LB7 Quadrasteer Suburban

[DAVe3283]

Well, I'm officially a member of the Duramax Suburban club!

My brother and I put this together last Christmas, and I ended up buying it from him over Thanksgiving.

It is a 2003 Chevrolet Suburban K2500 LT Quadrasteer, fairly loaded. Heated seats, power adjust pedals, etc. It was an Oregon vehicle, so federal emissions! And that means, oh yes, a federal LB7 got dropped in! 0 emissions controls, 100% legal!

For now it has the truck transfer case (NVG 263 XHD), but I have the stock NVG 246 still. I plan to hybrid them together to get the stronger chain along with the auto mode. Basically I want to do [THREAD=71842]what chrisuns did[/THREAD], but I might end up paying my local transmission shop to do it (my brother is the mechanical whiz, I'm the electrical/computer guy).

Speaking of the transmission shop, I had a mild build done, since it will only ever run [THREAD=42711]NoLogic 3.0[/THREAD] (425 RWHP / 748 lb-ft). If I recall, it was GPZ clutches, the normal valve body mods, and a modified LML converter. They figured a single disc LML with a billet lid and some tweaks could hold the mild torque I'm making, and so far, so good! Dirt cheap converter this way. Oh, and how could I forget: they did the Suncoast 6-Speed conversion too!

The fuel system is a bit of an experiment. It has an AirDog II-4G DF-165 lift pump on the passenger side (all custom bent hard line by yours truly!), and since I was modifying the harness anyway, it is run from a relay in the stock fuse block with its own fuse. Wiring looks 100% factory. We decided we didn't need the return fuel cooler since it won't tow heavy. Watching fuel temps seems to back up that theory, even with the tanks almost empty, it never goes over 80°C on hills, and it usually stays closer to 50°C. That's not much different from my truck, which has the cooler.

Most people modify the fuel filler to prevent slosh between the tanks, and/or just run a line between the tanks so they drain into each other. I decided that was a hardware solution to a software problem, so we left the weird stock filler hose/diverter setup alone. I swapped a dual-tank segment in to the OS, and after playing with the tank level tables, got everything working perfectly! Even using the stock gasoline transfer pump in the rear tank.

Well, until last month, when it got a BUNCH of water (not sure from where?!) in the tanks, and it burned out the transfer pump. It even pushed water through the AirDog filters and started filling up the factory separator! Got all the water I could out (we pulled over a gallon of water ) and swapped to a single tank tune for a bit until I can drop the rear tank and put a new transfer pump in. Made me really glad I didn't bypass the stock filter, and really makes me question the AirDog water separator. I run a Baldwin on my truck, probably should put one on here too.

Anyway, it runs and drives like a dream! It turns ridiculously tight, it is almost unbelievable coming from my CCSB truck. Heck, it turns tighter than my Pontiac. I'm going to keep this one almost stock (still have my truck to play with), but there are a few more tweaks I will do over the next few years. I'll keep this thread updated with any developments.

 

[DuramaxRamRod]

We decided we didn't need the return fuel cooler since it won't tow heavy. Watching fuel temps seems to back up that theory, even with the tanks almost empty, it never goes over 80°C on hills, and it usually stays closer to 50°C. That's not much different from my truck, which has the cooler.

Did you mean °F? I thought the sweet spot was ~70°F for diesel.:dontknow:

 

[Awenta]

That’s awesome. Nice work!

Post up some more pics


Sent from my iPhone using Tapatalk

 

[Chevy1925]

Did you mean °F? I thought the sweet spot was ~70°F for diesel.:dontknow:

no hes reading in Celsius (dave is weird like that ). So thats 172*F at the highest and 122*F at the average. yes you want to be as close to that temp for the overall best working conditions but the stock defuel in teh computer doesnt start kicking in till 195-200* IIRC and dave is saying he doesnt see much difference with the cooler he is running so not worth it to add one.


That thing is rad Dave! any concerns with the rear d60 holding up to that torque?

 

[DAVe3283]

Did you mean °F? I thought the sweet spot was ~70°F for diesel.:dontknow:

This is reading the return fuel temperature, which is much hotter than the fuel feed. Yes, the fuel feed should be as close to ambient as possible. I am too lazy to measure the feed temperature, and the Duramax already has a return temperature sensor. I am just comparing the return temp between my truck (with a cooler) and the Burb (without a cooler), and it isn't that different. If I ever see any issues, I will add a cooler. But so far, it doesn't seem necessary.

no hes reading in Celsius (dave is weird like that ). So thats 172*F at the highest and 122*F at the average. yes you want to be as close to that temp for the overall best working conditions but the stock defuel in teh computer doesnt start kicking in till 195-200* IIRC and dave is saying he doesnt see much difference with the cooler he is running so not worth it to add one.


That thing is rad Dave! any concerns with the rear d60 holding up to that torque?

I was a bit worried about blowing up the rare quadrasteer version of the D60, so I actually copied the axle torque limits out of the gas 6.0L tune. It defuels a bit in first (you can see it in the logs more than feel it), but not enough that I can't fry the tires if I want! :woott: The big advantage of using the axle torque limit in the tune is when I use 4LO it will keep the axle in one piece, theoretically. Time will tell, I suppose, but I feel pretty good about it.

 

[DAVe3283]

More pictures, as requested!

Donor truck coming apart:


Suburban coming apart:


6.0L/4L80E/NV4246 being palletized:


Donor LB7 ready for an ATI damper (I have spun the damper off stock LB7s with this tune in low traction situations):


LB7, 6-Speed converted Allison, the NV263XHD, and the factory federal exhaust in place:


Modifying the Suburban fuel basket with the larger Duramax lid:


AirDog with hard lines in progress:


Dropping the body back down:

 

[oscyjack]

Sick

 

[DuramaxRamRod]

This is reading the return fuel temperature, which is much hotter than the fuel feed. Yes, the fuel feed should be as close to ambient as possible. I am too lazy to measure the feed temperature, and the Duramax already has a return temperature sensor. I am just comparing the return temp between my truck (with a cooler) and the Burb (without a cooler), and it isn't that different. If I ever see any issues, I will add a cooler. But so far, it doesn't seem necessary.

I see it now, I was just wondering 80°C seemed hot. Which tank does the return dump into, the main saddle tank?

 

[chrisuns]

Awesome job on the fuel lines! Cool project! I still want to add quadrasteer but they're hard to find for a decent price!

The 246 I have it still holding up! Ironically, I haven't touched it since I replaced the last encoder motor last year. I want to say, I have around 15-18K miles on it now.


****There's a TL: DR; below this, if you're not in the mood to read****
In regard to the encoder motors failing me in the beginning (IIRC 2?), I had an interesting issue pop up last month - My interior systems went haywire a few weeks ago, so I was like,"Hmm, that was odd, there's no common ground points and some of the systems don't use class 2 for that feature, it must be a positive wire." Well, come to find out, the wire supplying the 12v+ from the battery to the UBEC was completely corroded - I found out when I started my truck to move it less than 5 feet, so under 30 seconds of run time and that wire had to be every bit of 140F+ because I burned my hand touching it, while checking to see if it was loose or something. Well, I replaced that with 4 gauge wiring and immediately noticed my voltage gauge went up and even my lights at nighttime were much brighter than before (I never minded that gauge, since I always figured I didn't put the pointer back on in the right spot, after I added leds).
Well, come to find out, that wire was causing some pretty wicked voltages drops; and my truck has always done weird things like: not shifting into 4wd with my old 263, so I would have to push the button twice, and it did it with the 246 few times. Now, it all behaves as normal and I no longer say,"Oh, that's just typical GM electric gremlins, no worries!":roflmao:

TL: DR; Power wire supplying 12v+ to the UBEC corroded, caused all types of gremlins with the 4x4 system, likely dropped the voltage low enough to fry those encoders a few times too.

I may take it apart next year to check on it, but it's behaving perfectly behind a 500hp truck that weighs close to 8500lbs with me in it. I've had a few 10k loads behind it too. So I questions why take it out, lol... I'm more the reactive mechanic these days, heh!

My parts for intellibeam will be here Thursday too. I'm bored this week, so I figured I'm a bit overdue for that, so I'll make a write up of that too.

And if anyone has noticed, I am in a talkative mood today... :woott: This is unsual :rofl:

 

[DAVe3283]

I see it now, I was just wondering 80°C seemed hot. Which tank does the return dump into, the main saddle tank?

Yeah, the return dumps to the main tank. If the ECU sees the rear tank going up (from return fuel), it gets angry, so you have to return to the same tank you draw from. I don't think the temperatures I am seeing are a problem, the 80°C was a hot summer day, almost on E, pulling a hill. I've seen the same temps in my truck with a trailer, and never had any problems. It is a bit of an experiment, so we shall see!

Awesome job on the fuel lines! Cool project! I still want to add quadrasteer but they're hard to find for a decent price!
...
My parts for intellibeam will be here Thursday too. I'm bored this week, so I figured I'm a bit overdue for that, so I'll make a write up of that too.

And if anyone has noticed, I am in a talkative mood today... :woott: This is unsual :rofl:

Thanks! My brother and I pulled out all the stops on the wiring and plumbing for this thing. It is the nicest/cleanest GMT800 I've ever seen, and we decided to keep it that way.

And heck yes please do a writeup! I love seeing that kind of thing get added. On a somewhat related note, I ran across a couple Head-Up Display units from the 1998+ Pontiac Grand Prix, and I think I can send all the critical data to them. I am probably going to try and wire one into my truck next year, and if that works, the Suburban will get the other.

 

[gl4787]

Not to take away from the awesomeness of this build but an HD front end would really set that thing off.

 

[DAVe3283]

Not to take away from the awesomeness of this build but an HD front end would really set that thing off.

You know, I used to think the same thing, but I saw one in real life, and the angular 2003+ front end combined with the smoother body of the Suburban just didn't do it for me.

I have toyed with the idea of the 2001-2002 HD front end, as it is smoother / less angular, and should match the Suburban much better. But I was so put off by the 2003+ front end, I am a bit gun shy.

Maybe this is why I like my GMC so much; it is smoother/rounder than the Chevrolet :dontknow:

 

[Chevy1925]

Ive seen a duraburb with the 01-02 front end on it, they look mean!

 

[bigmackmiller]

I'm with you Dave, not a Cat Eye fan, especially on a burb, but the early LB7 I think would look sweet :thumb:

 

[NC-smokinlmm]

Throw a Denali clip on it... Bad ass truck! I had a quadrasteer back in 04, I loved that thing...

 

[SmokeShow]

Such a sweet build! I still want a Tahoe with duramax. Man that'd be soooo nice!

 

[Muff]

Very nice work. :thumb:

 

[JoshH]

Cool build!

I have a good friend who, between him, his father, and his brother, has built no less than 4 Duramax powered trucks and Suburbans with Quadrasteer. His daily driver has had a Quadrasteer rear axle under it for around 4 years with no issues so far. He has ran it lifted with 40" tires and lowered on 22x12s. The power has been there as well. It has always had a lift pump and as much fuel as it can get (on an LBZ), and he doesn't drive it easy. He broke a piston in it a little while back; now it has another stock motor with a set of old MPI twins while he builds a motor for it. I wouldn't be too worried about breaking that rear axle.

 

[Kriesel]

Nice work! I just finished my LBZ swapped Quadrasteer Burban last month.

I'm still working out some bugs, but have driven mine about 800 miles since the swap.

I did a build thread for mine here:

http://www.dieselplace.com/forum/63-gm-diesel-engines/374-frankenstein/938378-kriesel-diesel.html

What did you do for the body lift? Did you move the bumper mounts to line up with the body?

 

[DAVe3283]

What did you do for the body lift? Did you move the bumper mounts to line up with the body?

We put on 2" spacers throughout, but I want to do the tapered lift (2" at the front, 0" at the back) to level it out and get the clearance on the rear bumper correct again. We did move the front bumper mounts up to line up with the body, but that means the recovery hooks had to come out. I am still considering options there.