Stainless exhaust baffle advice please?

[Ozzie54321]

My S2 gives out am annoying rattle from the exhaust, no problem at idle, but when it's nice and warm and the revs are dropping, there is a metallic rattling sound from the rear of the car, I can hear it especially when on a narrow walled road. The thinking is that the baffles have become loose, so I guess it needs repacking. It's a SS aftermarket job, so I've found a guy with tig welder who can do the job, but what should I repack with, are there any recomendations, or is just something like rock wool? Would there be a performance difference from doing this, as I guess no baffles at all would let the engine breath better and stuffed full of "stuff" may choke it, I guess it's a balance, what are the thoughts?

[King Fisher]

Ozzie54321 said:

My S2 gives out am annoying rattle from the exhaust, no problem at idle, but when it's nice and warm and the revs are dropping, there is a metallic rattling sound from the rear of the car, I can hear it especially when on a narrow walled road. The thinking is that the baffles have become loose, so I guess it needs repacking. It's a SS aftermarket job, so I've found a guy with tig welder who can do the job, but what should I repack with, are there any recomendations, or is just something like rock wool? Would there be a performance difference from doing this, as I guess no baffles at all would let the engine breath better and stuffed full of "stuff" may choke it, I guess it's a balance, what are the thoughts?

Just cut it all out and be done with it ;-)

[steve j]

Maybe the exhaust is touching the chassis.

[King Fisher]

steve j said:

Maybe the exhaust is touching the chassis.

Nick has this problem with his, it's a constant battle of adjustment unfortunately (as once the exhaust gets disturbed, usually by a speed bump, it comes into contact with the chassis).

[Gerald-TVR]

Double check all exhaust clamps brackets etc - had the embrassment of taking my car all the way to Devon, 250 miles or so return, because my silencer was resonating only to be told all they had to do was tighten the clamps from the manifolds to downpipes and then to the exhaust system

[techbotics]

Ozzie54321 said:

My S2 gives out am annoying rattle from the exhaust, no problem at idle, but when it's nice and warm and the revs are dropping, there is a metallic rattling sound from the rear of the car, I can hear it especially when on a narrow walled road. The thinking is that the baffles have become loose, so I guess it needs repacking. It's a SS aftermarket job, so I've found a guy with tig welder who can do the job, but what should I repack with, are there any recomendations, or is just something like rock wool? Would there be a performance difference from doing this, as I guess no baffles at all would let the engine breath better and stuffed full of "stuff" may choke it, I guess it's a balance, what are the thoughts?

the exhaust place should be able to guide you...

re performance and louder = faster, according to my ass dyno this is not true my current quieter exhaust seems to give the car more power than the old loud one.. I guess exhaust design is important too..

thanks

Damian S3

[Griffinr]

techbotics said:

re performance and louder = faster, according to my ass dyno this is not true my current quieter exhaust seems to give the car more power than the old loud one.. I guess exhaust design is important too..

thanks

Damian S3

I would agree subjectively, now my exhaust has been modded to make it quieter the car seems quicker, is definately smoother and I'm sure the fuel gauge needle heads south slower. Oh yes, and I think I can hear music, there must be a radio in here somewhere!!
Rob.

[Ozzie54321]

What were the "mods" made to your exhaust to get these results? Mine is a SS aftermarket, but no idea how "high tech" it is?

Griffinr said:

I would agree subjectively, now my exhaust has been modded to make it quieter the car seems quicker, is definately smoother and I'm sure the fuel gauge needle heads south slower. Oh yes, and I think I can hear music, there must be a radio in here somewhere!!
Rob.

[Griffinr]

Had the front half cut off as the pipe diameter was too big and had individual straight through silencers towards the front. It was very load and rasped horribly when you revved it.
The new section has twin 50mm pipes back to a powerflow straight through 2 in 2 out oval box located under where the standard silencer would be. This is connected to the old rear section which is 54mm pipe. The tailpipes have homemade perforated inserts that I made a while ago and have left in for the moment, may try taking them out one of the days.
Ground clearance under the box is 3 inches which may be a problem on bad roads but I am planning to stiffen up the springs anyway which should help.
I think the key to a good exhaust is getting the optimum back pressure for the engine to work correctly, yes you want it free flowing but you can go too far.
I shall be at Chatsworth on Sunday if you want to take a look.
Rob.

[techbotics]

mine is twin pipes from manifold into 2 cherry bomb style cans then a large single with crossover pipe to twin v8 style end pipes.

zorstec made if for me.

cheers

Damian S3