Quickspool Valve.

[luke gtr]

I was thinking the longer arm with actuator repositioning, or an electric actuator of some specification.

That's all I can think of this close to bed time.

[HtwCHACtkh]

Great work Shaun and Stao,

I'm interested in seeing how this progresses. For those who doubt the theory consider bernoulii's theorem.

First assume the exhaust gas is not getting compressed (density is constant) and flow within the system is ideal, then the flow out of the head must equal the flow out the turbo. If the area to the turbo is halved then its velocity must increase by a factor of approximately 1.4 (Bernouli's theorem, Conservation of Energy). Momentum is then consequently increased by about 40% => 40% faster spool time.

So in an ideal theoretical world - it works great but a lot of R&D is required to reduce ineffeciences.

Stao: Is this sort of setup possible in one of your super street turbos?

[zebra]

You mention twin scroll manifold....youre shutting off 3 cylinders until 4000rpm?

[HtwCHACtkh]

You mention twin scroll manifold....youre shutting off 3 cylinders until 4000rpm?

Twin scroll turbo, single outlet manifold for this setup. You want to make all the gas go through the turbo faster by making the area smaller until it starts to create backpressure in which case you begin opening the valve on the turbo slowly until it eventually is open entirely flowing entirely AFAIK.

[nisskid]

i still don't understand how this works, the wheel and housing stays the same size, in my head it's like putting a restrictor in any part of the manifold, the diametre decreases, so the velocity increases through the restrictor, but as soon as the diametre increases again, it simply slows down again. i know this "restrictor" is immediately before the turbo, but it's still the same volume being pushed through the same area around the wheel.

i can only think there is some merit to the idea of the pressure being directed onto a more efficient part of the blades.

[rockabilly]

guys, my set up is a full divided twin scroll 6 boost amnifold and a gt4094 full twin scrioll turbo, what has happened is part of the twin scroll in the exhaust housing has been removed and fitted with a flap. the flap closes the rear most port of the twin scroll housing but at 45 degrees, this does 2 things . directs all 6 exhaust gases through the front scroll of the turbo exhaust housing, and 2, because its at 45 degrees reduces heat build and helps to increase the gas flow.

you do not do any mods to the manifold what soever.

as mentioned above, i run a link g4 ecu, i am going to fit a linear electric actuator, wired through a relay and driven by the ecu output using rpm to determine the gate opening piont.

thanks again for the contributions guys. will update as and when

[zoidbergmerc]

Wouldn't it be better to switch it on load rather than rpm?

[DVS JEZ]

Will need a bit of R/D to see which method is best

[Harey]

You mention twin scroll manifold....youre shutting off 3 cylinders until 4000rpm?

The exhaust gases from 3 of the cylinders on one side of the manifold travels straight through to one scroll of the turbo housing and the exhaust gases from the other 3 cylinders enter their own scroll of the turbo housing but are redirected to join the same scroll of the turbo housing.

This redirecting occurs within the turbo housing itself.

This way the exhaust flow from all 6 cylinders are using only one scroll of the twin scroll turbo until the point that the valve is opened.

I am guessing when the valve does open you might get a small dip in boost pressure as the exhaust flow has to start from scratch on the second scroll?

[scotty nm35]

I would assume so Harey, unless you can open it slowly.

My design didnt modify anything, it's removable and between the TS manifold and TS turbo housing as I wanted to keep the TS when the flap was open. I ended up not making it as the GTX4508 turbo I designed it to go under was too big to fit in the engine bay with 3 inches added to the manifold height.

[Harey]

I would assume so Harey, unless you can open it slowly.

My design didnt modify anything, it's removable and between the TS manifold and TS turbo housing as I wanted to keep the TS when the flap was open. I ended up not making it as the GTX4508 turbo I designed it to go under was too big to fit in the engine bay with 3 inches added to the manifold height.

Ah ok so your design is an piece that sits in between the manifold and turbo housing? So would raise the turbo up by the amount of your part.

GTX4508 turbo lol ur a nutter

[Rolls]

Interesting bit of gear. I've also made a prototype with the similar sort of swing valve, the problem I've found is the exhaust manifold pressure on the flapper valve was too strong for the actuator to engage, which it never opens. But there are ways around it.

Can just you just use a very long lever with lots of mechanical advantage and a strong solenoid?

[Rolls]

i still don't understand how this works, the wheel and housing stays the same size, in my head it's like putting a restrictor in any part of the manifold, the diametre decreases, so the velocity increases through the restrictor, but as soon as the diametre increases again, it simply slows down again. i know this "restrictor" is immediately before the turbo, but it's still the same volume being pushed through the same area around the wheel.

i can only think there is some merit to the idea of the pressure being directed onto a more efficient part of the blades.

You are using a twin scroll turbo so the turbo doesn't stay the same size.

Wouldn't it be better to switch it on load rather than rpm?

Ultimately you need a 3D map with rpm and boost (not load).

Edited December 19, 2011 by Rolls

[luke gtr]

now i want one

maybe the next build.

im already schemeing ways of doing the flap internal to the manifold rather than the turbo housing.

and trying to make it so the gasses dont load it up too much to open with an actuator.

hmmm, time to start drawing.

[nisskid]

You are using a twin scroll turbo so the turbo doesn't stay the same size.

ok so the twin scroll stays separated right up until exiting the wheel? i was under the impression it was only separated til just before the wheel.

i'd like to see this thing tested on track cars, additional moving parts with track temps makes me nervous.

i would rather see a back swept design, which is spring loaded (adjustable) which is opened by exhaust gases, once the exhaust gases build up enough pressure, the flap starts opening, once they reduce, it closes back up. the design could be much simpler, with less parts to fail.

[32vspec2gtr]

The only reason why you can't do that Nisskid is due to the fact that it would eliminate the purpose of having the twin scroll turbine

housing as you wouldn't be able to block the center where the gas switches from one side to the other. You would how ever be able to run it like a standard v-band housing, even though you would be utilising a modified twin scroll housing and a divided manifold.

Hows it going with this anyway? Any more results? Looking at doing this with my build in the near future.

[Rolls]

ok so the twin scroll stays separated right up until exiting the wheel? i was under the impression it was only separated til just before the wheel.

If you did that the turbo still sees the same mixed exhaust pulses, it has to be separated the entire way otherwise it won't be of any benefit, hence the separating takes up space and the AR is reduced for the same physical size.

[32vspec2gtr]

By the way has anyone thought of using a stepper motor, similar to those found on the intakes of some cars in reference to boost pressure? Just use the ecu to put out a Pulse width modulated signal in accordance to boost.

You don't need to take it too full boost as its only when the engine is trying to begin to spool a turbine that takes the longest, so say if desired boost level is 24psi just make it full open at 14psi.

By doing that you eliminate any of the issues with exhaust restrictions, boost spikes, etc as the system would be regulated via the wastegate. Realistically rpm wouldn't really matter as its only operating on boost pressure imo.

Also the stepper motor running of a pulse width would be able to be opened gradually rather than straight open and shut

[Adriano]

Having just read a thread about tuning VCT turbos on a 1uz, you need to remember that when the valve is shut, it has a big effect on the Volumetric efficiency of the engine, fuelling and timing changes will be massive compared to when the valve is open

[Adriano]

I think the guy who did it ended up using an exhaust manifold pressure sensor and having the valve reference it to boost pressure. Basically he said you can make heaps of boost down low, but if the valves(s) are shut to make the boost, then the motor wont make any power. BTW it was all ecu controlled.

Edited January 29, 2012 by Adriano