Jim_Patterson

iTrader: (13)

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?

Cajun Power

iTrader: (3)

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".

Jim_Patterson

iTrader: (13)

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.

jmartinez1170

iTrader: (21)

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

Killboy

iTrader: (2)

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.

fromWRXtoEVO

iTrader: (18)

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.

4-BNGR

iTrader: (3)

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

BuLocal

iTrader: (4)

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