Quote:
Originally Posted by goodhart
What exactly are the flaws? care to point them out? just curious.
|
This is quoted from doug on widsm.org, there is much more info in the thread, and upgrades to his design. this is just the first post
I consider this forum my home forum, so I thought I would post my progress on here first. As you may know I am currently involved in long expensive build with my GVR4. In a nut shell, my goal is to build the ultimate street car. A car that has massive power and can also be reliably and safely driven on the road. As we all know one thing you generally need to make big power, is a big turbo. My turbo of choice is the Borg Warner S374. This is the same turbo our friend Tim Zimmer is running, as well as both of Chicago's insane fast Evo 2's. One of which makes over 1100 at the wheels. The problem is obviously that these cars are not the most fun things to have on the street due to lag. For example the one Evo2 does not start making power until 6-7k rpm, and still doesn't start reaching his peak power band until around 7.5-8k. Mr. Zimmer is able to spool a bit earlier due to running a stroker, smaller turbine housing (compared to the evo), and other things. But that still didn't satisfy me. My goal is big power with a big power band.
With nitrous out of the question, I became very interested in Sound Performance's "Quick Spool Valve." This device is meant to work with divided turbine housings. It mounts between the turbo and manifold to seal off one scroll of the turbine housing, accelerating exhaust gasses through the open scroll. Then once a desired boost pressure is reached, the valve opens. Although I saw a few drawbacks had I chose to run their device. The biggest one being it's only able to function with an undivided exhaust manifold. Reason being if you ran a divided manifold, it would completely seal off two cylinder's exhaust gasses when the valve is closed. After much research I found that the whole "spool valve" concept has never really been implemented in 4g63 and other 4 cylinder applications. Reason being? Best answer I could come up with is no one makes undivided manifolds in T4 flange sizes. So after being basically ignored by a few manifold fabricators and Sound Performance themselves about how I could make this work, I said fuck this I'll make my own. And, I'll make it better. Here is what I came up with:
I overcame 2 main problems that I had with the SP design. First, I created the ability for usage with a divided turbo manifold by removing the divider between scrolls. Which means my device can work with any and every T4 sized manifold made, divided or undivided. Second, I never liked the SP's flapper design and position. To me, it would seem to create too much exhaust gas turbulence and restriction above the device when the valve is closed. If one were to do a flow simulation with their valve you would see the exhaust gas will hit the flapper, then have to travel back up the surface and over the divider creating a small amount of turbulence above the divider itself due to gasses flowing down directly into the other scroll. (see my picture of the SP device for reference) Less importantly you would also see a small amount of restriction when it's open due to the flapper's shaft. (similar to a throttle body's shaft design) So I angled my flapper down toward the open scroll (also a must due to not having a scroll divider), removed the shaft material from the top flapper surface, and milled the shaft material on the underside. Therefore theoretically creating less turbulence and restriction when the valve is closed, and also greater flow when it is open. Still, SP has tested their valve with great success. So it can only get better, right?
My flapper actuation is also done by a vacuum actuator. Though I have designed a variable-position bracket that allows you to rotate the actuator 360* to allow for any clearance issues. (not shown in pictures) This is also an advantage over SP's fixed actuator design.
The flapper plate/shaft will both be made from ___(TBA)___ for superior heat resistance. The flange will be stainless or some stainless alloy. I am currently working with a friend whom has a machine shop equipped with a water jet and all sorts of cool things. So we are working together with all the technical specifics.
If you are curious to how this works, think of putting your thumb over a garden hose. The hose being the turbo manifold, water being exhaust gasses, and your thumb being the spool device. You put your thumb halfway over the garden hose to accelerate the water's rate of flow. The same thing happens when the butterfly valve seals off one scroll of the turbine housing. Then once you reach boost, the valve opens and you are at normal exhaust flow.
The concept:
http://forum.widsm.org/showthread.ph...nd+performance
Linear Mode
