Tuned length extractors

[KurtHS]

$200 a cylinder?! That's cheap!

[Sam-Q]

Of course it depends on the engine with it's specs and the exhaust design. However what I said isn't hearsay it's according to the official quoted numbers from TODA on both of their offerings, a workshop and the direct result of a guy I know. The workshop was IDB auto with one of the earlier generation of engines of 3sge that was a quad throttle race engine. They found with testing the 4-2-1 design made more power even up top.

So while I am sure there may be exceptions for under circumstances it seems overwhelmingly that's not the case.

[Sam-Q]

My apologies I was looking at the main pic only which looked like something else so I am wrong and you're right. This does beg the question though- what bunch of idiots can make pipes for a living and not know this?

[Frak]

Agree, I've done ALOT of testing with this stuff over the years on the dyno, basically below 9000rpm I'd use a properly designed set of 4-2-1's. Unless I wanted a little more at the top and used inconjunction with a close ratio box.

P.S. stepped diam, 4-2-1's work wonders.

[drift kid]

By stepped you mean like 1.5" primaries into 1.75" secondaries into 2.25" finals? Sorta thing?

[fantapants]

sam i think the confusion over those merge sets stems from the builders copying half a v8 manifold. and being cheap.

fwiw design and precision are more important than arbitrary 4-2-1 or 4 -1 setups. This is only my opinion, but making sure you get the numbers right will have a greater bearing on how the exhaust perfoms than making it fit with pretty junctions.

Dont skimp on merges. These are the make or break of a proper manifold. Get them wrong and the whole lot is just a shiny piece of shit.

[drift kid]

Yeah, it makes sense, I have thought about making my own, that way the quality is in my hands, I've looked at buying a pipe stretcher to do the slip joints but still not sure what direction to go

[Frak]

Ben, say having a set of 4-2-1's and the primary pipe is different in diams, so the step may be in the primary pipe only.

Pat totally agree, it's so interesting, cos sometimes something which theorectically should work, doesn't and some piece of crap, works good. I find nowadays getting gains over factory stuff can be hard, or where you gain somewhere you lose somewhere else, even though the manufacturers have to package, they still do quite a bit of work.

I've been quite slack lately but have collected quite a large number of 4age headers(4-2-1, 4-1, long primaries, short primaries etc etc) and have been meaning to do a back to back and see how they all perform on the same engine.

[Sam-Q]

if oyu want something really nice try this place:



probably costs a fortune though

[drift kid]

Yeah man that's the ones I've had my eyes on, roughly $150 for a 2-1 merge