True but the rasp on hfc's is hardly even noticeable comapared with tp's

 

There was a comparison done between test pipes and HFCs in a past issue of Import Tuner (i think). they said that their tests showed a gain of +1 hp with test pipes vs HF cats. Unless you're FI, go with HF cats.

 

Go HFC's.
No noticeable HP difference.
No smell.
No CEL.
Less pollution
Crawford, Kinetix, Megan have reports of cracking so be forewarned. Some have fitment issues too.
Ultimate Racing have none of the above issues....I run them and have been happy.

 

I have Test Pipes on my 350Z and it does sound to have a bit more rasp when flat from 3500-5000 but then it sounds good. Also if you like to roll with your windows down and you stop at lights you can smell your car. But it does sound a bit noisier after the 5,000 RPM when flat.

 

I'm guessin that the dealership wouldn't like it if i rolled in for an oil change with test pipes on huh? I could always get mine passed but my Z is still new so i bring it to the dealer for oil changes (its my first new car). hmmm decisions decisions...

 

what if you just leave the stock cat on with new headers and cat back???????? Or does this defeat the purpose of either one? Sorry if this is obviouse question - I think I understand the pros and cons of the test pipes and high flow cats.

 

The dealership won't give a isht about the test pipes.

 

I put Strup test pipes on my car (along with Greddy EVO2 and DC Sport headers). The rasp just plain sucks. Although as I break them in, it gets less noticable. No stinky smell either....fitmet is perfect. Which I thought was kinda weird. I'd worry about the rasp before I'd worry about anything else. Makes it sound ricey for sure. Couldn't tell you the gains...still breakin in my clutch, so I can't really stomp the gas.

 

Awesome info ceo. That just sealed the deal for me

 

Thats weird, i figured they would say something. I remember when i had my mustang and i brought it to an exhaust shop to get new tail pipes. They put it up on the lift and handed the keys back to me b/c i had an off-road x-pipe.

 

transformers robots in disguise

 

i HAD test pipes and now have high flow cats from Fast Intentions and couldn't be happier. I think they were worth the money and the sound is great

 

how much and what kind of difference in sound did you notice? and did the car pull noticeably haarder or have any noticeable performance increases?