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Old 03-22-2008, 11:27 AM
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Originally Posted by mthill View Post
As stated by 29Firefox, The CP3 is capable of well over your 550 hp number. Period. You have some other limitation that is preventing it from working as well as it could/should.

What is your fuel supply pressure (to the CP3). To get into the 700s, you may need 70-80psi. You need enough pressure to keep it full of fuel. Running it at these levels will degrade the life of the pump. But, you can buy several pumps to replace a single stock unit for the price of the dual kit (~$3000 USD). Redundancy of course has some value, so it's not for nothing.

The 735hp QSB that Banks did was back in '02. It was done on a single CP3. I don't think dual pump kits weren't even being considered back then. Another version of this engine was built for boats. "At the request of the United States Navy, Banks' Cummins turbodiesel engine developed for Sidewinder Dakota is redesigned and "marinized" for use by Navy SEALs for military application" from http://bankspower.com/timeline.cfm. A 700hp marine QSB is possible, but to make it live, a substantial number of changes should be made.

The intake manifold isn't necessarily a limiting factor, but the intake and exhaust ports are. Substantial gains can be had with some mill work, a bit more with a lot of work. Intake port flow at 28"H2O can be readily increased 25% or more. This is very beneficial to overall performance and efficiency.

The "Brazil" head 29Firefox mentioned still has room for improvement. More importantly, it's cast from a better alloy. He can certainly give you a lot more detail than I can. For 700hp, the stock head, ported, will get you there for awhile. I agree with Firefox that studs aren't necessarily the right solution. Bottom tapping for additional thread engagement is probably of little use, but it can't hurt.

52 psi of boost is more than enough to make 700hp if you can get the mass flow up by improving flow t the cylinder and out of the exhaust. Any restrictions result in an lower mass flow for a given boost pressure. Fix the restrictions instead of trying to force the air in with more pressure. This isn't rocket science, it's an air pump.

Think of it like this: sitting on your couch, watching TV, you could probably breath comfortably through a drinking straw. No go out for a run, trying to breath through the same straw and see how far you get. Replace the straw with one the size of a garden hose and things get better. Adding a turbo (or a bigger one) to the engine doesn't change the fact that the QSB intake port is a straw.
A stock dodge cp3 will have its limits at around 550 hp ,a modded cp3 as you probably mean can produce more power ,look at industrial injection page.
Industrial injection has different stages of modding cp3,s ,I was looking at the sidewinder banks project ,they said the cp3 unit is capabel of 800 hp ,don,t believe everything you read,there is no way a stock cp3 can deliver that much fuel,if it was like that ,company,s like industrial injection,and other company,s would never sell any modded cp3 pumps .
the dual fuelers are 2 bosch cp2 pumps with the same output ,combined they deliver fuel up to 1200 hp ,according the manufacturers,I would say 2 x 600 hp =1200 ,if one stock pump was rated for 800 hp ,it would have said 1600 hp,I guess I,m 50 hp off .

Last edited by stirling; 03-22-2008 at 03:37 PM.
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Old 03-22-2008, 06:06 PM
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Hmmmmm

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Originally Posted by stirling View Post
At maximum torque the engine has the longest injector duration pulse width (max duty cycle) and when the engine is not turning that fast the cp3 pump isn,t pumping at its max speed too,thats why the draining starts lower in the powerband.
the injector duty cycle is where the injector gives the most fuel in comparing with engine speed /revs..watch the injector time /duty cycle time in a 2 d field at max torque.
Understand what your saying, done spent hours reading data snap shots on the screen but old boy's symptoms just don't figure. Pressure drop in the fuel rail happens for various reasons. Leaks, defective FCA, loose electrical connections, bad fuel map in the in the program template, bad sensors, bad Cp3 pump and the list continues to grow. But never has a healthy Cp3 pump failed to deliver across the power/rpm band till you get up somewhere between 750 to 800 hp. The loss of pressure right at peak fuel flow is probably not from peak usage. There is some underlying problem that peak usage exacerbates. Thats if he is having that problem at all. He has never had an INSITE tech plug in and get up into whats going on. He has a pick up truck after market turbo set up, after market ECM programing and numerous other tweaks. I've seen common rail engines with fuel pressure problems. Once pressure loss manifests itself the engine hits a plateau and doesn't go any higher. Also the "popping" he describes seems more air related than fuel. Besides the fuel being at peak out put when your hitting the torque range the turbo is hitting its max rpm. As manifold pressure builds the turbo is going to lose a little rpm. But in that transition area where the turbo spools up the pressure hasn't built yet in the intake manifold. The tips of the turbo blades can get up to supersonic speed. The popping is the same thing as a jet airplane breaking through the sound barrier. At that moment you lose boost till the turbo slows down. Some cases it's real violent and can even shut the engine down some cases the engine is right at the tipping point going back and forth and the engine picks up anyway. As the boost builds in the manifold the back pressure holds the turbine just below supersonic. I might be wrong because all i have is the info given me over the internet not up close and personal diagnosis.

Last edited by 29Firefox; 03-22-2008 at 06:11 PM.
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Old 03-22-2008, 08:41 PM
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Fuel Pump:
Modified or not, it's not worth arguing. The point is that you don't need two pumps for 700hp. You can get there with one.

Fuel System:
Without data, it's only speculation. Do you know for a fact you're losing rail pressure, by reading the rail pressure data from the ECU? If so, have you checked the supply pressure and/or tried increasing it? It's an easy test if you have an adjustable regulator.

Turbo:
It's possible that the compressor wheel tips are going supersonic, but if that's true he'll know for sure pretty quickly, because they'll not be attached to the wheel anymore. This is typically the limiting speed of a turbo, and other precautions should be taken from getting to that point. A compressor can reach this speed at many different operating point. If this were truly the source of the noise, one fix could be a different turbine wheel or turbine housing to reduce the drive energy. Or, go to a different compressor with a more appropriate map (it sounds like he wants a higher pressure ratio and mass flow capability).
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Old 03-23-2008, 04:05 AM
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Industrial injection is making several single pumps that are modded ,and support big horsepower,the dual fueler was my firs option,because the 3000$ price is cheaper than a single 230% more cp3 unit that they sell.
+ that if one fails ,there,s still rail press.

I have a rail press gauge ,and a egt gauge ,I can raise rail press ,timing ,duration ,and monitor whats going on ,and what happens during loading the engine.I can even log data for an half hour .

the blade tips are not overspeeding ,because I can hear the turbo,s inside the cap spinning (very loud) and its easy to hear if I press this unit to more pulsewidth,the engine is holding back during acceleration,especially in overdrive lock up where the load is at its highest point,and the turbo,s are not at max rpm yet.(the unit throw more diesel to spin the turbo faster) at least that is what I.m thinking,but I could be wrong.

Maybe I use the wrong word (popping ) it sounds like the engine is loosing power ,then start making power ,then power loss,power build up,power loss, all happens in a few seconds,so the intermitting is very fast, so on and on until the engine accelerates trough this rpm range up to higher into the powerband ,where its gone ,when this occurs the truck starts shaking a bit .

I know off a lot other guys with these engines that said they have had the same issues like me ,until they modded the cp3 ,or upgrading to a bigger or duals.
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Old 03-23-2008, 08:07 PM
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More of my 2 cents

Quote:
Originally Posted by mthill View Post
Fuel Pump:
Modified or not, it's not worth arguing. The point is that you don't need two pumps for 700hp. You can get there with one.

Fuel System:
Without data, it's only speculation. Do you know for a fact you're losing rail pressure, by reading the rail pressure data from the ECU? If so, have you checked the supply pressure and/or tried increasing it? It's an easy test if you have an adjustable regulator.

Turbo:
It's possible that the compressor wheel tips are going supersonic, but if that's true he'll know for sure pretty quickly, because they'll not be attached to the wheel anymore. This is typically the limiting speed of a turbo, and other precautions should be taken from getting to that point. A compressor can reach this speed at many different operating point. If this were truly the source of the noise, one fix could be a different turbine wheel or turbine housing to reduce the drive energy. Or, go to a different compressor with a more appropriate map (it sounds like he wants a higher pressure ratio and mass flow capability).
Pump: Yup I'm with ya can get past 750 hp with a stock one.

Fuel system: He just hasn't given up enough actual info.

Turbo: On going supersonic I've seen some go BOOYAH once and suck all the turbine blades through the motor.You can guess what kind of mayhem followed I've seen some start popping and no damage at all. Also seen lots of things in between like real slight erosion of the trailing corner of the blades.
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Old 04-14-2017, 03:47 PM
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Old thread, good read.... ? If you had a choose, which would you buy, 440 HP Yanmar or the 480 HP Yanmar? Both have the same amount of run time on them, ~150 hours.
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