I just ordered my Pro-1 Y pipe from 350zforums.org and wanted to know if anyone has the helix hi flow cats?? i was going to soon be in the market but wanted some feedback if anyone has them??? It's either these or the crawfords....price diff. $450 for helix, $500 for crawfords so price isnt really important factor, want performance, dont mind a lil sound for sake of performance, any ideas??

 

I am getting my helix cats installed on friday, will let you know the results

 

I've got the Crawfords. Had them for close to a year. Workmanship and fitment are top notch. Noticeable power increase, no rasp. Nothing to complain about. All of Crawford's merchandise, IMO, is top notch.

Lou

 

lowrider,

Did the noise level increase dramatically with the high flow cats? Do you have a cat back system?

I have the Injen SES, and it is already pretty loud. I've read that the high flow cats increase the exhaust volume.

Thanks

 

yeah... I was gonna ask the same question.. which one is better between helix and crawford hi-flo cats?
Lowrider mentioned that there is no rasp.. what about helix, is there any rasp?
Ajay, I'd really appreciate it if you can share your feedback on helix hi-flo cats.. how it perform and about the raspiness...

 

Yes Im really curious to know as well the diff. in the two. I hear people speak of 'rasp' when it comes to exhaust (Y pipe, muffler, pipes etc), but what exactly do you guys refer to when you use the term? Is this the like a loud annoying buzz that comes from ricey honda's?? I can appreciate a deep throaty sound or growl, but am not quite sure if I understand the rasp. Again any feedback is appreciated guys!!

 

pdjafari,
I was on the my350z site and i saw that there's this company called megan racing selling really good looking resonated test pipes for $95.

Check under the performance forum.

 

Dizz,
I also frequent my350z.com. I would DEF go for some test pipes but heard that cars in VA wont pass emissions unless they have Hi flo cats. I would much rather run w/ test pipes (whatever brand is best) not only are they lighter but cheaper and prob. better for performance. Unless of course there is something I am missing??

 

No, you pretty much got it. Emission's is the $20k question.
I figure, if you mechanically inclined you can swap them out before you go and get smogged.

 

well, how are those helix cats? i wanna get them but how do they sound and any difference i performance? please post
thanks

 

So I should note that my exhaust was totally stock before this. I've only had everything in for a few hours... my car ain't so quiet anymore. The high end is a nice kick in the pants, it was a little scary how fast I accelerated after 4000 rpm, but the noise... I am wondering if I will be able to put up with the noise for the long term. The low end seems a little worse, no surprise due to less back pressure.

There's no raspiness, but don't expect your car to be quiet anymore! (Could be the greddy evo 2 exhaust causing the noise too). I love the sound, but I wonder how many girls will be able to handle it, they'd come in thinking they were in a luxury car until I pressed the gas...

 

how much louder is it? I think your greddy caused the loud sound. I heard that greddy exhausts are mostly loud. but correct me if i'm wrong.

 

Is replacing the cats do-able with just a pair of rhino ramps and ratchet/torque wrench with extenders?

 

Replacing the cats is hard to do without a lift, because the location of one of the bolts is hard to reach.

Also, you may have to relocate your o2 sensor to prevent the check engine light from coming on.

I am also going to add a silencer to the greddy exhaust to make it a little quieter, I've decided it's too loud for my tastes, and my speech stuff *probably* will function worse with too much noise.

 

I'm considering Crawford cats. Will there really be a noticable HP gain, or can this be placebo with the sound. Please be brutally honest, I'm about to drop $500