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-   -   S2 stock cat and HJS cat questions (https://www.rx8club.com/series-ii-aftermarket-performance-modifications-162/s2-stock-cat-hjs-cat-questions-265987/)

UnknownJinX 08-04-2017 10:27 PM

S2 stock cat and HJS cat questions
 
Seems like I can't find too much info on the Series 2 cat.

So are there any improvements in the longevity for the OEM cat for S2? I know there is a huge price difference, but I am not sure if OEM S2 cats can fail as easily as OEM S1 ones.

Another thing worth my concern is that sometimes after hard accelerations, I can smell a bit of sulfur in my car. A search of this on the web returned results ranging from "it's fine" to "fix your cat NOW!" Should I be concerned about a potential cat clog? I will be taking my cat off for a quick look at some point, but I just want some opinions.

Onto the HJS cat. I have asked @Steve Dallas about this, and I got a lot of info. Seems like it's impossible to source the one I am looking for(HJS-Nr. 90 95 0182) in North America as of now. Is my only hope ordering this cat from Germany if I want the HJS tuning cat + BHR mid-pipe route?

Jdmx13b 08-13-2017 01:41 PM

Drop your cat right now!! Put it in storage or just somewhere out of the way. Get either a test pipe or the bhr dual resonated mid pipe and run that year round until inspection then put your cat on do a couple drive cycles until the cel disappears and then your good to go, get home drop your cat again and don't use it for till the next inspection. The s1 and s2 cats are garbage not necessarily mazdas fault either. Rotaries are really hard to make emmissions legal and require special cats that filter a lot of shit out and because of the unburnt fuel and oil plus the insane amount of heat our cars put out equals horrible catalytic converter life expectancy

TeamRX8 08-13-2017 04:38 PM

I was the first person to use an HJS cat here back in 2006. I bought that one and then a second one in late 2009 both from Germany. A year or two later after that HJS started a USA branch, but apparently they no longer have that. Buying one from Germany is no big deal. You just have to go through one of their distributors. However, I was using their super high flow motorsport cat for an emissions legal race class. So I can't tell you how long it will live with regard to emissions effectiveness for street use, but what I can say is for the type I used it will never fail/breakup or clog up like a factory cat converter.

The last one I used (now sitting in my garage because I'm changing to a non-emission class) was their largest, highest flowing 100 cpi model HJS-Nr. 90 95 0050 GT 1407/10 PE rated up to 400 hp with a 3" inlet/outlet size and also rated for 1000*C continuous temperature. Think I paid around $950 for it shipped. They released a bigger one recently though, now rated for 500 hp!

The cat you chose is a 200 cpi universal tuning cat. It's supposedly modelled after their motorsport cat, but the one thing I don't see on their website is the max operating temperature. I would recommend you contact them and ask for that information just to be sure.


Homepage - HJS Motorsport & Tuning


On this engine it could be a problem to put off checking it. If it looks fine then you should definitely be checking the coils and spark wires to make sure they're working properly.

UnknownJinX 08-13-2017 07:13 PM


Originally Posted by TeamRX8 (Post 4831582)
It's very irresponsible to openly tell people to break the law and be gross polluters.

I was the first person to use an HJS cat here back in 2006. I bought that one and then a second one in late 2009 both from Germany. A year or two later after that HJS started a USA branch, but apparently they no longer have that. Buying one from Germany is no big deal. You just have to go through one of their distributors. However, I was using their super high flow motorsport cat for an emissions legal race class. So I can't tell you how long it will live with regard to emissions effectiveness for street use, but what I can say is for the type I used it will never fail/breakup or clog up like a factory cat converter.

The last one I used (now sitting in my garage because I'm changing to a non-emission class) was their largest, highest flowing 100 cpi model HJS-Nr. 90 95 0050 GT 1407/10 PE rated up to 400 hp with a 3" inlet/outlet size and also rated for 1000*C continuous temperature. Think I paid around $950 for it shipped. They released a bigger one recently though, now rated for 500 hp!

The cat you chose is a 200 cpi universal tuning cat. It's supposedly modelled after their motorsport cat, but the one thing I don't see on their website is the max operating temperature. I would recommend you contact them and ask for that information just to be sure.


Homepage - HJS Motorsport & Tuning


If you just leave it off between emission checks like Mr. Duphus suggested above you'll be smelling serious hydrocarbon fumes all the time. On this engine it could be a problem to put off checking it. If it looks fine then you should definitely be checking the coils and spark wires to make sure they're working properly.

We don't have emission inspection here, but I still want to reduce the emission. Like you said, it smells bad, is toxic, and will damage my rear bumper paint. Not worth it just for some flames.

Without an emission inspection, I don't have to worry about the exact amount the car emits. I just want less fume and a cat that will actually hold up, so an HJS cat should do.

Good to know they are holding up well. Steve Dallas uses the Tuning cat with the BHR mid-pipe, btw. He said his setup is holding up well even with track uses. I will look into both options and see which one I want to run.

About the sulfur smell... I realized that it only comes out when the car accelerates hard and the AC is on, so it's most likely just mildew from the AC. Ignition components are also all good, I put on some new spark plugs when I bought the car, and I installed the BHR coils and wires a while ago. That said, I will pull the cat soon to give it a good look.

wankelbolt 08-14-2017 04:19 PM


Originally Posted by UnknownJinX (Post 4831593)
About the sulfur smell... I realized that it only comes out when the car accelerates hard and the AC is on, so it's most likely just mildew from the AC.

Changed your cabin air filter lately? :eyetwitch

UnknownJinX 08-14-2017 05:00 PM


Originally Posted by wankelbolt (Post 4831699)
Changed your cabin air filter lately? :eyetwitch

I bought a set of new paper ones to replace the old aldehyde ones when I got the car because I didn't know better.

I ordered an aldehyde ones from the dealership. Really expensive, but I couldn't find better prices anywhere else. I will see if it improves anything.

UnknownJinX 08-14-2017 05:12 PM


Originally Posted by Charles R. Hill (Post 4831713)
Also be sure to clean out your drip/drain hose from the A/C. Those tend to get clogged and cause the mildew smell when the A/C compressor is defeated but the circulation fan is still running (such as during WOT).

As far as I can tell, the condensation water still drips out when AC is run for a while.

Not using my AC as much anymore. It's cooling down in BC now.

I will add that to my checklist.

TeamRX8 08-14-2017 06:10 PM

I had no idea Canada didn't have emission laws. Thanks for educating me.

UnknownJinX 08-14-2017 07:35 PM


Originally Posted by TeamRX8 (Post 4831726)
I had no idea Canada didn't have emission laws. Thanks for educating me.

Not sure about the other provinces. I just know BC doesn't have any right now. I have heard we used to, but that was like 20+years ago or so.

Provinces in Canada have different rules regarding vehicle licensing and such, so it can be different across Canada.

Actually, I have another question now: how much gain should I expect from a BHR + HJS setup? I have heard that HJS has almost no restriction according to some dynos online. Results here ranged from no gain to most gain without going FI, and I haven't seen an exact figure.

UnknownJinX 08-21-2017 12:26 AM

So here is little something I was able to test out tonight:

There is a part of the road where I sustained 5k RPM and above for a little bit. The road leads to a calm seaside drive where I can pull over and look under the car(without anyone around to see me doing it, LOL). While the cat itself isn't glowing, I can definitely see the rear O2 sensor having an orange glowing ring around it.

Drove the car home, which I just drove normally, so around 3k RPM. The rear O2 sensor didn't glow.

So is it safe to say that my cat is dying?

Edit: looked around, and the general consensus here is that if it's glowing, it's shot. Mine only seems to glow after sustained high RPM, however, so it will just give me enough time to start getting a new cat. I will take it easy on my car now, no revving past 5k for the time being. May even consider renting a car for the time being.

wannawankel 08-21-2017 08:58 AM

My dealer looked at my cat in its current condition (same glow as yours) and said pay the bill your cat is fine. My temperatures appear fine right now (and same range as Steve Dallas data). So I'm keeping a very watchful eye on the cat and hoping I can see a change and then get it in quick to the dealer for a new cat under the 8 yr Federal Warranty.

UnknownJinX 08-21-2017 12:02 PM


Originally Posted by wannawankel (Post 4832578)
My dealer looked at my cat in its current condition (same glow as yours) and said pay the bill your cat is fine. My temperatures appear fine right now (and same range as Steve Dallas data). So I'm keeping a very watchful eye on the cat and hoping I can see a change and then get it in quick to the dealer for a new cat under the 8 yr Federal Warranty.

So does it only glow after sustained higher RPM?

This is why I am suspecting my cat is dying, but not quite there yet, as it doesn't glow after a normal drive.

I was also accelerating hard at times and seems like the car is accelerating slower in 2nd gear than I have seen in a video of an R3 accelerating, so maybe there is a slight clog, but not enough to give a more apparent symptom. I don't have any misfire. My symptom falls under the "revs slowly but smoothly" a bit, which means either the cat is clogged or the front O2 is shot, one of the two. The air filter is out of the question, as I just replaced it when I bought the car and it has no clogging from inspection.

I mean, taking it off and looking at it is the best option, but I just don't have the time to do it rn. I would have to wait for at least a week to take a closer look.

The cat glowing kinda looks like this(from another thread), although mine is a little more orange than this. Mine only glows after staying in 5k RPM or so for about a minute.

https://cimg3.ibsrv.net/gimg/www.rx8...0b696b3874.jpg

TeamRX8 08-21-2017 03:33 PM

The whole thing is glowing. You can only see it there because the sensor mounting boss isnt insulated with a metal outer cover like the rest of it.


https://cimg9.ibsrv.net/gimg/www.rx8...8271710529.jpg

UnknownJinX 08-21-2017 08:15 PM


Originally Posted by TeamRX8 (Post 4832671)
The whole thing is glowing. You can only see it there because the sensor mounting boss isnt insulated with a metal outer cover like the rest of it.


https://cimg9.ibsrv.net/gimg/www.rx8...8271710529.jpg

Make sense.

The thing I am a little bit confused about is that most of the cat clogs from what I have searched tend to affect the car in other negative ways, like misfires. My car didn't misfire or have any other apparent symptoms.

The only thing I think that's a little bit off is the MAF reading is a bit lower at idle. It reads between 4.9~5.0g/s, whereas it's supposed to be like 5.5~5.6g/s, at least for an S1. There are no vacuum leaks, and fuel trims are pretty normal(LTFT is at 1.6%), so that means there might be a bit of restriction. Is that a correct assumption?

UnknownJinX 08-23-2017 03:59 PM

So I emailed HJS regarding the 90 95 0182 and 90 95 0190 Tuning cats, and this is what they told me:


the best working temperature for both mentioned catalyst is between 250 and 650 degrees centigrade.
Max. duration temperature is 950 degrees centigrade, max peak temperature 1050 dc.


(for American folks, 250~650 C is 482~1202 F, 950 C is 1742 F, and 1050 C is 1922 F)

Just leaving this here for anyone curious.

TeamRX8 08-23-2017 06:32 PM

You might want to quit wasting time guessing and instead pull the cat to inspect it ASAP.

:eyetwitch

.

UnknownJinX 08-23-2017 06:42 PM

Will do tomorrow morning.

TeamRX8 08-24-2017 05:29 AM

Max temp on a well tuned, good compression Renesis is around 1650 degF on an egt thermocouple near the exhaust port. Running a little richer on fuel ratio will be less. Too rich though and it will light off at the cat converter and be much higher there. If you pull the cat and it looks ok then you might want to start investigating that instead. Inspecting the cat asap us the priority though as that could damage the engine long term if not addressed soon enough.



.

UnknownJinX 08-24-2017 06:37 PM

3 Attachment(s)
Okay, so I pulled the cat today for an inspection. Doesn't look clogged, as it looks hollow all around(the photo only focuses at a single point, but looking at it with my own eyes, it looks fine).

The front O2 looks a bit worrying, though. Does this look bad? If that is bad, maybe that means my car is running rich for a while now. I ordered a new one anyway, given the age of the car.

I am leaving the car home as for now, as one of the bolts broke off.

(before anyone asks, the compression numbers are fine, and there are no issues with cold or hot starting)

TeamRX8 08-24-2017 11:50 PM

You can't guess at AFR, it needs to be measured accurately. By appearance alone it doesn't appear to be that unusual for a lot of mileage.

TeamRX8 08-24-2017 11:59 PM

You might need to test the coils and wires with a load spark tester. It won't necessarily show up as a misfire code.

UnknownJinX 08-25-2017 12:10 AM


Originally Posted by TeamRX8 (Post 4833267)
You can't guess at AFR, it needs to be measured accurately. By appearance alone it doesn't appear to be that unusual for a lot of mileage.

So would live readings of front O2 from an OBD2 reader help?


Originally Posted by TeamRX8 (Post 4833268)
You might need to test the coils and wires with a load spark tester. It won't necessarily show up as a misfire code.

They are BHR coils and wires, and I never felt misfires myself at any RPM, but I might just grab a cheap spark tester to see what's up.

UnknownJinX 08-25-2017 04:20 AM

It just occurred to me: isn't the OEM cat made of 2 pieces? Oxidation and reduction?

The visual inspection can only work on the front piece, but not the back. The flash light won't shine far enough down the pipe, and the structure and weight of the pipe means you can't point it at sun and look through it.

The only way to look at the back one is to knock out the front one, which I am reluctant to do because I want to get some more cash for recycling this thing in a whole piece. I am getting the mid-pipe anyways, as I need something more durable, powerful and lighter.

TeamRX8 08-25-2017 09:08 AM

It's less likely. The rear O2 is between them. Typically being red there is a light off indication in the front section. Yes, you need an ODD2 tester. You need to verify coil and wire integrity. All parts are subject to failure regardless. Repairing a car properlyis not an assumption or guessing game. You follow a path of logic with testing and verifification.

UnknownJinX 08-25-2017 06:41 PM

I am trying a more logical approach, maybe some guesses, but since I am not with my car right now, I am just searching the possible failure points and try to test them. With slow but smooth revving, the troubleshooting procedures I have seen point to some kind of restriction in airflow, or a O2 sensor fault.

Coil failures tend to lead to failures that involve some kind of roughness, like misfiring or stumbling. Not that it's impossible for me to have ignition failure, but I just think it's also unlikely since the symptoms I have don't match up.


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