Sooooo been pouting over my cat convertor issue's tossing me into restricted performance daily when driven. Car has 30,000 miles and has got to the point I am now not driving it for fear of doing more harm. Tried magic juice to clean convertor twice and it did make a difference in that the exhaust side of the cats read 200 degrees hotter than the inlet side after treatment indicating that they were operating more efficiently. However I feel the right side is partially plugged and needs replacement.


Contacted a few forum vendors on 200 cell cats and was working with one to send my convertors in and he would make up a set for $950.00 but there seems to be a delay in receiving raw materials on his end. I can no longer wait and must proceed down another path.


This brings me to this post and my last bad idea to save me a boatload of money. Why can I not just take my cats off cut open the convertors removing the 600 and 400 cell bricks and weld them back together empty? How would I make it work? Can it work? Why not as no immersion testing in Wisconsin. I know environment and all for this post just think of it as a track car. How do they deal with it? How would I deal with the CEL and O2 sensors? All impute welcome on both sides of the fence!

 

You probably will get errors from the O2 sensors with the cats modified or removed. Best way around this is a tune to remove the senors from the ECU map. I would contact Stuart @ VelocityAP for assistance with this. He just wrote a new map for my car which I will be loading and testing in the next week or so, weather permitting.

 

If it being ridiculously loud afterwards won't bother you, then go for it. I ran without cats for a summer on my 2010 xkr. I just kept clearing the codes every 100 miles or so. Where you at in Wisconsin? If you are close to iowa, I could help you out with this if you wanted to take a trip here sometime.

 

jahummer ( I would contact Stuart @ VelocityAP for assistance with this. He just wrote a new map for my car which I will be loading and testing in the next week or so, weather permitting. )


Will do and please keep us posted on your tune and how it works out as I would be very interested. Did you also delete your cats or not?


bigdhenderson ( If it being ridiculously loud afterwards won't bother you, then go for it. I ran without cats for a summer on my 2010 xkr. I just kept clearing the codes every 100 miles or so. Where you at in Wisconsin? If you are close to iowa, I could help you out with this if you wanted to take a trip here sometime. )


Loud would be an issue but I'm sure reinstalling fuse 19 will make it somewhat more pleasant around town at least...ish. How bad was the drone inside the car? is yours a coupe or convert? Would like to get together sometime and swap notes. We are located in Eau Claire about a half a mile off I-94. I have been contemplating trying to get some forum members to meet up somewhere for lunch around Madison/Rockford this summer sometime.

 

I'm in Charles City, I'd love to take a trip up there some weekend.

Mine is a 2010 xkr coupe, with no cats or valves on the rear muffler it was just way too loud. Yours may not be too bad with the valves closed. Only one way to find out! And not sure if you have checked, but there are cats for your year on ebay for around 300$ each. Nothing fancy, but it would fix it. But I say gut em!

 

Another option would be to buy new cores and have them installed in your old housings

 

I would not be against putting in new 200 cell cores. Where would one source these? I found O.E.M. style cats direct fit for $300.00 but these would have the 600/400 cell count bricks like stock. This is my fall back. So it sounds like the O2 sensors may be able to be tuned out of the loop. How did you handle your O2 sensors when you deleted your cats for the summer?

 

Even if you put 200cell cats in you will get the P0420/P0430 codes for cat efficiency and a check engine light. You still need to address this in the tune.

DO NOT run extensions or minicats on your downstream O2 sensors to fool the readings. The downstream sensors on these cars are also used for fuel trims.

 

This is my concern if the O2 sensors are adjusting fuel trims without my cats in place what does the fuel management system think of that? Is it dumping fuel to get more heat into the missing cats? A CEL light is not the end of the world but it's the only issue I am willing to deal with if I delete the cats. I have come to realize that there will always be something illuminated on the gauges of my Jags. Me and Jag warning lights are old friends. Best option would be source some 200 cell bricks and rebuild my cats. 200 cell or less are necessary for future mods this is the reason I would like to fix this issue on the cheap for now as an upgrade is coming that will require more flow. Can the O2 sensors be tuned out of the loop completely with no downside?

 

I just kept clearing the codes. Honestly Id just gut yours for now and have the monitors turned off with a tune.

That way when you do eventually get high flow cats you won't have to worry about the codes then either

 

I wouldn't do that to the mother nature. there are plenty of catalytic converters available. Even on RockAuto. Those ones are 300 cell.

 

No that's not how it works.

300 cell, 200 cell, 100 cell, there's not a huge amount of difference in regards to performance, there will be cost differences. I have 100 cell on my XJR but that's only because they were cheaper than 200 cell...

No. You still need the downstream sensors working correctly for the fuel trims.

But what can be done "in the tune" is to disable the Catalyst Efficiency Monitoring functions (i.e. a Euro2 emissions spec tune) or it's possible to simply disable/delete the P0420 & P0430 codes so they never get flagged and you don't get a CEL for those codes.

 

So correct me if I'm wrong and I usually am. No down side to gutting cats other than CEL light/environment/sound. No harm to the car or systems.

 

Yep

 

I second Cambo. IMO gut 'em now, save some bucks, have a drivable car, and when you've got the funds get some down pipes made with whatever combo cell cats you prefer......if you still aren't running as a "track car"

 

Things that make you go hmmmm.

 

I will attempt to source some replacement 200 cell bricks however finding ones that will fit into my housings I spect will be difficult at best. If unable to source and I move forward with gutting cats this will increase the sound significantly the way it sounds. The exhaust note now is intoxicating and it would be a shame to loose it. It's nothing but labor to gut them and then I would have a dedicated set for "track days".

 

Modifying these cats will not be too tough. My only concern is the noise level inside the car. Idea... good or bad please advise. What if after removing the catalytic brick I replace with a perforated 2.5" exhaust tube and pack glass around essentially producing some mini glass packs. Do you feel this would be worth the effort or would it have little effect on sound level and I am wasting my time? Would the close location to the engine be of any issue?

 

Unfortunately over the years the cats have been integrated more and more into the cars system. It appears at times there may be a way to fool the system but my bet is there is a downside to trying this. Changing from stock to smaller cells most likely affects the ECU but depending on how much variation the ECU can take may work. All of this stuff was engineered in during the design phase of the overall system. I don't even think the tuners of the world know what parameters they effect during their tune that might create a problem. By the way do you have to sign a waver when buying this tuner service. Now back to the cats take a look at their function and what parameters they affect. I'm not saying don't take the risk but if you do then you need to assume any problems. If you can't afford to maintain it and need to look for a cheap solution then that is a different issue.

 

I have hollowed mufflers and made glasspack/resonators just as you describe with perforated pipe and fiberglass in the past. I have also interchanged glass pack/resonator combos on varieties of cars downpipes over the years and feel safe saying that the sound yielded from a glass pack built into a down pipe will subdue the exhaust note in similar fashion to a 100-200 cell hi-flo cat.
My car is not an X150, so I am not familiar with its fuel trim "tolerances" in relation to your downstream O2 with cats vs no cats but.......my X308 XJR has no cats and does NOT throw any codes with or without O2 bung spacers installed with no modifications to the ECU to compensate. Different cars will yield different results/codes, luck of the draw