Contour Enthusiasts Group Archives Forums Modifications Duratec Maintenance info on gutting the precats

Here is the MIL eliminater how-to.

I don't think anyone can post an "average gain" because there hasn't been enough accurate data posted to make any averages!

Everytime someone guts the pre-cats there is something else done simultaneously.
If your pre-cats are starting to plug up you will gain back the lost power. If your pre-cats are not plugged up then I don't think you will gain any 5-8 HP. If the pre-cats have enough flow area to equal the flow area of the piping following them, then you will gain nothing other than an expansion chamber which = BAD. The honeycomb will induce some drag, but at least the flow is laminar and not turbulent which could be worth a lot of power.

What I can say for sure is I didn't notice any improvement going to gutted pre-cats, but I noticed a huge improvement going from gutted pre-cats to MSDS headers, and I dyno'd this proof to the tune of 7-11 ft-lb increase in torque in the 3000 rpm range and at least a 4 ft-lb increase in torque 2000-5500 rpm range.
They are not equivalent mods, the MSDS headers flow better, increase scavenging and are probably 40% lighter so you drop weight off the car.

I would only gut the pre-cats when they are beginning to fail.
I'm only speaking from experience since I've done both of the mods we're talking about.

warmonger

Thanks for the info guys im doing this right now, I was just lost on how to get the stuff out of the front cat but now I know thanks much!

Hi, I have this great idea, car companyâ??s spend countless time and money getting the cars emissions down to what they are and you guys want to throw all of this away?? Whatâ??s the point? Make some kind of other improvements, why take your cars back to the 70's? With all of the options out there, just don't seem like a good option at least I wouldn't want it on my conscience. Now you guys are throwing out all kinds of soxâ??s, noxâ??s, and even unburned hydrocarbons into the air. I am not some tree hugger but have respect for the world around me. It kind of like going back to leaded gas, I mean there is a performance advantage but hello????

Gore has a great environmental outlook; just because I care and am educated in the subject doesnâ??t mean I voted for Gore. I donâ??t trust Gore running us in a war situation and I donâ??t trust Bush with anything having to do with the environment. Maybe you just enjoy fâ??ing earth up, open your eyes.

You are so right, its all clear now. I just took all of my cats off all of my cars. Global warming is for the birds. I would love to know how many of your sources are from republican sponsored research. Did you hear that Bush just hired a select committee to try to find that global warming wasn't a problem and they found out the opposite? This was his own guys!!! I am really not a big fan of Gore's, I respect him, but I disagree with a lot of things he does and says. I am not some Gore fan, but saying that your gutted cars arenâ??t polluting the environment is just plain ignorant. Thatâ??s the problem with the world people like you with a high school education believing whatever is thrown at you. If you want the data of a 1970â??s car (which is yours without cats, or little for cats) vs. an average carâ??s now emissions I have it. There is around a 5 to 10 fold difference, but hey dumass its was faked right by Gore I am assuming???

If you passed the Ca sniffer test, then you are fine by me, excellent job!! My beef is with people who gut everything mostly. Gutting your precats will effect your emissions during your first couple of minutes of your drive cycle. This is due to them being close to the engine and allowed to heat up to operating temperature very quickly. So this isnâ??t the worst thing you could do, especially if you make long trips. When however, you gut your main ones you are just throwing shite into the air we breath. Just not a good alternative, especially when all the research has been put into making these system behave the way they do which is really well!!! I am surprised your car didnâ??t flag something if it was a cold start????