Basic Bolt ons: Exhaust Headers/Flex Pipes

[warneej]

In this section I will go into detail describing the kinds and brands of exhaust headers and flexpipes.

When it comes time to choose an aftermarket header for your car you have a few things to consider. Mainly you want to decide if you are going to stay emissions legal. If you are going to stay emissions legal then don't install a header. Due to the combination Catalytic Converter/Exhaust Manifold, or Mani-Cat, you are unable (technicalities aside) to pass emissions with an aftermarket header installed. If meeting emissions requirements isn’t necessary then a race header is one of the best bolt-ons for the Duratec engine.

Here are some of the headers you are likely to see on the market.

FocusSport
OBX
Cosworth (discontinued)
F2 (discontinued)
Weapon-R

PROS
For the money, if you plan to make serious NA power a header is absolutely necessary. Also they cannot be beaten when it comes to price. Average headers go for between $325 - 375

CONS
Installing a header requires removal of the catalytic converter. Many folks cannot remove their cat for emissions reasons. This makes a header impossible to use. Also, noise is drastically increased with the installation of a header.

All of the headers listed come with the Flex Pipe included (except the FocusSport which is available seperately). Keep in mind there are different flex pipes for ATX and MTX so be sure to select the proper piece!


Comments, discussion, and corrections welcome!

[Sponsor]

[Waffles ZX3 Kona Sport]

Can I install a FS flexpipe on a Draxas header? And do I need new gaskets for my header? If so, where can I get them?

[warneej]

If the Draxas header will bolt up to a stock flex pipe then it will bolt up to an FS one

[jetrinka]

It will bolt up, yes but will the length of the FS flex be too long or too short is the real question. And since when did the flex off the stock manifold come off? Mine is welded on. What flex did the Draxas use? Did it come with its own?

[warneej]

Mine unbolted from both the mani-cat and the exhaust system

[jetrinka]

Huh. Might have changed from 04-05. Weird.

[captcurt_18]

Which is better for the D20 and the D23? I know one of them has bigger primaries which makes it more optimal for the D23, but i forget which one.

[focusedin]

The exhaust that was given to me was a gift but it was only a 2.25 and most headers have a 2.5 collector. Problem??

[warneej]

Originally Posted by captcurt_18

Which is better for the D20 and the D23? I know one of them has bigger primaries which makes it more optimal for the D23, but i forget which one.

The general consensus is that the F2's smaller primaries work better on the D20 and the rest's larger primaries work better on the D23. I don't know how much proof of this there is beyond theory however.

Originally Posted by focusedin

The exhaust that was given to me was a gift but it was only a 2.25 and most headers have a 2.5 collector. Problem??

No.

[hatchesrock1989]

i got a question i have the f2 header and it gets some leaks because the f2 flex is very short and stiff. i had to push up my exhuast quite a bit was wondering if i can use the stock flex and bolt it up to the f2 header ??