yoza

I was at a meeting at Vauxhalls car plant the other week, along with a few Scooby owners. A guy pulled up in his scoob and it sounded strange. "I bet thats got equal length headers" someone said, "yes it sounds like" I said(confused), not knowing what the **** he was talking about.

Now its been troubling me since, so what is an equal length header?

Thanx Yoza

Tony MY03WRX

Yoza
I belive the term equal length headers means that the down pipes from the exhaust manifold are all the same length. This can change the exhaust sound.

Tony

yoza

Fankyou.

So therefore on my standard WRX,I have un-equal length headers.

greasemonkey

Look at the design of your engine and the way the exhaust stubs are connected to the turbocharger. The "left" hand bank of cylinders is on the opposite side of the car and further away, and the exhaust gas from this side has to travel across the front of the engine before it meets up with the "near" bank, and travels through the up-pipe into the turbine.

It's because the exhaust gas has different distances to travel that the headers are referred to as unequal length, and it's also the reason why most Subaru turbo engines have that distinctive offbeat engine note.

Equal length headers have extra tubing inserted into the right bank, meaning that the gas has, obviously enough, an equal length of header to travel before it gets to the turbo, no matter which cylinder it has come from.

It doesn't just make the car sound different, BTW. Equal length headers also even out the interval in which each pulse of exhaust gas hits the turbine, making both it, and the exhaust system in general, work more efficiently.

[Edited by greasemonkey - 9/9/2003 9:02:30 PM]

yoza

Cheers, and would you believe it, there is a group buy on "headers" just been put back to the top.

Personally I like that lumpy, eneven sound, I take it that there is some more power to be had from this mod.

yoza

Ah Mr Monkey, you edited and answered my question.

greasemonkey

Yes, in a word, but it's a bit more complicated than that!

It's not just the relative lengths of the two banks that has an effect on performance, their internal diameter also makes a big difference.

Heavily modified engines running loads of boost like larger diameter headers because of their ability to flow more gas. Put the same ones on a more standard engine though, and the larger diameter can slow spool-up and reduce throttle response. Under these circumstances, a group-buy may not suit you, so it pays to do your homework!

yoza

Do not fear.....my 212bhp is dangerous enough for an old codger like me.

johnfelstead

the gruppe s headers arnt equal length, they are just tubular rather than cast.

genuine Spec C equal length headers.

yoza

They look like an art exhibit.

Expensive, me thinks....

Thanks, I am now able to sleep.

greasemonkey

These particular ones aren't that expensive, they're standard production items on the Japanese market '03 STi's.

These won't fit your car though, they only mate with the new twin scroll turbochargers, and also need a new sump pan and oil filter.

[Edited by greasemonkey - 9/9/2003 9:31:03 PM]

yoza

"Twin scroll", Yeah right, your talkin to a baffoon here!

I know what an oil filter is though.

And I once topped up my washer bottle, all on my own.