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Thread: Dual CP-3

  1. #21
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    Two questions:

    1) How high can the psi sensor read?

    2) What happens when you exceed this limit?
    Kennedy Diesel-owner
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  2. #22
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    Quote Originally Posted by Kennedy
    Two questions:

    1) How high can the psi sensor read?

    2) What happens when you exceed this limit?
    How high? LLY/LB7 can read 26200 psi IIRC. The LBZ can read up to 29000psi, but I have not see this for myself. I'm trying a LBZ sensor in my rail ASAP.

    When you exceed the limit of the psi sensor I think the rail psi goes higher but don't let you see it. You would need to test this on the dyno or have a psi sensor built into the rail to verify this.
    Twin Turbo LLY

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  3. #23
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    Quote Originally Posted by Bobo
    How high? LLY/LB7 can read 26200 psi IIRC. The LBZ can read up to 29000psi, but I have not see this for myself. I'm trying a LBZ sensor in my rail ASAP.

    When you exceed the limit of the psi sensor I think the rail psi goes higher but don't let you see it. You would need to test this on the dyno or have a psi sensor built into the rail to verify this.
    Think about what you've said here for a minute. You can command 36,000 psi. You can read 26,200 psi MOL. The issue here is that if you call for a value higher than the sensor can read, you no longer have control of the pressure. Just like the early Edge Juice for the LLY with it's boost cap, this is not a good idea...
    Kennedy Diesel-owner
    More than just a salesman-I use and test the products that I sell on a daily basis!
    Superflow Lie Detector in house
    2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
    2005 Chev K3500SRW D/A CC Long LT(SOLD)
    2007 Chev K2500 Classic EC Short LT (Sold)
    2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
    2016 GMC K3500SRW D/A CC short LTZ

    Custom tuning in house using EFI Live tuning software!

  4. #24
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    Kennedy is correct. This is one reasone the Duramaximizer work so well. You can command as much pressure as the sensor can see, then you can tweek even more out of it and still have control over the pressure......

    Dan

  5. #25
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    Quote Originally Posted by Dan@PPE
    Kennedy is correct. This is one reasone the Duramaximizer work so well. You can command as much pressure as the sensor can see, then you can tweek even more out of it and still have control over the pressure......

    Dan

    I've stayed way from pressure foolers as there is really no need with proper programming, but I'll see if we can get on the same wavelength here. Adding foolers can be tricky business and dangerous as well. The numbers I'll use in my examples are not absolutes, and have been chosen for simplicity of math/illustration. I'm also using a linear scale 0-5v again for simplicity. Actual curve/correlation between psi and v is different.


    Say 25,000 psi = 5v and you command right up to the sensor's limit of 25,000 psi like you mention. Enter the Duramaximizer and fool out say 10% of the voltage. The Duramaximizer reports 4.5v to the ECM and it tries with everything it can to make the 5v (25,000 psi) but no matter what it does, the Duramaximizer won't tell it any more than 22,500 so it keeps trying and is now running blind. This can be very dangerous especially with the added capacity of dual pumps.

    The only place that a Duramaximizer or other fooler works properly, safely, and controlled is where the command is low enough that the sensor can report back all of the increased psi to the Duramaximizer.

    Say you command 22,500 and the Duramaximizer is set to fool out a percentage (this is where the math gets complicated so I'll leave it out) of the voltage, yet the sensor has sufficient headroom to feed the Duramaximizer enough voltage that when fooled equals 4.5v or 22,500 psi. In other words (again pulling nimbers from the sky) the sensor outputs 4.75v or23,750 psi but the Duramaximmizer reports back 4.5v (22,500 psi) so all is well and the pressure is regulated. If you push or cross the 5v mark you are running the risk of uncontrolled pressure regulation...
    Kennedy Diesel-owner
    More than just a salesman-I use and test the products that I sell on a daily basis!
    Superflow Lie Detector in house
    2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
    2005 Chev K3500SRW D/A CC Long LT(SOLD)
    2007 Chev K2500 Classic EC Short LT (Sold)
    2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
    2016 GMC K3500SRW D/A CC short LTZ

    Custom tuning in house using EFI Live tuning software!

  6. #26
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    Quote Originally Posted by Kennedy
    Think about what you've said here for a minute. You can command 36,000 psi. You can read 26,200 psi MOL. The issue here is that if you call for a value higher than the sensor can read, you no longer have control of the pressure. Just like the early Edge Juice for the LLY with it's boost cap, this is not a good idea...
    John,
    I know what I said. You can do it. Did I say it was safe? Did I say what happens after you command over that amount? This whole argument started to see what the gains from a LBZ cp3 will have if you use it on an LB7 or an LLY. For the reasons you stated above, I'd say none. If you do some monitoring with gauges and changing out sensors, you might see the benefit of the LBZ pump. I performed some other tests that I thought of, but the safest way to raise the psi under control is to monitor the psi. On another note....I've tuned a few trucks with very large injectors and twin CP3's. The ones with LLY/LB7 pumps had no problems holding and sustaining very high rail psi. I'm not switching to LBZ pumps on my truck and I think it is a waste of money unless you utilize their benefits with other modifications. Nobody has proved that the LLY/LB7 pumps are not adequate in a twin CP3 setup. I'd say save your money on the LBZ CP3 at this point. Get twin CP3's and call it good.
    Twin Turbo LLY

    EFI Live Tuned by Me
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  7. #27

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    As for 'streetability' - can an otherwise daily driven truck be driven reliably on the street with dual IPs as described? Can you run ECM switchable tunes that allow the truck to start and drive out nearly stock, then 'unleash the beast' at will?
    2011 Chevrolet Tahoe 5.3L daily driver
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    • Total GM diesel miles to date : ~950K

  8. #28
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    You can command a lot of values with EFI Live that fall well outside the normal range of operation. That does not mean it will go there.
    Kennedy Diesel-owner
    More than just a salesman-I use and test the products that I sell on a daily basis!
    Superflow Lie Detector in house
    2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
    2005 Chev K3500SRW D/A CC Long LT(SOLD)
    2007 Chev K2500 Classic EC Short LT (Sold)
    2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
    2016 GMC K3500SRW D/A CC short LTZ

    Custom tuning in house using EFI Live tuning software!

  9. #29
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    Quote Originally Posted by Mark Rinker
    As for 'streetability' - can an otherwise daily driven truck be driven reliably on the street with dual IPs as described? Can you run ECM switchable tunes that allow the truck to start and drive out nearly stock, then 'unleash the beast' at will?

    Yes, the truck drives as normal. Carry a spare belt though as I doubt you'll find one on the shelf somewhere.

    You will not see any real benefit running stock turbocharger though. At least not enough to warrant the expense. The dual CP3 mod is more of a race mod and I'll caution those crossing 550-600RWHP mark that it's only a matter of time before things go boom unless you build the lower end...
    Kennedy Diesel-owner
    More than just a salesman-I use and test the products that I sell on a daily basis!
    Superflow Lie Detector in house
    2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
    2005 Chev K3500SRW D/A CC Long LT(SOLD)
    2007 Chev K2500 Classic EC Short LT (Sold)
    2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
    2016 GMC K3500SRW D/A CC short LTZ

    Custom tuning in house using EFI Live tuning software!

  10. #30

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    Somebody asked earlier about the larger pumps being run on the CTD - a new concept pump isn't actually being offered that I know of. 5.9L CTD owners just have the benefit of a big brother 8.3L, and there are a few places selling the 8.3L pump as a "hot rod" 5.9L pump IIRC. I don't know what if any mods are being made to that pump to make it work though.

  11. #31

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    As for Bobo's questions, I don't see them as being argumentative at all. They're all valid questions and if you're planning on spending the money to buy the product, why is it unreasonable to want to know everything you can about it? He's asking questions that only somebody that's spent that money already would know to ask, so he could be saving you a couple bucks of your own depending on how his questions are answered...

    Mark Rinker - they're very streetable. Low RPM driving quality shouldn't change as the pumps are constantly splitting whatever the commanded load is.

  12. #32
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    Quote Originally Posted by Kennedy


    Say 25,000 psi = 5v and you command right up to the sensor's limit of 25,000 psi like you mention. Enter the Duramaximizer and fool out say 10% of the voltage. The Duramaximizer reports 4.5v to the ECM and it tries with everything it can to make the 5v (25,000 psi) but no matter what it does, the Duramaximizer won't tell it any more than 22,500 so it keeps trying and is now running blind. This can be very dangerous especially with the added capacity of dual pumps.

    ...

    John,

    The Duramaximizer will indeed allow the pumps / pcm to achive its comanded pcm pressure all the way to the cp3's maximum output if so desired in a very accurate variable control. Therefore pumps in no way will run blind with the maximizer..
    Now on the otherhand you can indeed turn the pumps up to max output also if desired by maxing out the maximizer control knob,
    Hope this helps...


    Dan

  13. #33
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    Quote Originally Posted by Dan@PPE
    John,

    The Duramaximizer will indeed allow the pumps / pcm to achive its comanded pcm pressure all the way to the cp3's maximum output if so desired in a very accurate variable control. Therefore pumps in no way will run blind with the maximizer..
    Now on the otherhand you can indeed turn the pumps up to max output also if desired by maxing out the maximizer control knob,
    Hope this helps...


    Dan
    I don't doubt that it CAN perform as advertised. I've used it before. What I'm saying is that the scenario that you described earlier is unsafe as if you command psi that is at or close to the limit of the sensor's output leaves you nowhere to go safely...
    Kennedy Diesel-owner
    More than just a salesman-I use and test the products that I sell on a daily basis!
    Superflow Lie Detector in house
    2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
    2005 Chev K3500SRW D/A CC Long LT(SOLD)
    2007 Chev K2500 Classic EC Short LT (Sold)
    2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
    2016 GMC K3500SRW D/A CC short LTZ

    Custom tuning in house using EFI Live tuning software!

  14. #34
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    John,

    If you modify the actual fuel pressure to show 2000 less psi and you are commanding 26000 psi (approx sensor limit) the Maximizer will add to the top what ever you take off the bottom, because the fuel system is closed loop.

    For example commanded psi 26,000 Maximizer modifies actual 2000psi less it will now make 28,000 psi....

  15. #35
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    I should probably keep my mouth shut, but...

    I think what John K was saying is there is a point where the pressure sensor hits its upper limit. If the rail pressure exceeds that limit the feedback loop is broken. The controller will keep trying to raise the pressure, and it may go up, but the sensor will not reflect that. what happens next is anybody's guess...
    The Constitution needs to be re-read, not re-written!

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  16. #36
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    The fuel pressure sensor will read higher then the pcm will reflect on the tech2, when the sensor tops out then you will have no control over fuel pressures. At this point the Maximizer control knob has been turned up significantly per the user request.

  17. #37
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    Quote Originally Posted by JohnC
    I should probably keep my mouth shut, but...

    I think what John K was saying is there is a point where the pressure sensor hits its upper limit. If the rail pressure exceeds that limit the feedback loop is broken. The controller will keep trying to raise the pressure, and it may go up, but the sensor will not reflect that. what happens next is anybody's guess...

    Exactly...
    Kennedy Diesel-owner
    More than just a salesman-I use and test the products that I sell on a daily basis!
    Superflow Lie Detector in house
    2002 Chev K2500HD D/A CC Long LT 11.77@ 124mph at 7700# fuel only-e.t. needs help
    2005 Chev K3500SRW D/A CC Long LT(SOLD)
    2007 Chev K2500 Classic EC Short LT (Sold)
    2012 GMC K3500SRW D/A CC Long LTZ Happy Birthday to me! Built 1 working day after my birthday and delivered 7 days later.
    2016 GMC K3500SRW D/A CC short LTZ

    Custom tuning in house using EFI Live tuning software!

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