Test Pipes without removing DP's?

[Bimmer2Audi]

So I finally got my piggies done today, but am kind of wishing I had done test pipes as well. Would it be possible to cut the main cats and either weld or clamp in some test pipes with 02 sensor bungs and VAST 02 CELiminators? My big idea would be to clamp in the test pipes when I take it to the track, then clamp the main cats back on for regular daily driving. Would clamps work or would that be a bad idea? Should they be welded in? Can they be welded in with out removing the downpipes?

[gointoscott]

I havnt done either test pipes, or piggies yet, but I have seen enough guys have problems with exhaust leaks. To me I think you would have problems with leaks if you tried just clamping them.

[Daft]

There's just no room in there to do it properly and without carnage to any other parts.

You really have to remove them.

[Bimmer2Audi]

There's just no room in there to do it properly and without carnage to any other parts.

You really have to remove them.

Thats kind of what I figured...

[Rajan147]

i think if you sectioned the exhaust there would be enough slack to cut out the main cats.

When i was putting in my aftermarket exhaust there seemed like a decent amount room, but i'm forgetful

Then just code out your ecu for the rear o2 sensors, why screw around with bungs and 02 sensors.

And just live with your polluting ways, your already burning precious 93 oct


my .02 cents

[Jayco88]

I did my piggies recently and left the main cats. The rear o2's are coded out. But I want to find a way to have test pipes year round, and just swap in the cats for CARB next year, without having to go through all the pain and agony of removing downpipes every time.

Does anybody know if removing the main cats have any significant gains to merit my effort? I mean, how restrictive can they really be?