Higher in the powerband ,from 2700-3500 ,I don,t have the popping ,and reach 52 psi max in overdrive lock up.
Funny that some tell the Yanmar 440 can do an easy 480 -500 hp , I guess we,ll see what happens on the dyno,with an EGT gauge in the exh manifold ( pre turbo )
The endurance run was "sanctioned" by SBI.
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.
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.
Last edited by stirling; 03-22-2008 at 01:34 PM.
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