Bmr4life

I'm currently catless, but have to pass emissions soon. I'm going to get either the metallic or ceramic Pypes cats and install them in my Pypes H-pipe. I know I'm getting a Brenspeed tune.

Is it even worth taking the High flow cats back off? Do they hurt performance that bad?

Mods are in sig and I have some DR Cams going in soon.


I guess I have a part B question also. How do high flow cats effect the exhaust note? I'm plenty loud right now and wouldn't mind if it went down just a tad, but not much.

Simon1

Depending on what the regs are in your location, some hi flow cats won't work well enough to pass emissions.

Alot of the hi-flow cats tend to get clogged easier than OEM.

Nuke

Clogging and passing/failing emissions aside, consider the performance of hi-flow cats to fall somewhere in between OE cats and no cats, probably leaning more towards no cats, IMO.

timmbo

If GA is anything like TN all they will do is an OBDII port test and no sniffer. If your test stations are anything like ours you'll get a guy with orange lips in a hurry to get back to eating his Cheetos grab a long handled mirror for the surveillance cameras to half *** glance under you car to check for the cat when he really doesn't give a rip. Before you know it the OBDII cable is hooked to your car, your receipt is printed and your off on your merry way. It's a joke really. But ya better have real cats and no fake shells on your pipes because it will be painfully obvious from the Nascar smell that you don't have them lol.

You may find leaving the cats on smooths out any trumpeting from your exhaust. I thought about leaving mine on but I hate the sulfer smell. When you add cams like FRPP Hot Rods or Detroit Rockers your cats will work very hard. Trust me. With cams your better off running catless because of the extra fuel those cams don't efficiently burn at idle will drastically shorten the life your cats. Metallic or ceramic.

I highly recommend Brenspeed with your mods for both a performance and emission tune. They worked perfect for me last year.

Bmr4life

I looked it up online.

I read that as NO sniffer.


Thanks for the replies. Sucks that I'll have to hack up my H pipe to add cats and buy another one to go back to catless.

Just had a thought. After I cut the H-Pipe to clamp in the cats. Maybe I can have a muffler shop fab a pipe that I can clamp back in in-place of the cats. That make sense?

timmbo

Might be better not to hack your H pipe at all. Just drive to the muffler shop and ask them what they would charge to yank the H pipe off and then just make 2 separate pipes right and left with the converters welded on. Doesn't have to be a fancy X or H. All they would need to do is flare the end for the header connection and provide 2 pipe flanges because you will be able to use the factory band clamps to connect the new pipe to the over the axle pipe at the rear.

808muscle

I have two Pypes HF cats which I took off my car after I installed my m90 for sale if you want them. I bought them from brenspeed. They were on my car for 8 months with 3k miles. I paid $189. You will have to weld them on. Shipped $100 if interested.

http://www.brenspeed.com/cvm10k.html

Bmr4life

Thanks for the offer. I ordered those same cats from Brenspeed this morning. They said they've give me a revised emissions tune for free as long as I got the cats from them.

808muscle

All good. I have a pile of parts I need to shoot pics of put in the classifieds. LOL Those cats really do work. Once I took them off, wow did the stink smell increase.

jlr84

@808muscle... I know this is random as hell from an old thread but I was just researching some stuff and came across this. Do you still have those high flow Pypes cats that you want to sell? Let me know... Thanks.