Does anyone have experience with these on the X308? I'm in the process of transplanting the drivetrain of an '01 XJR accident victim into an old Mark 2 (if it's not too painful for you guys you can see the process over in the Mark 2 forum). I need to install a custom exhaust system from the heads back (nothing fits). I've been told by some that the position of the O2 sensors is critical to avoid fault codes. The OEM units have one sensor before and one in the middle of the converter matrix. I've read here where folks have used aftermarket units with no sensor bungs, so I'm assuming they've installed them before and after the converter. I'd appreciate knowing if this approach poses any issues.

Also let me know if anyone needs OEM cats (or a complete exhaust system including manifolds for that matter), as these are destined for a recycler otherwise. It was an Atlanta area car with 70k mi and the engine was running fine with no fault codes showing before I tore the poor thing apart.

 

I personally don't have any experience with aftermarket cats on the Jag. However,......I recently helped a forum member who put aftermarket converters on his car, and the car could not pass the smog check. He tried and tried, and the cats were just not getting hot enough.

 

The second sensor in the body shell might be actually positioned downstream because of the internal design of the shell.

However, take a look at how the nameless performance cats for the xk are constructed. That might give you some insight as to how to mount your sensors as they don't throw codes on the xkr with the same motor.

Guess you should at least pull the sensors and reuse them. But maybe the necks can be removed and new necks suitable for your application installed.

 

How much do you want for the pair of oem cats? And how many miles?

 

Were they the original distance from the exhaust ports or had they been moved further away?

 

Don't know Plums, the guy was here on the forum complaining that he can't pass CA smog, and no money to get the OEM cats, so I offered help. I never looked under the car. Got it smogged, and he was happy. Two years without THAT aggravation.

 

danielsand and plums, thanks for the replies. I checked the nameless and Beacham websites and both locate the 2nd sensor after the converter, so I'm thinking that's probably a safe bet. With the beast registered as a '65 Mark 2 passing smog isn't an issue - just don't want the thing throwing codes.

WaterDragon, the car had 70k miles and the engine was running fine with no codes, so I assume the cats are in good shape. It looks like the recyclers get $100 apiece so $250 for the pair works. If that's giving them away (I notice OEM new is like everything else Jaguar - really stupid expensive) let me know what they're worth and I'll take more.

 

You forgot the smiley

On the aftermarket cats, you could go with any reputable brand and some of them are advertised as low restriction. Magnaflow and Walker come to mind. Doesn't have to be nameless or beacham. I doubt that nameless in particular are large enough to actually fabricate their own. They are adding necks that happen to fit the application. They must be getting their cats somewhere. Be aware that there are a number of complaints on this site related to long waits for delivery and non-communication with customers.

BTW, if you are using the stock ECM, it is not just a question of not throwing codes ... you need the sensors operational to get into closed loop.

 

I'm removing my cats and toying with the sensors... i'll report back to you in a day or two on what we are doing.

 

I have no cats, bung extenders for the 2nd downstream sensors, no codes and passes NY emissions.

 

Steve,

How is the sound of your exhaust now? I'm going no cats, x-pipe and some glass packs on 2.5" pipes all the way thru

 

Pretty loud! I have a similar setup with no cats, 2.5" free flow exhaust with X-pipe and straight through mufflers.

 

Steve, did you notice any increase in power?

 

With exhaust not so much; maybe about 10 hp according to drag testing.

Downpipes also about 10 hp:

https://www.jaguarforums.com/forum/x...es-dyno-41275/

 

I was asking about the price for the cats because a friend of mine needed to set but apparently he already bought a set paid 350.

 

If i get 15-20hp i'd be happy, not to mention the glorious thunder that will come out of it. I'm going 2.75in. pipes all the way thru with an x-pipe and two glass packs


I really need the throttle body ported and then make a final decision on Avos twin screw... at 150k miles, my supercharger is probably dead weight

 

Also keen to hear results here, will be doing cat back first unless you guys reckon that any good quality but non oem Hi flow cats can be substituted in si long as the o2 sensors are plumbed after the cats, then I'll do them too?

 

After talking with a couple more exhaust techs I decided to go with these Magnaflow cats with the O2 bung located midbed, which appears to duplicate the original setup (model # is for the 2 1/4" pipe I'm running). I noticed a couple of aftermarket setups playing with upstream bung extenders (I assume to balance readings), so I'm hoping to avoid that. Unfortunately the project won't be finished for a couple of years so I can't report how things worked out - at least not for quite awhile.

Thanks again to everyone for their interest and help.

 

You don't mess with the upstream sensor at all, only the downstream if they need it.

Since aftermarket cats have less material to work with than oem, I would think you'd want to position the downstream sensor after the cat to get the most out of them.

Btw, on my 99 XJR the downstream sensor was positioned after the cat (oem). Looks like they changed it on the newer years.

 

Steve M. Thanks but im confused. In Doug's post above, the cat he refers to doesn't appear to move the upstream sensor. ?

You mentioned not to move it. Does that mean you're on the same page as him or don't recommend those cats?

Cheers.