sound with stock to ssi heat exchangers

[47silver]

we like the sound of our 75 stock system.
But I have a set of 74 steel heat exchangers and a stock 2 in 1 out muffler.
though I realize that hp will go up a little, my concern is how will it affect the sound?
Has anyone changed their stock 75 to SSI type and has the sound change been good or bad.

[76FJ55]

If you're not concerned with the HP gain and you like the current sound, why not keep it as it is?

[47silver]

thinking the header type of exhaust may be beter for the motor as the oil line will not be adjacent to the muffler on the back. But been driving as is since 2002 and as you suggested may just keep it.
If the gain was 15 hp that would be noticeble but 5 hp would not be worth the time to change it out.

[PeteKz]

Without other work, you won't get 15HP just from the exhaust. More like 5.

On my 1973 car with a 3.2 engine, I have the SSI's and OE 2-in 1-out muff. I don't think it's noisy at all. There's more wind noise and engine noise than exhaust noise.

[fanaudical]

I have a '75 Targa, 2.7, SSI's, and a stock 2-in-1-out from a '74. It sounds right to me (and most people who listen) and it's not overly loud. It's relatively easy to swap the muffler if you don't like the sound, but definitely put on the SSI's.

EDIT: One benefit of the SSI's over stock exhaust is that you don't have to worry about the units rusting or developing pinholes which would release CO into your cabin heating air.

[47silver]

Thanks all, I will post before after this winter.

[jerrykrug]

Here is a good thread w/ some ideas (video) of sound and explanations to different exhaust
https://forums.pelicanparts.com/porsche-911-technical-forum/1170438-muffler-swap-w-ssi-s.html

There are two threads by same person (i think) so looks at both - ]
Hope this helps

Jerry

[47silver]

Nice thanks