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16v Exhaust system help!

 
Old 02-22-2019, 07:39 AM
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Claret Badger
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Default 16v Exhaust system help!

Hi everyone

Finally able to use my 1981 4.5 auto after two years of body restoration and so now trying to sort all those little niggles etc!

I have original headers going into a Haywood and Scott Y pipe, then angled to a H&S small silencer and then to a 928 kidney which I thought was period correct but turns out to be for a 4.7 928S. I enclose a diagram and also photos of the kidney back box.

Im disappointed with the exhaust note/lack of V8 noise and wanted thoughts on what I should do. Sell the kidney and get a RMB? I like the black twin exhaust look and for originality would like it angled like it should be. Any suggestions for who could make something much appreciated!


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Old 02-22-2019, 10:04 AM
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z driver 88t
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Claret, I don't think they make RMBs for the OB style cars. I had looked into that at one time for my '84. Two relatively simple and inexpensive solutions would be:

1. Have a muffler shop make a pipe connection to put in place of the center muffler. It would only be two flanges and a piece of pipe. Probably very inexpensive and would retain all the same stock look.

If that's not to your liking, consider..

2. Reinstall the mid-muffler and pull the rear muffler and replace with a pipe fabricates with dual black tips to retain the stock look. This approach would be a bit more difficult because the exhaust shop would either have to crush bend the pipe to get the angle right or piece together some mandrel bends to get everything to line up at the right angle. Either way, its a bit more labor intensive to get the desired result.
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Old 02-22-2019, 04:28 PM
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I bought a cat-back system from 928 intl. years ago for my '81. It is a bit loud (for me now) but a very good unit.
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Old 02-22-2019, 05:02 PM
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Originally Posted by joejoe View Post
I bought a cat-back system from 928 intl. years ago for my '81. It is a bit loud (for me now) but a very good unit.
We do not make that anymore but the Borla system is well made and a great sound
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Old 02-22-2019, 06:16 PM
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had a BORLA cat back on my 81 , sounded great , even a little more HP
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Old 02-22-2019, 07:26 PM
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+ 1 on the borla, but with no cat I think you will find it to be too loud and too much V8 sound. I have stock headers-> Y pipe->cherry bomb->borla rear section. Sounds like a hopped up Camero. I really liked stock cat with the Borla cat back. Civilized yet aggressive.
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Old 02-22-2019, 10:26 PM
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what eva design you end up with pa-lease get the exhaust tips oriented properly as this RL'r has done..posts 113-117:
https://rennlist.com/forums/928-foru...-orange-6.html



Last edited by 77tony; 02-22-2019 at 11:51 PM.
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Old 02-23-2019, 03:29 AM
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My Euro 83 S has a LARGE first muffler (which looks like its got a non-original skin on it, but otherwise original), 2 out pipes to a 2-in 2-out rear pumpkin, and its pretty boomy at a fast idle, and around 1500rpm going through the gears. Has been known to set off alarms in adjacent cars in parking garages.
jp 83 Euro S AT 57k
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Old 02-23-2019, 07:38 AM
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http://www.nixsoft-consulting.co.uk/928spares/index.php?id=products

These guys make one for the S and S2 if that's any use. I have the S4 one (w silencer). Very nice.

Wait until after brexit and if the pound crashes you'll be able to get one for a few dollars.
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Old 02-23-2019, 01:25 PM
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Originally Posted by 77tony View Post
what eva design you end up with pa-lease get the exhaust tips oriented properly as this RL'r has done...
This is not even close to being properly oriented (per original).
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Old 02-23-2019, 01:43 PM
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77tony
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​​​​​​it is compared to whats on there now...


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Old 02-23-2019, 01:53 PM
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Originally Posted by 77tony View Post
​​​​​​it is compared to whats on there now...
That rear muffler is actually 'factory' original for a Japanese market 928.
It exits the body the same as the typical original, then turns straight back.
It can be 'cut back' to the original offsets & slant-cut tip lengths.
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Old 02-23-2019, 01:59 PM
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I came up with this early type RMB. Each tip has a built-in resonator.




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Old 02-23-2019, 02:21 PM
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Originally Posted by Jadz928 View Post
That rear muffler is actually 'factory' original for a Japanese market 928.
It exits the body the same as the typical original, then turns straight back.
It can be 'cut back' to the original offsets & slant-cut tip lengths.
Good to know Jim.
Originally Posted by Jadz928 View Post
I came up with this early type RMB. Each tip has a built-in resonator.



^^now thats the ticketT
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Old 02-23-2019, 10:52 PM
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On my supercharged '79 I'm running OEM headers to a 928MS stainless Y-pipe into a Borla.

It's on the louder side, but why not hear that great German v8. Without cats it is a little stinky though.




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