First of all what the heck is a test pipe??? and second are they any better than a cat..I understand that cats are more restricted but do they perform any better?

 

seriously, do a search man.

testpipe is a pipe -- no regard to pollution. -- illegal for street use.

cat is a catalytic convertor --when people say "HF CAT" theyre referring to high flow cat which is less restrictive than the stock cat... hence some performance gains. depending on which one, they MIGHT be legal.

if you dont know what a catalytic convertor is, then its time to use google or search within here.

 

Dude no need to be rude..ive been searching these forums for the past several days. I know what a Cat converter is...but being a new z owner, and I only have had four wheel drives in the past have never had to use nor Knew what a test pipe was, had no use for one. I apoligize for not being as well educated as you are about these, but I have only recently purchased my z about a month and half ago. It sits in my garage with 375 miles on it while i sit here in Iraq, so i can only do so much research. But other than that..thanks for the useful information..i bow to u..

 

dude stop being rude to people that have questions...sometimes it's a pain to use that search button and find legit info...if you knew the answer which looks like you vaguely know as much as he does..you either explain it or leave it..

 

ouch i'm totally not trying to be rude guys -- perhaps my choice of words were harsher than i had intended at 4am heh sorry. i suggested to do a search first and foremost (which is what people tend to reply), then tried to make an effort to give a fairly high level answer since it seems like that might be enough to get the discussion started for others to come add to it. what would be rude is to say "do a search" and end it there. i'm not claiming i'm smarter so i dont start gettn on the defense. as for zownz, your subtle comment to insult me is just as rude but clever. -- anyway .. cheers

 

A test pipe is simply a straight through pipe that replaces the section of exhaust where the stock cats were. They will come with different diameter piping and should have 02 bungs welded in for the stock 02 sensors. Some may have brackets mounted on them to help support the exhaust weight and attach to the stock cat mount that the cats bolt up to. Test pipes will yield a bigger overall HP gain than HF cats because they are less restrictive, however they also tend to make the exhaust note much louder. This can be good or bad depending on the current exhaust note of your current exhaust setup. Some aftermarket exhausts can easily get away with test pipes whereas others become very loud and raspy. You can get test pipes with built in resonators that will help with the raspiness to a certain degree. These still maintain that high HP gain, but eliminate some of the negative sound characteristics associated with plain test pipes. Test pipes with resonators are a little more expensive though. Either type of test pipe will not pass a visual inspection if you state does this.

HF cats are simply that, catalytic converters that are less restrictive than the stock cats allowing a higher flow rate of exhaust thus increasing HP. They are more expensive, better for the environment, some will pass inspection and most do not have the negative sound characteristics of test pipes.

If your state does inspections, then HF cats would be the way to go unless you don't mind swapping them out before and after the inspection. If your state doesn't do inspections, then the test pipes may be a very good route depending on the rest of your exhaust setup and your opinion on what sounds good.

 

but "clever"...haha jk...sorry bro maybe my choice of words were harsher than i had intended=P

 

Great Information..Should be a sticky..thank you sir

 

Man that was good info..thanks for all of your help...including u jkoc...lol.. u guys are too funny

 

Another thing to keep in mind when considerng HF cats or test pipes are CELs or check engine lights. While test pipes will give you better performance they will also throw a CEL in almost all cases. The CEL is the small engine shaped light on the dash and is there to alert you that there is a problem with the emissions system, i.e. no cats = bad emssions. These can be very annoying and it's debatable if the engine pulls timing and switches to a "safe-mode" due to this. Some ppl offer what are called O2 simulators which trick the ecu into thinking the cat is still there and functioning. These are cheap electronics that can be made from parts at your local Radio Shack but require hacking into your wiring harness and some wiring & soldering know-how.

HF cats should not give you these CEL issues and like zzzya mentioned will pass inspection if you live in a state that has them.

 

which hiflow cat performs the best or which one is the best i should say and can i place hi flow cats with my stock exhasut . How would that affect it overall. And I am planning on getting the borla true dual in future no prbs with compatablity correct

 

This may help

https://my350z.com/forum/intake-exhaust/114798-tp-w-resonators-or-carb-legal-hf-cats_.html

https://my350z.com/forum/intake-exhaust/116664-ts-headers-and-helix-hf-cats-pics.html

Good Luck,
Zquicksilver