2.5" vs. 3" Cat Test Pipe
08-30-2002, 05:07 PM
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2.5" vs. 3" Cat Test Pipe
Can I get some informed feedback re the the relative merits of the above? All the 3's I've found are made of SS and considerably more expensive.
For a very mildly modified motor (chipped, high flow cone air filter,) will there be any performance difference between the two?
FYI my headers are leaking, so I'm figuring SS headers are somewhere in the future, too.
For a very mildly modified motor (chipped, high flow cone air filter,) will there be any performance difference between the two?
FYI my headers are leaking, so I'm figuring SS headers are somewhere in the future, too.
08-30-2002, 06:54 PM
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Your answer is fairly simple. Can you get more delicious beverage through a standard drinking straw, or one of those big fat honking 7-11 Super Slurpee straws? If smaller were better there would be a 1/2 inch pipe somewhere.
08-30-2002, 07:38 PM
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[quote]Originally posted by ArcticCzar:
<strong>Your answer is fairly simple. Can you get more delicious beverage through a standard drinking straw, or one of those big fat honking 7-11 Super Slurpee straws? If smaller were better there would be a 1/2 inch pipe somewhere.</strong><hr></blockquote>
Try cutting your straws into 3rd's then put them together with two parts of the smaller straw on the ends and the bigger straw in the middle and let me know how much more of your beverage comes through compared to just the small straw.
I have to agree with David on this one.
<strong>Your answer is fairly simple. Can you get more delicious beverage through a standard drinking straw, or one of those big fat honking 7-11 Super Slurpee straws? If smaller were better there would be a 1/2 inch pipe somewhere.</strong><hr></blockquote>
Try cutting your straws into 3rd's then put them together with two parts of the smaller straw on the ends and the bigger straw in the middle and let me know how much more of your beverage comes through compared to just the small straw.
I have to agree with David on this one.
08-30-2002, 08:47 PM
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Don't take my post wrong, I am all for 3", as a matter of fact when I arrived home today, at my back door was a SFR 3" testpipe and catback to go along with the 3" downpipe I have.
If you do a 3" testpipe and catback, go for it, just not 3'' stuck in between 2.5".
By the way the SFR exhaust is a work of art! <img src="graemlins/bigok.gif" border="0" alt="[thumbsup]" />
If you do a 3" testpipe and catback, go for it, just not 3'' stuck in between 2.5".
By the way the SFR exhaust is a work of art! <img src="graemlins/bigok.gif" border="0" alt="[thumbsup]" />
08-31-2002, 09:51 AM
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Which companies make a 2.5" cat pipe beside Bursch? Does the Bursch pipe have the inlet from the wastegate? Does it come as a complete kit, ready to bolt right up, or does it require additional hardware, gaskets, etc? Who has the best price?
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08-31-2002, 04:41 PM
#8
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I say go for the 3" cat-bypass. You'll eventually get the 3" cat-back and have the highest flowing combo possible. When I installed my 3" exhaust from the downpipe back, I picked up 1.5psi of boost just like that! So I turned down the max-boost level back down to what it was before, but with the benefit of 1.5psi more in areas that were low before. Such as from 2500-3500rpm and from 5000rpm+.
09-01-2002, 02:39 PM
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'Testpipe' and 'cat bypass' are the same piece. In order, it goes: header...testpipe...cat-back. 'Cat-back' just stands for everything from the CATalytic converter to the BACK of the car.
09-01-2002, 04:11 PM
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'Testpipe' and 'cat bypass' are the same piece. In order, it goes: header...testpipe...cat-back.
Actually it goes: header, crossover, turbo,
downpipe, testpipe, catback;^)
Actually it goes: header, crossover, turbo,
downpipe, testpipe, catback;^)
09-02-2002, 12:51 AM
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I will eventually go with a full 3" exhaust, but for now I'm only looking to replace the catalytic converter portion. I would appreciate any information from those of you who have made this swap or can answer the questions in my previous post above. Thanks! 
09-02-2002, 01:28 AM
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All you need to do is cut off the catalytic and weld on a straight 2.5" pipe to replace it. As for t he wastegate, leave it venting into the atmosphere and weld on a resonator for the wastegate pipe. A local performance shop did it for me for $65. Don't spend over $200 for a test pipe of a cat bypass pipe. That is if you can find some one that will do it for you. I simply gave them the excuse that its a "track car".
09-02-2002, 03:19 AM
#15
RAD951,what kind or style of resonator did you use for you wastegate? Do you have a picture?
I've been running open wastegate all summer and i really need to reduce the sound,and i want to keep it atmospheric.But i can't seem to find a proper resonator. I want something small so it will not show to much from behind the car.
Thanks....
I've been running open wastegate all summer and i really need to reduce the sound,and i want to keep it atmospheric.But i can't seem to find a proper resonator. I want something small so it will not show to much from behind the car.
Thanks....