[Neale]

I've been calling various places in my area, and NO ONE will do this for me...they say that they can't do it. Ce la ve, well, I was thinking of doing it myself, but I need a few things answered first:

What does it do for your car?
Will it make the car sound deeper?
Is there any long-term detriments from doing this?

Thanks-a-much

 

[eurocrisp]

hehehe... im just kidding.

Its been covered a bunch of times since the dawn of fastcougar.com,

But reportedly:
Gives you a nice noticable gain in top end
loses a small amount of low end
makes the car sound more burly
doesnt hurt long term drivability.

just make sure when you go to emissions your main cat has had enough time to get up to temp. (10 mins)

 

[Neale]

Yeah, but can it be done by a newbie, since none of the shops around the lower IN, Northwestern KY area won't do this.

 

[MetallicaCougs]

Neale I have mine done. PM me and sometime I will arrange so you can hear them. jaged, Brandon, and myself have them done. Most everybody does them themselves.

Neil, Indiana doesn't have emissions, so we don't have to worry about it :biggrin:

 

[Massiv]

Hey... can someone give me a rundown on the negatives to this, or can I please hear from the people who have LOST power by doing this? Why is more backpressure beneficial for torque down low anyway?

Thanks,

Massiv.

 

[B3NN3TT]

Nobody loses power doing this. It still doesn't flow as well as a set of headers, and headers are one of the best bang-for-your-buck mods ever.

Gutted precats = halfway between stock exhaust manifolds and headers.

Nobody will do it for you because it is technically ILLEGAL. It's basically the same as asking your muffler shop to cut out your catalytic converter. They could get in huge trouble with the government by doing that.

That is why everyone does it themselves.

 

[Joemm]

Originally posted by: Massiv
Hey... can someone give me a rundown on the negatives to this, or can I please hear from the people who have LOST power by doing this? Why is more backpressure beneficial for torque down low anyway?

Massiv.

Technically, it is not backpressure but exhaust gas scavenging that is beneficial.

If your exhaust piping is too large or if the main catalytic convertor is gutted, e.g., it's a big empty chamber, the exhaust gas flow will slow down, cool (cold gases flow less efficiently than hot gases), and the pressure that "pushes" the exhaust gas through the exhaust system will lower. All this leads to less efficient removal (scavenging) of the exhaust gas. Think of how a given volume of water flows with higher velocity through a 1-inch hose verses the same volume of water flowing through a 4-inch hose.

On the other end of the spectrum is that too small of piping and/or restrictive mufflers etc. don't let the exhaust gas escape efficiently because of high backpressure.

The trick is to maximize exhaust flow/scavenging but not going too far so efficiency is lost.

A Cougar specific questions is whether gutting the three way catalytic convertors/manifolds (precat) will allow the exhaust gas velocity to slow down enough to actually have a overall detrimental effect? It seems because the precat is so close engine (where gas pressures are highest) and the size (empty chamber) is relatively small compared to a main catalytic converter, this may not be an issue?

Does anyone know for sure by having before/after dynometer results or something?

 

[Massiv]

Interesting. Also, I've heard of people passing emissions (in Ontario) with gutted precats. What about MSDS headers? Can people pass emissions with those? And what about the need for MIL eliminators? Is using MIL eliminators a must do after gutting or switching to MSDS headers?

Thanks,

Massiv.

 

[Tygerr]

So headers WILL or can void the warranty. Now, will it void any engine work or electrical work since you have to add the eliminators, or maybe both.

 

[eurocrisp]

Headers wont void a warrantee, but are NOT d.o.t. approved for legal road use because of the lack of catalyst. Weather or not the dealer will care is altogether a different issue... but legally they cant say, "No, we wont replace your alternator. Why? you have Headers." due to the fact that having headers wouldn't be related to alternator failure.

MIL eliminators WILL be necessary in either case, (unless you have an 01 / 02, they dont have O2 sensors in the exhaust manifolds) because the O2 sensors will read that the mixture is F'd up. The eliminators convert the signal the O2 sensors are outputting to make the ECU see the same readings as if there cats still in place. Emissions shouldn't be a problem if you still have a main catalytic convertor. The Precat's are there to make DOT happy so the car technically pollutes as little as possible, but precats only help when the car is cold. After everything warms up a main cat will provide more than enough environmental friendliness.

 

[Tygerr]

Awesome dude. Thanks. So since i have an 02 there's no need for eliminators? So they can't say i spun a bearing or w/e because i had headers, i thought everything after the engine didn't effect your engine warranty but i read otherwise about an incident with an exhaust. I don't have emissions but am thinking of throwing a high flow in there anyway just cause i don't think there would be much of a diff.

 

[eurocrisp]

If you take it to a ford dealer to get repairs done should something bad happen to your motor in the future, the wors theyd do if you convinced them to work on it is charge you as much as possible for every little thing they had to do... but they couldnt NOT fix the car. However, say, If you got careless and let a piece of wiring harness rest against the header tubing and then took it in to get that piece of harness replaced under warrantee, they wouldnt do it. I bought my car used and got 3rd party warantee coverage so i can go anywhere to get repairs made. I dont know about ford warantee tho. you prolly have to go back to ford.

Id like to see that thing you read about the repair dispute. Legally the modification has to DIRECTLY effect the part that went bad for them to deny coverage. if they cant 100% prove it, they just have to bite it and fix the car. what you read might have been someone who didnt push the technicalities and let the shop win?