deadening manifold ringing

[Pupp]

Decatted Y-piece and decatted TVR manifolds (no reversal cones)... makes quite a 'ringing' racket at tickover/low rpm, especially when cold and probably intensified by lumpiness due to the cam profile. Wrapping seems like it should damp some of the resonance but I'm wary of rot and/or cracking that might result from that. Any other ideas to tame it (short of a nice set of ACT pipework)?

I'm assuming it is the walls of the 'fat' area that are pinging so wonder whether just wrapping that to the Y-piece clamp might be an option (less chance of issues on the simple form of that section)?

[dogbucket]

Rightly or wrongly I just wrapped the pre-cat area after taking them out to deaden the ringing. Have not had any problems but the car is garaged so does not get damp ever.

I used the grey carbon impregnated wrap and wired it on as it is more robust than the plain white stuff.

It has suppressed the ringing which is the main thing.

[roseytvr]

dogbucket said:

Rightly or wrongly I just wrapped the pre-cat area after taking them out to deaden the ringing. Have not had any problems but the car is garaged so does not get damp ever.

+1 and how damp can the precat area get? Its well protected from water and surely the temprature it runs at would boil off water almost immediately IMO. That said I know some have had problems but until I wrapped mine the ringing was not good

[Alexdaredevilz]

No rust, no noise, do it

[SILICONEKID340HP]

I have the ACT decat Y piece and it still makes a clatter type noise.This is the answer..smaller bore Y piece and manifold.

[MADMAX2]

every ACT y piece sounds different mine sounds like the earth is vomiting and the sky is caving in when i give it some!! along with a sleeved straight through exhaust its one of the loudest!!

[Pupp]

Suspect it's not the large bore size as such that causes it but the fact that the gases are expanding into the volume it affords after exiting the primaries. As an alternative to wrapping, I'm wondering whether doing something to alter the accoustic properties of the manifold wall there might be worth trying... even something as low rent as a couple of jubilee clips or an exhaust clamp just there to alter the frequency response of the steel. Probably just end up with an equally irritating noise but at a different pitch

[carsy]

I`ve not heard people complain about Clives Y piece, i wonder how his differs.

[Meatball]

I tried exhaust wrapping the standard y piece after de cat and it still sounded terrible, act y piece or clive f options the best way to go.

[Pupp]

It is an ACT Y-piece that's fitted; I'm tring to damp the ringing of the manifolds

[Simon says]

Pupp said:

It is an ACT Y-piece that's fitted; I'm tring to damp the ringing of the manifolds

I would try and wrap the pre-cat area as mentioned already 1st I think its a case of some ring slightly and some are a nuisance mine are the former fortunately I have no pre-cats with the ACT y piece but stock exhaust system cant see that wrapping just this area would increase the risk of cracking the manifolds as this area runs much hotter with pre-cats installed standard

[Pupp]

Simon says said:

would try and wrap the pre-cat area as mentioned already 1st I think its a case of some ring slightly and some are a nuisance mine are the former fortunately I have no pre-cats with the ACT y piece but stock exhaust system cant see that wrapping just this area would increase the risk of cracking the manifolds as this area runs much hotter with pre-cats installed standard

Job done, time will tell. Seems a bit less raucous without having driven it yet...

As said above, I suspect the cam charateristics of each motor will be a major determinative factor in the noise (big pulses = more ringing)

[SILICONEKID340HP]

Simon says said:

would try and wrap the pre-cat area as mentioned already 1st I think its a case of some ring slightly and some are a nuisance mine are the former fortunately I have no pre-cats with the ACT y piece but stock exhaust system cant see that wrapping just this area would increase the risk of cracking the manifolds as this area runs much hotter with pre-cats installed standard

Got the same setup as you ,i must say it does get on my nerves but my son loves it , He thinks it sounds like a Yank motor.The problem is the manifolds and Y piece were designed for cats ..Ask V8FROG he does not have the problem ,correct diameter pipes..

[Simon says]

Pupp said:

Simon says said:

would try and wrap the pre-cat area as mentioned already 1st I think its a case of some ring slightly and some are a nuisance mine are the former fortunately I have no pre-cats with the ACT y piece but stock exhaust system cant see that wrapping just this area would increase the risk of cracking the manifolds as this area runs much hotter with pre-cats installed standard

Job done, time will tell. Seems a bit less raucous without having driven it yet...

As said above, I suspect the cam charateristics of each motor will be a major determinative factor in the noise (big pulses = more ringing)

I would tend to agree with that