Catalytic Converters -- What should I look for?

[Travisty FTT]

Hi guys,

I'm in the midst of upgrading my exhaust at the moment and currently have little knowledge about Catalytic converters. This seems like a pretty serious issue to not have any knowledge about, especially when I see numbers like 100, 200 and 300 cell cats out there. What should I be looking for to suit a 2 and a half inch S/S system on a 6 cylinder?

Cheers.

[Travisty FTT]

Oh, and how do I know if I have a "LIVE AXLE"?

[POELWYK]

balisttic 100CPI raceing cat is a good cat

anything with 100CPI is good

[sleeper393]

Magnaflow , original METALCAT & kenobi, make sure they are full metal , with a metal substrate core.




THE LAST ONE AREN'T REAL GOOD , MAKE A FUNNY PURRRRRRING NOISE.

[BZINGA]

Originally Posted by POELWYK

balisttic 100CPI raceing cat is a good cat

anything with 100CPI is good

Yep alot of guys on the forum run these cats, myself included .. give Sureflo Exhaust a pm .. they are a forum sponsor and will help you out.

[JC]

For the record, 100CPSI cats are technically not street legal. 200CPSI are. But who's going to be able to tell the difference? So depends on if you want to be street legal or not. I chose to stay legal, so run a 200cspi cat on the territory. No idea what's on the XR, but wouldn't be surprised if they're the stock cats still.

Your car is a forte? It's live axle. Live axle is solid diff with watts linkages etc. The other option for an AU sedan is IRS, but only some XR6s, all XR8s, T series, all ghias and fairlanes got IRS; even the good old Fairmont (not Ghia) is live axle.

[Travisty FTT]

Originally Posted by JC

For the record, 100CPSI cats are technically not street legal. 200CPSI are. But who's going to be able to tell the difference? So depends on if you want to be street legal or not. I chose to stay legal, so run a 200cspi cat on the territory. No idea what's on the XR, but wouldn't be surprised if they're the stock cats still.

Your car is a forte? It's live axle. Live axle is solid diff with watts linkages etc. The other option for an AU sedan is IRS, but only some XR6s, all XR8s, T series, all ghias and fairlanes got IRS; even the good old Fairmont (not Ghia) is live axle.

Whats the difference between the 100CPI and the 200CPI and what are the estimated costs of these? Do they weld the cat to the rest of the cat piping that attaches to the exhaust and the extractors?

[The Monty]

The Ballistic 100cpsi cat is Euro 2 compliant, which means for the AU it is legal. BA on it isnt.

[Travisty FTT]

Whilst on the topic of Cats and Exhausts etc -- how many exhaust boxes are the best to be running on an AU? One on the front portion and one on the end? Or one on the front and a hotdog on the end? What would be best in your opinions?

[JC]

Thanks Monty - wasn't aware of that (so that's my learning for today!).

Tekno - the difference is in how many honeycomb cells there are in a given area (cells per square inch, or CPSI). The less there are, the less effective the cat is (but it still works) and the "better" the flow rate through the cat. On an I6, 200 CPSI is already probably enough in terms of flow rate/less restriction, but as the 100cpsi is legal and flows better, you might as well go for that. The cost difference is not a lot (maybe $50) And yes, these cats usually need to be welded in, so if the cat costs you $200, expect another $100 for fitting.

In terms of mufflers, depends on how loud you want it and if you care about droning at highway speeds. The redback systems come with one main muffler and a resonator at the rear - still gives a nice bark, and is quieter and gives no drone compared to a system without the resonator at the rear. My advice (having had both types) is to get the resonator - the other is louder, but used to give me headaches because of the drone at highway speeds.

[The Monty]

Good info there JC.
Also, in the first post, about Live rear, yours is a S1 Forte, its live rear.
Youll notice the exhaust runs over the top of the axle from the diff, on the IRS, it runs underneath.

[sleeper393]

Originally Posted by Teknoslasher

Whilst on the topic of Cats and Exhausts etc -- how many exhaust boxes are the best to be running on an AU? One on the front portion and one on the end? Or one on the front and a hotdog on the end? What would be best in your opinions?

Im running PACEMAKER 4499 , full s/s genie system with magnaflow 200cpsi cat magnaflow muffler & magnaflow ress
sound like this on the dyno-

http://img820.imageshack.us/img820/8633/aufalcon.mp4

[Day-mow]

that sounds maddddd sic sleeper393.!!

i've got a kenobi 100 cell cat. its a winner. got it off Ebay. but i rekn the magna flows on a group buy is the best option.

here's mine.
http://www.youtube.com/watch?v=nyxbbLUKTAQ

4499 headers, 100 Cell Kanobi cat, custom SS exhaust with a single lukey Race muffler

[blueoval]

Check out Venom Cats. Very good quality and priced well. Prices are advertised on the website which includes postage if send in Australia.

http://www.venomexhaustworks.com.au/

[Falconxr68]

Originally Posted by blueoval

Check out Venom Cats. Very good quality and priced well. Prices are advertised on the website which includes postage if send in Australia.

http://www.venomexhaustworks.com.au/

Don't like to revive an old thread, but I just wanted to ask if anybody has had any experience with Venom cats. They seem very reasonably priced. Does anybody know if 100 CPSI cats are legal in VIC?

Cheers

[Day-mow]

I think Kanobi are similar priced and I've got one of them and it works fine. Made it decently loud. I like it.

[MGGT RAA]

Originally Posted by Falconxr68

Don't like to revive an old thread, but I just wanted to ask if anybody has had any experience with Venom cats. They seem very reasonably priced. Does anybody know if 100 CPSI cats are legal in VIC?

Cheers

Yeh i got venom cats on the AU, been on for about a year - no problems. Noticed a much deeper sound with the venom cats, we put ballistic cats on the ba xr8 ute and wasnt much of a note change there.

I'd go with venom - much better value for money!

[blueoval]

AFAIK 100cpsi cats are not legal sound wise but flow the best, but 200cpsi are noise legal and only slightly more restrictive but probably stuff all difference in the scheme of things. Don't quote me on this, I believe it comes down to the entire exhaust system you have to test what will pass in a sound test.

[AUIIPURSUIT]

yea, its the entire exhaust thats tested. Pending the engine/car will determine what revs its tested to and also the backoff is what stings most people. it used to be only tested on acceleration, but i think most states now test decelleration as well.

if you get an epa notice, just chuck a stock cat back exhaust on. Even with a high flow cat and extractors, you should pass no problems.

[Falconxr68]

I just got a 2.5 inch redback exhaust today with 1 muffler and a rear resonator and its a little louder than what I expected but I like it. I also left my old exhaust there because I didnt want it to take up space, also because they cut it off from one of the joints...

Do you reckon the exhaust will attract attention?

[blueoval]

Originally Posted by Falconxr68

I just got a 2.5 inch redback exhaust today with 1 muffler and a rear resonator and its a little louder than what I expected but I like it. I also left my old exhaust there because I didnt want it to take up space, also because they cut it off from one of the joints...

Do you reckon the exhaust will attract attention?

Give it a week or 2 to carbon up. You will find the exhaust will quieten itself down once some carbon builds up in the system. Then see if its still too noisey for ya.

[Falconxr68]

Thanks Shav, if I do get an epa notice, how much do stock exhaust cost and are they difficult to come by?

[blueoval]

if you are looking for a stock exhaust Id be asking exhaust shops if they have any lying around from upgrades done on the cheap. Also depends on if you have IRS or live axle too. But you could find a stock system at a wrecker for cheap. I wouldnt pay more than $100 for a cat back system from anybody, wrecker or private.

[Falconxr68]

Yea, im just thinking whether or not i should go back and get it from the workshop (if they havnt gotten rid of it yet!). But im guessing he thought i wanted to leave it there which is why he just cut it off instead of unbolting it..

[blueoval]

thats a hard one. Might be worth ringing the exhaust place and asking them how hard it would be to refit the old one if needs be.

Alternatively, I'd just look at adding another muffler if you get done by the EPA to get it down to the required db levels.

[Falconxr68]

yea that sounds better, rather than taking off the whole thing. I did take the oval tip though in case I wanna change it later on, which i doubt though. I went with the twin tips (2.5 inch i think). I'll start my own build thread or post up some photos when I have more time.

PS: what setup do you have Shav?

[AUIIPURSUIT]

also, not that i told you.. but a few steel wool pads lodged back at the cats can do wonders...

[blueoval]

Originally Posted by Falconxr68

yea that sounds better, rather than taking off the whole thing. I did take the oval tip though in case I wanna change it later on, which i doubt though. I went with the twin tips (2.5 inch i think). I'll start my own build thread or post up some photos when I have more time.

PS: what setup do you have Shav?

My setup is designed for low Db and flow.

I have pacemaker 4480's, generic hiflow metal core cat, hot dog, redback straight through offset muffler, a resi in the tail pipe and the end of the exhaust turned down before the end of the bumper so it looks stock. No tips or anything. All these are connected by 2.5" mandrel bent redback pipework.

The reason I got this was before I went boost, I initially was going to go for a cammed engine n/a option.

What I really need is basically the same setup but with 3" mandrel bent piping instead. I could see another 10-15rwkw with that alone once tuned.

The system I have now is too restrictive in the top end and can't make anymore power.