XJR owners. I made a mistake with exhaust system a few weeks ago.

The GOOD - Had the primary down pipe cats replaced with two new Magnaflow spun stainless metallic core. The secondary underfloor cat had been removed by previous owner and a X-Pipe installed. While the shop was replacing the cats I also had them swap the four O2 sensors with new OEM sensors purchased from Rockauto. Stinky exhaust solved.

The BAD - I had the shop remove the 1st set of mufflers, the original Jag ones in front of the IRS because they had an annoying midrange buzzy sound coming from them. The previous owner had replaced the rear mufflers with Edlebrock TruFlo mufflers. The car is now way too loud and sounds terrible, very "ricey" from 2000 - 4000 RPM.

I am thinking of having the exhaust shop weld in two glass pack mufflers where the 1st set of OEM mufflers were removed and replacing the Edlebrock rear mufflers with another pair of glass packs. I want a free flowing exhaust with a nice growl, not too loud but want to still be noticeable when I put my foot down.

Does this sound like a good solution? Has anyone had success with similar set-up?

 

I left the original resonators on my car and replaced the mufflers with Thrush turbo mufflers. The Thrush mufflers are cheap, but they have a nice sound when paired with the original resonators. I may eventually switch them out for magnaflows. I feel that the stock resonators do a good job of keeping the noise levels down in the cabin and paired with just about any higher flow muffler have a nice sound. I'm too old to be driving around without resonators on a car.

 

I am wishing that I had not had the shop remove the resonators, but alas it is done and they are scrap. Short of searching for Jag OEM replacement resonators, any suggestions on aftermarket solutions?

 

I have four quick questions:

1) What model# down-pipe catalysts did you use?
2) Did the four stock O2 sensors that install above and below the down-pipe bolt right in without modification?
3) When the previous owner removed the under-floor catalysts, did they retain the O2 sensor that is installed after the under-floor catalysts?
4) Do you get any OBD codes or check engine light?

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1) Magnaflow 59905
2) Yes they threaded right into the original bungs, NTK 25018.
3) They must have, when I bought car the second set of sensors were directly downstream of the down-pipe cats.
4) None, well not until I unplugged my EGR Valve Now I have 5 pending codes, but that is another story.

 

There isn't one after the underfloor cats, only the downpipe cats. You can remove the underfloor cats and the ECU will never know.

 

Apparently neither does the emissions testing equipment, cause she passed even before the new downpipe cats and sensors.

 

Ah gotcha, you are correct My memory got confused from the discussion we had here a while back where we were brainstorming the opposite, eliminating the upper catalysts with the OEM catalyst-delete downpipes and instead maybe putting the downstream O2 sensor after the underfloor cat:

https://www.jaguarforums.com/forum/x...ntages-152568/



So John, good news that the new catalysts worked fine, O2 sensors went right in and didn't trip any codes.

You think these Magnaflow catalysts are higher flow efficiency than the OEM?


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The MagnaFlow 59905's seem to flow better than the originals, no loss of performance, MPG is up a slight bit.