gota911

almost any good muffler shop should be able to do this. I had my local Meinekie (sp?) shop do my 996 mufflers. The shop manager did it himself "off the books" for $60.

gota911

almost any good muffler shop should be able to do this. I had my local Meinekie (sp?) shop do my 996 mufflers. The shop manager did it himself. He originally quoted me $80, but offered to do it "off the books" for $60, which I agreed to do.

billco

Would this mod affect emmissions. Has anyone had theirs smog checked after this mod?

Gundo

No problem - this hack is after the cats. But CA is a strange state with crazy emissions rules.

Matt(inMA)

I just took a couple of Gundo's pictures with me to the muffler shop along with the mufflers and walked them through what I was looking to get done. One thing I did point out was the importance of not having any of the cross-over pipe inside the muffler pipes. It was all complete in a day and the results are really great! I took them home, sprayed the cross-over pipes with VHT paint and reinstalled.

Matt

buz3rd

may you explain what the underlined means?

Carrera Mike

I'd make sure that these low priced shops are using stainless/high quality pipes or they'll just rust-through in time 'cause of disimillar metal.

buz3rd

showed the muffler shop the gundos pix and he commented that the connecting pipe could be done at nearer to the inlets so that more bypass is done and hence louder..

I wonder where is the optimum spot... he said gundos design is to hide it and also easier to do since its larger space.

See pix for what i mean.. the green line is where he said could be done

buz3rd

buz3rd

how is that different from gundo design?

basically, another pipe is attached out from the muffler like a secondary outlet.

i think once the the exhaust enter the mufflers, it will have little effect no'
?

gota911

The mod in post #7 is how the PSE is set up, but PSE has a valve to open/close the pipe on the left. These mufflers have 3 chambers and this mod lets exhaust out of the first chamber which has with minimal sound dampening.

The gundo design takes some of the exhaust (and sound) straight from the cat and sends it out the exhaust tip, so it bypasses the muffler completely.

Either of these versions will sound very similar to PSE. It is a "no lose" choice, no matter which one you choose to do.

buz3rd

thanks again.

Cant picture how the addiotnal outlet pipe creats more noise though.

care to explain?

I picture it like ths..


Gas from inlet enters muffler box where is is muffled and quiets down and leaves the outlet full stop.

how does addional outlet pipe create more noise.

Apologize but i someone please shed some light !

purrybonker

When the new short-circuit pipe is installed you do not want it to protrude within the inner diameter of the original pipes or the resulting lip will create interference or turbulence in the flow of exhaust gasses. This could have an adverse (albeit minor) effect on temp, wear and power output of the engine.

When the new pipe is installed it should be welded up to, rather than being inserted into and welded to the orginal pipes.

buz3rd

oh so now i get it..

anyone knows the gains for this set up



It combines a partial bypass setup and an addiotnal outlet pipe which supposedly is like the mk3 mod which gather more noise from the muffler box.

Also, anyone knows if the 997 can and pse can are the same inside and only the pipes outside sets them apart?

milez

To, gota911, gundo, buz3rd and many others. Gents, as a newbie, just wanna thank you for the posts and advice...I been following for awhile! This is my 1st post. I am about to "hack" my 3.4 2001 996 C4 mufflers. Will do the muffler to outlet pipe with 2inch(50mm) SS and inlet to outlet pipe with 2inch - maybe smaller, as space is tight . Are my sizes ok? Presume there will be no resonance. I just want some noise to wake to nhood! I live in SouthAfrica. Your commets and crit are welcome. Thanx, Milez.