whine n' a whistle
06-28-2010 | 07:30 PM
#41
This setup reminds me of certain turbine engines, particularly the P&W PT6. It has two compressors- a centrifugal flow and an axial flow compressor. The centrifugal one makes the pressure at low speed and then the axial one takes over higher up. There is an interstage bleed valve in between to prevent axial compressor stalling.
Your setup is very ingenious (though many have thought about it but never done it) and is likely what we'll see more of in the future.
Your setup is very ingenious (though many have thought about it but never done it) and is likely what we'll see more of in the future.
06-29-2010 | 01:40 AM
#42
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From: Detroit
This is the boost video I promised. The tune is still pulling a shitload of timing, enough that I can't build more boost or rev up a lot under load. But this is what sequential looks like...
Top gauge is turbo, bottom is supercharger.
Top gauge is turbo, bottom is supercharger.
06-29-2010 | 02:16 AM
#43
I knew that question would come up 
It is a good question though. With the way I figured on setting it up, the system does have to compound a little bit. The blower is at full boost until the turbo reaches that preset pressure, at which point the blower bypasses. But the pressure ratio of both combined until the blower goes into bypass works out to about 10.5psi compounded.
It is a good question though. With the way I figured on setting it up, the system does have to compound a little bit. The blower is at full boost until the turbo reaches that preset pressure, at which point the blower bypasses. But the pressure ratio of both combined until the blower goes into bypass works out to about 10.5psi compounded.video helps, you can see and hear it kick the bypass open. but it brings up another question, isnt the blower boost gauge in the lower manifold under the intercooler? i figured that then it would change to a combined or overall max boost reading once the bypass opened? or are you only making 5psi total right now?
Last edited by skolman91; 06-29-2010 at 02:27 AM.
06-29-2010 | 10:46 AM
#45
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From: Detroit
makes sense, i guess it is compound boost some of the time even tho your calling it sequential boost.
video helps, you can see and hear it kick the bypass open. but it brings up another question, isnt the blower boost gauge in the lower manifold under the intercooler? i figured that then it would change to a combined or overall max boost reading once the bypass opened? or are you only making 5psi total right now?
video helps, you can see and hear it kick the bypass open. but it brings up another question, isnt the blower boost gauge in the lower manifold under the intercooler? i figured that then it would change to a combined or overall max boost reading once the bypass opened? or are you only making 5psi total right now?
Sent you a PM.
Last edited by anasasisxenophontis; 06-29-2010 at 11:14 AM.
07-01-2010 | 02:51 AM
#46
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From: Detroit
Well I certainly learned something today. I guess the orientation of the MAF sensor can affect performance. Not direction of flow, but literally rotation away from where the sensor was at in its stock configuration. It caused the MAF to report more air flow to the engine when there actually wasn't excess flow, so it ran extremely rich. Still more kinks to work out in the tune, but it pulls a hell of a lot harder now.
Kudos go to Justin at Blackbear for that tip.
Kudos go to Justin at Blackbear for that tip.
07-01-2010 | 10:39 AM
#49
The only way to ditch the MAF with the newer PCM's is to run a custom OS like a 2.5bar setup. Stock, they use a virtual VE (no primary VE table) so diabling the MAF in order to run a SD tune doesn't work well.
07-01-2010 | 11:47 AM
#50
Interesting setup. I like it. I got to thinking about the tuning. Unless the transition from blower to turbo boost PSI is consistent, IE no spikes or drops.... it is gonna be a pain to tune IMO in SD.