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Resurrecting the SpoolieJobbie


TimZ

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Yes, that right - SpoolieJobbie lives again!

 

(In case you don't remember SpoolieJobbie, it was first talked about here )

 

When I first tried to implement this I had some serious problems finding a reliable actuation method, and the turbo that I had before was just to small to benefit from cutting its A/R in half. Since this isn't really a problem with the 1.15AR GT42R that I'm using now, I started thinking about dusting this project off.

 

I started poking around on eBay and found that the GSX-R bike comes stock with a similar device, and it's owners often strip this off, thinking it buys them horsepower. So, I picked one of these up for cheap - as it turns out it's even setup with position feedback for use with a position controller. The setup drives a pair of push-pull cabls that control the throttle position, so the motor can be mounted remotely. I decided to actuate the throttle through a stainless flexible shaft, so the cable assembly is also isolated from the heat.

 

A little more poking around turned up this position controller, that is capable of taking an analog input from my TEC3r and controlling the throttle position to it. And I'm off and running...

 

SJ1.JPG

 

SJ2.JPG

 

SJ3.JPG

 

SJ4.JPG

 

Initial results are looking pretty good - the graph at the bottom clearly shows the new boost response (ignore the horsepower curve - I had to back off a bit at ~5100rpm due to wheelspin).

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Hi Tim,

 

Great work as usual! I'm still baffled as to why this works when forcing exhaust gas to the center of the compressor as compared to hitting the fins where they would be easier to spin at the outside. I guess that's why it takes me 2 months to get afr readings in sync between the tech and handheld huh?

Anyway, great work and I'm glad to see her back together and making great power!

 

Joe

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Hi Tim,

 

Great work as usual! I'm still baffled as to why this works when forcing exhaust gas to the center of the compressor as compared to hitting the fins where they would be easier to spin at the outside. I guess that's why it takes me 2 months to get afr readings in sync between the tech and handheld huh?

Anyway, great work and I'm glad to see her back together and making great power!

 

Joe

 

You mean the turbine, right? Not compressor?

It's so sneaky because it's so simple. It essentially cuts hit turbine size in half so the lesser amount of exhaust at lower rpm (and mostly off boost) yields a higher velocity when it hits the turbine; therefore making it spin to higher rpm for the given exhaust flow.

Kudos! It's essentially a similar device to VNT, but very elegant. And that is substantial gains!

 

The only thing that bothers me in the comparison is the fact that you make substantial more power with slightly less boost from 5,000 to 6,400 rpm. What else was changed between these two dyno sheets?

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You mean the turbine, right? Not compressor?

It's so sneaky because it's so simple. It essentially cuts hit turbine size in half so the lesser amount of exhaust at lower rpm (and mostly off boost) yields a higher velocity when it hits the turbine; therefore making it spin to higher rpm for the given exhaust flow.

 

Yep. Thinking turbine and writing compressor.:bonk:

 

I know what it's doing, just don't understand why Tim's blocking the half of the charge that he's blocking. No need for further explanation as Tim tried the first time around and my old brain wasn't grasping it.

 

Joe

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The only thing that bothers me in the comparison is the fact that you make substantial more power with slightly less boost from 5,000 to 6,400 rpm. What else was changed between these two dyno sheets?

 

Wheelspin. The reference was from a 4th gear pull on a dyno with no wheelspin, the "current" was from a 3rd gear pull on a less than perfect stretch of road (my usual stretch of road is under construction). That's why mentioned to ignore the hp and torque numbers. I should have been clearer on that - for now I was just trying to show the boost/RPM relationship for before and after.

 

Joe - it doesn't matter which half I block off, so long as I block one of them off. My 1.15AR split turbine housing is essentially a pair of .575AR scrolls that act on the same turbine wheel. If I block one of the scrolls off, it turns the turbine housing into a .575AR housing for better spool (think of putting your thumb over the end of a hose). Then as I start making power, I can open the SpoolieJobbie back up and get the full 1.15 AR. Make sense?

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I think I got it now. You really aren't trying to direct the gasses at a particular spot on the turbine, only speeding up the gasses by forcing then through a smaller space?

 

Makes perfect sense now:mrgreen:

 

Joe

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I think I got it now. You really aren't trying to direct the gasses at a particular spot on the turbine, only speeding up the gasses by forcing then through a smaller space?

 

Makes perfect sense now:mrgreen:

 

Joe

 

Yeppo. :mrgreen:

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I think I got it now. You really aren't trying to direct the gasses at a particular spot on the turbine, only speeding up the gasses by forcing then through a smaller space?

 

Makes perfect sense now:mrgreen:

 

Joe

 

Also, if he uses a true 'twin scroll' turbine, the efficiency of the spool valve will increase even further.

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So (after reading, finally), any idea what the longevity of the SJ is going to be? It seems to my (completely thermodynamically uneducated mind) that this setup would seize up within a couple thousand miles, since I'm not seeing any way to cool it or anything.

 

Also, you probably already tried this, but would it be possible to control the opening of the SJ like an internal wastegate? ie: as boost builds, it slowly opens up for the second scroll?

 

This thread gives my ideas for a non Z V8TT project I'd like to do sometime :P

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So (after reading, finally), any idea what the longevity of the SJ is going to be? It seems to my (completely thermodynamically uneducated mind) that this setup would seize up within a couple thousand miles, since I'm not seeing any way to cool it or anything.

 

Also, you probably already tried this, but would it be possible to control the opening of the SJ like an internal wastegate? ie: as boost builds, it slowly opens up for the second scroll?

 

This thread gives my ideas for a non Z V8TT project I'd like to do sometime :P

 

The throttle plate, shaft and bushings are all made from HastelloyX, an Inconel-like alloy with higher temperature ratings, so hopefully it should hold up. We went through the thermal expansion numbers to (hopefully) make sure that nothing would seize up. Also, since I'm running E85 there isn't much in the way of exhaust residue to crap things up.

 

The position controller that I'm using allows me to command the throttle position in ~200 steps, commanded by the TEC3r's GPO table, so I'm only limited by the speed that the motor can open and close the valve. What you described is pretty much exactly how I'm controlling it.

 

I haven't heard from James in a while - I think he's been pretty busy with life in general lately.

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The throttle plate, shaft and bushings are all made from HastelloyX, an Inconel-like alloy with higher temperature ratings, so hopefully it should hold up. We went through the thermal expansion numbers to (hopefully) make sure that nothing would seize up. Also, since I'm running E85 there isn't much in the way of exhaust residue to crap things up.

 

The position controller that I'm using allows me to command the throttle position in ~200 steps, commanded by the TEC3r's GPO table, so I'm only limited by the speed that the motor can open and close the valve. What you described is pretty much exactly how I'm controlling it.

 

 

Cool. You basically sold me on this concept for my other project :D

 

And any idea why the bikers think this robs power? Or is it one of those internet legends that aren't necessarily true, but everyone believes it anyways?

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And any idea why the bikers think this robs power? Or is it one of those internet legends that aren't necessarily true, but everyone believes it anyways?

 

That would be my guess - it's a naturally aspirated engine and I think they use it to increase backpressure at low rpm for better response. Maybe they don't like the opening points or something?

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  • 1 month later...
That would be my guess - it's a naturally aspirated engine and I think they use it to increase backpressure at low rpm for better response. Maybe they don't like the opening points or something?

 

 

That is exactly what they used it for. The bike I used to own had one. It was a Honda CBR 954RR.

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