On my 09 I have the JoeZ and love it. I dont want to do headers, but are the hi flow cats worth it? Louder and maybe a bit of gassy smell but do they add any noticeable power? Anyone tried them?
Thanks

 

Its worth it if you don't want to smell the gas smell after . Won't cost you but a few ponies and you know some green minded member is going to also say its better for the environment . If I ever went the headers route I would do cars to maintain comfort , and avoid nausea and future cancer from the fumes

 

Maybe I'm not understanding but your Joe z doesn't have any cats. So as of right now the only cats you have are in the factory headers. If you don't have any gas smell now then high flow cats aren't going to do much for you, quite things down a bit more and make your exhaust gas a little more 'green'.

Am I misunderstanding what the Joe z comes with stock?

 

Your primary CATs are all you need. The only reason you would install high flow CATs in my opinion would be if you installed headers or gutted out your primary's. I am running a PPE/Borla combo and have the ability to run with or without high flow CATs. When, hopefully soon, I track my car I will run w/o CATs but due to the smell I run with the high flows. If you really want to add ponies get a set of headers.

 

If you don't want to do headers, and you have left your stock exhaust manifolds intact, you really don't need to add HiFlows. The set of cats in your manifolds is sufficient to reduce emissions and eliminate any gasoline smell.

Lou

 

I think you are under the impression high flow cats 'add power'....not true.
Two reasons for high flow cats; to stay legal, and to get rid of the smell. The smell comes after you have installed headers and no longer have any cats on the car to clean up the exhaust. High flow cats are less restrictive compared to stock cats. They can also quiet down the exhaust note. And you will still see some loss in hp after installing high flow cats.

 

I'd only put hi flow cats on catless headers. On a stock exhaust I don't really see the need for one.

-Josh

 

What he said lol. I think I misunderstood the original post .

 

So can you install hi-flow cats w/ headers without modifying anything?

 

Short answer... no. You will need to modify your exhaust.

 

This is what I thought, so swapping back to no headers would probably not be an option. Hesitant to make a permanent commitment to a specific setup

 

You can swap back to your original exhaust manifold then take the exhaust to a muffler shop and have then cut the hi flow cat out and put a solid peice back in. But thats going to lessin the value of your exhaust assuming you are talking about an aftermarket exhaust.

 

You can't add high flow cats to aftermarket ISF headers, since there is no room for it.
It also wouldn't make sense to add high flow cats to your stock exhaust, since your stock exhaust already has cats. And high flow cats are for pipes with a wider diameter than stock.
High flow cats should only be considered for those with an aftermarket exhaust + aftermarket headers.

 

not STOCK.

he has Joe Z exhaust, so only has the cats on the stock headers

 

After running catless for the most part the past few years I can say with certainty it's worth having some in place. Interior was starting to pick up the smell, friends complained if they sat in the back of the car, I worried when followed by the PO-PO and of course it was a huge PITA to swap to stock exhaust each year for inspections. Now I don't have to worry about all that and it's a huge relief. The cats were not cheap, but they are considered some of the best money can buy.

GESI HIGH OUTPUT Series rated for 350-500hp each.
EPA Certified for use on OBD2 vehicles
Covered by a 5 year/50,000 mile warranty.