Will's Bug Out Rig: Duramax Van

[ericjon262]

Are you still looking at the NP203/205 doubler setup?
That's basically what the Atlas 4 speed T-case copies, right?

Novak says the 6L90E is 1 3/8" longer than the 6L80E
https://www.novak-adapt.com/knowledge/t ... matic/6l80

Don't forget the Quadrasteer. I just re-read a little bit of your thread... I had forgotten that you said the tow rating went UP on the Quadrasteer trucks. Wild.

I think the atlas was developed as a lighter alternative to the doubler, the doubler being a 203 rangebox, mounted to a NP205 transfer case.

I haven't forgotten about quadrasteer, there are a few problems that are difficult to overcome from a swap perspective, the biggest one being that the control modules and sensors are no longer made, and some of them are integrated with the steering column, which could be cheesy to adapt, or a royal PITA.

Novak's site is awesome, so much info on there.

[The Dark Side of Will]

Speaking of bad paint...

[The Dark Side of Will]

Oh yeah... I knew it does not have the 10.5" 14bff because it does not have the bolt circle around the pinion yoke.
I thought it might have the 11.5" 14bff because it's a 1 ton vehicle, but it would also be quite "generous" of GM to install that axle in a van that's obviously built to be as cheap as can be while still achieving advertised capabilities.
I found out on the DieselPlace forums that GM used the Dana Super 70 for non-locker vehicles and the 10.5" 14bff for G80 locker vehicles. I already knew mine does not have G80. I snapped some pics of the diff cover and axle tag and did some googling... sure enough I have a Dana Super 70. Interdasting.

The 10.5" 14bff is certainly a nice axle, but there's nothing at all wrong with the Dana. I don't really want a G80 anyway, as I intend to install an ARB eventually. ARBs are available for any of the three axles mentioned. I don't need an 11.5" 14bff for towing, since the GCW is 17-18000.

I'm more interested in the fact that both shocks are on the front side of the axle. I've read about having one forward and one back to control axle wrap/wheel hop. The shocks are leaned "forward" (chassis attachment forward of the axle attachment) by about 45 degrees and connect to brackets that hang down from the axle, so any wrap-up of the axle housing also involves damper displacement. I guess that's enough. I haven't noticed any wrap yet, and I'm not gentle on the throttle. I do need to try doing a brake stand, though.

[The Dark Side of Will]

First tank through the van returned 16.7 mpg. This was burning winter fuel with a bunch of short trips and cold starts. I need to organize some highway trips for it.

[ericjon262]

that's fantastic mileage for a big van, whats the axle ratio? 3.73?

[The Dark Side of Will]

Pretty sure all the diesels had 3.73's, although I need to confirm it has that RPO.

[The Dark Side of Will]

I finally pulled the shelves out and gave them to a friend. The tank was actually waste oil. I gave that to a friend of my dad's who burns it to heat his shop. After spending a second actually looking at it, it's obvious the tank was never fuel. It has a fill neck at the back and 1/2 or 3/4 NPT drain valve with 2 feet of hose on it... obviously not a fuel hookup for the engine driven air compressor.





I'm going to pull the plywood and the filebox in between the front seats, then get a for-realz empty/starting weight, then install things. I have front and rear hitches ready to bolt up. I can probably order some E-Track pretty soon too.

The mat is punctured and torn in places and the plastic step covers just inside each door are smashed. I need to get prices from GM for replacing all those pieces.

[The Dark Side of Will]

I just pulled a 180,000 mile oil sample from my 2005 Mercedes W211 diesel. The van is coming up on 140,000; I have another sample bottle, so I'll grab an oil sample from the van when it rolls over 140k.

Does anyone here do oil analysis? What lab do you use? I've heard bad things about Blackstone.

[pmbrunelle]

I'm more interested in the fact that both shocks are on the front side of the axle. I've read about having one forward and one back to control axle wrap/wheel hop. The shocks are leaned "forward" (chassis attachment forward of the axle attachment) by about 45 degrees and connect to brackets that hang down from the axle, so any wrap-up of the axle housing also involves damper displacement. I guess that's enough. I haven't noticed any wrap yet, and I'm not gentle on the throttle. I do need to try doing a brake stand, though.

My daily-driver Ford Ranger (with rear leaf springs) has a similar setup from the factory; one shock ahead of the axle, one shock behind.

It still has some propensity towards wheelhop... I'd say mostly on an uneven snow/slush/pothole-ridden unpaved parking lot.

So I dunno how much of a slam dunk technique this opposing-sides shock mounting method is.

Of course, this 289 000 km child doesn't get the TLC that my Fiero does... probably if I went through the suspension I'd discover a bunch of worn out parts.

In most conditions I'm able to launch without wheelhop; it's a rare occurrence that it happens.

[ericjon262]

Sorry, I don't do analysis, I just change the stuff regularly. All I know, is a bunch of buddies back home in Pensacola sent oil to blackstone every oil change though, I think most of them had more money than brains.

[The Dark Side of Will]

Sorry, I don't do analysis, I just change the stuff regularly. All I know, is a bunch of buddies back home in Pensacola sent oil to blackstone every oil change though, I think most of them had more money than brains.

There's plusses and minuses either way. Having an oil analysis done on straight 3,000 mile oil changes is a waste of money and effort.

Using multiple oil analyses to track your engine's oil changes over time to establish a 20,000 mile oil change interval, and then analyzing the oil on subsequent changes at the 15-18,000 mark to make sure it hasn't deviated from that pattern can save money over a long service life, as well as indicate how soon the engine might need major service.

I guess if you build something so radical you change your valvesprings every time you change your oil, you'd want to watch the oil for indications that you're wiping a cam lobe... but if you want to drive something like that on the street, you're better off spending money up front on DLC.

[ericjon262]

Sorry, I don't do analysis, I just change the stuff regularly. All I know, is a bunch of buddies back home in Pensacola sent oil to blackstone every oil change though, I think most of them had more money than brains.

There's plusses and minuses either way. Having an oil analysis done on straight 3,000 mile oil changes is a waste of money and effort.

Using multiple oil analyses to track your engine's oil changes over time to establish a 20,000 mile oil change interval, and then analyzing the oil on subsequent changes at the 15-18,000 mark to make sure it hasn't deviated from that pattern can save money over a long service life, as well as indicate how soon the engine might need major service.

I guess if you build something so radical you change your valvesprings every time you change your oil, you'd want to watch the oil for indications that you're wiping a cam lobe... but if you want to drive something like that on the street, you're better off spending money up front on DLC.

IIRC, one things that my buddies found, was that GM's oil life estimates performed by the PCM were a bit conservative, but not way far off.

I'm sure you already understand that there is a bit more to oil life than straight mileage, operating temperatures, PCV system operation (or lack thereof), contaminates from external sources, idle time and/or non running time can also have an effect on oil life.

Can an oil filter last 20K? I'd think they would clog after that long, or have degraded performance. there doesn't appear to be an easy way to monitor filter d/p, without adding additional instruments, but if you're going to go that long between changes it may be worth looking into. I'm sure something could be made using a couple of transducers like these

https://lowdoller-motorsports.com/colle ... ure-sensor

and an open source board could be used to calculate the difference output a 0-5 v signal that could be displayed on a gauge, then you just establish a baseline with a new filter and clean oil. obviously d/p will be much higher cold, and get lower as the oil warms. there is also on most vehicles an oil filter bypass so that when d/p gets too high, flow is still maintained, I'm not sure when those trip though.

alternatively, I googles 5v differential pressure transducer and found a few options in the $870 range... lol.

[The Dark Side of Will]

The initial series of oil analyses would look at metal particulates in the oil and give you a filter change interval that would be shorter than the oil change interval. A trash magnet can also capture the ferrous particles, which are the hardest and most abrasive that oil picks up, so that the filter doesn't have to deal with them.

[The Dark Side of Will]

And another aspect of the whole train of thought is that oil analysis for a car is kind of gilding the lily.
Oil analysis makes sense for a fleet of big rigs that require 10 gallon oil changes and get driven 100,000 miles a year; or in power plants and large fixed machinery which can require hundreds of gallons and for which minimum down time is VERY important... In the business world of facilities and fleet management, it makes sense. In the world of cars, it's much more a matter of curiosity than money saving.

[The Dark Side of Will]

Koni has FSD shocks for the Express at $180/corner!

[The Dark Side of Will]

Van's sitting at 140,002 miles right now... It's been that way for a couple of days, but it's pouring rain here so I haven't been out to grab an oil sample.

[The Dark Side of Will]

Pulled my oil sample and drove down to my dad's and back over the weekend. It's holding the 17.5-18 mpg range depending on how much screwing around I do in between highway trips. It'll be fun to see what it does when I head up to north Jersey for Northstar engine stuffs.

[The Dark Side of Will]

I stuck my head under a GMT-800 CCSB 2500 pickup that a friend of my dad's has.

Here are pics of the torsion bar crossmember:





The 1500, 2500 & 3500 GMT-800 pickups all use the same torsion bar crossmember: 15769710
This crossmember is stamped from 0.160" steel
This crossmember is rubber mounted using the SAME bushings as the AWD 1500 Vans use
The truck torsion bars are 1 7/16" (36.5mm) to within the tolerance a set of calipers in the field can measure on dirty parts.

The AWD 1500 (and faux 2500) Vans have a specific crossmember. It is stamped from 0.168 steel. This difference in thickness is probably just a matter of natural production variation in the mill that ran the steel the crossmembers were stamped from.
Both crossmembers have basically identical windowing/speed holes in the middle

The van crossmember is PN 15750844
Front:



Rear:


The torsion bar crossmember is located behind the transmission crossmember, and the torsion bars pass over the transmission crossmember
That being the case, I'll have to re-locate/re-organize the diesel fuel filter/cooler/fuel priming pump assembly (collectively: diesel fuel pallet) from sitting on the the transmission crossmember to... anywhere else.

I knew I was going to have to move the diesel fuel pallet, but I was initially thinking that I could wait until "Phase 3" and would only need to move it for the T-case and front driveshaft.

I have a van torsion bar on the way to compare a 1500-only application to the 2500 truck torsion bars. Some parts breakdowns I've seen say that the same torsion bars were used across all the trucks, from 1500-3500. The mechanism certainly allows for ride height adjustment, but it seems weird that GM would use the same rate on all three load classes of trucks.

[The Dark Side of Will]

The van torsion bar has a diameter of 1.350, which makes it ~27% softer than the truck torsion bar... so truck torsion bars it is!

[pmbrunelle]

Why the stiffer choice?

What is the mission profile of this van? Wanna land jumps without bottoming out the suspension?