poor mans downpipes?

[8nutz8]

poking around under the car the other day looking at my turbos/exhaust got me thinking . . . has anyone ever just upgraded the exhaust pipe coming directly after the cats to the factory exhaust? the "mid-pipe" i guess you could call it. not sure it would offer quite the benefit of full downpipes but it would be pretty easy for an exhaust shop to make a 2.5" piece and should be a good bit cheaper than downpipes and offer at least some performance gain. what is considered the major bottleneck in the stock downpipes anyway? at the cats or more in the pipes leading out?

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[StealBlueSHO]

Yes, this was done to my car by the previous owner. I can't speak much for it as I did end up switching it all out for a full set of DP's...

Problem was the shop that did it to my car used crushed bent piping and cheap flex pipe... The drone was incredible! Much better now that all that crap is gone.

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[8nutz8]

Yes, this was done to my car by the previous owner. I can't speak much for it as I did end up switching it all out for a full set of DP's...

Problem was the shop that did it to my car used crushed bent piping and cheap flex pipe... The drone was incredible! Much better now that all that crap is gone.

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aside from sound did you notice any gain from moving up to downpipes? was is a 2.5" pipe before DP's?


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[StealBlueSHO]

Yes, it was 2.5inch pipes coming off each cat.. crush bent so flowed less than 2.5 though.

I did a good amount of gain moving to the DPs.. couple tenths off my 0-60 times..

I attribute this to the high flow cats and mandrel bent piping from the turbo back to the exhaust. If you look at the piping connected to the cats from the turbos it's a big choking point.

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[StealBlueSHO]

http://www.ecoboostperformanceforum.com/index.php?topic=6632.0

Here is the post with pictures of what I had before hand...

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[Vortech347]

It'll suck when you do it the cheap way then end up spending the money twice getting the correct fitting parts.

 

[8nutz8]

http://www.ecoboostperformanceforum.com/index.php?topic=6632.0

Here is the post with pictures of what I had before hand...

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Yeah that's what i'm thinking of doing but done right the first time haha. Gonna keep all the flanges and make sure quality flex pipes and all mandrel bends are used. If i can get it done for around $200 i'd say it's worth it. and might as well get a quote for custom cat-back while i'm at a shop. Can't imagine there's a huge HP difference(if any) having full 2.5" exhaust from the cat-back flange vs having downpipes and stock exhaust. Price wise it might even be a wash

 

[StealBlueSHO]

It'll suck when you do it the cheap way then end up spending the money twice getting the correct fitting parts.

Yea, unfortunately the previous owner had the work done, so it costs me more money to fix it... Otherwise I would have just been able to bolt up the new DPs...

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[StealBlueSHO]

http://www.ecoboostperformanceforum.com/index.php?topic=6632.0

Here is the post with pictures of what I had before hand...

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Yeah that's what i'm thinking of doing but done right the first time haha. Gonna keep all the flanges and make sure quality flex pipes and all mandrel bends are used. If i can get it done for around $200 i'd say it's worth it. and might as well get a quote for custom cat-back while i'm at a shop. Can't imagine there's a huge HP difference(if any) having full 2.5" exhaust from the cat-back flange vs having downpipes and stock exhaust. Price wise it might even be a wash

There will be a big differences in over HP... The bigger pipes upto the turbo housing and lack of back pressure with the high flow cats allow you to build boost sooner. Also, if you are planning on maxing out the turbos with a tune the DPs really make a difference. IMHO... And 2 tenths of a second on the 0-60 times is a substantial increase....



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[8nutz8]

[/quote]
There will be a big differences in over HP... The bigger pipes upto the turbo housing and lack of back pressure with the high flow cats allow you to build boost sooner. Also, if you are planning on maxing out the turbos with a tune the DPs really make a difference. IMHO... And 2 tenths of a second on the 0-60 times is a substantial increase....



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[/quote]
^i would agree. guess i need to decide if i'm going to do downpipes before i throw any cash into this. still kind of on the fence about them.but for anyone that has decided not to run downpipes i think this would be a good move to achieve TRUE CAT BACK exhaust.
stealblue- i wonder if you would have noticed as much difference when switching to downpipes if you had a quality mandrel piece instead of the crush-bent crap setup you had

 

[StealBlueSHO]

There will be a big differences in over HP... The bigger pipes upto the turbo housing and lack of back pressure with the high flow cats allow you to build boost sooner. Also, if you are planning on maxing out the turbos with a tune the DPs really make a difference. IMHO... And 2 tenths of a second on the 0-60 times is a substantial increase....



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[/quote]
^i would agree. guess i need to decide if i'm going to do downpipes before i throw any cash into this. still kind of on the fence about them.but for anyone that has decided not to run downpipes i think this would be a good move to achieve TRUE CAT BACK exhaust.
stealblue- i wonder if you would have noticed as much difference when switching to downpipes if you had a quality mandrel piece instead of the crush-bent crap setup you had
[/quote]


Maybe.... the high flow cats I think made more difference... Crush-bent vs Mandrel bent is not going to cost a BIG amount.. maybe a couple HP's..