find this restricts the bypass somewhat. Anyway, I have no BOV "chuff" now but I attract less attention and improve overall shift performance and keep the turbo spinning, ready for throttle opening again, as opposed to having to let it spool all the way up from a stalled condition. BTW, that's another VTA negative I forgot to mention.

[MPS2NV]

The passion of the BOV debate.

[buzurk]

Thanks for the replies guys who helped, ill get myself a real bov then

the debate is a good one, the comments about the VL, get over it, i have a turbo car and if i want to make noise i will!

[KLEEMO]

I'm also inclined to recommend the Turbosmart Dual Port unit. Run it in 50/50 and set it correctly. I used to get the occasional backfire but in saying that I didn't get round to tensioning the spring correctly. I still maintain that most of my noise is intake (induction) related, the CAI is fairly loud when on boost, especially driving through Perth city

Rogwick, Do you remember how many turns you gave your Turbosmart BOV when setup??? as ive got the same one!!! Believe it's correct (well runs well) but my tension caps more facing upwards then to the upper lHS like yours!!! just wondering thats all!!!

[rogwick]

I haven't got round to setting mine up for VTA (with no backfire) At the moment I have it blanked. I've been meaning to try VTA with correct spring tension.
I know Doug has a Turbosmart unit too and I believe he has set his. It's a guess check and improve and also depends on mods (back pressure of exhaust) perhaps making a difference from my setting to yours?
I still get the occasional pop but that's when I'm off throttle usually coming down hill in 4th/5th gear.