Best Catalytic Convertor Apart From Hjs

[bradsm87]

HJS are awesome but very, very expensive.

I'm looking for something that's a really good unit but not quite the price of an HJS. Best product under HJS would be what I'm after.

round and metallic core are no brainers but there's still a huge difference in quality and catalyst effectiveness between brands.

[sydking]

anything thats hollow?

[Hanaldo]

VENOM.

/thread.

[scotty nm35]

I use the Xforce ones, they come in 200 and 100cpsi with a 4.5 inch body. Quite reasonably priced too. As long as the catalyst is welded to the body they are extremely robust, you definitely won't be bashing one out easily.

http://www.bestmufflers.com/bshop/

[The Dan]

$340 fitted is what I do the 3" metal 100 cell cats for but we have to weld them up in house because they don't come with flanges attached.

We use them on everything inc. our race cars (although they take a 4 inch )

[bozodos]

Ballistic 100 cpi metal cats from Sureflo exhaust.

Cheap too (but not bolt on)

[sydking]

Cant quote anyone on this page without it linking to Elite racing website,

Anyway.....Do you find thoes 100cell cats are a restriction? They dont pass emmisions so why have anything at all

[wedge_r34gtr]

Cause it something like a $10k+ fine if you get caught driving without a cat.

The idea of the 100cell cat is less restriction - i.e still restrictive, but less then the stock cat.

[The Dan]

Cant quote anyone on this page without it linking to Elite racing website,

Anyway.....Do you find thoes 100cell cats are a restriction? They dont pass emmisions so why have anything at all

They don't pass emissions down there maybe.

Having one is definitely better for your wallet than not having one

[sydking]

seriouly cant clik anywere without http://www.erd.com.au/ popping up in a new window

As i cant quote....Wedge R34gtr- Thats the maximum fine. Though there has never been a case of someone reciveing anywere near that. Not somthing that can be roadside tested either, Lots of talk about temp sensor guns, But how accurate is a reading going to be when your cat or De cat has the stock cover welded around it?

[wedge_r34gtr]

i don't know how they test it or what sort of accuracy they get with the heat guns.

But why risk any fine over ~5kw gain.

[discopotato03]

I keep hearing about XR6T cats but couldn't find reasonable pics or results with them .

I used to use a Catco 8007 large body large matric ceramic cats but not sure if they are still available .

I think the problem is getting enough cat cross sectional area is one thing but keeping this hot enough is another .

Something else to think about is running several of those 100 cel cats in series as close to the engine as possible and maybe even insulate the exhaust ahead of the cat/s .

I'm told cats are a two tier problem as in 1) having them present in the factory std location 2) having the emissions correct .

A .

[sydking]

correct me if im wrong though CATS work when they are up to a certain temp, and will also retain a lot of heat, Hence when temp tested if its cooler or same as the rest of the system then its obvious there is nothing there,

When I got EPA tested for noise he did check the CAT was in the correct place, Not sure if you would be allowed to go putting them were ever you like, What would insulating the exhaust do ahead of the cat?

[discopotato03]

I'm not sure if the RTA/EPA has a problem with extra cats provided they can't become a fire/injury hazzard .

Insulation could be something like thermotec wrap , often manufacturers go to great lengths to shield exhausts to keep the heat in the gas because it firstly heats the cat and secondly hot gas has greater expansion energy to drive it down the pipe .

I hate to say it because of weight and packaging issues but some of the most successful systems are actually dualled and have valves to open/close the extra one . Not so sure how this would work with paralleled cats but on an angry engine at running temp the exhaust temp should be up there if suddenly switched through a cool extra cat .

I think the greatest dramas overall for the manufacturers are at cold start when everything including the exhaust gas temp is cool . If you could run one modest system from cold start and open a second under extra load could kill two birds so to speak .

For us one big system is always going to be a problem because the gas speeds are low at part load/throttle and there is vastly more heat absorption in the extra tube area and it rejects a lot more heat as well .

Heat is everything with emissions and it can't be too cool or too hot . I remember years ago BMW (I think it was BM) looking at electrically pre heated cats to beat cold start issues . It was going to take more zap than your typical 12V system has so they started looking at I think 18 and 24V systems but I don't think it ever got to production .

Something to ponder is this . On paper a GTS25T has 184 Kw with an I think roughly 2 1/2" system . If you could somehow have two samish stdish exhausts under there but only ran one up to say 2800-3000 revs or pre boost revs anyway and then opened the second exhaust , would you have quiet legal 300 kw potential ?

Packaging nightmare but food for thought , cheers A .

[bradsm87]

The cat will be a foot behind the turbo with thermal wrap up to the cat so it should heat up fairly quickly.

None of the options listed are really what I'm after. I'm after something that actually does a really good job as a catalyst but sacrifices as little as possible flow. Something that's 200cpi and at least advertises that it's suitable for Euro 3.

The wastegate will be plumbed in after the cat because the cat does pretty much nothing at richer than stoich and the wastegate is NEVER open in any stoich condition. This will reduce the performance hit of running a cat with no sacrifice to emissions. I will argue until black and blue if any transport inspector tries to tell me otherwise but there is near zero likelyhood of the position of the wastegate merge location being picked up on.

I reckon I'll just try and find the cheapest reseller in Germany that respond to english emails and just fork out the extra :-(

[sydking]

The way i see it mate, Any CAT that is good for emmisions is bad for Flow, Any any CAT that is good for flow is bad for emmisions.

Take your pick..

[SS8_Gohan]

I've got a Sard cat which was the pick of the Japanese ones, but was uber $$ from retail pricing i dug up.

you talking about these guys?

http://www.hjs-motor.../catalysts.html

[Husky33]

$340 fitted is what I do the 3" metal 100 cell cats for but we have to weld them up in house because they don't come with flanges attached.

We use them on everything inc. our race cars (although they take a 4 inch )

Why run any cat at all on a racecar?

[Hanaldo]

The cat will be a foot behind the turbo with thermal wrap up to the cat so it should heat up fairly quickly.

None of the options listed are really what I'm after. I'm after something that actually does a really good job as a catalyst but sacrifices as little as possible flow. Something that's 200cpi and at least advertises that it's suitable for Euro 3.

The wastegate will be plumbed in after the cat because the cat does pretty much nothing at richer than stoich and the wastegate is NEVER open in any stoich condition. This will reduce the performance hit of running a cat with no sacrifice to emissions. I will argue until black and blue if any transport inspector tries to tell me otherwise but there is near zero likelyhood of the position of the wastegate merge location being picked up on.

I reckon I'll just try and find the cheapest reseller in Germany that respond to english emails and just fork out the extra :-(

You'll get stung for it like that, no doubt. To inspectors/police/etc, merging the wastegate pipe after the cat is the same as having a screamer pipe, albeit without the noise. It breaks the rule of having EVERYTHING that enters the engine pass through the cat converter, and they're even picky about that over here in the nanny state

Edited July 20, 2012 by Hanaldo

[bradsm87]

The way i see it mate, Any CAT that is good for emmisions is bad for Flow, Any any CAT that is good for flow is bad for emmisions.

Take your pick..

Not entirely true. If a cat uses better, much more expensive coatings, they are more effective and can have the same catalyst effect with less surface area and/or length. This is why an HJS 200cpi cat won't trigger a CEL code, even on a brand new Euro 5 car, even though it flows much, much more than the 400cpi ceramic cat it replaced.