Ceramic CATS and CAT recommendations

[Ryan Rotary Performance]

Thought I would post this up for general discussion.

A recent customer of ours has been recommended a Ceramic CAT for his car see the link below.

https://www.eurocarparts.com/search/724680060

Now I know my thoughts on these CATs, and they are should never be fitted to an RX8, the ceramics are too fragile and do not take well to the extreme heat cycles the rotary engine puts them through.

But just wondering on your thoughts and experiences and also CAT recommendations.

I now have two versions out myself here if anyone is interested:

Race CAT - 100 CEL FIA Approved
https://www.ryanrotaryperformance.com/s ... -converter

_MG_0017.JPG

_MG_0015.JPG

High Flow 200 CEL Approved CAT
https://www.ryanrotaryperformance.com/s ... -converter

_MG_0006.JPG

_MG_0010.JPG

Lets get a discussion going.

[Ryan Rotary Performance]

With my OEM style cat that I believe to be a cheapo replacement fitted by a previous owner unable to pass an MOT due to the huge chunk of material missing. I'll be following this. Your 200cel is high on my list of replacements Carl. Seeing what other people have used from a technical point will be great.

[Bigblueknight3k]

Am runing 200 cell power cat passed mot with it also but i like your model as it no doubt works as good as the coils but i dont think i would use anything else than oem and 200 cell cats magna flow 200 cell ones are not bad but best i had is 3 years but at £90 price tag its something u can live with

Sent from my LG-H930 using Tapatalk

[Keke]

I have the cat in mention, but it only goes on for mot day or maybe a couple of weeks later depending when I can be arsed to get under the car again!. After that I have your 100cell decay,
When I bought my car origanally it had a cat 4u on it and after a year it was almost failing.

Sent from my FIG-LX1 using Tapatalk

[PaulAV]

In the past I ran a ghetto decat, but the smell was just too much, when it came to mot time I fitted a killer cat from euro car parts, which passed no problem, I have since binned the ghetto and swapped to your mark 1 200 cell cat, still get pops (probably helped by the borla) no smell, no codes, just haven't seen an mot with it yet.

[New Duke]

I get the purpose of the 100 cel race cat. Pass race scrutineering and I'm sure it's light, looks and sounds great too.

Trying to figure out where a 200 cel fits in. Is the expectation that a 200 cel cat will pass an MOT? And would the RRP one therefore be a potential OEM replacement that's much cheaper than the Mazda one but will last daily use better than the ECP tat?

[chriskirkham]

The oem Mazda cat was toast at 47,000 miles when I bought the car - started to collapse with bits of material pinging out of the tailpipes.

Replaced with a Euro Car Parts version under warranty from the dealer.

This failed at 67,000 miles - when the back of the cat split - not really suprised as it was clearly cheaply made compared to oem unit.

Currently running a 200-cell sports cat from eBay, (sounds great with tubular manifold and Toyosport cat back).

Car has now covered 82,000 miles and I think that this cat is on the way out as we only just scraped through emissions for MOT - despite Cataclean and an "Italian" tune up on the way to test centre.

Tempted to just decat, but not sure I could live with the smell and that's also going to be an issue come next MOT....

Sent from my SM-T550 using Tapatalk

[Phil Bate]

My Mazda cat has just pipped 90k miles. I deleted the SAI pump about 40k miles ago and it has a small nick in the front of the monolith where a bit of apex seal escaped, but it operates perfectly and sails through the MOT without any special warming up.

I think they are pretty good as long as the ignition is looked after, and not burning sump oil probably helps.

[Ryan Rotary Performance]

I get the purpose of the 100 cel race cat. Pass race scrutineering and I'm sure it's light, looks and sounds great too.

Trying to figure out where a 200 cel fits in.

Haydn,

Thats right mate, the 100 CEL is for track use, it may pass emissions but not something I could guarantee, its as close as you'll get to a DeCAT without the smells.

The 200 CEL is an OEM replacement which will pass MOT inspection and suitable for daily drives.

[Ryan Rotary Performance]

My Mazda cat has just pipped 90k miles. I deleted the SAI pump about 40k miles ago and it has a small nick in the front of the monolith where a bit of apex seal escaped, but it operates perfectly and sails through the MOT without any special warming up.

I think they are pretty good as long as the ignition is looked after, and not burning sump oil probably helps.

I think Mazda OEM CATs are the strongest CATs out there, shame most of them now are far past there best and replacement is c£1500, ouch!!!

[v-rex]

Anyone know details of the original Mazda cat? Ceramic or metallic. Cells per inch. Etc. It's pretty pricey so unless its Mazda being cheeky they must be doing something in there to warrant the cost.

One thing is apparent is that it is the Dirk Diggler of CAT's. I can't see any others for the RX8, which have it's "girth", shall we say.

[v-rex]

It's a ceramic monolith, and yes it's a full on beefcake. Bear in mind that with conventional engines of a similar emission you would normally see two, in a one per bank kind of arrangement. No idea of the density but it looks similar to other original fit units

[v-rex]

Thanks Phil,

Do you know if Mazda used some sort of special alternate ceramic to help it tackle the heat cycles of a rotary ? Hence the cost ?

[Ryan Rotary Performance]

The OEM is so expensive as it contains precious metals such as platinum, palladium and rhodium, the actual construction method I'm unsure of but the CORE is classed as heavy and has a 3L capacity which aids in its longevity.

[HwAoRrDk]

A while back, when I needed a new catalytic converter, I went looking to see if there were any budget-priced cats with metal matrix construction, as I was wary of the poor reputation for durability of most of the existing ceramic ones. In fact, I made a thread about it, but I can't find it now, so I don't know if it still exists.

Anyway, the one I found was made by a company called TP Cats. Oddly, even though they're a UK company, I couldn't find any online retailer in this country to buy one from, so ended up ordering from some french website. I think they might sell mainly through trade parts suppliers, which might explain it. It was drop-shipped direct from the manufacturer, so I didn't have to pay international shipping. If I remember correctly, it was only about £160.

Can't really comment on the durability, as just haven't put enough miles on it (less than 10k), but it didn't melt in the first year like some others.

[ChrisHolmes]

There is a discount code of MID60 with ECP currently which drops the price to £150 !!!!!!

[Ryan Rotary Performance]

There is a discount code of MID60 with ECP currently which drops the price to £150 !!!!!!

Exactly! which worries me even more!

The CAT alone at traders cost to me when purchasing 25+ is more than that on mine!

[ChrisHolmes]

i just wrote a long and detailed reply but it didnt send as my net dropped out.... short summery: youll never compete with ecp’s garbage because it is just that, so pleas, dont try. id rather know im getting quality, and pay for it,

[PeteH]

I'm not sure my contribution is very useful for people with road cars, but for what it's worth.

My race car uses a Jetex, 100CEL, FIA approved, high temperature, stainless steel monolith, cat, with 5" body, and 3" pipes. It's not cheap (about £250 for the bare cat), but it does a great job. Jetex recommend this for up to 250bhp, and up 1600degC, and for race use only (although it has to be better than a decat, right..?).

This was the largest, highest flowing, highest temperature cat I could find. It does eliminate the smell, and it doesn't seem to restrict the flow at all, since my dyno results look great. And it has survived a full race season, which makes me think no road car is ever going to destroy it. Of course, fitting this isn't just a bolt on job (unlike RRP's cats), so it requires fabrication skills. Jetex make a similar cat in 200CEL, so it would be possible to make a system with exchangeable cats; one for MOT time, and one for "race use only...."

https://jetex.co.uk/product/5-fia-appro ... ipework-2/

[Phil Bate]

That's pretty much what I'll be doing if/when my original unit gives up. I have had a PTR Exhausts straight decat pipe sat on the shelf for years, ready to cut and weld a 200cel cat and resonator into. But the damn thing just keeps going

[v-rex]

I'm not sure my contribution is very useful for people with road cars, but for what it's worth.

So do the FIA have some minimum requirements for emissions ? I would have thought in racing, you could just decat and forget?

[v-rex]

i just wrote a long and detailed reply but it didnt send as my net dropped out.... short summery: youll never compete with ecp’s garbage because it is just that, so pleas, dont try. id rather know im getting quality, and pay for it,

So, what do you have ? I'm assuming that sponsored by RRP, that you might have one of their exhausts ?

[PeteH]

So do the FIA have some minimum requirements for emissions ? I would have thought in racing, you could just decat and forget?

No, there are no emissions tests. And no, you can't just decat. It would be impractical to try to emissions test race cars. But it's a requirement that all post-2003 race cars have cats fitted. If your event is an FIA sanctioned one then your cat will have to be FIA certified, but for most UK events any cat will do. There are really no regulations on what that cat must be, and it is an area which is ripe for abuse. I fitted the FIA certified one simply to avoid any controversy. And I was glad I did because in 2017 the organisers of my race series asked me to pull the cat off the car so that they could check it (they just looked to make sure it had a matrix in it).

I know of plenty of people who race with decats. Persoanally I don't see the point when it's so easy to fit a free-flow cat on anyway.

[v-rex]

i just wrote a long and detailed reply but it didnt send as my net dropped out.... short summery: youll never compete with ecp’s garbage because it is just that, so pleas, dont try. id rather know im getting quality, and pay for it,

So, what do you have ? I'm assuming that sponsored by RRP, that you might have one of their exhausts ?

no, my sponsorship deal doesnt quite stretch to that, they've been very generous ive had several £k of parts and services from them already.

i run a tubular manifold (with the ais ports removed and the narrow section replaced with 3”) a modified standard cat (cat section cut out and pipe welded in its place) and a borla catback.

its 3” throughout and not as loud as id expect, but i believe nice and freeflowing..

i put a borrowed cat (#kellytm272)’s on for mot time.

[v-rex]

PeteH,

That just all seems a bit bizarre. But as you say better to be safe than sorry so sticking a 100 cpi cat in ( which is the smallest cross-sectional area I've seen ) is a good cautionary measure.