Diesel Suburban Project
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My largest project right now is converting a Suburban to be powered by an efficient diesel engine. I was looking at economical family haulers and found out that they simply didn't exist. Most all of the reasonably-sized SUVs have real-world mpg in the teens. Government interference has historically killed the prospects of diesel powerplants in trucks, unless they are in at least the 3/4 ton class. When those 3/4 ton and larger trucks come with diesel engines, they are designed for hauling and towing large payloads. They aren't typically a good choice for hauling a family around, unless you are OK with so-so fuel economy. Granted, a big diesel pickup can get 20+ mpg, but with engines that start in the neighborhood of 6 liters and grow from there, they don't get the fuel economy that a diesel could potentially provide.
These pickups sounded great, but never made it to US soil.
A few years back I took great interest in Global Vehicles, who were going to import smallish trucks from Indian manufacturer Mahindra & Mahindra to the US (mid-sized, but with capacity > 1-ton!). These would have a small 2.2 liter engine and be capable of 30 mpg highway. A four-door version was to be available and it looked like the perfect hauler for my small family of four, plus a couple dogs. Year after year they failed to deliver and it finally ended in a lawsuit between GV and M&M. These vehicles won't be available in the US anytime soon.
At the time, all of the big three auto manufacturers in the US were talking about smaller diesels in 1/2-ton trucks that may have gotten as high as 30 mpg. After yet another government-induced bubble in our country burst, the auto manufacturers wound up in cost-cutting mode and the smaller diesel efforts were put on the shelf. So, again, 1/2-ton trucks with reasonable fuel economy never made it onto the market.
Our current primary drivers are diesels. I have a Jetta TDI that gets 45 mpg in mixed driving and is not a slow car, thanks to a manual transmission and gobs of torque. My wife has a 2005 Jeep Liberty CRD with an Italian VM Motori 2.8 liter engine under the hood that has good spunk (295 ft-lbs) and gets mid to upper 20s on the highway. These are nice, reliable vehicles, but they are simply too small for family vacations. Especially now that we have two German Shepherd mixes that would like to come along.
I'd been looking at the site 4BTSwaps.com for a number of years and in 2011 I decided that if our government-lobotomized market wasn't going to deliver what I (and many others) wanted, I realized I had to do it myself. Those Cummins 4BTs are pretty expensive, when you can find them, but I thought I'd start looking. Then, one day, I found out that a number of people are doing swaps for the Isuzu 4BD1T and 4BD2TC engines. Like the Cummins 4BT, these engines are 3.9 liter engines, but more civilized for a passenger vehicle. These engines are typically cheaper, as they are found in Isuzu NPR cab-over trucks that are often rebadged as Chevy and GMC products. I found out that one of the guys selling the kits had achieved 32 mpg on the freeway.
I found a 4BD1T at a nearby truck salvage yard. They were able to run it for me, so I knew the engine was in fairly good condition. If an overhaul is needed, fresh liners can be pressed in on this design, so at the price it was a low-risk investment.
Next, I needed a vehicle to put the engine into. I was looking for a 4-door pickup, but didn't find any in my price range. Suburbans share much of the same body, frame, and drivetrain components with the GM pickups, so I knew these were an option with adapters available. I did a quick search on Suburbans and was surprised at how cheap they were. The rising price of gasoline was leading people to dump them in favor of more economical rides. Ironically, I was buying one in order to build an economical family-hauler -- but most people aren't willing to get their hands dirty.
A 90s vintage Suburban in good shape -- a perfect match for my conversion
So, I bought this cheap, high-mileage Suburban with a near-perfect, rust-free body. The cloth interior looked new. The 5.7 liter V-8 was healthy, but the main feature of the drivetrain that interested me was the 3.42 front and rear-end gear ratios. With stock tires and an overdrive transmission, I realized that this vehicle could be driven at 70 mph while at the engine's peak fuel economy and torque rpm -- around 1900.
This was over a year ago. I thought I'd be done with the conversion by now, but these things take a lot of time. They aren't cheap, either. As this blog continues, I will go through this conversion subsystem by subsystem -- discussing the decisions I've made and what I'd do differently if I started over again.
--My recipe for success: More diesel and less government!