Dual CP-3

So much to learn, so little time... I've been aware of the concept for using a second high-pressure common-rail injection pump (i.e. CP-3) to boost fuel supply pressure, but I don't know a lot about how it works, and if it boosts (or supplies) both low & high fuel pressure to the system's original Bosch CP-3.

PPE offers a Dual CP-3 system that mounts in place where a second alternator would mount, and is belt driven.

I'm hoping PPE will chime in and explain how it works, what components are used, what sort of performance benefits are there beyond what an auxiliary electric lift pump might provide, and what sort of cost range we're talking about.

Ken Florey was using one on his 2002 GMC last summer during the Pull-Off, which was my first look at a dual CP-3 setup....

Thanks,

Jim

I've also seen a few of these dual CP-3 setups last summer. Mike Tomac's and Tony Burkhard's trucks have the PPE setup installed I believe.

They are making big power with their trucks at the local truck pulls.

Adding the second CP3 basicly doubles the volume of high pressure fuel. It helps maintain rail PSI with big injectors or a long duration tune. It works in parralell with the stock CP3 so it's only capable of supplying the same max pressure as the stock unit. I've been told that the LBZ CP3 can make more PSI, but how much more I don't know. The kits seem simple enough from a hard parts stance, but the controller part seems a bit more complex.

The dual CP3 pumps operate as mentioned in the previous post

What fuel rails are used with the dual pump setup? Do both pumps supply both rails, or are each bank of cylinders fed by one pump?

Along with Marks question, Do you run dual pickups at the tank, or still a single all the way to the additional pump. Just how much is necessary to not starve the single pump. Isn't that really the key? If that single pump can't supply enough volume with a lift pump for assist, you must be turning the world black when you run.

Ken was using an ATS Twin Cp3 kit, not PPE.

Quote:

---

Originally Posted by Dan@PPE

The LBZ pumps can make up to 29000+ psi, and should be run together….

The LB7 and LLY pumps can make up to 26000+ psi…. now remember with 2 pumps you will have double the available volume at these pressures if so desired….


Hope this answers some questions....

---

It does bring up a few questions. Why do you think the LB7 and LLY pumps can't make the same psi as the LBZ? Can you post a pic of your gauge on the truck you use to monitor the 29000+psi pumps you are using on your LB7(the stock rail sensor does not read that high)? I seem to be able to get over 26000psi with my LLY pumps on the ATS setup I run with F1 Diesel ovesized injectors. Maybe mine is a freak!:D

Quote:

---

Originally Posted by Mark Rinker

What fuel rails are used with the dual pump setup? Do both pumps supply both rails, or are each bank of cylinders fed by one pump?

---

Booth rails are fed, The factory crossover H/P lines get the pressure the same between the two rails.

Quote:

---

Originally Posted by SoTxPollock

Along with Marks question, Do you run dual pickups at the tank, or still a single all the way to the additional pump. Just how much is necessary to not starve the single pump. Isn't that really the key? If that single pump can't supply enough volume with a lift pump for assist, you must be turning the world black when you run.

---

With our setup we use the stock pickup and fuel feed from the tank. A lift pump is recommended but not necessary. You could always dual feed the Daul Fuelers and really have some Fuel volume....:D

[QUOTE=Dan@PPE]The dual CP3 pumps operate as mentioned in the previous post

Quote:

---

Originally Posted by Bobo

It does bring up a few questions. Why do you think the LB7 and LLY pumps can't make the same psi as the LBZ? Can you post a pic of your gauge on the truck you use to monitor the 29000+psi pumps you are using on your LB7(the stock rail sensor does not read that high)? I seem to be able to get over 26000psi with my LLY pumps on the ATS setup I run with F1 Diesel ovesized injectors. Maybe mine is a freak!:D

---

I believe our post did state.....
26000+, which means over 26000 psi....... So don't think yours is a freak.....

We do offer consumers other means of going higher psi on an LLY/LB7 or LBZ (duramaximizer), since factory tuning tables are a limiting factor in your application

We may have these gauges and special high psi senders available for purchase in a couple months.....

Quote:

---

Originally Posted by dieseldummy

Doesn't the ATS kit spin the second CP3 something to the tune of 10% faster? I'd think that would be a big no-no... I see a company or two have some beefed up singles for the Cummins to play with, why not for the Dmax?

---

I have not personaly worked with ATS kit, That would be question better answered by ATS...

There have been a lot of attempts at modifying the single CP3 and/or force feeding them. I haven't yet seen any that do a really good job. I've seen some gains, but the force feeding tends to take the "regulation" out of it.

Twin CP3's should be just that twin and run at the same speed. The CP3 doesn't like to spin much over 3500 rpm so spinning it 10% faster isn't really a good idea.

Lift pump(s) and pickup mods are even more important on a twin CP3 setup. 12-15"hg or more is common in a stock supply line. Add a second pump and it will only get worse...

Quote:

---

Originally Posted by Dan@PPE

I believe our post did state.....
26000+, which means over 26000 psi....... So don't think yours is a freak.....

We do offer consumers other means of going higher psi on an LLY/LB7 or LBZ (duramaximizer), since factory tuning tables are a limiting factor in your application

We may have these gauges and special high psi senders available for purchase in a couple months.....

---

We can command over 36000 psi with EFI Live. Have you tested the LB7 and LLY pumps vs. the LBZ pumps on the same truck with the same tuning? Did the LBZ pump hold higher rail psi? Have you used a LB7 or LLY pump on an LBZ to see if the pump will keep up? Do you have a pic of your gauge that reads 29000psi plus?

How high does the PCM show on a scan tool? Where does it max out? Or....is the programming (EFI, etc.) lying to the PCM in regards to the pressure?

Quote:

---

Originally Posted by Bobo

We can command over 36000 psi with EFI Live. Have you tested the LB7 and LLY pumps vs. the LBZ pumps on the same truck with the same tuning? Did the LBZ pump hold higher rail psi? Have you used a LB7 or LLY pump on an LBZ to see if the pump will keep up? Do you have a pic of your gauge that reads 29000psi plus?

---

You can command all you want with the tuning, it doesn't mean it will go there.

Quote:

---

Originally Posted by Kennedy

You can command all you want with the tuning, it doesn't mean it will go there.

---

It doesn't mean it won't go there either! :D

Um....huh?

BoBo, if you are seriously going to challenge EVERYTHING that anyone states here...well...eventually (soon) nobody will listen.

Just a thought.

Quote:

---

Originally Posted by Mark Rinker

Um....huh?

BoBo, if you are seriously going to challenge EVERYTHING that anyone states here...well...eventually (soon) nobody will listen.

Just a thought.

---

Get a gauge....then maybe you will listen...or you can just take everyones word and hope they are testing the things you need them to be testing. Good luck. Just because I don't post on here every day, don't mean I'm not involved with Duramax motorsports every day. I love the performance of these trucks.....but I'm very cautious as a consumer. I like to test products on my own dime and it has cost me a lot of money. Some are good, some are bad. Twin CP3 pumps have been great for the performance market. To be sure that upgrading two very expensive CP3 pumps from LB7/LLY to LBZ pumps is worth the money, I think we should do our own testing to see the benefits. When a stock data log can't pick much info over 26Kpsi on the LB7/LLY, I think it is a very good idea for the consumer to look into the claims of those that are selling products and making a profit to make sure that these claims are tested and proven to show some sort of gain for the money spent. PPE is claiming that the LB7/LLY pumps are good for 26K+psi and the LBZ pump is good for 29K+psi(you can't see much over 26Kpsi with the stock psi gauge for the LB7/LLY. You can command well over 26K psi on the LB7/LLY. Since you can't "see the difference" how will you know there is one? If the LBZ pumps run 29Kpsi and the LB7/LLY pumps only put out 27Kpsi on the same tune, there is no way to see the data with the stock configuration. Someone has to have an aftermarket fuel rail psi gauge that reads 40Kpsi to see the difference) To me it seems like the LBZ pump is capable of producing more psi. More psi generally produces more power. If you choose to spend your money without doing the research to back up your purchase, then that is your decision. I choose to look into how I spend my money. I'm running an ATS Twin CP3 kit on my truck with an old ATS twin feed CP3. That twin feed CP3 was sold for a very high price with a claim that it increased power. That was not the case and I got that CP3 for next to nothing since it did not work as advertised. Although ATS is a very reliable company on the cutting edge when it comes to performance break thoughts, the twin feed CP3 did not pan out how they thought it would. With that said, the LBZ CP3 is superior in design to the older units. The internal upgrades should benefit the flow characteristics of the pump. Will those internal upgrades show their benefit with stock regulators and electronics attached to the LBZ pump? If the LLY or LB7 regulator/electronics create any sort of disadvantage to the LBZ pump, the upgrade to the LBZ pump will be determined a waste of money until the better design of the pump can be utilized(kinda like the twin feed pump was kicked to the curb). Believe me, if I thought I could believe every claim I hear, I'd spend the cash. Since I've seen less than stellar results from claims that I've bought into, I'm proud to be a skeptic. If that makes me not believable, then so be it.

Two questions:

1) How high can the psi sensor read?

2) What happens when you exceed this limit?

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.:D

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.:D

---

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 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

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...

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.

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?

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.

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...

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.

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.

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

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...

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....

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 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.

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...