Is it long tube or short tube headers that improve low end torque? I don't need top end horsepower.

Also, many headers online come with a performance cat, but recommend the use of an oxygen sensor extension to get the second probe out of the exhaust flow. Does this actually work to prevent a CEL when you run a cat that isn't really a cat? No emissions requirements in NZ for vehicles prior to 2010.

 

Short Tube for low end.

The CEL fix with the O2 extender is not guaranteed at all.
The only guarantee for no CEL is to reuse or buy a factory CAT.

Taking the emissions out of the equation.
The factory CAT will not hinder performance and will also help to keep the exhaust volume in check.
The Header will make the exhaust louder, high flow CAT, even louder, no CAT, even louder yet.

 

What about using a mini-cat around the post-cat sensor?

http://www.bigdaddiesgarage.com/mini-cat-cel-fix.html

I like loud exhausts...

 

BlwnAway

INCORRECT..! Never been that way, never will. Fact of nature/physics..! Been their, done that.


Island -

But in this case, because you (most of us) are running full exhaust systems, the primary tube length by itself isn't going to make a huge difference either way. Especially for a more stock, lower rpm engine thru all three mufflers. Just don't go shorter than they (OEM) are...already too short..!

So...what will ? Large tube diameters slow the flow, so don't go too large on the primary size. The next step up from OEM is more than enough for what you are talking of.

Next and just as important, is the collector design. Think of how a funnel works. A short stubby funnel with a small outlet is NOT going to let the liquid out very well or very quickly. But a smooth longer funnel, emptying into a larger smoother outlet will allow the liquid out at a MUCH faster rate.

In NOT...shortening the primary tubes any, pick a header with the cleanest collector that you can afford. Don't pick a header with shorter primary tubes than stock.

Mike

 

Well then I guess I owe IM an apology.

I don't design or build headers, and since most of the people here on the forum would never custom build their own, or even have a custom built header made for them.
And since RMW was the only company I knew of that was offering a long tube header. I assumed he was inquiring about the differences between their "long tube" and their "shorty". And the shorty had always been advertised as being a better street option to help maintain low end power and torque as opposed to the long tube, that was designed to be better suited for a track centric build, where the power band and general use of the engine was in the upper RPM's for prolonged periods of time.

​​​​​​I personally have only ever used the shorty and found it to be just as good on the low end as the factory header, with the added benefit of not choking the engine in the upper RPM's, esp with a BVH.

Sorry IM.

but I'd still choose the short tube option over the long, if nothing more than to not have to modify the exhaust to accommodate the changes in the header.