To keep or not to keep..................?

[Critical_Mass 10]

Right, I had a raceland 6 branch fitted and although it didnt give any power gains (wasnt expecting that anyway) it did seem to slightly improve throttle response, which i was happy with. BUT when i first fitted it, it had a 'sucking' noise when giving the car revs - even more so when engine is under load. I was informed that this is simply the exhaust gases going through the tubular steel (makes sense) and it would stop when the carbon builds up in the tubes. But it hasnt stopped at all. Even when the manifold is wrapped the 'sucking' noise is still there :scratch:

 

Now, ive just fitted a Milltek sport cat and now the 'sucking' noise is even worse. I hooked the car up to vagcom and the O2 reading is fluctuating from 0.99 - 1.07, but no lambda fault codes, which im told is the lambda trying to adjust constantly and implies theres a leak before the lambda. The car went into the garage tonight to get CV joint front discs/pads etc fitted and have asked my mechanic to make sure the flexi joint etc are on tight enough, so will see how it is when i get it back.

 

To be honest its annoying me as it sounds awful, almost like the exhaust is blowing. So im considering just going back to the standard manifold and before i had the noise.

 

Can anyone advise me otherwise or what i can do to get rid of this noise or whether im right to go back to the standard manifold?

 

HELP!?? :lol:

 

PS - sorry to drag the above on a bit :lol:

[volksworld13 0]

at idle /or driving conditions, the sensor reading will not remain constant it will fluctuate between , 0.1v and 0.9v.

it maybe blowing, but then again i havent owned nor fitted one of those manifolds.

[Toad 0]

I don't think the lambda cycling is anything to worry about, AFAIK it's what they do.

 

Dunno about the noise though.

[Critical_Mass 10]

So the reading in vagcom the 02 reading is voltage? The thing is the reading doesnt jump from the lower end of the range to the higher end it will go 0.98 0.99 1.00 1.01 1.02 etc all the way up to 1.07 and then back down to 0.98.

 

Even if the lambda is ok and the manifold flange isnt blowing, theres still the 'sucking' noise to put up with :lol: Im kind of hoping the flange is the cause of the noise.

[SamG40 0]

No it isnt the voltage I made that mistake when first hooking up to VAGCOM. A Lambda does put out the voltages mentioned above but the reading shown in VAGCOM is the 02 mixture reading. That sounds about right I believe. You have a problem if it does actually stick on a reading like I had, then the Lambda is buggered.

[Critical_Mass 10]

No it isnt the voltage I made that mistake when first hooking up to VAGCOM. A Lambda does put out the voltages mentioned above but the reading shown in VAGCOM is the 02 mixture reading. That sounds about right I believe. You have a problem if it does actually stick on a reading like I had, then the Lambda is buggered.

 

ah fair do's! Cheers.

[Critical_Mass 10]

Ok... it turns out it is blowing ever so slightly at the flange that meets the cat. So im going to get it back on the ramps to seperate and refit. As theres only a slight gap the blowing isnt loud, and sounds worse when the car is jacked up - almost like the sound is being masked when the car is on the ground idling.

 

Not looking forward to having to get back under the car :(