lloydc

Does anyone know if changing out a clogged cat will provide a slight boost in performance? I'm asking because mine is at the dealer right now getting the cat replaced at 80K miles. I've only had the car for a few weeks, so I'm curious to see if I will notice a change with the new cat.

Philthy29

Yes, but since you haven't had it that long, you may not notice much of a difference. Those who have had their car for a long while would notice a big gain in response

lloydc

I am really looking forward to the car shifting better. Sometimes it would have problems going into higher gears for some reason. I think I saw something on here about a clogged cat leading to problems with shifting, so that would make sense. I also noticed a rotten egg smell whenever I would really get on it, something else I read about which is a symptom of a bad cat. I'm hoping it was clogged pretty bad, so I can notice some real change. I got this car about a month ago, coming from a 269hp Volvo S80. I love the way this car drives, I just wish it had a little more power. I've been hoping the cat had something to do with the sluggishness. We'll see, I suppose.

mk2tmr2

iTrader: (1)

You'll still wish it had more power. But it should feel a bit more peppy.

Also try pulling the negative battery terminal and resetting the ECU. This will force the car to re "learn" your driving style. You may find it maps shift points and spark maps a little more aggressively for you. If nothing else, it'll clear out the fuel trims and you should feel that impact immediately. In conjunction with a de-clogged cat you should feel an overall boost in pep.

lloydc

Thanks man, I will give that a try!

ThomasGS4

iTrader: (19)

Yeah it'll definitely help.

Another solution to increasing the performance is by cleaning the MAF sensor and throttle body.

entryspeed

iTrader: (3)

If you had a completely clogged cat you can expext to see and feel a bit of difference in performance. If the cat where simply slightly clogged you might notice better top end and fuel economy. GL

lloydc

Ya, I'm looking forward to the better fuel economy. I don't have the numbers, but they weren't good. Just in time for the price of gas to skyrocket.

lloydc

Picking my car up from the dealer today. Will report back with any noticeable changes in performance, if any.

sethjon

Is this a trick question? If it gets clogged enough the car won't start. Having said that if its very clogged and you install a new one it will be a world of difference and gas mileage should go up too.

DMPesso

results? these wud be beneficial to anyone researching cats...

JLAWS

If you are not getting a check engine light for the cats stating "efficiency below threshhold" then there is NO reason to change them.

Nothing you can really do but to go from a Gs300 to a 400/430 if you want more power. Sold my mint 2002 GS300 with 90K miles I bought from my sister and sold it and got a 1999 GS400 with 125K miles with $3K left over from the sale. NO REGRETS. The V8 is a whole different experience.

BayAreaLex

Just depends on how badly clogged it is. How was it diagnosed as a clogged cat?

Also, hate to see another buy with V8 envy. Should started with the 400/430 from the get go. I almost made the same mistake and glad to talked some sense into msyelf.