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After market downpipe or custom made?

Posted: Thu Feb 12, 2004 10:00 pm
by J-MoNeY
I am debaiting on if I should have someone I know make me a custom turbo back down pipe in to a 3in with no cats and no muffler, or just do a 3in cat back, with no muffler. I have seen that the best design is the 4in bellmouth into a 3in down pipe. Now, let's say that I had the 3in made all the way back, it would proably not have the wider waste gate exhaust dump that I would get from an after market downpipe. If I got the 3in cat back for now, wouldn't I just be able to buy a downpipe later, then have them cut out the cat, make a custom falange and mate the catback to the aftermarket down pipe?

Posted: Thu Feb 12, 2004 11:12 pm
by ciper
I suggest getting one of the premade downpipes and have the rest custom made. Thats what I plan to do. Im going to use a high flow cat, a resonator and a muffler all in 3 inch.

Posted: Fri Feb 13, 2004 12:59 am
by J-MoNeY
ciper wrote:I suggest getting one of the premade downpipes and have the rest custom made. Thats what I plan to do. Im going to use a high flow cat, a resonator and a muffler all in 3 inch.
Pffst. Muffler...ha. Well, actually I may need one, it may be too loud. :shock:

Posted: Fri Feb 13, 2004 1:09 am
by ciper
A muffler of good design does not change performance. Realize the items I speak of (both resonator and muffler) are usually straight through.

I personally would like my car to be silent if possible, if not equal to stock. Being loud does not equate to being fast.
Look at the second page of this post for the list of parts I wanted to use http://bbs.legacycentral.org/viewtopic.php?t=1307

Posted: Fri Feb 13, 2004 5:18 am
by Matt Monson
J-money,
Have you checked out the picks of my custom turbo back? Now that Diz is in possession of it, maybe he can post pics of it off the car. For starters, 4" is huge unless you are running a huge turbo. The things you state matter of factly about DP design are highly debateable. That aside, my DP was a PDM (now defunct) divorced wastegate piece. It had a 2.5" outlet and 1.5" wastegate. This is more than ample for anything less than an AVO450 or IHIVF-34. What turbo are you realistically gonna run on this thing?

But as Ciper said, get a good WRX DP of your choosing. Mine was catless, and I recommend this route. Shop around and you should be able to find a really nice used one for $350 or less.

Then I had a custom mid-pipe made from the back end of a WRX mid-pipe with a high flow cat in front of it mating up to the 2.5" DP flange. I was running a stock muffler, but would have gone with nicer piece if I kept the car. Do what you want on your car, but if you haven't read this, you should. This biggest exhaust doesn't neccessarily make the most power, just the most noise...

http://www.cobbtuning.com/tech/exhaustdesign/index.html