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07 3.6 4mo passat wagon
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275 Posts
Discussion Starter · #1 ·
i am only planning minor mods for the engine

cobb intake
borla header
high flow cat(s)
exhaust


i am stuck on whether to get a 2.25 or 2.5 piping

I am pretty sure I am going to get the piping done custom at a place I have had work done before and have them do the header and cat(s) there also.....my only descrepency is will I lose power with a 2.5 and is there any real sound difference between the smaller and larger piping....I plan on a borla muffler also
 

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00' 2.5rs w/04 wrx full swap
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111 Posts
I went with the custom 2.25" header back exhaust. I felt a great smoothness throughout the whole rev range, but most of the power is from 3500 to redline (it wants to keep pulling) with no loss in the bottom end.

My knowledge is that the 2.5+" is good only if your going turbo. cause the bigger exhaust will cause low end loss but major top end gain which can take a turbo to its limits, on a minor mod N/A you will lose more low end than you gain in top end.
just my opinion.
p.s. no more hesitation in the power band and a deep growl is 2 more pluses to 2.25" vs stock.
 

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MY00 Alpine White RS
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63 Posts
have been running Rallispec 2.5" cat back for the last couple of years and have had no noticeable low end loss. It also sounds really nice with the borlas and random tech cat that I just installed this past weekend. If the prices are not that much different go with the 2.5 you will not notice a real difference between the two sizes......

Rubasu
 

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'93 L wagon, '04 FXTi
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1,682 Posts
Most Suby gurus, like Mike Shields at SPD Tuning and the fellas at i-Speed, among others, suggest not going larger than 2.25" for N/A, and not less than 2.5" for forced induction. I personally am a month away from a custom 2.25" Magnaflow setup, I have heard wonderful things about it.
 

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i have 2.25' header back with no cats, it pulls hard all the way to redline now, which is a lot more than can be said of the stock piping. i have no complaints, except that i wish it was quieter.

Originally posted by Rubasu
have been running Rallispec 2.5" cat back for the last couple of years and have had no noticeable low end loss. It also sounds really nice with the borlas and random tech cat that I just installed this past weekend. If the prices are not that much different go with the 2.5 you will not notice a real difference between the two sizes......

Rubasu
you probably havent noticed a low end loss because you only have a cat-back, would i be correct in assuming your cat-forward piping is still stock? you haven't lost any exhaust velocity because it's still going through that small diameter piping before it gets to the 2.5
 

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MY00 Alpine White RS
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63 Posts
hah....you posted the quote and did not read it all the way through...I just installed a set of borla headers (2.25) and a random tech cat (2.25)..I have been riding around on them for the last week and if I have lost any low end torgue then it must be minimal because the thing pulls like it never wants to stop. I love the sound also it sets off alarms on my block when I am coming home from work at midnight..........hehe

Rubasu
 

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MY00 Alpine White RS
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63 Posts
everything after the cat is 2.5 but I still do not see the point. All I am doing is expressing my opinion of how my car feels to me regardless of how big the exhaust pipes are. borlas 2.25, random tech setup 2.25 and everything else 2.5.

rubasu
 

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all im saying is you wouldnt feel a power loss from 2.5 unless ALL the piping was 2.5, if there is a power loss. im not trying to knock your setup or anything.
 
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