Exhausting Question!
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From: SF Peninsula
Exhausting Question!
Does anyone have experience with converting the 993 exhaust for use on the 964? I am curious if it will really make more power than using any combination of mods such as a G-pipe and Cat bypass. If it does indeed make more power then maybe it is worth the cost and effort, but I do wonder if it is just urban legend. 
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From: Virginia
I thought that the boost from the 993 came as a result of BOTH the intake and the exhaust being modified. It would seem to me that one would have to do both alterations to really get any significant improvement. I guess it does depend on your personal definition of "significant improvement".
-JD
-JD
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From: Halifax, Nova Scotia , Canada
The biggest problem is fitting the standard 993 mufflers in the NB 964 !
My 964 has a 97 993 motor but has a sorted 964 system . With no DME alterations the bhp is standard 97 993 !
I know that people get very excited about the 993 system but I have never seen any worthwhile power improvement on a 964 , provided that the 964 has the transverse rear muffler sorted .
Even the gains from muffler alterations on a 993 have to be studied closely .
Seperating the cat join so the system is a true dual can bring some + results .
Geoff
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KS400200,the oldest 964 on Rennlist,unless you know differently !
My 964 has a 97 993 motor but has a sorted 964 system . With no DME alterations the bhp is standard 97 993 !
I know that people get very excited about the 993 system but I have never seen any worthwhile power improvement on a 964 , provided that the 964 has the transverse rear muffler sorted .
Even the gains from muffler alterations on a 993 have to be studied closely .
Seperating the cat join so the system is a true dual can bring some + results .
Geoff
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KS400200,the oldest 964 on Rennlist,unless you know differently !
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From: Santa Rosa, CA
If you search, you should find a couple threads about it. A friend did it. It requires cutting/welding and rerouting an oil line. It's not a trivial change.
I'm with Geoff, it really doesn't provide a performance gain and I certainly don't think it would be worth the cost. I got the best dyno numbers with a cat bypass and a secondary bypass (using stock primary). However, if you want ot try, I have some 993 headers and mufflers available...
I'm with Geoff, it really doesn't provide a performance gain and I certainly don't think it would be worth the cost. I got the best dyno numbers with a cat bypass and a secondary bypass (using stock primary). However, if you want ot try, I have some 993 headers and mufflers available...
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From: Halifax, Nova Scotia , Canada
Tom,
Interesting comments. I needed low noise for long trips so had a proper primary silencer made by a pro muffler company .
The primary is the 964 exhaust system flaw .Its flow rate/internal design is crap !! Makes the secondary look like a jem .
Thats why the CUP pipe came to life .
I have a CUP but needed the primary noise reduction - getting too old !!!
There have been " cut open " pics of the primary posted on Rennlist .
I did dyno before/after measurements and thats where the problem is ,once you are going up the bhp path !
Geoff
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KS400200,the oldest 964 on Rennlist,unless you know differently !
Interesting comments. I needed low noise for long trips so had a proper primary silencer made by a pro muffler company .
The primary is the 964 exhaust system flaw .Its flow rate/internal design is crap !! Makes the secondary look like a jem .
Thats why the CUP pipe came to life .
I have a CUP but needed the primary noise reduction - getting too old !!!
There have been " cut open " pics of the primary posted on Rennlist .
I did dyno before/after measurements and thats where the problem is ,once you are going up the bhp path !
Geoff
----------------------------------------------------------------
KS400200,the oldest 964 on Rennlist,unless you know differently !
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From: Cheshire, England
We currently have one of two UK registered RHD 964RS 3.8 (widebody) road cars in our workshop; interestingly this car is fitted with a set of 993 heat exchangers, cats and silencers with custom twin oulets from the factory.
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For a couple years I raced with a cat bypass, hollowed out primary, and secondary bypass. A week or so ago I installed a stock primary (not hollowed out) and the low end torque is much greater and smoother with no noticeable effect on top end power. My hollowed out primary is now shelved!
Geoff, do you have dyno numbers/graphs for a primary vs. no primary setup? Others have posted differernt findings that support the primary is the best to keep, as Tom found. Plus, the secondary is not as durable as a primary - numerous accounts of holes being blown in the side of the secondary have occurred when used with a cup pipe, but no accounts I've come across with the primary blowing out.
Geoff, do you have dyno numbers/graphs for a primary vs. no primary setup? Others have posted differernt findings that support the primary is the best to keep, as Tom found. Plus, the secondary is not as durable as a primary - numerous accounts of holes being blown in the side of the secondary have occurred when used with a cup pipe, but no accounts I've come across with the primary blowing out.
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Three Wheelin'
Joined: Dec 2004
Posts: 1,779
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From: Halifax, Nova Scotia , Canada
Garrett ,
I would have no information for a hack job on a primary muffler internal . Just removing the center would not be a good move and I believe a definite power loss . Mufflers need design in the equation !
The CUP gives more bhp than a standard primary . Hopefully there are mountains of data on that ,starting with Porsche Motorsport .
I would have to go back through data 15 years old to find that stuff !!
All exhaust modifications can need fuel/timing recalibration to ensure correct motor running .
I guess what makes you feel happy is best .
Geoff
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KS400200,the oldest 964 on Rennlist,unless you know differently !
I would have no information for a hack job on a primary muffler internal . Just removing the center would not be a good move and I believe a definite power loss . Mufflers need design in the equation !
The CUP gives more bhp than a standard primary . Hopefully there are mountains of data on that ,starting with Porsche Motorsport .
I would have to go back through data 15 years old to find that stuff !!
All exhaust modifications can need fuel/timing recalibration to ensure correct motor running .
I guess what makes you feel happy is best .
Geoff
----------------------------------------------------------------
KS400200,the oldest 964 on Rennlist,unless you know differently !