Okay I have that itch again to do something to my 2005 XJR.

This time to increase the exhaust note to a healthy rumble.

I have bolt on 200 cel cats installed and as far as I can discern they made no difference at all to the exhaust sound.

First thought, and this is at least a month out, I am considering deleting the two middle resonators and installing an X pipe.

I have read many posts on this topic and it seems that just maybe I will not get any increase in "V8" sound.

If that is the case I will then think about adding exhaust cutouts after the X-Pipe and before the factory mufflers. At least I will be able to control the sound.

Second thought is doing a muffler delete but keep the resonators. Problem with this is that I will have no control over the sound and if I do not like it I have to rework everything.

Also I have read many different opinions on the effect of lower "back pressure" from freeing up the exhaust flow. Negative and positive.

Btw everything has to be "bolt in" not welded just like my 200 cel cats.

My goal is a satisfying "V8" sound and not improved performance but I do not want noticeable lack of torque at low revs.

 

On my NA engine, I did 200 cell cats, xpipe and Mina Gallery mufflers and have an amazing sound that always gets compliments. The tone is somewhere between American muscle and Italian exotic. Its just the right tone and the right volume.

At first I thought I had lost low end torque but I soon realized it was a psychological effect of the added exhaust noise. In comparison to the stock volume, it sounded like I should be going much faster, but you quickly get used (and addicted) to it. You'll really notice the extra oomph in the mid to high range, from 30-100. The power just keeps coming effortlessly.

 

Did the xpipe replace the resonators?

 

Yes. They cut out the two middle resonators and welded in the xpipe.

 

Jackra and others - where did you find bolt on 200 cell replacement cats?

My '07 XJR has a bad cat. I had in mind to pull the OE cats and weld in generic replacements. The factory cats are stupid expensive (and seem to be short lived)

 

hisport I installed Paramount 200 cel cats.

They were not cheap but I want to be able to go back to stock if necessary.

They were easy to install. I did have problems with the mini cats so I run with out the mini cats and the O2 sensors are direct screw in like stock.

 

I installed a set of Nameless 200 cell cats just over a year ago. Direct bolt on replacement. I don't think they make them anymore.

 

I have 100 cell cats, xpipe and OEM rear boxes. All the pipe work is 3in up to the rear boxes.

Its quite loud but you do get a euro v8 sound.

Initially I installed the cats only. This changed the tone but not the sound level.
I latter tested a number of rear boxes before putting in the xpipe and center muffler delete.

From testing the rear boxes I settled on the dynomax vt. This has a flap that opens up under high flow. It was great prior to the center muffler delete but is way too loud afterwards. The reason being that its effectively open pipes under load. I will be putting these back in but will be fitting some center resonators first.

Once I do that, I think it will be the ideal system.
As a starting point Id recommend cat update and xpipe. Leave the rear boxes and resonators in place. Replace the first (dual) muffler with the xpipe. Use hi flow weld in cats. If you want more add a dynomax vt in the back.

If you have issues with cel's contact cambo to have the cel disabled. You may also want his tune at the same time which is well worth it.

Cheers
34by151

 

Great; thanks

No engine light (eg P0420) issues?

 

I got mine from Parts Geek. DEC brand fur around $240 each. Pretty much direct bolt on. Read my reply on catalytic converter thread.

 

When I installed my 200 cel cats I also installed the mini cats that came with them to prevent any codes.

However on hard acceleration I could see clouds of smoke in my rear view mirror.

No fault codes tho.

I removed the mini cats and installed the O2 sensors as normal, direct fit.

No clouds of smoke and no fault codes.

 

I started getting catalyst efficiency codes so I installed some o2 extenders. Worked like a charm.

 

No excessive smoke when accelerating hard?

 

Not that I can see in the rearview.

 

I installed Magnaflow 200cell cats (no codes), deleted the mid resonators & install Magnaflow X-pipe, this made it louder and more power in the mid-high range. However, the sound was a little raspy due to the rear Jaguar mufflers. I replaced the rear mufflers with Magnaflow 5x8x14 ovals and it now sounds like a beast!!! Although, it's quiet when driving normal and not mashing the pedal to the metal, still has a V8 growl though. My Magnaflows were all welded.

 

Does it drone at ~2000rpm? I also built my system on magnaflows. But i used oversized 2,75" tube.. ceramic magnaflow cats, true-x resonator plus rear ovals. Yes, its true beast now)) but droning at cruising a bit annoying. I'm going to weld in 1/4-wave J-pipes.. according to our motor they should be 500-600mm each. I don't want to add more silencers as it will make all system quieter.

 

No drone at any RPM At cruising the exhaust is barely noticeable until mild acceleration, most of the growl is going out behind the car.


With the original Jaguar mufflers & Magnaflow Cats/X-pipe/resonator deletes there was a slight low level drone when backing off the accelerator and getting back on it around 1400rpm, but nothing at cruising.

I removed the Jaguar mufflers and installed 4" round Magnapacks, these had massive drone and boom. I ripped these straight off.

I installed the Magnaflow 5x8x14" straight through ovals, also replaced the original Jaguar rear pipes with larger pipes (2.25"), these connect to the straight pipes that were installed where the middle resonators were deleted. The Magnaflow ovals are 2.5" inlet/outlet. I used the original exhaust tips and had them reattached to be flush with the rear bumper.

It appears the mufflers played the biggest role in drone control/elimination.

 

Hmm.. very intresting. I have one more silencer (tru-x resonator instead of x-pipe) in the system and i can not say my system is "barely noticeable"..

Is it pipe size that matters so much?? Actually 2.5" magnaflows inlets are bigger as they designed to snap over 2.5" pipe. Mine welded in butt-end. That is exact my pipe size, in the mid of 2.5-2.75"

My specs are:
Cats 2x99775HM
Trux resonator 12468
Rears 2x14211

A few pics:

 

How loud is your exhaust?

The specs for your cats are 2.25" in/out. Why did you go with 2.75" pipe if the cats are only 2.25"? I asked my exhaust guy whether larger pipe would make a difference in performance and he said no, not if there's a smaller pipe/connection up stream, eg the 2.25" cats.

Did you try with just an X-pipe and not X-pipe resonator?

 

I didn't. Should i? That will be definately louder.. Because outlet from collector is actually 2.5".. I just wanted to make straight 2.5 all the way. I thought magnaflow's 2.5" is 2.5" but in reality they are 2,65".. that's why i used 67mm. Cats being cones from both sides easily shortened a bit to match 2.65, that was not an issue. I realized that when received them.. i mislead at my MF reseller or somewhere else about cats inlet size. But if you can see mine are actually bigger than used at nameless downpipes for example. They are rated for 4.4L bmw engines.. pretty close efficency for ours 4.2SC





What are your specs to compare?