Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Ok so how about gutting the cats

Ok so looks like my precats are plugged. I dont have the money to buy new ones so I know a place that will gut them for me. I also understand that I need to make MIL eliminators which is no prob for me to make. While I'm at it, I will also replace the center cat with a high flow performance one and do a custom cat back with magnaflows in the back. Oh a resonator will be used as well of course since I'm tired of the drone - but I probably will get drone back with my luck.

Now the question is this. People say that with pre-cats gone, the car sounds very raspy and very loud. Is this like a really nasty ugly sounding raspy or just more raspy compared to stock without a resonator (which is what my setup is now). Do real headers like the MSDS sound raspy as well?

Also a few people posted about having gasoline smell in the car after gutting the pre-cats. Is that the general consensus? Shouldnt the cat in the center be able to burn the extra gas? I know these are stupid questions

Last thing. I dynoed 164 with the stock setup except for the modded stock y-pipe and KKM. Maybe I can hit 170 with the gutted pre-cats, high flow cat and custom catback?

Thanks guys... I know I've been asking tons of questions lately

your car shouldnt get much different soundwise from the gutted precats, my friends cougar with a borla just got slightly meaner but it needed it. MSDS headers add some rasp too. I've never noticed a gas smell riding with him, and he hasnt mentioned it. sometimes on cold starts and idling I can smell gas with a 100% stock setup on my car

If you are going to gut your pre-cats why do you need a "high-flow cat"? If your other cats aren't clogged don't replace them. A "high-flow cat" is designed to replace the 70's bead type cats, which are very restrictive. The style on your car are the monolith type that flow a suprisingly (sp?) large amount of air. The high-flows are the monolith style too.

Thanks guys for replying so quickly.

So the cat in the center then is of pretty good quality and so I dont need a better cat - or wont see any power gains if I go to a different cat. Hmm I guess the exhaust shop can test to see if that cat is good or not.

Makes me wonder if 6 months ago when I ran the 15.40@90, if my cats were partially clogged or not. I was kinda hoping to hit 15.20 on a stock SVT with a KKM, modded y-pipe and missing resonator. My best 60 foot was a pathetic 2.36 or something. That was on Eagle GT IIs.

Now I'm rambling about different stuff...

If you want to hear a slightly modded Duratec with MSDS headers and y-pipe with a SVT ehaust minus the resonator let me know since you are close to me. For the record I get alot of rasp and drone. If you are still getting drone right now I'm going to go out on a limb and say your precats aren't to badly plugged up over all.

Also if your pre-cats are plugged chances are they will have affected your main cat. They tend to crumble when they get cooked. This goes down stream to the next restriction.

With a borla cat back, no pre or main cats, i get very, very little rasp. It shouldnt sound bad at all if you have a decent cat back.
If youre taking the precats off and making mil eliminaters, you might as well just put in a straight pipe or off raod y-pipe instead of a high flow cat. As stated, I dont think just a high flow would get you that much, if any extra power. From what I've read, the stock one flows fine.