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DLC360
Joined: 18 Sep 2012
Posts: 76
Location: Parma Hts Ohio
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 Posted: Thu May 15, 2014 8:08 am Post subject: Recomendations For a New Exhaust System. |
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Ok, so today on my way to work the exhaust system decides to be my next repair / modification. It broke right at the back end of what looks to be a cherry bomb muffler right off of the manifold (could be a converter, not sure).
So, what I would like to find out is what is the recomended exhaust system of everyone here? I would like to upgrade it for both sound and performance. Its for a `87 924s with 144k on the clock.
Thanks for any and all ideas. |
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fiat22turbo
Joined: 18 Jan 2006
Posts: 4040
Location: Portland, OR
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| Posted: Thu May 15, 2014 8:26 am Post subject: |
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The 2.5 isn't the most melodic motor, IMO but either a 944 turbo take-off system or any of the cat-back solutions for the 944 will work.
http://www.google.com/#q=porsche%20944%20cat%20back%20exhaust
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose) |
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DLC360
Joined: 18 Sep 2012
Posts: 76
Location: Parma Hts Ohio
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| Posted: Thu May 15, 2014 10:57 am Post subject: |
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| I figured those would work, I just was just wondering if there was a better upgrade than stock. I also was thinking of taking off the cat, but im worried how that will effect the performance with the computer. |
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jason c
Joined: 13 Jan 2014
Posts: 1018
Location: Nwi
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| Posted: Thu May 15, 2014 11:34 am Post subject: |
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| DLC360 wrote: | | I figured those would work, I just was just wondering if there was a better upgrade than stock. I also was thinking of taking off the cat, but im worried how that will effect the performance with the computer. |
Oxygen sensor is before the cat so its no problem. It might be a problem if you have emissions testing though. |
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fiat22turbo
Joined: 18 Jan 2006
Posts: 4040
Location: Portland, OR
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| Posted: Thu May 15, 2014 11:45 am Post subject: |
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Also doesn't improve performance very much.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose) |
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DLC360
Joined: 18 Sep 2012
Posts: 76
Location: Parma Hts Ohio
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| Posted: Fri May 16, 2014 2:50 am Post subject: |
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| fiat22turbo wrote: | | Also doesn't improve performance very much. |
I wasn't sure if it would make that much of a difference. THANKS for the input.
It was an interesting ride home at 1am last night, trying to be quiet around the local police and random state trooper.
THANKS AGAIN for all the input. |
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fiat22turbo
Joined: 18 Jan 2006
Posts: 4040
Location: Portland, OR
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| Posted: Fri May 16, 2014 2:57 am Post subject: |
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| DLC360 wrote: | | fiat22turbo wrote: | | Also doesn't improve performance very much. |
I wasn't sure if it would make that much of a difference. THANKS for the input.
It was an interesting ride home at 1am last night, trying to be quiet around the local police and random state trooper.
THANKS AGAIN for all the input. |
I should clarify that a new aftermarket cat is fairly high flowing and can help with noise a little. An original cat, which may be plugged up by now could impact performance. When you decide on an exhaust system, take a peak at the cat while you're under there to check it for being plugged. No sense in leaving performance on the table or having to do work twice 
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose) |
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Lau Christophersen
Joined: 17 May 2013
Posts: 123
Location: Denmark/Copenhagen
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| Posted: Fri May 16, 2014 4:27 am Post subject: |
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| For a 931 with higher boost(1,0bar) and some other modifications(220-240 hp) would 2,5 or 3" pipe be the best if I want to make my own stainless exhaust? |
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Fasteddie313
Joined: 29 Sep 2013
Posts: 2595
Location: MI
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| Posted: Fri May 16, 2014 4:31 am Post subject: |
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stock exaust is a bit bigger than 2.5 but slightly smaller than 2.75...
so if you an "upgrade" then 2.5 would be more of a downgrade..
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80 Turbo - Slightly Modified |
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fiat22turbo
Joined: 18 Jan 2006
Posts: 4040
Location: Portland, OR
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| Posted: Fri May 16, 2014 4:31 am Post subject: |
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For a turbo, you want to go as large as possible. 3" is my recommendation. The turbo introduces back pressure into the system and any back pressure after that just reduces overall power output and slows turbo spool up.
I will caution that some 931's have reported boost spike issues with wide open exhaust systems, so you'll want to ensure you have effective wastegate control.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose) |
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Lau Christophersen
Joined: 17 May 2013
Posts: 123
Location: Denmark/Copenhagen
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| Posted: Fri May 16, 2014 7:04 am Post subject: |
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What about 3,5" then? it is too big?
I don't want it to be too lout - its only for the road not the track at the moment - so I still want 1 middle silencer and 1 back silencer like the stock system, just "full flow" silencers and bigger diameter on the pipes, and then in stainless steel...
I do have 1 full stainless exhaust special made with manifold and middle silencer in 2" pipe for the 924 N/A but I think it will be too expensive to ship to you, otherwise it was for sale... |
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fiat22turbo
Joined: 18 Jan 2006
Posts: 4040
Location: Portland, OR
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| Posted: Fri May 16, 2014 7:50 am Post subject: |
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Whatever size floats your boat. Larger diameters tend to produce a deeper sound, going too large and you'll lose some velocity. You can remove some noise with some straight through style mufflers (dynomax bullet for example).
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose) |
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DLC360
Joined: 18 Sep 2012
Posts: 76
Location: Parma Hts Ohio
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| Posted: Wed May 21, 2014 10:53 am Post subject: |
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OK, sorry I haven't been on for a few days to talk about this. I was out of town for the weekend and just took the car in this morning for a new system.
First off the cat has already been removed and had a resonator installed. The shop installed a new 2.5 inch pipe on the back of that. They then installed a generic brand flowmaster and a new stainless tip for $145.00. The sound is great, doesn't sound "ricey" and has a good deep sound to it. |
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fiat22turbo
Joined: 18 Jan 2006
Posts: 4040
Location: Portland, OR
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| Posted: Wed May 21, 2014 2:14 pm Post subject: |
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Flowmasters suck. Honestly, you wasted money on that. I'd have gone with a cheaper super turbo if I wanted a restrictive muffler. Replace it with a dynomax race bullet or anything else that is straight through. Sell the flowmaster to a V8 guy.
Summit or Jeggs has great deals on Dynomax and similar products.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose) |
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