Undivided T3

[Remps]

Is there a undivided T3 exhaust manifold available for purchase, or does one have to make their own out of a divided one?

[Remps]

I want to do this so that I can run a spool valve on a smaller ball bearing turbo. So it'll need all six cylinders breathing through the front port on low boost.

[oldestof11]

/divided one will work.

[ahale2772]

why would you want to run a spool valve on a small turbo?

[JustinRhodes]

Whats the benefit of getting an undivided t3 housing?

[Tacoclaw]

Not much for us.

Since our turbos are designed as a twin-scroll setup, having a divided T3 foot is what they use. The only real drawback to our setup is that it can only 'gate off half of the cylinders in stock form.


(loose definition of twin scroll)
A twin scroll turbine housing uses dual side by side passages into the housing. When coupled with a pulse converter manifold that separates exhaust pulses as many crank degrees in the firing order as possible, a twin scroll or divided housing works to reduce lag, decrease exhaust manifold backpressure on the top end, reduce the potential for reversion, and increase fuel economy. The twin scroll is based off the same reasoning a tri-Y header uses: keep spent exhaust gases out of an adjacent cylinder drawing in fresh air. At high rpm on a turbo car, exhaust backpressure is usually significantly higher than atmospheric pressure, and often higher than intake manifold pressure as well. A divider between each of the two volutes allows the cylinders to expel the exhaust gases without it interfering with the fresh air for combustion. Since there are two openings, each a smaller overall volume than a single scroll design, the exhaust velocity of each pulse can be maintained. This also spins the impeller more easily because lag is a function of the scroll area. A single turbine housing opening isn't as efficient since cylinders on the exhaust stroke of the 4 stroke cycle contaminate the cylinders that are on overlap with exhaust gas. A conventional turbine housing is not as effective in using exhaust pulse energy to help spin the turbine up to speed as it does not exploit the energy contained in the pulses as well.



What I figure is that he's either going to try to gate into the small scroll to get super-fast boost, or he's going to try to get them all into the bigger scroll at cruise to try to get exhaust out more efficiently, or so they can all be 'gated bu the wastegate in a factory setup.

Don't know for sure though.

[Remps]

A divided t3 manifold would completely close off the back 3 cylinders with the spool valve closed. Asfar as I know the back 3 and front 3 cylinders are divided from each other, are they not? It'd be easy to gut the t3 outlet so all 6 cylinders could flow through the front volute with valve closed. SDX makes them, and a company called sound performance as well. http://www.youtube.com/watch?v=I6ZCOTFET6s

[ahale2772]

yeah, you're right but still why do u want to run the valve? anrt they designed so you can spool up big turbos?

...just curious, steed speed makes a manifold that has the gate port split between the splitter, Levi has one but IDK if he got the one with the gate port?

[Remps]

I just want as fast of spool up as possible, to try and clean up low end smoke quicker. Basically to make the 5x18 and getrag more user friendly around town. Probably with a GT 3782 or 3788. What y'all think? (I don't want to hear turn down the pump, or get smaller injectors )Thats interesting about the steed speed manifold..

[oldestof11]

I would be leary of a very quick spool up (sub 1500 RPMs) with the Getrag.

Tighten up the AFC spring and/or put the stock fuel cone back in on the shallow side.

[Tacoclaw]

This *may* be an option, though I figure it will just end up being more of a restriction than anything.

http://sourceautomotive.biz/12steelspac ... ercut.aspx

I don't think you'll get the result you're looking for here. On a bigger turbo, there is probably enough volume to get 6 cylinder's worth of exhaust through the smaller side of the scroll, but I don't know if that'll be the case on a normal-sized turbo. If it can't handle it, you will not only spool up slower, but the truck will probably run even hotter and more smoky than before.

I don't know for sure that this would be the case, but I would hate to see you spend a bunch of money on a non-split header or something just to have that happen.

I know you said you don't want to turn down your pump any, but it might not hurt to play with the AFC at least a little bit if you haven't already.

[Remps]

Hmmm...maybe a T4 spool valve on a GTX 4508 in a 3782/4508 twin setup would be more helpful? Possibly spool as fast as a 3782/GTX4202 twins with more total airflow? Or would a 4508 still be too big?

[Remps]

The afc is set pretty tight already with a stiffer spring. Can't really expect much of the h1c, but its not that bad to drive. Hopefully get the new pump on this weekend so I can drive it again.

[Tacoclaw]

So you're running 5x18 injectors with a baby H1c?

What size exhaust housing does it have? If you haven't tried another turbo yet, I don't think I would worry about the smoke until you did. BB turbos supposedly spool up faster anyways, due to the decreased friction. If you plan on getting one anyways, do it and see what happens to your smoke problem.

[Remps]

Yup, factory turbo. Probably for another few months. It doesn't smoke if I drive it really easy, can't wait to get a good turbo and headstuds.