bolsen

iTrader: (2)

Hmmm RNR told me they were going to post in here....

Tho, I think I've made my decision...

2k4EvoVIII

iTrader: (15)

So what decision did you go with?

4G63>OOOO

iTrader: (1)

Well, the ATP is KIND OF twin scroll. The turbocharger isn't, but it retains the stock manifold, so it is twin scroll in that aspect.

Everyone else just uses a standard scroll.

Joe

2k4EvoVIII

iTrader: (15)

Um the turbo is pretty damn close to twin scroll. The housing is divided into 2 sections somewhat. I dont know kind of hard to explain. It is not divided completly but it is divided. And your right all the other use the single scroll. So question is why would they use the single scroll? Too much money to produce? Wish some vendors would chime in!

Fenris Ulf

iTrader: (-1)

It is not a twin scroll at all. It is not completely divided meaning it has none of the advantages of a twin scroll over a standard scroll; the pulses are not separated through the turbine housing.

2k4EvoVIII

iTrader: (15)

The turbine houses has a small divider but does not connect to the other end you are right. But were the divider counts the most is off the manifold were the gases will be escaping the engine and not conflicting with the other ports and are on the oposite stroke of the engine. From what i understand that is the most important part of the twin scroll setup.

Fenris Ulf

iTrader: (-1)

Wherever you are getting your sources...

They call it a twin scroll because, you guessed it, there are TWO scrolls. The divider is very important all the way from exhaust port until the pulse hits the turbine blades, not just in the manifold.

If it was a true twin scroll housing I might consider the ATP kit, but I do not like the idea of doubling the cross sectional area of flow (more than doubling it, actually) from one combined runner of the factory exhaust manifold to ATPs exhaust housing inlet.

Without this divider you are forfeiting any benefit of the twin scroll manifold...

4G63>OOOO

iTrader: (1)

The reason why no one offers a twin scroll upgraded turbo is...

Garrett doesn't make any twin scroll housings.

Yep, it's that simple. You'd think that ATP would have done it that way, but they didn't.

2k4EvoVIII

iTrader: (15)

Um garrett were the ones that developed twin scroll technology. This is directly from there website. And back to the comment above i still think that you will have a benefit with the twin scroll manifold becouse the 1and 4 cylinder are tied together when they go off and same with the 2 and 3 cylinder when they go off. THere is no way of it mixing the airflows. But look enough said no sense in keeping this up back and forth. I understand what you are saying and i appriciate the new outlook on the idea!

Originally developed for commercial diesel applications, turbochargers with a twin-scroll turbine housing have now been successfully adapted for use with passenger car engines (both gas and diesel). By utilizing dual openings, or volutes, into the turbocharger's turbine housing, exhaust energy is optimized which results in better engine performance at low speeds, decreased backpressure at high speeds, and significant gains in fuel economy.

Traditionally, passenger car turbochargers have had only one volute through which exhaust gases leaving the engine cylinders can enter the turbine housing (where they are used to create torque). Unfortunately, this single entry design can sometimes lead to combustion inefficiencies, since some cylinders are expelling burnt gases while others are inhaling fresh air for combustion. What happens is that the hot, dense exhaust gases from the first set of cylinders are drawn into the second set of cylinders, causing the combustion occurring in those second cyf the fuel it's consuming.

Several wastegate solutions were considered to counter this problem, with a twin-scroll design ultimately providing the best solution. A twin-scroll, or twin-entry, housing allows each set of cylinders to release its exhaust gases into a dedicated volute. That way, it doesn't interfere with the other set of cylinders, which is taking in fresh air at that same time. Of course, refinements were necessary to account for the divider between the two volutes, but thanks to the dedication of Garrett engineers, those challenges have been met.

As this technology is further developed, even smaller passenger car engines will be able to experience the benefits of the twin-scroll turbine housing design including those fueled by natural gas. And, as with all the products Garrett manufactures, twin-entry turbocharger technology will continue to be developed with an eye toward even greater efficiency and maximized performance

lancerpartstrad

doesn't HKS make a twin scroll BB setup?

FOURCED

I used twin scroll successfully on my 4 banger Stang. It works so well I hesitate to even discuss it but if you wanna take a look @ how I set it up there are several good pics there.

It is more difficult to gate and as you can see, I ended up with 2 Race Gates and still could only get it down to a 20psi minimum. Exhaust velocity (energy) is Very High!
The small tubes (1.5"O.D.) make most people nervous, but I can assure you they will support 200HP per cylinder.

If I did it on an Evo (and I will), I would feed the gate from a large tube welded directly to the turbine hsg..

http://hometown.aol.com/fourced/index.html

JDB

Fenris Ulf

iTrader: (-1)

Yup, would have been cool for ATP to have put in the extra effort since they were already making a mold, but oh well. Always good to have room for improvement...

Fenris Ulf

iTrader: (-1)

There are twin scroll ball bearing turbos out there, just not rotating the same way as our mitsu ones. If stealth is not a concern, someone will develop a twin scroll manifold that will allow the use of a standard rotation twin scroll housing. Until then I am sticking with the stock turbo

lancerpartstrad

IHI VF38 is reg. rotation ball bearing twin scroll. Those manifolds allready exist.

bolsen

iTrader: (2)

Very interesting. Don't suppose you have a picture of your tubo housing do you?