Exhaust Woes (Advice needed plz)

"Akio Ohtori - RIP Oppo" (akioohtori)
06/30/2020 at 10:40 • Filed to: The Hot Mess

Well shit Oppo. I was all excited to get back to work on the Jaaaaag and thing seem to have gone awry quite quickly.

When I bought the Jag the dealer admitted to gutting the passenger side catalytic converter because it was plugged. I us ed this as a negotiating tactic and here we are.

I’m finally getting around to putting a cat back on because, against all odds, I believe in emissions equipment on newer cars. However.... this is my first time dealing with the wide world of aftermarket catalytic converters and I can safely say it has not gone well.

So what I did is get on RockAuto and order the only catalytic converter they had available for my vehicle. It is a direct fit unit made by Davico for about $210, which seemed about right. Most importantly, it had the O2 sensor port in the right place. The Jag has kind of an odd setup where one O2 sensor is right on the inlet of the cat and the other is in the middle.

Oddly as research for this article I’ve noticed it isn’t shown that was in the FSM... so I have some questions.

Anyway, I get the cat in yesterday and immediately notice it is much smaller than the stock cat. I’d say..... 50% of the diameter?

Well shit. I feel like this is going to stifle the 4.2L Supercharged V8 a bit...

A little sleuthing shows that Davico uses the same cat on both the NA and Supercharged engines, which doesn’t seem right. Jaguar has different part numbers for each, though there seems to be no difference in cost.

Ok... I think I could reasonably convince RockAuto to take the cat back for free as it just... isn’t right. But what are my alternativ es?

Pretty slim, as it turns out.

Magnaflow makes a direct fit for $650 but the cat also looks pretty small.

Magnaflow also makes a universal fit with the center tapped O2 sensor, but no inlet O2 sensor for $90. This looks to be a little larger than the Davico one. Maybe.

Stock cats are available for between $1,100 and $1,300, which is a hard pass.

Lastly, a German company I’ve never heard of makes a CARB compliant direct fit for, you guessed it, $650, which, right again, also looks to be smaller than stock.

Questioning the Jaguar community has turned up no help other than people in the same boat and a few that are willing to put up the money for custom cats and ECU tunes which... no.

So right now my options are:

Put the Davico unit on and pretend I saw nothing ($210 + fitting)

Buy the Magniflow universal fit and have my exhaust shop weld it in ($90 + fitting)

Buy the Mangiflow direct fit ($650 + fitting)

Buy the CARB compliant direct fit ($650 + fitting)

Take it to my exhaust shop and see what they think

Delete the cats ($??)

Honestly #5 seems like the next step, but I wanted to see if Oppo could school me on aftermarket emissions equipment because I feel like I’m taking crazy pills right now.

Halp!

Doggo for your time.

DISCUSSION (22)

gettingoldercarguy > Akio Ohtori - RIP Oppo
06/30/2020 at 10:51

No, use a green cat, gesi , etc. They’re the only high performance cat worth a shit.

https://gsportbygesi.com/

https://www.jegs.com/i/Kooks-Custom-Headers/579/GE-90140/10002/-1

sony1492 > Akio Ohtori - RIP Oppo
06/30/2020 at 10:59

Deleting the cats is the most reasonable option cost wise. If you know what caused the cat to clog in the first place and fixed it then it might be worth replacing but if there is no obvious underlying cause then the new cat is going to die too.

I like cars: Jim Spanfeller is one ugly motherfucker > Akio Ohtori - RIP Oppo
06/30/2020 at 11:02

Generally aftermarket replacement cats are smaller. They have enough catalyst in them to clean the exhaust enough to pass emissions check, while factory original cats are designed to meet higher standards for new cars (as I understand it).

If you are planning to daily drive the car and the environmental impact gives you pause, you should order the OE cat or the CARB compliant one. The CARB compliant one should be sufficient, since it’s for areas with tougher regulations.

However, if the vehicle is a weekend/once in a while commuter type car and you just don’t want to be bothered by an emissions CEL or exhaust smell, the small aftermarket cat will be fine.

How rusty are the flanges for the cat itself? If they’re pretty crusty, I wouldn’t bother trying to DIY it. Rusty exhausts are pretty much the only thing I take cars to shops for.

Akio Ohtori - RIP Oppo > sony1492
06/30/2020 at 11:04

The car running super rich seemed to be the cause of the failure. It isn’t doing that anymore after my tune up, but I don’t know what the actual cause was. According to my gauge it was running open loop before and is running closed loop now. Not sure what caused it to get better. The rear plugs looked pretty bad so... maybe that?

I sure would rather not do a cat delete if I could help it. I know performance blah blah blah but it seems like a lot of trouble to go through to screw the environment and resale value. If this car was a keeper maybe...

WasGTIthenGTOthenNOVAnowbacktoGTI > Akio Ohtori - RIP Oppo
06/30/2020 at 11:05

The obvious answer is to make an entire exhaust system out of the oem cats.

Akio Ohtori - RIP Oppo > I like cars: Jim Spanfeller is one ugly motherfucker
06/30/2020 at 11:07

Not a DD and the environmental aspects won’t keep me up at night. However the whole point of this is to get rid of the CEL. Just don’t want to step on the performance mostly.

And yeah... no... either way I’m taking it to the exhaust shop. They will be way more equipped to make that happen.

Wrong Wheel Drive (41%) > Akio Ohtori - RIP Oppo
06/30/2020 at 11:08

Open headers are free! And save weight. Verticle straight pipes with flappers if you want to get fancy.

Akio Ohtori - RIP Oppo > WasGTIthenGTOthenNOVAnowbacktoGTI
06/30/2020 at 11:16

That would be the California way anyway :-P

Future next gen S2000 owner > Akio Ohtori - RIP Oppo
06/30/2020 at 11:21

I would go for the CARB compliant one that is a direct fit and have a shop do it.

Just a guess, but I think the OEM one is bigger to have a longer life. The aftermarket ones will probably die sooner or not quite work exactly as intended in the outer limits of operating range. I would think they’d pass an emissions test and be fine for normal use.

Nick Has an Exocet > Akio Ohtori - RIP Oppo
06/30/2020 at 11:23

I would take it to the exhaust shop. In most cases, they will make a carb legal recommendation. If you care about passing smog, you’re stuck unless they have access to cats that you don't.

Akio Ohtori - RIP Oppo > Nick Has an Exocet
06/30/2020 at 11:26

Sorry should have mentioned that we don’t have a smog requirement here, so CARB would only be a “ nice to have” . The Davico one is 49-state compliant.

Sovande > Akio Ohtori - RIP Oppo
06/30/2020 at 11:41

I would take it to the exhaust shop and let them know that you want the cheapest, working solution. I’d bet you end up with the universal fit with a spacer for the O2 sensor.

Sovande > Akio Ohtori - RIP Oppo
06/30/2020 at 11:44

Closed vs open loop is a product of the O2 sensor, right? Maybe one of those is bad?

Keep the cats. I’m about to add them to my El Camino. Smelling like exhaust for no reason is not that cool. And cats don’t have any appreciable, noticeable impact on power, no matter what the internet says.

gettingoldercarguy > Akio Ohtori - RIP Oppo
06/30/2020 at 11:55

Gesi are 50 state compliant

PyroHoltz f@h Oppo 261120 > Akio Ohtori - RIP Oppo
06/30/2020 at 11:59

Live in CA, can confirm this is what people seem to think is acceptable.

PyroHoltz f@h Oppo 261120 > Akio Ohtori - RIP Oppo
06/30/2020 at 12:01

5 or check various online junkyard listings for a stock replacement?

dogisbadob > Akio Ohtori - RIP Oppo
06/30/2020 at 12:07

Aftermarket cats are all smaller than OE because they don’t have to last as long. Aftermarket cats only have to last for 2 years/25k for catalytic performance, 5 years/50k for structural integrity.

California requires aftermarket cats to last 5 years or 50k for catalytic performance, so they have more catalyst material precious metals, which is why they cost more. But they still don’t have as much of that as OE cats

The factory cats have a warranty for 8 years/80k, but they usually last the life of the car.

How long do you plan on keeping this Jaguar for? If you plan on keeping it more than a year, get a CARB-compliant one. Magnaflow makes a CARB-compliant universal cat that’s under $300, but it has to be welded in.

twodudesnape > Akio Ohtori - RIP Oppo
06/30/2020 at 12:31

If you are just after getting rid of the CEL and tricking the computer to run normal fueling, pick up one of these . Website looks slightly sketchy/early 2000s but it shipped fast and worked as advertised until I could get a new midpipe for my Miata.

Neil drives a beetle and a fancy beetle > Akio Ohtori - RIP Oppo
06/30/2020 at 12:31

It seems like the Magnaflow universal should be workable. I’d go talk to an exhaust shop and start the conversation with the universal one you found.

MM54 > Wrong Wheel Drive (41%)
06/30/2020 at 12:40

I vote for this option just because I need to see 8 pipes straight up from the hood with a flap on each one

I like cars: Jim Spanfeller is one ugly motherfucker > twodudesnape
06/30/2020 at 17:33

$50 is pretty cheap. I’ll be picking up one of those if I gut my cat at that price.

Nick Has an Exocet > Akio Ohtori - RIP Oppo
06/30/2020 at 20:41

Oh hell, in that case: weld in the magnaflow and a bung for the O2 sensor :D