ncsu602

iTrader: (10)

After several setups on my car, I'm finally pleased. Since I've ran all three, I thought I'd give my experience. The car is a 99 Z, cam/bolt ons, M6 with 3.73s. I've got Mac midlenghts, custom 2.5" y with a Flowmaster merge, and a Hooker catback with an e-cutout. Nothing has changed other than the cats. When I bought the car, I bought a set of Thunderbolt ceramic cats so it would pass inspection. It killed all the cam sound, 1/2 of my sound level, and what felt like 20hp. I kept them on long enough to get it inspected, then gutted them and welded them back up.

I ran it this way for a year and then decided I'd try it again due to the tune being slightly rich and being tired of my clothes smelling like exhaust after 5 min. I bought the same Thunderbolts, only this time I ordered metallics. The metallic ones are supposed to have less cells per inch and flow alot higher than the ceramic ones. I put them on this weekend and I'm very pleased. It maybe took away 10% of my overall sound, got rid of what very little rasp I had, and no butt dyno difference at all. Plus, it killed 90% of the rich exhaust smell! When I was searching, I couldn't find any comparison like this, so I thought I'd post up my experience to maybe help someone out in the future. Thanks for reading!

'00_Z

iTrader: (3)

Good to know. I have been contemplating switching to a catted y and am looking at the options.

01formula6

iTrader: (7)

Good info. I have the Thunderbolt metallic cats sitting at home waiting for install.

JonPMH53

Did you put two cats on the Y-pipe or just one after the collector? I'm considering doing the same thing for the same reasons only I was thinking of just putting one cat on the back of the Y-pipe to make it easy...

jthunderz28

Thank you for sharing your experience. I think you just prevented me from making a $200 mistake.

I just almost ordered the magnaflow universal spun ceramic cat.

The issue i now face is finding a metallic in a 2.5 inch inlet/ outlet to bolt to my BBK y pipe.

Can anyone recommend a good priced 2.5 inch metallic cat that could be welded to the BBK Y PIPE?????

kyoytey1693

iTrader: (7)

I've thought about just putting one in the I pipe too. I dont know if its a good idea or not. I dont know if that would be more restrictive than two or not? Not sure what it would do to the sound either?

ncsu602

iTrader: (10)

Glad I could help....I figured I'd wasted enough money on this for everyone! Mine are 2.5", I welded them at home. I'm not familiar with a BBK y-pipe, but you should be able to weld it no problem. With my ORY to begin with, I measured and cut enough so I could slip them in. I put everything back up under the car and adjusted so it fit right then tacked everything in place. Then I pulled everything back down and finished welding. Also, you could get some flanges and get someone to weld them up for cheap, that way they bolt in and out. A muffler shop probably wouldn't charge that much.

I put two right after the header collector. Putting one back in the ypipe probably won't work. I don't think it will get hot enough to be effective. I noticed very little restriction, even with two.

ausls1

good info Metal cats are definitely worth it over ceramics, ceramics also have a tendency to melt together i guess you could say when they get too hot or poor mixes flowing through and cause a restriction, also seen a lot off factory ceramics break apart and rattle like crazy inside the cats.

99Bluz28

iTrader: (35)

FYI, all the Magnaflow cats I recommended to you are Metallic, not Ceramic.
The lower models are Ceramic.

jthunderz28

The ones you had recommended # 59959 were 3" and i discussed with my welder and he said they have to be 2.5" to fit the bbk y pipe.

99Bluz28

iTrader: (35)

All of these are 2.5" in/out,#59956, 59906, 59976.
I only recommended the 59959 (3" in/out) if you wanted to just put a cat right after the Y-pipe exit. It's all in the PM I sent you.

jthunderz28

Yup you are right, whoops. Thanks again for your help. I can't wait to get them on and have the car tuned. I really hope I made a good choice with the BBK's, last night i was kind of having regrets about not going with the TSP Stainless with catted Y pipe for only 300 bucks more after I factor in the cost to buy these metallic cats and have them welded in.
I didnt factor that in the equation at all.

But hey, 300 bucks is 300 bucks and that will get me a nice set of LCA's and plus a little more cushion for the clutch and the tune.
Thanks again for your help.

DeLaRosa25

iTrader: (10)

Bringing this one back, anyone running 1 cat? Thinking about getting just one 2.5in/2.5out to eliminate some of the smell. At the end of the ypipe or would it not get hot enough?

99Bluz28

iTrader: (35)

You can run a magnaflow #59959 (3" in/out)off the Y-pipe merger exit, it'll still work, just not as good as right off the headers.

M1tch

Don't run Cat's unless you have to!

I love the way my car sounds after headers, y pipe, and a 3" cat back. I havent gotten a tune yet but it runs perfect without them. I get the same if not better gas milage and its less weight and cost less. There is a certain resonance the muffler makes at 2000 RPMs that sounds amazing and i know that if it had cats it wouldnt come close to sounding this good.