On the bottom of my Down Pipes there are 2 other pipes coming from the wheel archers and going to the exhaust what are they?? . Also do i need the crappy aluminium sheilds on down pipes because it sounds like ones blowing underneath it but when i looked i can't see anthing because of it.

 

DAVE

Dave,

 

The Crappy Aluminium Shields are the heat shields for your cats, I have taken mine off as they rattled because 2 of the bolts holding them had sheered off, makes no difference them being off just don't park on dry grass after a long journey!!

 

From your description it sounds like the AIV's, I know they are a pain in the arse and make your wheel arches gurlge (at idle) as they are attached to a box behind the wheel arch which fill with water and 'gurgle' until drained.

 

I had mine done, drained and a small hole drilled at the lowest point of the box and that lets out the water to stop it collecting. Symptom? Can you hear 'gurgling' behind you arch at idle? (it does sound like your exhaust is blowing even though it's not)

 

I had this problem, looking for a blowing exhaust and it was my AIV's 'gurgling'!

 

But on the other hand I could be on the wrong lines and in that case ignore me!

 

 

Matty.

 

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Hi Matty thanx alot for the reply, Ive already taken the Cat heat shields off and the cats come to think of it but my down pipes had an aluminium casing on them filled with fibre glass well did have as ive ripped it off now. I had a lil hole in the exhaust where the mounting bracket meets but sorted now. Could u tell me what the AIV's do please. When I looked at an after market exhaust I dont rememeber seeing the holes that they screw into so do i need these AIV's. Most interested, cheers mate Dave

Nissan's description :-

 

The air induction valve sends secondary air to the exhaust manifold, using a vacuum created by exhaust pulsation in the exhaust manifold. When the exhaust pressure is below atmospheric pressure (negative pressure), secondary air is sent to the exhaust manifold. When the exhaust pressure is above atmospheric pressure, the reed valves prevent secondary air from being sent back to the sub-air cleaner.

http://www.300zx.org.uk/terminology.htm

 

 

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Z32 technical article index

Andy P,

 

So that's a no then! Still clear as mud to a non techie like me!!!!

 

Dave,

 

I know they are not needed but they put them on, makes no sense at all.........I can't honestly see/hear what they do. If they are to do with what AndyP mentioned mine are buggered as they now have holes in them, makes no difference to performance or anything else for that matter but with the holes drilled in them they dont fill up with water and do not gurgle anymore!

 

Matty.

 

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Dave

...I got fed up with the gurgling as it comes back even if you clean everything out - so I took the whole lot off. No difference re performance etc though the car is lighter. I might have a problem at MOT time re emission readings - I'll let everyone know if I do - but you'll all have to wait till ...shit, I can't remember when the MOT is due...

 

good luck

 

Jack

thankyou very much everybody ,

now i know wot they do now and im now goin to take them off and weld the holes up.or i might even buy a new stet of pipes.

thanx

dave