Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Anybody have pics to the gutting precats site?

There should be no effect on low end power with gutting precats. This is due to the principal that lower rpm requires less airflow and therefore there is less exhaust. The flow of the manifolds will be more than sufficient for low rpm. If anything you should notice and increase in higher rpm power since they will be more open and can handle the increased exhaust flow that high rpm pushes through. I would expect not to see any improvement until over 5K rpm UNLESS...unless they were starting to plug up. BUt if that were the case you should have gotten a catalyst inefficiency code already.

Only two ways to help the low end grunt. well three ways:
1. Increase timing -- need a chip
2. decrease header pipe diameter -- good for velocity but kills top end power,
3. Install headers -- takes advantage of exhaust pulses and wave dynamics by design.

If you are smart, you can see that numbers 1 and 3 are good, number 2 is bad.
If you are really smart you see that number 1 + 3 will be the best method!
Start with three, then add #1 and get a dyno tune. Plan on $1000 to accomplish these two mods but you will get a huge increase in performance for that $1K if your chip is done on the dyno.

Yes I've been pulling the 0420/0430 codes constantly starting about a month ago. It was finally time to do it.

Review:
Torque! I notice a lot more torque at lower RPMS. My car does not open up it's secondaries as quickly when I depress the gas pedal. This means that I stay in lower gears longer than normal. This feels awesome as I don't need to use more gas and I generally get more control. No quick jerky shifting with my l33t slushbox! (note that I DO have the TSS sensor fix which helped a shitload with the shifting)Also, the car would stop quicker when I let go of the gas. (note that I DO have the throttle hang fix for some whistley goodness)

I took a drive home from my friends tonight and at one point I had to grab onto the handle with both hands when the RPMs went to above 6000 RPMs to shift. This was when I was going 65-80mph(?) and had the overdrive off. The torque seemed to really kick in at the highest RPMS. I didn't expect it. lizard: I'd say there's more low end torque. The highest RPMs have a bit more power to them for sure as well though.

One odd thing is that mod seems to really take effect once the car is warmed up, especially at lower RPMS. I can't seem to notice anything special when driving for the first 15-20 mins. It could just be my imagination.

All in all it was a great mod especially since I had to get this done.... the lawful fix was not in my budget. The best part was taking off the Y and revving that sheeit up! The Duratec unmasked sounded like a Harley (imho).


NEXT STOP:
Modified Y pipe land.
Population: Me.

your cats must have been significantly plugged, or you are on drugs.

How can you not narrow down your shift point to less than a 15 mph spread?