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Exhaust Control Valve Location From Previous Owner Doesn't Look Right

Joni Boi

By Joni Boi,
in R Series (R30, R31, R32, R33, R34)

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Joni Boi Contributor

Joni Boi

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Posted (edited)

Hey guys,

I just bought my R34 two days ago, it runs good and I love it. I noticed the previous owner had a APEXi ECV exhaust control valve fitted to the exhaust and control lever next to the hand break. I asked him about it and he said he hasn't connected it up. But the next day I looked under neath the car and saw it is connected but the butterfly valve isn't moving. That's not why I'm here though. I saw that the valve is located in the centre of the car's exhaust pipe. Normally they would be fitted at the end of the bore right? Have a look at the pics:

5_zps3gfzf8sr.jpg

1_zpsaijbcrjm.jpg

2_zps9yzy1hen.jpg

From the other side (passenger side)

3_zpsldvshtx7.jpg

exhaust_zpscm1oc12z.jpg

My concern is if that butterfly valve were to close, the exhaust fumes have no were to go. Usually they fit these control valves onto the end of the aftermarket exhaust and have an extra hole behind the valve so when it closes the fumes are forced into that opening and will travel down the length of the muffler usually 3 times before it exits (so I've heard) and that makes the muffler silent. Does anyone about these things? Does that setup look right? I'm planning on making the valve work so it will be handy to use for when I'm starting my car at 5am in the morning so I don't wake everyone up in the neighborhood, or if a bored cop tries to follow me.

Edited by Joni Boi
Joni Boi Contributor

Joni Boi

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Posted

The valve is never fully shut, also doesn't matter where it sits.

Less exhaust flow means less noise.

Oohh really? I thought it would shut it completely

Joni Boi Contributor

Joni Boi

Posted
  • Author
Posted

Yeah, I'm thinking of taking it apart and see whats what. Just seems odd why it would be located there, that's why I'm asking if anyone has seen this before.

GTofuS-T Grand Master

GTofuS-T

Posted
Posted

My concern is if that butterfly valve were to close, the exhaust fumes have no were to go. Usually they fit these control valves onto the end of the aftermarket exhaust and have an extra hole behind the valve so when it closes the fumes are forced into that opening and will travel down the length of the muffler usually 3 times before it exits (so I've heard) and that makes the muffler silent.

What you're describing/expecting here is something like the varex muffler (as below), what you've got is just a butterfly valve in the pipe, which should have a mechanical way of stopping it from being completely shut. The only reason I can think of placement would have an impact is if the valve couldn't handle the heat being closer to the turbo than say the muffler which it's had a split second to cool??

varex_Settings.jpg

jiffo Mentor

jiffo

Posted
Posted

I bet you'll find the valve plate is either limited such that it can't fully close as John suggested

OR the plate has a heap of small holes to restrict the gas flow/noise.

A bit like the sheet of holey metal we'd slip in the cat flange joint to instantly lose those dB.

Joni Boi Contributor

Joni Boi

Posted
  • Author
Posted (edited)

What you're describing/expecting here is something like the varex muffler (as below)

varex_Settings.jpg

That's exactly what I had in mind. I've never dealt with these things before, that's why it was odd to me.

what you've got is just a butterfly valve in the pipe, which should have a mechanical way of stopping it from being completely shut.

Yeah must that. Thanks guys :biggrin:

Edited by Joni Boi

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