Need help for stock bpv/bov. Done something and want to know if it is safe

Hi guys. Don't know too much about my new ms3 gen1 yet so Im gonna speak in very basic terms.

The stock bypass valve on the gen 1 has 2 pipes coming out of it. One thin 1 at the front (I think that's vacuum)?? and a fatter one at the back (the 1 that goes back to the turbo)??

Anyway, a mate showed me that if I disconnect the fat rubber pipe at the back of the bpv, and seal it up so it is air tight, it gives off a very loud whoosh (vrrrrchhhhhh) like a blowoff valve.

It sounds amazing, but I wanted to know if by doing this, will it damage anything at all? Or is there any reason I shouldn't have it disconnected?

Any feedback would be greatly appreciated
Thanks!!!

it will backfire alot and i would say get an aftermaket bov and a sri and still have the noise safley.

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Originally Posted by Jrbris

it will backfire alot and i would say get an aftermaket bov and a sri and still have the noise safley.

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Yes, I had ordered a turbosmart 50/50 BOV but I couldn't justify paying $400 for it now after I heard the sound from disconnecting the rubber pipe.

However, when I am in first gear changing to second it jitters a bit once I take my foot off the accelerator (not nesecerily high revs, just driving around in the street). I'm wondering if that will go away once the ecu learns about the disconnected pipe?

And yes, still looking into a Sri

:)

personaly i wounldn't run it like that.

No the ecu will never learn about the VTA unless it's retuned by someone. You're also running slightly lean anytime you reduce throttle.

+1 on just buying a hot air intake.

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Originally Posted by Nuliaj

No the ecu will never learn about the VTA unless it's retuned by someone. You're also running slightly lean anytime you reduce throttle.

+1 on just buying a hot air intake.

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Yes I'm looking for a hot air intake (cai) ;)
but I just want to know if it will damage anything? After all, isn't it just air??

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Originally Posted by Alexai

After all, isn't it just air??

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LOL yes its just air. Air that has been measured on entering the system to calculate the proper/safe Air to fuel ratio. So if you let this air escape without the ECU knowing about it it will cause the engine to get a bad mixture with isn't good.

CAI or SRI with stock BOV will give plenty of sound

Dont let mates who KNOW nothing about these engines play with them . As Toddy stated above . Also as stated the ECU will NOT learn that a plumb back pipe is closed off DUH.

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Originally Posted by Oldhead

Dont let mates who KNOW nothing about these engines play with them . As Toddy stated above . Also as stated the ECU will NOT learn that a plumb back pipe is closed off DUH.

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Good point ... But I'm just wondering why you chose the word "know" to capitalize ? Surly the keyword is "nothing" ;)

Also if you run the BPV with the recirculating valve closed off you will get compression surge and may damage your turbo

Thnk you all for your input, I have returned everything back to stock and the car is running a lot better, I guess just time to start looking for a Sri

if you want a loudish noise when your valve vents but still want to keep it legal, why not invest in a Forge V1 BPV. Nice metallic noise when venting and you can pick them up for around $200

As I said in another post somewhere, there are plenty of "mates" long on enthusiasm and short of actual practical knowledge, experience or smarts, and I think a lot of these cars that folks are inclined to tinker with can suffer from that.

It seems remarkably few people look at an original assembly and ask themselves the first question: "why is that there and what function does it fulfill". Plainly it is not just decoration. Then ask the next question: "if I make a certain change to this configuration, what will the effect and consequences be?".

Such an approach will save a lot of headaches.