Guys,

Just wondering now that I have fitted extractors & other exhaust improvement mods whether there is much to be gained power wise by replacing the OEM main cat with a higher flowing cat. Especially now that this is the only cat left in the system.

Did some research and it seems the way to go is a 200 cpsi metal cat with 2 1/2" inlet & outlet. Metalcat seem to be the best but they are also a little pricey, around the $350 mark. Best value for money and still good quality (and legal!) seems to be the 'Zetti' brand from Scotts Rods in Qld, $169 & $20 postage to SA.

Also see this post from SH00T from March 09, refering to his Magna and the exact same cat I am considering:

Just had a high flow cat fitted by Scott's Rod's in yamanto. (pre ECU Re-flash) Very helpful, clean neat and fast.
$250.00 all told. And he didn't scoff at fitting a high flow cat to a magna, or my injection system.

Views & thoughts appreciated.

KJ.

If you've gone to the trouble of extractors and all that entails (O2 sensor adaptors etc) I'd definitely do it.

Are you goiing to get it dynoed?

Yep, gotta get it dynoed one day soon.

Just don't know who/where.

Steve Knight Racetech seems to be the dyno of choice for AMCers, especially those in SA, but he doesn't seem to have a web page or even an email address that I can find. The Steve Knight Racing web page and email address seem to be years out of date. He's also a fair way away from me (I live northwest of Adelaide, he's way done south).

Any suggestions as to a good dyno place in Adelaide that doesn't cost the earth and is preferrably north and/or west of the Adelaide CBD will be much appreciated.

KJ.

Yep, gotta get it dynoed one day soon.

Just don't know who/where.

Steve Knight Racetech seems to be the dyno of choice for AMCers, especially those in SA, but he doesn't seem to have a web page or even an email address that I can find. The Steve Knight Racing web page and email address seem to be years out of date. He's also a fair way away from me (I live northwest of Adelaide, he's way done south).

Any suggestions as to a good dyno place in Adelaide that doesn't cost the earth and is preferrably north and/or west of the Adelaide CBD will be much appreciated.

KJ.

Hey KJ, SKR might be bit of a drive but you will get a 'true' out-put figure compared to many places that just want to make you happy. call Steve-0419827850., Al.

i would get a high flow next. only restictive exhaust part left. plus its not really a cat its a white cat. originally was desighned to help with emissions but due to the front cats it was pointless.

i got mine dynoed at skr. price was $70 originally for 3 runs but he ended up doing about 10-15 to get a consistant reading.

Speaking of this, would there be much/any benefit in me fitting a high-flo cat? (No extractors, 3 cats still, only rear muffler changed)

Speaking of this, would there be much/any benefit in me fitting a high-flo cat? (No extractors, 3 cats still, only rear muffler changed)
Mate, I don't think it would be worth it while you have the highly restrictive precats in place still.

Guys,

Just wondering now that I have fitted extractors & other exhaust improvement mods whether there is much to be gained power wise by replacing the OEM main cat with a higher flowing cat. Especially now that this is the only cat left in the system.

Did some research and it seems the way to go is a 200 cpsi metal cat with 2 1/2" inlet & outlet. Metalcat seem to be the best but they are also a little pricey, around the $350 mark. Best value for money and still good quality (and legal!) seems to be the 'Zetti' brand from Scotts Rods in Qld, $169 & $20 postage to SA.

Also see this post from SH00T from March 09, refering to his Magna and the exact same cat I am considering:

Just had a high flow cat fitted by Scott's Rod's in yamanto. (pre ECU Re-flash) Very helpful, clean neat and fast.
$250.00 all told. And he didn't scoff at fitting a high flow cat to a magna, or my injection system.

Views & thoughts appreciated.

KJ.

If you have done the rest I'd say do the cat too. I have a 3" metal cat not sure of the brand though.

Is it true the front pre-cats are one piece with the manifold? Not sure how that could be done but can't see diddly squat with all that heat shielding there to find out.If so ,what happens many K's down the road when your cat's need replacing?Buy a complete manifold and cat set-up?That couldn't be cheap?

Is it true the front pre-cats are one piece with the manifold? Not sure how that could be done but can't see diddly squat with all that heat shielding there to find out.If so ,what happens many K's down the road when your cat's need replacing?Buy a complete manifold and cat set-up?That couldn't be cheap?

Yes. Knotched posted photos of his, ages ago. If he reads this, maybe he'll link them up again, or I'll do a search for them.

Yes. Knotched posted photos of his, ages ago. If he reads this, maybe he'll link them up again, or I'll do a search for them.

Yep, will do ....hang on....

http://i189.photobucket.com/albums/z179/Krossbolt/Car%20Pics/My%20Car/Manifold/30Oct002reduc.jpg

To the right of the base of the orange arrow you can see the bottom of the second and rear front cat

Thanks guys.Still not sure how you make a cat one piece with a cast iron manifold?,must be welded too it? Any pics of the manifold itself available ,maybe without the heatshields? Had a look at some parts diagrams but they don't show squat!

380 exhaust manifolds are stainless steel clam shell design ( 2 halves, upper and lower welded together with flange plates), then the cat is welded to it. The 3rd cat isn't a cat as previously noted it's there only to keep thhe exhauust back pressure the same as when the cat was fitted. It was found late in development that it wasn't needed but to delete it would have required a full engine remap and Bosch wanted to shaft MMAL for that so MMAL went the low cost white brick rout.

Cheers Dave

Thanks Dave,you know abit about this,did you work at MMAL?Delivered motors to the dyno room once,the guy their was tops,let me have a look around and all! So when replacement cats are required do we have to buy a whole assembly or would the cats be cut of and new ones welded on at the dealer do you think?

So Dave, back to my original question, now that I no longer have the two cats in the stock manifolds, is there anything to be gained flow/power wise by replacing the remaining cat with a 200 cpsi metal cat?

Put another way, does the remaining 'white brick' restrict flow much or not?

Or would I be wasting my time & money fitting a new cat?

KJ.

kj380 you have no cat in the exhaust system at all. Your car is illegal at the moment (insurance?). Not having a go just making you aware. Yes the white brick is a restriction how much I don't know, not alot I would say. Personally I would put a hi flow cat were the white brick (UCC) was and least it looks sort of legal, even though it would fail an emissions test. but it would look ok from an insurance issue.
Replacing cats on a 380, buy complete exhaust/cat manifolds or see if a exhaust shop could cut the old cat off and weld a new cat to the old factory manifold.
Yes I was at MMAL engine development (Lonsdale dyno) 2003-2006 could of been a number of us we loved the place and liked sharing it with fellow workers. Still miss the humm of those babies doing a 520hour endurance:cry:

Cheers Dave

Cool,might have been you Dave! yeah picked up a load of motors at the airport(from Japan I think)and dropped them at the dyno.I think the engine plant had closed and I got the feeling the guy was the last ,or one of the last left at the facility and had a good chat about the blocks and heads I could see around.The blocks I remember looked tough as nails with alot of webbing and a girdle from memory and the quality of the casting on the head runners was sweet! The guy said they were hard to improve on and only needed a bit of de-shrouding when fitted to the Ralliart.Yeah I could imagine working there would have been great and I reckon I'd miss it too!

kj380 you have no cat in the exhaust system at all. Your car is illegal at the moment (insurance?). Not having a go just making you aware. Yes the white brick is a restriction how much I don't know, not alot I would say. Personally I would put a hi flow cat were the white brick (UCC) was and least it looks sort of legal, even though it would fail an emissions test. but it would look ok from an insurance issue.
Replacing cats on a 380, buy complete exhaust/cat manifolds or see if a exhaust shop could cut the old cat off and weld a new cat to the old factory manifold.
Yes I was at MMAL engine development (Lonsdale dyno) 2003-2006 could of been a number of us we loved the place and liked sharing it with fellow workers. Still miss the humm of those babies doing a 520hour endurance:cry:

Cheers Dave

Dave,

So a 'white brick' cat is just a pretend cat?

It has the ceramic substrate but no rare metals doing their thing to remove Nox etc?

Is that right?

KJ.

I guess we now have to factor in relocating the existing CAT when putting on the headers instead of leaving both of them off.

Or we could replace the 3rd pretend CAT with one of the 2 front CATS?

I guess we now have to factor in relocating the existing CAT when putting on the headers instead of leaving both of them off.

Or we could replace the 3rd pretend CAT with one of the 2 front CATS?

As far as I know, the header cats are smaller and built into the header pipe, unlike the main line cat, and cannot be removed. So if you are talking about relocating these cats, I don't think you can. You either get new headers without them (from RPW) or new headers with them (from Hurricane?).
Another question along these lines though... if you delete the first 2 cats, is this third "pretend" cat strong enough to go solo now? Or is that where the hi-flo cat comes in?

So Dave, back to my original question, now that I no longer have the two cats in the stock manifolds, is there anything to be gained flow/power wise by replacing the remaining cat with a 200 cpsi metal cat?

Put another way, does the remaining 'white brick' restrict flow much or not?

Or would I be wasting my time & money fitting a new cat?

KJ.


kj380 you have no cat in the exhaust system at all. Your car is illegal at the moment (insurance?). Not having a go just making you aware. Yes the white brick is a restriction how much I don't know, not alot I would say. Personally I would put a hi flow cat were the white brick (UCC) was and least it looks sort of legal, even though it would fail an emissions test. but it would look ok from an insurance issue.
Replacing cats on a 380, buy complete exhaust/cat manifolds or see if a exhaust shop could cut the old cat off and weld a new cat to the old factory manifold.
Yes I was at MMAL engine development (Lonsdale dyno) 2003-2006 could of been a number of us we loved the place and liked sharing it with fellow workers. Still miss the humm of those babies doing a 520hour endurance:cry:

Cheers Dave


As far as I know, the header cats are smaller and built into the header pipe, unlike the main line cat, and cannot be removed. So if you are talking about relocating these cats, I don't think you can. You either get new headers without them (from RPW) or new headers with them (from Hurricane?).
Another question along these lines though... if you delete the first 2 cats, is this third "pretend" cat strong enough to go solo now? Or is that where the hi-flo cat comes in?

Grubco, if you remove the front 2 cats when doing the RPW header install, the car becomes illegal due to the fact the 3rd CAT does nothing. So you car will be pretty much running without any CATS.

Grubco, if you remove the front 2 cats when doing the RPW header install, the car becomes illegal due to the fact the 3rd CAT does nothing. So you car will be pretty much running without any CATS.

That is exactly why I haven't done it yet.

Guys,

Best value for money and still good quality (and legal!) seems to be the 'Zetti' brand from Scotts Rods in Qld, $169 & $20 postage to SA.



Ordered one of these two days ago, it was delivered this morning, looks the goods, top service & top price.

Now to get it fitted.

KJ.

Ordered one of these two days ago, it was delivered this morning, looks the goods, top service & top price.

Now to get it fitted.

KJ.

:iough: more noise .......

:iough: more noise .......

We'll see (hear). Getting it fitted a week today.

Hey Fooz, on your members machines thread you say you'll be getting your exhaust/mufflers sorted before you fit the new S/C and get a tune.

Can you let us know what you are planning WRT the mufflers?

KJ.

We'll see (hear). Getting it fitted a week today.

Hey Fooz, on your members machines thread you say you'll be getting your exhaust/mufflers sorted before you fit the new S/C and get a tune.

Can you let us know what you are planning WRT the mufflers?

KJ.

Haven't 100% decided what I'm doing yet but will let you know. If all else fails I will give your Commo mufflers a go.

380 exhaust manifolds are stainless steel clam shell design ( 2 halves, upper and lower welded together with flange plates), then the cat is welded to it. The 3rd cat isn't a cat as previously noted it's there only to keep thhe exhauust back pressure the same as when the cat was fitted. It was found late in development that it wasn't needed but to delete it would have required a full engine remap and Bosch wanted to shaft MMAL for that so MMAL went the low cost white brick rout.

Cheers Dave

My exhaust system is stock, If I was to remove 3rd cat only would I need an engine remap as qouted by Dave tj.

My exhaust system is stock, If I was to remove 3rd cat only would I need an engine remap as qouted by Dave tj.

If your exhaust is stock probably not much point unless you do the muffler as well. It will run fine without a remap but obviously with a tune you will get the best benifit.

I'd say what Dave meant was they would need to remap to clean up the AFR's for ADR compliance, basically an emmissions thing.

sorry to steal your thread, didnt want to annoy people with another exhaust thread....... Was there a bolt on catback made for 380's or do all u 380 owners go custom??

:iough: more noise .......

Got the high flow cat fitted a few hours ago, and then went for a little run.

No increase in exhaust noise or drone that I could detect. If anything, a slightly louder and nicer induction roar than before (but still not at all too loud). And what feels like a slight improvement in responsiveness throughout the rev range. Overall sounds better not worse than before, goes better than before, and now I have some peace of mind about emissions compliance.

Slightly OT, a heads up for those considering fitting RPW extractors.

The extractors/exhaust developed an annoying rattle a couple of weeks ago. To start with a loud metallic rattle on start up with a stone cold engine that went away after about a minute, once the engine warmed up a little.
Then lately, a consistent (but not overly loud) rattle all the time.

Tracked it down to the two primary extractor pipes hitting each other just where the front bank pipe passes under the rear bank pipe.

My exhaust guy quickly & easily welded a little bracket to the pipes so they they are now held slightly apart, no more rattle!

So the RPW extractors aren't quite a perfect fit after all.

KJ.

Got the high flow cat fitted a few hours ago, and then went for a little run.

No increase in exhaust noise or drone that I could detect. If anything, a slightly louder and nicer induction roar than before (but still not at all too loud). And what feels like a slight improvement in responsiveness throughout the rev range. Overall sounds better not worse than before, goes better than before, and now I have some peace of mind about emissions compliance.

Slightly OT, a heads up for those considering fitting RPW extractors.

The extractors/exhaust developed an annoying rattle a couple of weeks ago. To start with a loud metallic rattle on start up with a stone cold engine that went away after about a minute, once the engine warmed up a little.
Then lately, a consistent (but not overly loud) rattle all the time.

Tracked it down to the two primary extractor pipes hitting each other just where the front bank pipe passes under the rear bank pipe.



My exhaust guy quickly & easily welded a little bracket to the pipes so they they are now held slightly apart, no more rattle!

So the RPW extractors aren't quite a perfect fit after all.


KJ.

my extractors did that from word go but was fixed straight away.

So...with fitting RPW headers, and removing the forward cats, then fitting a High flow rear cat to make it legal.....

what happens to the FOUR front oxygen sensors?

I presume that you just get a constant emissions check light?


.

So...with fitting RPW headers, and removing the forward cats, then fitting a High flow rear cat to make it legal.....

what happens to the FOUR front oxygen sensors?

I presume that you just get a constant emissions check light?


.

Blackstar,

Check out posts 57 & 70 on the Extractor questions thread here:

http://www.aussiemagna.com/forums/showthread.php?t=67072

All four O2 sensors connected & working, and no CEL.

And the good news is that RPW have recently modified their 380 extractor kits so they (supposedly) come with all the bits & pieces you need to connect the four O2 sensors without going to the mucking around I did.

KJ.

OK

could you remove the whitecat and just have a straight through going to the muffler?

As you would still have the two precats on a stocker for compliance ???

OK

could you remove the whitecat and just have a straight through going to the muffler?

As you would still have the two precats on a stocker for compliance ???

I suppose you could and I guess it would still be emissions compliant.

But I doubt it would achieve much performance wise, as the two pre-cats in the stock exhaust manifolds do most of the strangling (together with the stock rear muffler).

KJ.

Knotched currently is running this setup I believe.

^
That's correct. It would make a some difference. The exhaust shop suggested it as a good move (same exhaust shop did Foozer's current setup).

cool may have to have a chat to Trotty about it

any problems with O2 sensors and that or just cut drop weld away you go??