Is a Downpipe Worthwhile w/o and exhaust?
Thread Starter
Teching In
Joined: Nov 2008
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Is a Downpipe Worthwhile w/o and exhaust? I am thinking about a DP with cat for my Impala SS. I really don't want to do the Magnaflow exhaust. Will the DP give me any gains alone? Or is the exhaust the bottleneck in the system?
I had a Magnaflow on my old GXP and eventually took it off (partly because I needed the cash and partly because I didn't like the sound at 4 cyl mode). I really don't want to do the Magnaflow again.
I'd appreciate the input.
I had a Magnaflow on my old GXP and eventually took it off (partly because I needed the cash and partly because I didn't like the sound at 4 cyl mode). I really don't want to do the Magnaflow again.
I'd appreciate the input.
TECH Fanatic
Joined: Jan 2007
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From: LITH, IL.
Not that I doubt you, but I have not personally seen proof that a downpipe makes any measurable difference. Can someone point me to said proof?
sorry if I hi-jacked the thread
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TECH Apprentice
Joined: Feb 2006
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From: Ohio
I noticed a diff with a good flowing down pipe. I think a catback exhaust is a waste without a high flowing down pipe. The stock down pipe goes down to 2-2 1/4 inches before the flex piece. The quickest na ls4 had a stock cat back exhaust with a high flowing down pipe.
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When I finish my Z06, the Impala is next. I will dyno before and after (after results will not have a tune). I'll post the results.
Here's a link from ZZP's dyno, i know its not the same engine, etc...but it does show some gain.
http://www.zzperformance.com/products_img/551_2.jpg
http://www.zzperformance.com/products_img/551_2.jpg
Last edited by GXPolice; Mar 12, 2009 at 08:44 PM. Reason: forgot link!
Teching In
Joined: Sep 2008
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From: Clinton Twp., MI
Just ordered myself the catless dp, i'm gonna keep the stock catback, was wondering if I should remove or leave on the stock cat and/or the resonator?
Leanin towards removin the cat and leavin the resonator on to keep the rasp down I guess
Leanin towards removin the cat and leavin the resonator on to keep the rasp down I guess
Please read existing threads....
Stock catback, you should remove the resonator it does nothing except muffle a great sounding exhaust.
As for the cat if you keep it, it will not hurt performance as it is a high flow cat from the factory, nor will it change the sound as cats don't really effect it. But if you do remove it remember it will throw a code that you will have to get tuned out.
Stock catback, you should remove the resonator it does nothing except muffle a great sounding exhaust.
As for the cat if you keep it, it will not hurt performance as it is a high flow cat from the factory, nor will it change the sound as cats don't really effect it. But if you do remove it remember it will throw a code that you will have to get tuned out.
TECH Fanatic
Joined: Jan 2007
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From: LITH, IL.
Here's a link from ZZP's dyno, i know its not the same engine, etc...but it does show some gain.
http://www.zzperformance.com/products_img/551_2.jpg
http://www.zzperformance.com/products_img/551_2.jpg
TECH Fanatic
Joined: Jan 2007
Posts: 1,029
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From: LITH, IL.
I disagree, you might save a few lbs of weight, but I have yet to hear of anyone who does not have drone with any exhaust system after removal of the resonator. To myself, and probably most people, listening to drone on a long highway trip is not a good thing.
There is no drone, but perhaps you don't appreciate a good sounding exhaust?.... ;-) I also disagree that the majority of others feel the same way as you...
But to each their own. Every single person who has heard my car before and after prefers it after. And I have never had one complaint about the sound, long or short drive, most people don't even hear it on the highway... Wind noise is worse! I think?
But to each their own. Every single person who has heard my car before and after prefers it after. And I have never had one complaint about the sound, long or short drive, most people don't even hear it on the highway... Wind noise is worse! I think?
TECH Fanatic
Joined: Jan 2007
Posts: 1,029
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From: LITH, IL.
Cool beans on your particular set-up not having any drone, but your singular experience does not make a majority. As far as not appreciating a good sounding exhaust? Perhaps it is you who does not, or the both of us. Your experience in a purely subjective evaluation means exactly the same as mine to someone else, nothing.