I just gave a deposit on the engine, so I guess I will spill the beans. It is a 2005 Cummins 8.9L ISL 400hp engine from a motorhome. WillWagner had the closest dart. Loved the slant 6 guess though, amongst others.
The 8.9L ISL is a stroked version of the 8.3L. It also consists of several modernizations over the older 8.3L, such as a 24 valve head, variable turbo, roller cam/lifters, high pressure common rail electronic injection (multiple pulses per combustion event), and the motorhome engines typically consist of an engine compression brake (Jake brake), which can be configured to use 1-6 cylinders during activation. The ISL is not as popular as the 8.3L or "C" series engines in the market, as the ISL was typically reserved for higher HP needs of larger and heavy vehicles such as RV's and fire trucks. It is rated for GVW up to 60,000lbs, and has the highest power/weight ratio of Cummins engines, but likely also a much shorter life due to the same reason. But considering how far we drive our hobby MV's, that is not a concern here. The engine has 77,000 miles on it.
It is electronic, and does have an ECM, wiring, all that, but Cummins runs their packages as self contained as possible. You really only need to feed the engine ECM power, ground, ignition command, and convert to an accelerator pedal sensor (drive by wire) vs conventional cable. I will need to devise a good way to still have this pull the transmission modulator cable as long as I retain the automatic trans. I need to see if it would require a different ECM to feed it 24V, and if so, then I would just run the engine as-is off of 12v. She runs about 33lbs of boost across the majority of the RPM sweep thanks to the VGT. Cold starting should be even easier with the intake air grid heater (there goes my ether system) and EFI.
We don't know how the transmission and transfer case will hold up, but I do run empty 99% of the time. If it takes out the trans, then that is the time to switch to a manual gearbox. If it takes out the transfer case, then we will look at maybe an M915 type of t-case or...? I considered grabbing the 6 speed Allison with it since it is rated for the power and likely the same size, but I really want a manual. Engine torque rating is 1200ft-lb @ 1400rpm. The latest ISL can be had as high as 450hp. The 2005 may be reflashable up to 425hp, I need to check by serial number, but the 450hp rating requires a different high pressure fuel pump and injectors, so I don't see that happening. Aftermarket companies can add 52hp to this engine by faking out the fuel rail pressure sensor, which then commands a higher fuel rail pressure than normal (more fuel delivery per spray). So, I could go as high as 450hp, but this module is $500, so we'll hold off for now.
Large benefit of using an ISL is the same external dimensions and pattern as the 8.3L. Absolute worst case is to run an earlier 24 valve ISL cylinder head which used mechanical injectors, and a P-7100 pump can be easily adapted. I will lose the ability to increase RPM over the factory 2100-2200 if I stay with the EFI, but 67mph on the truck is fast enough I guess, considering tire ratings and all that, unless I go 395's. I could crank it higher than 2200rpm if I use the mechanical P-7100 pump with an aftermarket governor spring kit.
I have been watching people turn up their 8.3L fuel, and then battle high EGT's. By going the ISL route, I am hoping to have a factory certified smoke free 400hp, without even needing an EGT gauge. I will need to add a front mounted charge air cooler, but no issue there, already purchased and was going to do anyway.
Below is a picture of an 8.9 ISL that has been converted to a conventional P-7100 mechanical pump. You can see beside the wider 24 valve cylinder head, this is the same as an 8.3L engine. My stock 8.3L engine will be available for sale after the conversion is complete, along with one of the two P-7100 injection pumps I have acquired. I wanted to go big bore engine like a 14L 550hp Series 60 (good guess, red), ISX, or the like, but it was hard to pass up one that bolts right in, especially if I need to move the radiator back 2.5" for the full size Volvo charge air cooler (thanks 4xdesign for your work and photos on this). Plus I like the lighter weight of the smaller engine, along with the modernization of the mechanicals.
I'll update this thread once the engine is acquired and able to run on a stand. Yes IGM, I have not replaced my broken back window yet. Priorities....
This 6 pot should be able to pull some strings, 400 of them we're hoping. Simp, come get some...