does a test pipe or a hollow out cat create back pressure??

Depends on the size of the pipe. Test pipe is completle unrestrictive. And bad for the enviornment.

The green house affect, is a matter of opionon

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chewy[Ek &raquo;</TD></TR><TR><TD CLASS="quote">]does a test pipe or a hollow out cat create back pressure??</TD></TR></TABLE>

Why would it?

The point of hollowing out the cat or using a test pipe is so the air can flow more freely.

I see that as being the opposite of creating backpressure.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chewy[Ek &raquo;</TD></TR><TR><TD CLASS="quote">]does a test pipe or a hollow out cat create back pressure??</TD></TR></TABLE>

Only if the inner diameter of the test pipe is smaller then the inner diameter of the collector.

thanks for the responses

Okay will this set-up create back pressure for me.

2 inch collector to 2.5 cat converter to 2.5 inch pipes to 2.25 muffler.

Reason Im asking is cause thats what my setup will be.<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bb_one &raquo;</TD></TR><TR><TD CLASS="quote">

Only if the inner diameter of the test pipe is smaller then the inner diameter of the collector.</TD></TR></TABLE>

2 inch collector is kind of bottle necking the whole system. If those are inside diameters you should upgrade to a 2.5 inch diameter collector!

Okat say I go that route will the 2.25 muffler affect back pressure