3" test pipe?

[tizzalonTSI]

I'm looking to replace my F'd up cat with a test pipe. I have a 3" down pipe and 2.5" cat back. my ? is should i be ordering a 3" test pipe? the ones i see on E-bay and from megan are 3" inlet and 3" outlet. will the flange on my buschur cat back bolt to the 3" outlet on the test pipe?

 

[romeen]

I've never seen an aftermarket catback that expands to a larger diameter at the cat end. They usually have a neckdown to make it possible to mate to the stock cat. More than likely your Buschur catback has this neckdown if you still have your stock cat. So a 3" test pipe will not work with your catback unless you cut and weld an new end on one of them.

If you can afford it you really should consider getting a 3" catback. Having your exhaust go from a larger diameter to a smaller one is not good for optimal performance. You can find some great deals on ebay. Search for ebay exhaust for a long thread.

 

[1992awdlaser]

A 2.5" test pipe made for the stock exhaust will work. A 3" one won't work.

 

[nfernotalon]

A 2.5" test pipe made for the stock exhaust will work. A 3" one won't work.

I dont see how that works since his DP is a 3in

 

[knochgoon24]

I dont see how that works since his DP is a 3in

His 3" downpipe probably isn't 3" outlet. Chances are, it necks down to the 2.5" for the cat.

 

[crimsondragon]

Just an FYI, my catback bolts up perfectly to my 3 inch dp. My 3 inch catback necks down to 2.5 inch where the cat is suppose to be. The flanges have been machined to accommodate 2.5inch and 3 inch. Of course it's unsightly and looks very out of place and probably doesn't do much for performance either.

 

[nfernotalon]

My catback has a coupler that you unbolt for a full 3in exhaust.

 

[1992awdlaser]

I dont see how that works since his DP is a 3in

The downpipe bolts up to a stock cat so it will bolt up to a 2.5" test pipe that is made to fit a stock exhaust.

 

[nfernotalon]

The downpipe bolts up to a stock cat so it will bolt up to a 2.5" test pipe that is made to fit a stock exhaust.

So whats the point of having a 3in DP if it necks down at the cat?

 

[1992awdlaser]

So whats the point of having a 3in DP if it necks down at the cat?

To have it able to bolt up to the stock cat for people that don't want to remove the cat.

 

[nfernotalon]

Ok I guess.

 

[crimsondragon]

Pointless really. Just get a 3 inch cat, weld some flanges on and install it. Get rid of the neckdown as well.