Bolting up 3" DP/cat to 2.25" exhaust? Help!
02-13-2006, 08:13 AM
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Bolting up 3" DP/cat to 2.25" exhaust? Help!
I'm upgrading from a greddy kit on my stock D16Y8 this spring, and I'm going to be running a ramhorn manifold with a SC50 .48 a/r and 3" downpipe. 
I plan on running a 3" Carsound high-flow cat (should I get the short one or the regular size?) with the 3" downpipe (NO TEST PIPES FOR ME).
My question is, how can I bolt up a 3" high-flow cat to my 2.25" DC Sports exhaust? I don't plan on upgrading my exhaust any time soon, because it's sooooo quiet I love it! I'll probably upgrade to a full 3" exhaust next summer though, when I get another car for a daily driver. 
Will I need some sort of adaptor? Thanks in advance for the help
I plan on running a 3" Carsound high-flow cat (should I get the short one or the regular size?) with the 3" downpipe (NO TEST PIPES FOR ME).
My question is, how can I bolt up a 3" high-flow cat to my 2.25" DC Sports exhaust? I don't plan on upgrading my exhaust any time soon, because it's sooooo quiet I love it!
I'll probably upgrade to a full 3" exhaust next summer though, when I get another car for a daily driver. Will I need some sort of adaptor? Thanks in advance for the help
02-13-2006, 12:11 PM
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Re: (sk8shorty012)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sk8shorty012 »</TD></TR><TR><TD CLASS="quote">3" > 2.25" = pointless, dont bother getting the 3" if you plan on keeping your exhaust</TD></TR></TABLE>
If you could read, I'm upgrading next summer. I need something for this year.
If you could read, I'm upgrading next summer. I need something for this year.
02-13-2006, 12:20 PM
#5
the point is, you might as well wait for to put on the kit or run without an exhaust cause 3" > 2.25" = teh sux0r. If you cant do a kit completely, then dont do it. Itd be like getting everything for a turbo kit minus a turbo, but not having enough funds for the turbo. Basically, either upgrade to 3" now or dont get the kit yet, youd just be wasting money getting an exhaust shop to fab you some custom adapter or whatnot, just wait til you can do it all at once...
02-13-2006, 12:26 PM
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Re: (sk8shorty012)
Go to autozone or pepboys and see if you can find a reducer.
I'd get the short cat, get the reducer, and the flanges needed to put everything on.
-Put on your DP, put on the short cat, weld on a two bolt flange to one end, weld on a 2 bolt flange onto the 3" end of the reducer, and weld on another flange onto the 2.25" side of the reducer to match your DC sports exhaust.
Make sense? If not I can try to make up a diagram as to what I mean.
-Nick
I'd get the short cat, get the reducer, and the flanges needed to put everything on.
-Put on your DP, put on the short cat, weld on a two bolt flange to one end, weld on a 2 bolt flange onto the 3" end of the reducer, and weld on another flange onto the 2.25" side of the reducer to match your DC sports exhaust.
Make sense? If not I can try to make up a diagram as to what I mean.
-Nick
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02-13-2006, 12:49 PM
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or just do a 3'' d p> E-cut out befor the cat > reducer to the cat > 2.25 exhaust. So while strolling around it's quite and when racing open the cutout
02-13-2006, 12:52 PM
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Re: (six7one)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by six7one »</TD></TR><TR><TD CLASS="quote">or just do a 3'' d p> E-cut out befor the cat > reducer to the cat > 2.25 exhaust. So while strolling around it's quite and when racing open the cutout</TD></TR></TABLE>
I might end up going that route, since it'll be mainly a street car.
I might end up going that route, since it'll be mainly a street car.
02-13-2006, 12:58 PM
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Re: Bolting up 3" DP/cat to 2.25" exhaust? Help! (boostincoupe)
check out kteller.com they have reasonable priced 3 inch cat back bolt up exhaust systems. you would be restricting your exhaust with 3" dp going into a 2.25 exhaust. I don't think it will be any louder than the 2.25.
02-13-2006, 05:23 PM
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The autozone here has reducers for a couple bucks a piece. I don't think they have a 3" to 2.25", but they would have a 3" to 2.5", then you could stick a 2.5" to 2.25" on there. It's ghetto, but it would work.
03-04-2006, 04:32 PM
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Re: (bubs)
Thanks for the tips fellas, I'll be sure to check that stuff out this week.
Which Carsound cat do I order? I was looking on eBay at the Magnaflow Carsound units, and they have a universal one, then a cat for "smaller engines".
Which one do I order???
Which Carsound cat do I order? I was looking on eBay at the Magnaflow Carsound units, and they have a universal one, then a cat for "smaller engines".
Which one do I order???
03-04-2006, 04:39 PM
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When you build your DP, just taper the end of it and allow the DP to insert into the cat. Weld brackets on THE DP so you can utilize the stock cat bolts and springs.
I have a 3" DP to my 2.25" exhaust and it does suck. I made 330whp at the tire with the exhaust and then a whopping 410whp without it.
Good Luck!
I have a 3" DP to my 2.25" exhaust and it does suck. I made 330whp at the tire with the exhaust and then a whopping 410whp without it.
Good Luck!
03-04-2006, 05:54 PM
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Re: (themorphious)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by themorphious »</TD></TR><TR><TD CLASS="quote">80 HP difference becasue of a small exhaust!!!?!?</TD></TR></TABLE>
80whp; even worse!
with exhaust, 10psi (MBC)=330whp
open 3" DP 14psi (We didnt change the fuel maps or the MBC, an open DP allowed the turbo to spool more boost)=410whp
80whp; even worse!
with exhaust, 10psi (MBC)=330whp
open 3" DP 14psi (We didnt change the fuel maps or the MBC, an open DP allowed the turbo to spool more boost)=410whp
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