Duraburb Project

klmore

Adventurer
I have only put two and a half tanks of GAS in it since I got it back from Eric, which is really nice.

How's that working out? lol

Well at least I did pump the correct fuel. Amazingly enough I have never been tempted to put gas in it out of habit.:)
 

klmore

Adventurer
What kind of mileage are you getting now by the way?

I'm getting around 13.8 to 14.5.depending on the tuner selection. I have been running on the 5 position the past few days, but the second tune seems to be the best on fuel economy. This is mixed city and highway.
 

klmore

Adventurer
Long haul trip

This past week I put the Duraburb to the test. I towed a car hauler with my Yukon on it, while towing a wave runner behind that. The entire rig towed very well as a unit. I don't plan on towing the double trailer set up again, but I was surprised at how stable it was.

The most interesting part was the fuel economy. I averaged 11.9 MPG at around 70 MPH. I filled up outside of Shreveport, LA and drove straight to Pensacola, FL using half a tank of fuel. Tomorrow I am heading to Orlando to pick up my supercharged 6.0 that was in my truck before. Eric was nice enough to store it until I could come pick it up. I will post some new MPG's in the next day or two.

This will also give me the opportunity to check out Eric's shop and give my opinions on that.
 

FellowTraveler

Explorer
Your fuel milage

Nice job on conversion!

I suspect something wrong w/your mpg's have you corrected the VSSB for tire size, or?

I have crunched the numbers many times for my burb w/NAVISTAR 6.5 turbo diesel and get constant 22 mpg @ 60 mph when seriously loaded or towing (less than 5k lbs) take maybe 4 mpg's away from that figure.

Can lift and the tire selection have such a negative effect on mpg's?
 
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Wilbah

Adventurer
This has been a fascinating thread as I have been thinking about a project like this (wife, 3 kids and a dog! LOL) but it is technically beyond my expertise. Thank you so much for posting it and providing so much information about what you went through. What a great truck!

As to the mileage/break-even discussion here is how I see it- if a gas version gets 8 mpg and the diesel gets 14 (in your experience) and diesel costs $0.50 more per gallon it would require you to drive 98,823 miles to breakeven with a $15,000 conversion cost. If the difference between the fuels is $0.75 per gallon it would require 112,000 miles to breakeven. If you WERE able to get 20 mpg (which given the gears and tires seems unlikely) your breakeven would be 63,000 miles. So it COULD be done for cost reasons depending on how long you keep the vehicle and how often you drive it. If you tow heavy loads a lot then that would decrease your breakeven point even more given the greater impact on gas powered vehicles vs. the (minimal) impact to a diesel. In theory this would make a lot of sense for a daily driver/brand new vehicle if someone had the coin (assuming it was still only a $15,000 upfit cost). Just my $0.02.
 

klmore

Adventurer
Nice job on conversion!

I suspect something wrong w/your mpg's have you corrected the VSSB for tire size, or?

I have crunched the numbers many times for my burb w/NAVISTAR 6.5 turbo diesel and get constant 22 mpg @ 60 mph when seriously loaded or towing (less than 5k lbs) take maybe 4 mpg's away from that figure.

Can lift and the tire selection have such a negative effect on mpg's?

I am sure the lift and 37" tires have a huge negative effect on fuel economy. Not to mention the drag from the ARB front bumper. I really wish at this point I had not lifted my Sub so much.
 

klmore

Adventurer
Orlando Trip

I drove my Sub to the Duraburb shop with a empty car hauler and managed 14.3 MPG at 80+ MPH.

Eric was very nice and loaded up my 6.0 with out any issues. The shop is smaller than I expected, but you can tell they have the conversions down to an art. There were two newer model Subs in the shop about half way done. I may step up to a 2011 Suburban in the future with much less lift.

After leaving Orlando my fuel sender started acting up. It would go to empty and then it would read correctly for a while and then back to empty. I stopped over in Pensacola for the night and topped off the tank with 40 gallons of fuel. I drove home the next day without issue. On the way in I stopped by the office to check my workload and I left the truck running out front. I jump back in the Sub to head home and three miles later the truck just shuts down. Normally not a big deal, but it was raining like hell and I was towing a trailer. The up side of a small town is my friend passed me two minutes later and stopped to help. I'm home 20 minutes later very wet, with my trailer and no Suburban.

After I had a talk with the service manager at my local dealer he agreed to work on the truck and talk with Eric if needed. Eric was very helpful and talked with the tech directly to help find the issue. I was very impressed with the service manager who had a above average knowledge of the Duramax. Come to find out he is building a drag car with diesel power.

After trouble shooting at the local Chevy dealer it is determined that the fuel sender in my rear tank went out. When the sender cuts out it turns off the transfer tank pump. So I basically sucked the front tank dry and the rear tank was full. My fuel gauge was reading a half a tank at the time, but all of the fuel was in the rear. It is an aftermarket Auto Meter sender.

I have the sender on order from Summit Racing and it should be here on Monday. I will give an update later in the week.
 

klmore

Adventurer
The new fuel sender fixed the issue and I am back on the road. The GM dealer had no issues repairing the Sub and all I had to do is supply the $39.00 autometer fuel sender.

I have had some time to upgrade my trailer with the truck down. I will try to post some pictures this week of my truck and trailer together.

One thing we did notice today that is not so good. I had to make a sudden stop while towing after a Hyundai had a blow out in front of me and decided to stop in the middle of the road. As a result my rear bumper was no longer level. I assumed the bumper brackets were bent, but actually my rear frame rails were bent down slightly. I now know the limit of my Suburban towing. This is a common problem on all 1/2 ton Yukons, Tahoes, and Suburbans. If they get hit from the rear hard both frame rails bend down. I have seem it on some 2500's, but not many. I think the TowPro series of the Duraburb has about 12k -14K towing limit.

I will have the frame rails realigned and then refab the rear bumper mounts. I think the bumper mounts need to be longer to distribute the load on the frame. I may box the rear 24" of the frame for extra insurance.
 

BCHauler

Adventurer
You have a very interesting thread going here. Thanks for sharing.

With respect to your bent rear frame rails, I'm not sure that boxing the rear portion of the frame would solve the problem. My uneducated, small brain wonders if doing so would only transfer the torsion farther forward on the frame. I would be tempted to have a custom hitch made that has. Significantly longer frame mounting surface. I would think that would help to spread the load on the frame rather than transferring it to a different point.

All of that being said, I'm certainly not an engineer. Good luck with it and please keep us updated.
 

FellowTraveler

Explorer
Assume you were towing trailer when the damage happened. Having not seen your trailer attached to your Duraburb I suspect your bent chassis rails are more likely than not from a drop down draw bar acting like a lever when it moved forward increasing downward leverage instead of in a forward linear motion when you hit the brakes bending the rear frame rails down, this damage is quite common when extreme dropped draw bars are used. Focus on eliminating the lever effect.

GM up-fitter manuals have a great breakdown of reinforcing/extending chassis and boxing gussets can be fabricated for reinforcement.
 

klmore

Adventurer
Assume you were towing trailer when the damage happened. Having not seen your trailer attached to your Duraburb I suspect your bent chassis rails are more likely than not from a drop down draw bar acting like a lever when it moved forward increasing downward leverage instead of in a forward linear motion when you hit the brakes bending the rear frame rails down, this damage is quite common when extreme dropped draw bars are used. Focus on eliminating the lever effect.

GM up-fitter manuals have a great breakdown of reinforcing/extending chassis and boxing gussets can be fabricated for reinforcement.

I think you are a 100% correct. I believe the drop hitch played a big role in the frame damage, but I also believe I didn't have my brake controller set correctly. I towed my ammo trailer all day with out issue even with the frame rails bent. My M101 trailer does not require a drop down hitch.
 

noJeepshere

Adventurer
Looks good. I like Erics quality of work that he put into this project. I especially like the fact that he can do the newest body style duramax swap. One thing I have learned is that when you do custom work of any kind, there will always be issues from then on.
 

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