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Welcome To Mopar1973Man.Com LLC
We are privately owned, with access to a professional Diesel Mechanic, who can provide additional support for Dodge Ram Cummins Diesel vehicles. Many detailed information is FREE and available to read. However, in order to interact directly with our Diesel Mechanic, Michael, by phone, via zoom, or as the web-based option, Subscription Plans are offered that will enable these and other features. Go to the Subscription Page and Select a desired plan. At any time you wish to cancel the Subscription, click Subscription Page, select the 'Cancel' button, and it will be canceled. For your convenience, all subscriptions are on auto-renewal.
This thread will be about tuning a late CR with early CR pistons and BBi Stage 1's.
Truck: 2005 5.9L QCLB 3500 SRW NV5600 4x4 3.73's
Pertinent Mods: BBi Stage 1 for MY03, QSB480 pistons, Hamilton 178/208 cam, Garrett GT3782R, rest in sig.
Tuning: Smarty S-06 Revo UDC.
Truck Use: In the summer it tows the camper around for plenty of family trips (17-19k GCW), and in the fall/winter it's used for hunting (lots of slow speed driving) and playing in the snow. It's not my DD. It sees a LOT of dirt/gravel, towing and not towing, as well as pulling steep grades loaded and unloaded. The truck weighs about 8,500 loaded for winter.
My previous dyno/tune net me 415/850 corrected and that is where I plan to tune the new setup to, peak hp may go up but I am shooting for 300 rwhp at 2,000 rpms. It works well for how I use the truck and I rarely have to worry about EGT's when towing up 6%+ grades, unless it's 85 deg at 6,000 feet plus.
Thanks to the stock injector flow sheets that Brian provided I was able to compare the flow of the MY03 BBi Stage 1's to the OEM MY04.5 nozzles at 3 pressures from 0-2000us (3626, 14503, 23206). What I noticed right off the bat is the BBi's flow very similar to OEM nozzles at low pressure and pulse width. That's a GREAT thing because that means the idle, cruise, and low power tuning is smoother and more likely to be smoke free. I think I was able to find the point where the injectors start increasing their flow, and when they do they are very uniform in the added flow. This again really helps the duration map adjustment, especially since I am decreasing duration to keep the same amount of fuel being burned as previous.
So I am sure people are going to wonder why I spent the money on BBi's when I plan to cut the fuel to not increase power, well the ability to cut the fuel is a big reason. In addition to cutting fuel the BBi's have a great reputation on quality, and that's something I wanted. I needed to swap nozzles at a minimum and couldn't see spending money on OEM injectors with 93K miles on them, even thou they tested near perfect. It just made sense to give these a shot, both in the tuning and the longevity/efficiency departments.
Okay, back to cutting duration. I feel this is a GOOD thing, and provides many benefits. My research has shown me that peak pressure should occur 12 - 15 ATDC, but there is no way to measure it. By using less injector open time I can reduce the timing, which reduces negative torque (combustion prior to TDC, nearly impossible to not have and still make peak pressure at the desired point), and it reduces stress on the cylinder head bolts/studs/gasket. I should be able to get a short, hi flow injection that burns quicker and more efficient than a longer pulse for the same fuel. A shorter pulse width also means that the injector will be open less time ATDC, and hopefully create peak pressure at the desired point. While it still makes power having the injector open after 12-15 doesn't make the motor as efficient as it could.
The other thing I plan to do is drop peak rail pressure from 23,206 to 21,756. I personally don't feel that the 1450 less psi will effect atomization, and thus combustion efficiency, but it will reduce the parasitic drag on the CP3 putting more power to the flywheel. This lower peak pressure will also reduce wear in the CP3 and injectors. The main reason many tuners increase rail pressure is to inject more fuel in the same amount of time, which reduces the need for a lot of timing. Since I am already able to cut my duration by quite a bit the additional 50-75us required to get the desired fuel injected isn't a big deal since I will already be reducing my WOT pulse width by 500-600us.
I have peeked at the MY03 stock files, but their pilot is smaller so the timing (especially at idle) isn't going to be apple to apples with a MY04.5 ECM. Some of the timing difference MY03 vs MY0.45 are hardware, some are pilot, and most are emissions.
This is an example of the difference in timing and duration for my previous tune and the BBi's. Values are removed, and this was my initial tune and the values have changed, but not much.