interesting - reason to go twin-scroll...?

[Jason Swan]

thread: http://ls1tech.com/forums/forced-induction/1077263-zombies-quick-spool-valve-testing-pics-nerd-like-graphs.html

Short version: with twin-scroll turbo, valve inserted after turbo outlet.  Idea is to close off one side of the twin-scroll (and therefore halve the AR) at no or minimal boost, and open once boost builds to some small value (5-10 lbs), therefore resulting in faster initial spool.  Interesting concept.  Can't imagine why it would not work or what negatives it could create.

This could be quite interesting to play with on a dsm with a larger holset....

[KevinBuckham]

This tech was being talked about a bunch about 2 or 3 years ago, but everyone's gone silent.  I assume it doesn't work all that well, as I know some DSMers were testing them but I never heard any positive reviews. 

Mazda used something similar (not the same) in their turbo FC.  It was an interesting twin scroll design to help spool.

[Robert Vorley]

Sounds simple but it doesn't sound easy.  It is recommended to go with a slightly larger a/r when switching to twin, but it would be interesting to see how much larger you could go with this kind of set up, assuming they can make it work reliably.

[Brett Haviland]

yeah this never caught on cuz VGT's  (variable geometry turbo's) took hold. 

[Carl Gould]

My brother has a quick spool valve on his Supra, when it goes for final tuning this year (possibly next year though) I can post some dyno graphs if people are interested.

[Jordan Kruger]

The concept is cool. I remember reading about the newer style Porsche turbochargers using "stator vanes" in the housing which when closed, would create a smaller turbo housing, yet when the open , they allow for maximum airflow. This is involving the housing around the turbine which is a totally different concept. Yet still very effective for allowing better spool.
As far as twin scroll goes, its there to maximize the efficiency of the exhaust pulses to the turbo. Obviously most of you guys know this already but Im just sayin.   It would seem to me that having a blockoff plate would make for some serious turbulence in the exhausts path to the turbo. My only concern with that is it could cause for hot spots and an odd collection of heat where the heat normally flowed past. And wouldnt closing up a port on the twin scroll setup allow for only 2 cylinders to operate the exhaust flow to the turbo? As far as I understand the manifolds are engineered to reduce the fluctuating exhaust pulses to the turbo and allow for better efficiency. I thought twin scroll started with (in our case) 4 runners divided accordingly based on firing order and length. 2 cylinders utilizing one side of the housing, and the other 2 cylinders to the other side of the housing.
Am I wrong?

[Carl Gould]

The concept is cool. I remember reading about the newer style Porsche turbochargers using "stator vanes" in the housing which when closed, would create a smaller turbo housing, yet when the open , they allow for maximum airflow. This is involving the housing around the turbine which is a totally different concept. Yet still very effective for allowing better spool.
As far as twin scroll goes, its there to maximize the efficiency of the exhaust pulses to the turbo. Obviously most of you guys know this already but Im just sayin.   It would seem to me that having a blockoff plate would make for some serious turbulence in the exhausts path to the turbo. My only concern with that is it could cause for hot spots and an odd collection of heat where the heat normally flowed past. And wouldnt closing up a port on the twin scroll setup allow for only 2 cylinders to operate the exhaust flow to the turbo? As far as I understand the manifolds are engineered to reduce the fluctuating exhaust pulses to the turbo and allow for better efficiency. I thought twin scroll started with (in our case) 4 runners divided accordingly based on firing order and length. 2 cylinders utilizing one side of the housing, and the other 2 cylinders to the other side of the housing.
Am I wrong?

With a quick spool valve you use a twin-scroll turbo but an open manifold. This way when the valve is "closed" it's directing all 4 cylinders down one scroll. Personally, I think a system where the flapper is built into the turbine housing (as the scroll divider) would be a better solution, as then you could keep the advantages of a twin-scroll manifold while still having a quick spool valve.

[Robert Vorley]

With a quick spool valve you use a twin-scroll turbo but an open manifold. This way when the valve is "closed" it's directing all 4 cylinders down one scroll. Personally, I think a system where the flapper is built into the turbine housing (as the scroll divider) would be a better solution, as then you could keep the advantages of a twin-scroll manifold while still having a quick spool valve.

I agree. Keep it simple. Then all that has to be added is a method to actuate a diverting valve or a gate that allows the flow to join and divide through pressure change.   

[daniel Dee]

is it volume? or velocity of air that spools the turbo.?
Hard to find this balance.
I say use a electric motor to spool the turbo.
http://www.treehugger.com/cars/electric-supercharger-boosts-torque-50-and-reduces-co2-by-20.html

[Robert Vorley]

That balance is what makes its so difficult to keep things simple. 

That electric supercharger (ES) looks interesting. I didn't see how much potential range is lost to power it?

Energy capture devices similar to those used in F1 and LeMans that produce a short term "boost" would be fun for the street, although the ES looks like a good idea since it offers a full time boost.

At work we use electric lift-trucks and reach-trucks that generate charge while coasting/braking to increase range, similar to newer hybrid/electric vehicles.  It is nice not to have to apply the brake all the time as the system produces enough drag to slow the lift when not accelerating.