Hey whats up guys. As you can tell from my sig I was gonna get test pipes but I now decided to get the helix HFC's. For those of you that have them on their Z, do u guys think it's better than the crawford's. I know the old crawford would blow a gasket and would cause a CEL to go on. Do the helix ones have any problems like that. I don't it to throw a CEL and my car is an 04.5. Keep in my mind I plan on keeping her NA so are they good for NA applications? Thanx guys.

 

I like mine... $450 shipped for high polished SS cats with 200 cell metal substrates.

The only downside was no way to attach them. I created a bracket along with U-bolt that secured the cats to the OEM flex brace. No problem really...

Crawford are decent as are UR, imo.

Zquicksilver

 

Did u get a CEL?

 

hfc = NO CEL ON ANY MODEL YR CAR. It will work just like stock cats. The reason you get CEL is because you REMOVE the stock cats and replace them with straight pipes (no cats). The ECU runs a check to see if the downstream sensors are reading 'cleaner' exhaust than the upstream sensors. With test pipes, the sensors (the downstream vs the upstream) read the same and thus you get a CEL. With the HFCs in place the exhaust is still being 'cleaned', so the sensors will read the same as if you had the stock cats in place.

Bracket is completely unnecessary.

 

Thanx Zivman.

 

Nismo... the answer is no. Refer to Zivmans explaination.

Zivman,

Maybe so... but I thought I would play it safe. I really don't feel like messing with cracked or hairline cracked headers because of unessasary stress. I'm not a 100% sure if the engineers placed those brackets on there for safety precautions yrs down the road when everything begins to rust and fall apart or to greatly reduce stress on the headers due to the weight of the stock cats??? Without cat brackets, the weight of the headers, cats and Y-pipe are all suspended between the motor and B-pipe bracket.
It's quite a bit of stuff in my opinion. The way I look at it, it doesn't hurt to have some kind of support mid-way.

Zquicksilver

 

The stock cats are pretty heavy. If you compare those to your new HFC, the weight difference is most likely pretty significant. the bracket is uncessary on HFCs, but not bad. If it gives you peace of mind, then that is reason enough to have them.

 

Do they RASP with headers and aftermarket exhaust?

 

I don't have headers, but they do rasp a bit above 4K RPM with aftermarket y-pipe and fuji exhaust.