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Old 05-04-2007, 11:48 PM   #1
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Default Stock exhaust pipe size at the cat

I am putting in a 3" DP welded into the stock exhaust. What is the pipe diameter between the cat and the resonator? I have the stock SLE exhaust from the DP back. What size adapter do I need to make the reduction?
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Old 05-05-2007, 01:32 AM   #2
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We have no idea what size you have. What have you swapped? Do you have the SLE exhaust, or L67? Did the exhaust swap with the drivetrain? Are you aware deleting the Cat will make you lose some low-end torque and is illegal? And that any member here that turns you in will get a $250 reward? As well as any shop that notices it'* missing?

I can tell you with certainty you will not be happy with the loss of low-end torque. And your current mods don't spell cat outflowing.

(can you tell this is a pet peeve of mine? )
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Old 05-05-2007, 03:21 AM   #3
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Bill you whine more than your SC.

The stock pipe size going into the cat is 2 1/2"

Mine now goes 3" all the way........... and I didn't lose any low end torque
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Old 05-05-2007, 10:27 AM   #4
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Paul, you flow alot more than Jared.

Every member with a mildly-modded L67 that ever removed a cat felt a reduction in low-end torque. Including another one just last week.

I felt it too for the short time I ran catless until my replacement arrived. VERY noticable.
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Old 05-05-2007, 10:38 AM   #5
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Quote:
Originally Posted by 2000SilverBullet
Bill you whine more than your SC.

The stock pipe size going into the cat is 2 1/2"

Mine now goes 3" all the way........... and I didn't lose any low end torque
I assume that the pipe leaving the cat is also 2 1/2" then that enters the resonator? Thanks Paul. And I guess I'm not deleting the cat. Thanks Bill.
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Old 05-05-2007, 10:43 AM   #6
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Good deal. Go hi-flow. Can't remember who that was last week, but he ran for quite some time catless, then added one on our advice. He thanked us. Never sacrifice your low end. That'* what makes up somewhat for your heavier car. You gotta get it moving.
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Old 05-05-2007, 08:52 PM   #7
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Quote:
assume that the pipe leaving the cat is also 2 1/2" then that enters the resonator
Never assume anything but yes stock it exits at 2 1/2" into the resonator but comes out of the resonator at 2 1/4" then splits into twin 2" in and out of the mufflers.
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Old 05-06-2007, 12:05 AM   #8
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So... whats the stock downpipe diameter then? I'm assuming it'* 2.5" if thats what it is going into the cat, correct?
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Old 05-06-2007, 12:28 AM   #9
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The stock downpipe is a double walled pipe. 2 1/2" inside and 2 3/4" outside diameter. The biggest restriction in the stock downpipe is the stock flex connector. It'* inside opening necks down to 2".

The TOG'* braided connector is 2 3/4" inside diameter I believe.
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Old 05-06-2007, 12:39 AM   #10
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Hmm.... well then, I sure am glad I bought that 2.5" downpipe for a really really good deal. Already modified to fit 2000+ Bonne'* also!
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