I'm wanting to purchase 200 cel cats (FrickenFast) for my 2007 XKR, but am concerned about tripping C.E.L.'s (not preferred). Am I correct in my understanding that this a 'might-be-sometimes' problem...or, is more like a 'certainly-frequent' problem?

 

I installed 200 cel cats on my 2005 XJR and originally used the mini cats that were supplied with them.

With the mini cats I got an error code immediately plus I could see lots of smoke in my rear view mirror on anything close to hard acceleration.

Removed the mini cats and everything has been fine ever since.,

 

Nothing against FF but you can pick up 200 cell cats from Summit for a song and have your local muffler shop install them. Then if you don't like them or they code you aren't out a ton of cash and can either weld the old ones back in or go with a higher cell count.

Also, for reference it's described as cells per square inch. So a 400 cell cat has double the wall density of a 200 cell cat. Plus the stock cats are actually two catalyst modules with a gap between. So even replacing the stock cat with a replacement same cell count cat will double the sound coming from the converters.

200 cell cats without the muffler sounded like a Nascar racer. Pretty darned loud and raucous.

 

400 cell cats actually seem to be the sweet spot noise-wise and won't set off any codes.

From memory the original cat has two blocks being 400 & 600 cell

Ranch is correct get your local muffler shop to make you up a set up.

 

As for "noise" I did not notice much difference at all with the 200 cel cats vs the stock.

Now with the front resonator delete my car is louder but not raucous. I did try a total resonator delete but that was raucous to say the least.

Did not cost too much as I did everything myself and that includes a hydraulic exhaust expander.

 

I'm running 100s with an enlarged crossover pipe and it's very loud under wot

 

Thanks guys..wasn't expecting such quick responses!

Currently, I have deleted the second resonator and replaced the back box with two MagnaFlows. My purpose there..was to deepen the sound and get rid of the craclkle and pops (not my liking). So, right now, it's not loud at all...though the bass is pretty deep and rich. My current aim is to open it up a little bit with the lower count cats to quicken throttle response...and as far as loudness, I'm thinking it may not be much worse than the original stock exhause..sans crackle and pop.

My only concern, at this point, is not having a setup that is a nuisance regarding constant C.E.L.'s.

 

Honestly, any mods you've done to the exhaust already can go out the window when you fit 100/200/300/400 cell cats. The car WILL get louder, especially on a car with higher mileage where the original cats are going to be past their prime, the exhaust note will change, and perhaps not how you expect.

Went though this on my XJR, and again on my XKR.

The codes can be defeated in a (proper) tune.

 

Cambo,
I apologize in advance (for it has been a long day for me..at work), but after reading your post and rereading my own, last, post...I think my wording may have given the wrong impression. And/or, perhaps, I'm mistaking your intent.

My primary goal is performance. Quality of exhaust note, though still important, is secondary.

After already having done the upper pulley & tune (via Eurocharged - two free tunes remaining), I'm now attempting to work out the exhaust system.

First Goal: Get rid of the silly...(my personal opinion only - don't mean to offend anyone)...crackle and pop. Path: Replaced back box with Magnaflows. Result: Eliminated crackle and pop, but, exhaust note very, very quiet (way too quiet for my tastes).
Second Goal: Increase the exhaust note. Path: Delete the second resonator. Result: Exhaust note increased a little, but not by much..really...and still way below the loudness of the original stock exhaust note. But, I like the 'quality' of the sound.
Third Goal: Install different cats for increased exhaust flow and throttle response. NOTE: Lower cell counts WILL make exhaust note louder, true/understood...but, this is part of the strategy...as it is to, ALSO, increase the loudness of the exhaust note.)

Third Goal Dilemma: A) How far down in cell counts to go (to maximize performance) without taking the 'loudness' factor too far back up into the 'silly' range. B) I like/prefer the bolt-on factor of the FnF cats, so I'm leaning heavily in that direction. However, since their 300 cell is $500 more than their 200 cell...my original question had to do with "How big of a risk do the 200 cell cats really present regarding constant C.E.L.'s"?

So far, combining your experience with Jackra's and Steve's, I'm still thinking the 200 cell might be the way to go for me. Especially since you say the codes can be defeated with a "proper" tune. (If it turns out that a Eurocharged tune isn't able to defeat the codes...could you point me to those that can?)

 

Glass packed style muffler will drone with more flow. I spent a lot of time building a pair of Helmholtz resonators to minimize it.

 

Looking at your goals the first thing that comes to mind is how do/will you measure performance success. It goes without saying that mods don't have an ROI other then personal preferences. So how do you or did you measure these improvements . Is it dyno HP or torque or is it 1/4 mile times or speeds. Also track performance as well. As far as sound is it Db or just ear pleasure. Now days you buy performance off of the factory floor unless you are a street outlaw but that's a difference game. I take my hat off to all that take the time and money to try to improve their cars. So that being the case how do you measure your success.

 

Smiles per mile

 

I went with bolt on 200 cel cats. More expensive however an easily reversible mod as with all my mods I can go back to original if necessary.

Messing with my exhaust system required several attempts to get what I wanted.

When I move to MA I may have an emissions problem. We will see.

 

I'm with you there and I can live with stock too.

 

There are all sorts of members on this forum which is great.

Some like to do their own maintenance and some never get there fingers dirty and that is ok.

Similar to some of my friends who hire contractors to do simple work around the house. They have no interest in doing it themselves.

Some see where others have made modifications in order to drag race to achieve a fraction of a second faster 1/4 mile times.

Those modifications are therefore proven to increase performance.

Others post their dyno runs before and after mods and again useful info.

I am one of those that likes the challenge of doing my own maintenance and of improving performance of my car.

I also like to help people on this forum who are tackling issues that I have successfully tackled.

I do not claim any HP gains since I have not done any dyno runs unlike some people in this forum.

Yes I could buy another car with higher performance but that is not the point.

Also doing that would actually cost a heck of a lot more money than what I have sunk into my 2005 XJR.

 

You shouldn't as long as no error codes are being thrown.

 

I also wanted to wake up the exhaust after adding a tune and pulley to my 2013 XKR.
After following Rancheros' build, I had a friend cut out the original cats and replaced them with the Magnaflow 100 ct cats and added the O2 bungs. I had Eurocharged Performance adjust my tune for the hi flow cats and I have not had any problems with the car throwing any codes.
I love the sound. It is still subtle with the exhaust in default mode, but wakes up a lot under WOT in dynamic and sport mode.

 

I am keeping my fingers crossed that you are correct.

 

Ranchero,
Honestly, a little drone wouldn't bother me (as long as I know why)...but I take/understand your point. The degree of 'acceptable' drone, for me, IS yet to be defined.

Jagtoes,
My overall measure of success is whether (or not), the result pleases me...and I know that's not exactly helpful to others, unfortunately. Specifically, after the last exhaust mod, I did notice a decrease in throttle response (not necessarily unexpected). So, one measure of success will be whether (or not) I can detect a return to previous experience, or maybe even an improvement over previous experience.

I should note here, that...
This is a daily commuter car for me, not a race/drag car. I really have little interest in the performance of the car at the top end (or, wot), or 1/4 mi times, or lap times etc.. I'm mostly interested in quicker response times in the low to medium range. So, reasonable exhaust notes during reasonable drive modes is a good thing...even "raucous"ness at wot in rare moments isn't necessarily a bad thing. I like to "smile" every once in a while too!

 

Me, too (mostly). It keeps me out of trouble and and it's cheaper than a psychiatrist!