Manifolds, equal length,or not?

[NYEVO00]

Looking to purchase a tubular manifold for my '03. I found that some of the offered manifolds seem to be equal length, where as some are not. With the mitsubishi twin scroll/reverse rotation turbo set-up is there reasoning that the non-equal length manifolds are more efficient?? In my opinion, as with any other turbo set up, equal length will produce most power gains and possibly smoother "power curve". I am also considering to purchase an ATP GT35 turbo kit(not sure what A/R yet). Im sure that the length of the runners will influence the turobos overall performance. (the ATP kit uses prototype/custom housing with garret BB turbo). If anyone has some helpful advice/tips for me that would help.

[NYEVO00]

If anyone has any info regarding the manifold design, let me know

[turbolarry]

Originally Posted by NYEVO00

With the mitsubishi twin scroll/reverse rotation turbo set-up is there reasoning that the non-equal length manifolds are more efficient?? In my opinion, as with any other turbo set up, equal length will produce most power gains and possibly smoother "power curve". I am also considering to purchase an ATP GT35 turbo kit(not sure what A/R yet). Im sure that the length of the runners will influence the turobos overall performance. (the ATP kit uses prototype/custom housing with garret BB turbo.

An equal length manifold keeps these gasses hitting in the right order and keeps the turbo steadily fed. Equal length runners also keep the exhaust from one cylinder from having to compete with another when trying to sqeezing through the turbine. Based on the firing order; cylinder 1's exhaust pulse will hit the turbine first, then 3's, then 4's, then 2's. Does that make sense?


P.S.
Keep these things in mind when considering a tubular manifold too;
The stock manifold retains heat and hot gasses flow better.
A tubular manifold flows better, but retains less heat.
Cast iron weighs more than stainless steel tubing.
Turbo's love exhaust's heat energy.

[NYEVO00]

So the whole "reverse scroll" setup will benefit from equal length as with any other turbo setup.
In addition, is there any downsides to installing the ATP GT35 kit to an aftermarket tubular manifold?(other than the heat related issues)
I've heard about slight lag associated with the ATP kit, have you heard the same?
(the ATP kit retains OEM manifold, or aftermarket tubular replacement)
Thank you.

[turbolarry]

Originally Posted by NYEVO00

In addition, is there any downsides to installing the ATP GT35 kit to an aftermarket tubular manifold?(other than the heat related issues).

A tubular manifold will have a high chance of cracking. My $.02; pick up a spare exhaust manifold and port it.

Originally Posted by NYEVO00

I've heard about slight lag associated with the ATP kit, have you heard the same?
Thank you.

I've never driven a car with one so I can't say. Is this the kit your talking about?
http://www.atpturbo.com/Merchant2/me...gory_Code=VEVO
If so, a .63 A/R is going to spool better, but the .82 A/R is going to have better top end. It's a trade off.

[NYEVO00]

Thanks for the advice. startin to like this site(only forum i ever used).

[turbolarry]

I was at RRE last night and they are coming out with a NICE cast manifold (T3 flange) and O2 housing.
I hope they don't mind this;
http://www.roadraceengineering.com/e...manifold-1.jpg
http://www.roadraceengineering.com/e..._fitment-9.jpg
http://www.roadraceengineering.com/e..._housing-1.jpg

[DTEK]

To a point longer runners are better. The point would be the tuned length of the header if the car was NA. Unfortunately, nobody but totally dedicated race cars can afford the space, so we make do with roughly hald that.
Tubular doesn't mean cracks, it's just that most manufacturers use 304 stainless (of which there are may varieties) and very few use 321 as it is very expensive.
304 shines up better and the welds are beautiful.
321 welds are ugly and the metal doesn't keep a shine well. It's expensive to buy and harder and more technical to weld...BUT it's strength under extreme heat is MUCH greater. That's why the good shit costs more.
Check www.magnusmotorsports.com to see what I mean.

Rob