Im thinking about getting a test pipe since I dont need emissions where I live. Right now i have the helix high flow cat, would hollowing out the hfc be pretty much the same as getting a test pipe?

 

Measure the total length (20.5" if I remember correctly) and have any local performance / muffler shop weld up an extension pipe. Tell them you are extending a regular cab truck to make it extended cab and need the extra length. That way they don't have any trouble "replacing a cat".

 

Well getting a test pipe isnt a problem, the shop that I had my v8 s10 exhaust done at will make a test pipe, but im wondering what the difference is between the hollowed out hfc and the testpipe.

 

what for your going to waste a good high flow cat man , just buy a test pipe they cost under 90 bucks man.

 

I would think the exhaust flow would be faster and less turbulent with a test pipe than with a gutted cat. I've got a slightly used Perrin cat-delete here you can have for $20 if you want. I switched to a DC Sports downpipe that has the cat-delete built-in, so I don't need the Perrin anymore.

 

Now days you can get a test pipe in the $60 range. It would be a pittyfull waste of money if you use the HF cat as a hollow cat. At least keep it, it could be beneficial in the future.

 

Save your money and hollow out the stock catalytic. Keep the hfc for emissions testing down the road... Instant freebie horse power

 

I would think there might be a small amount of resistance with the hfc hollowed out, kind of like a small resonator.