BANKS SIDEWINDER TURBO KIT FOR THE 6.2L DIESEL

I have a 1989 Suburban 4x4 with the naturally aspirated (non-turbo) 6.2L diesel. I had the engine rebuilt about 125,000 miles ago, but earlier this summer, it developed a block crack spirally inside a cylinder. Why it waited 10 years and so many miles to do this is beyond me.

In any event, I found a running 1993 6.5L mechanically injected turbo engine I am having rebuilt for the truck. I very rarely haul anything,

and when I do, it’s lightweight stuff—not anything like the 8,000 to 12,000 pounds I see guys on forums talking about towing. Most of the time, it’s just me and all my field gear; lots of volume but not more than probably an extra 250 pounds of weight. I’m building it back for max fuel economy, which is why I bought it in the first place. I was talking to my machinist about swapping out the earlier, smaller port pre-cups into the head, but he is not convinced. There appear to be about six or eight types of cylinder head pre-cups. So, when you say, “earlier,” I assume you mean the original single-dot 6.2 pre-cups?

The 6.5L engine came out of a dually that was being used for hauling cars, so I want to make sure anything geared toward heavy hauling/low fuel economy gets taken out.

The heads have the larger port turbo spec “T” cups in them. My truck has 3.42 gears, a rebuilt 700R4 transmission with the extra-sturdy rebuild, and I’m running 31-inch tires. Using an online gear calculator at 70 mph, the engine should just be turning over a bit more than 1,800 rpm. I never actually drive 70, and we don’t have a lot of big hills, so my interest in the turbo is strictly to make similar levels of power with a lighter touch on the accelerator pedal.

I got the running 6.5 with a functional factory turbo that spins freely and with no play in the bearing. It spent most of its life as an Alabama Power truck, so I am sure it was well maintained.

Is there anything else to think about? Are a pyrometer and boost gauge and/or mechanical/ adjustable wastegate actuator worth the bother for someone like me? And, again, I was fairly happy with the power levels of the 6.2. I figure I was making somewhere around 160 hp with the mods I had done to it; maybe a bit less. I have driven a Suburban of about the same year with a 6.2 turbo, and I noticed it stayed in overdrive all the time. According to specs, the extra torque of the 6.5 should keep me plenty happy without needing to resort to anything crazy to try for more power.

Thanks for any input you can provide.

James Lamb Livingston, AL

James,

People sometimes get lost in the minutia of precups. In general, there are two basic types: one for turbo engines (large port) and one for non-turbo engines (small port). As long as you have a full matching set, you’re golden. Otherwise, consider the small port pre-cups in the cylinder heads if your primary interest is fuel economy. With the small port pre-cups, the engine should produce very similar fuel economy numbers to those the original 6.2L produced.

The Turbomaster wastegate actuator would make an excellent choice for the factory turbo. Unfortunately, the factory 6.5L turbo system won’t work for your 1989 Suburban. There’ll be interference between the turbo and the A/C components mounted to the firewall, and the factory 6.5 turbocharger downpipe creates a major interference problem with the frame rail. For your year vehicle, I recommend the Banks Sidewinder Turbo Kit made for the 6.2L Diesel and your year vehicle.

Look at ebay, Craig’s List, bulletin boards and anywhere else you can think of for pieces/parts of the Banks 6.2L Diesel Sidewinder Turbocharger kit. Sometimes, the Banks passenger-side exhaust manifold turns up in one of the abovementioned sources. If you find one, buy it.

Everything else can be either fabricated or pieced together from factory parts. For a turbocharger, I’d consider a Holset HX-35W. It’s a perfect match for the Banks manifold and the airflow/ pressure requirements of your engine—and, it will bolt right onto the Banks manifold. Banks has on again/off again sold its 6.2L Diesel turbo kit. Always check with Banks first to see whether the kit is currently being offered. (I’m glad Banks hasn’t completely let go of that kit.)

Until you round up everything you need for a turbo system, run it non-turbo. Be sure to have the 6.5 block inspected while it’s apart. Look for cracks in the main webs before spending any money on it or making other commitments.

A boost pressure and exhaust temperature gauge set would be advisable if you plan to build more power. And, the gauges help you tune the engine (fuel and boost) to maximize performance without damaging the engine. Without gauges, keep the smoke level low.

Let me know if you need anything else.