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Q: Want To Drive A 6.5LI'm a die-hard Chevy fan and I'm looking into buying a 6.5L turbodiesel. My question is: are there any certain years I should try to get my hands on? What about performance upgrades? My intent is to put some money in it right off the bat to upgrade the cooling system and then pursue additional power. I know the truck will never really be able to compete with the modern-day diesels, but I'm willing to live with that.
Donnie Bullock
Clinton, Missouri
GMC and Chevrolet 6.5L turbodiesels...
GMC and Chevrolet 6.5L turbodiesels can be had for pennies on the dollar compared to newer offerings. While they'll never be powerhouses, they can be good workhorses with simple cooling upgrades and a few bolt-ons.
A: The 6.5L engine is by no means a powerhouse, and its injection system is limited as far as performance potential goes, so it's time to seek outside help. Back before aftermarket parts were readily available, diesels had to rely on injecting propane, a water-methanol mix, or nitrous oxide to make power. Since nitrous is more of a competition-only modification, we'd suggest propane or water-methanol as a power adder. A lot of people bash propane, but we've ridden in a few trucks that are on the 'pane, and we can tell you it makes one heck of a difference. Count on adding about 40 to 80 hp depending on how much you inject. Going the water-methanol route not only means more power, but a lot lower EGTs when towing with your truck. If you don't like the idea of having to carry around a bottle to make power, Heath Diesel (phone: [877] 894-6266 or visit www.heathdiesel.com) offers a line of performance packages for 6.5L-equipped rigs. Prices range anywhere from a few hundred bucks to a few thousand, so there will be a kit within your price range no matter what your budget is. Another good resource is Kennedy Diesel (phone: [715] 255-9433 or visit www.kennedydiesel.com), a 6.5L guru that sells lift pumps, tuned ECMs, and more. As for a year to buy, we'd shoot for a '97-and-up model. They have oil-cooled pistons, a revised, higher-capacity cooling system, a better turbocharger, and more performance potential. We'd expect to pay about $3,000 to $6,000 for a low-mileage truck in decent shape. Depending on the area you live in, you may be able to find one cheaper. Even with a few modifications, don't expect any more than about 200 hp at the wheels. If you're willing to live with that, then go nuts. There are many 6.5L trucks out there just doing their daily diesel duties, and fuel mileage is often in the 20-plus-mpg range with trucks equipped with 3.42:1 axle gears.