NP203-splitcase - need the warm and fuzzies (1 Viewer)

[kcustom73]

I'm finalizing the drivetrain selection for my 40 build and I need to get warm and fuzzies about my choices.

Initially I was going to put a GM 6.2 NA diesel in front of a 700R4 with my 203 splitcase combo. The 6.2 in its best form would only give me 160hp and maybe 300ft/lbs

Because I'll be towing my 2300lbs (dry) travel trailer with my stretched 40 I've decided to go to a warmed up GM 6.5 turbo diesel in front of a 4L80e transmission. The new engine will be producing roughly 250hp and somewhere between 450 and 500 ft/lbs

I know that the NP203 will be able to handle the torque from the engine but will the splitcase??? Just need someone who has put this kind of torque through the splitcase to tell everything is going to be good.

Thanks

 

[boots4]

What is your diff gear ratio and tire size? Depending on the combo you'll see more or less stress throughout the drivetrain.

That said I'm running a cummins 4bt putting out about 400ft lbs of torque into a 4L80 mated to a 203 GRB attached to my splitcase. I have 37's with 4.10 diff gearing and have not had any issues with my splitcase. I wheel, DD, and tow with my set up. Having an auto helps absorb some of the shock loading that occurs in the drivetrain when stepping into it pulling a load or when wheeling an obstacle. You're going to love having a auto with a doubler.

 

[kcustom73]

Boots4, the axles are going to be 3.7 with 33's. I know the 33's will add less stress then your 37s on the drivetrain. The main reason I went with the doubler is because I've gone to the 3.7 and 1st gear on the 4l80 is only 2.48 so I wanted to get so low end back. The bonus of the setup is I'm making most of my torque between 1800-1900rpms.

 

[Mace]

You will be fine

Axles will break before the tcase does

 

[uglyoinker]

Can you give some more info on the 6.5? What do you have done for the warming up? What year 6.5? Mech or electronic injection pump? Do you have a build thread?

 

[kcustom73]

Here are some of the specs on the engine. With these mods I should be able to get the numbers below without intercooler. I might still put a water/methanol cooler if I want more power or things get hot when I tow.

BASE ENGINE
Remanufactured Rear Turbo Long-block

INTERNAL UPGRADES
Balanced Rotating Assembly
Coated Piston Crowns
ARP Cylinder Head Studs

EXTERNAL UPGRADES
Complete Rear/centermount Turbo Kit (w/ Reman Turbo)
Adjustable Boost Controller
Ceramic Coat Exhaust Manifolds and Turbo Housing
6.5L Turbo Injectors
6.5L Turbo Arctic Injector Pump (Reman)
Fluidampr
Complete Serpentine Kit (early style with pass. Side a.c compressor)

I should add this info to my build thread, but I'll until have some pics to show with it.

 

[handcannon]

All the specs listed are good for reliability, longevity, and a good base for mods but don't seem to be what would add much HP and torque. Will you be doing anything to change the compression ratio? Also, what turbo/boost are you planning to use, as that can make a big difference in your HP and torque.

I'm not sure about the arctic IP. Is it mechanical or electronic? Is it the one with internal friction reducing mods to run on ULSD fuels and thin fuels like jet fuel?

Sounds like you've put some thought into your gearing as what you've chosen should work good with the 6.5 for RPMs, HP and torque curve.

Don

 

[kcustom73]

Don, good to hear from you again on the diesel subject. I'm actually getting more info on the pump but it was recommend to by Jamie at the Diesel Depot. There the ones building my motor for me.

The mods are to make sure the motor will stay nice and strong as we up the boost and fuel. We'll start at 8lbs and see how it goes. I just want to be able to tow my 3000lbs (wet) travel trailer. For off-road and just cruising along with the 40 the drivetrain should be good.

We might add water/methanol setup for towing in the summer if I need a little extra cooling. I'm just hoping I can get enough radiator for the engine.

 

[handcannon]

I'm not an expert on the 6.5, but I can tell you what my experiences are though.

I have a 5500 lb travel trailer (fully loaded) that I tow with my 94 K2500 6.5TD (6500 lbs loaded). So my combo is about double what you will be dealing with. The only time I have concern is going over one of the local passes, usually Santiam Pass. Santiam is just over 4800 ft in elevation. Most of the pass is easy, no stiff climbs, no problems. There is about a five mile section on either side of the summit that takes any real care. I don't know what the grade is, but the worst is on the east side when going west. From Suttle Lake to the summit is about five miles and about a 1500 ft climb in elevation. As long as I don't get hung up by any slow vehicles, trucks or RVers, I can pull that at about 40-45 MPH at the slowest. What I generally do is drop out of OD and keep the RPMs up to keep the coolant temps down.

Cooling is a major concern for the 6.5 TD. I have a brass/copper radiator, not the stock aluminum that it came with new. Heath Diesel claims the 6.5 will do better with an aluminum rad. I don't have any experience with one as I had to find a replacement to get the pickup on the road and the older brass/copper was what I found used that I could afford.

To aid cooling I went with the 2000 year model balanced flow water pump (supposed to be the best available) the HD low temp fan clutch from Heath, and a DMax fan blade. My pickup was a rebuilder (the PO slid on ice and kissed a tree, he helped me get it from his insurance) so the coolant crossover was broken. I found a later model dual stat crossover, but according to Bill Heath the single stat coolant crossover is actually slightly better as the single stat has a bypass restrictor built into it.

If you have a dual stat crossover, put a restrictor in the bypass between the water pump and the thermostat housing. This will make the majority of the coolant of a warm motor go through the stats and into the rad instead of letting a lot go back through the pump and not go through the rad.

I have the 4L80E tranny, 4.11 gears, and 265/75/16 tires so this should make up for the heavier trailer that I tow. Just use common sense, watch the temps and EGTs and you'll be fine as long as you have enough radiator.

I'll be curious as to what you find for a radiator. I'm collecting parts to do similar to what you are doing. What I'm doing is 6.2 NA (maybe turbo in the future), ranger OD, Toyota H42 four speed, 203 doubler, one piece transfer case, and 33" tires. This makes for a long driveline (as yours will be also), but according to my calculations it will fit.

Don

PS: I would rather have a splitcase, but that is out of the question for now.