If you're sick of dealing with VGT issues, a 2008 6. 7 cummins 2nd gen swap is probably already on your radar. It's one of those modifications that most Ram owners eventually talk themselves into once they realize how much simpler life is without the variable geometry turbocharger. The 2008 model year was part of that early 6. 7 generation where the emissions gear and the factory VGT turbo really started showing their faults. By swapping over to a 2nd gen style setup, you're essentially backdating the exhaust manifold and turbo configuration towards the legendary layout located on the 1994-1998 12-valve trucks, but keeping the massive displacement and power potential of the 6. 7.
Why Even Bother With a 2nd Gen Swap?
Let's be real—the factory HE351VE turbocharger that comes on the 2008 6. 7 Cummins is a bit of a headache. Don't get me wrong, the quick spool-up is nice for daily driving, and the factory exhaust brake is a good feature for towing. But that VGT is notorious for getting "sooted up. " The sliding nozzle inside gets stuck, and before you know it, you've got a truck that won't build boost or, worse, builds way too much drive pressure and puts the head gasket at risk.
When you go with a 2008 6. 7 cummins 2nd gen swap , you're ditching that complex VGT for the fixed geometry turbo. You lose some of that instantaneous low-end response, but you gain massive amounts of reliability and top-end flow. Plus, the sound is unbeatable. There's something in regards to the way a 6. 7 sounds through a T3 or T4 2nd gen manifold that just the actual truck feel more like a "real" diesel. It gets rid of that weird, muffled VGT hiss and replaces it with a crisp, clean whistle.
What Parts Can even make Up the Swap?
If you're looking at kits online, you'll see they vary quite a bit, but the core components are always the same. You can't just slap a different turbo on your stock manifold; it doesn't work that way.
The Exhaust Manifold
The heart of the swap is a 2nd gen style manifold. On a stock 2008 6. 7, the turbo sits way back near the firewall, and the manifold is designed to accommodate the bulky VGT. A 2nd gen manifold centers the turbo between cylinders three and four. This creates much more even exhaust flow across all cylinders. Usually, you're looking at a high-flow cast iron manifold, normally a T3 or T4 flange depending on just how much power you're chasing.
The Turbocharger
This is where the fun starts. Most guys doing a 2008 6. 7 cummins 2nd gen swap opt for an S300 or S400 frame BorgWarner turbo. For a daily driver that still must tow, an S363 or S366 (with a 63mm or 66mm inducer) is the sweet spot. If you're building a dedicated track truck or even a high-horsepower street machine, you might step up to an S467 or bigger. Since these are fixed geometry, they don't have the moving vanes that the stock turbo has, making them much harder to break.
Piping and Plumbing
Since you're moving the turbo to some new location, nothing of your stock plumbing is going to reach. You'll need a new downpipe to connect to your exhaust system, a new cold-air intake pipe, and a new intercooler pipe (the "hot side" pipe). You also have to deal with the oil lines. The factory oil feed and drain lines won't line up, so a good swap kit will include braided stainless lines or custom hard lines to make sure the new turbo has got the lubrication it needs.
The Sound and Performance Trade-off
I'll be the first to inform you that if you love the way your 2008 pulls a heavy trailer from a dead visit 1, 200 RPM, the 2nd gen swap might feel a bit different initially. Because a fixed geometry turbo relies entirely on exhaust volume to spin up, there's naturally going to be a bit more "lag" compared to the VGT.
However, once that turbo lights, it stays lit. The power delivery is much more linear and feels more aggressive with the mid-range and top-end. Most people find that using the right tuning, the lag is barely noticeable. You learn to drive around it, and the trade-off in lower Exhaust Gas Temperatures (EGTs) and lower drive pressure is well worth it.
After which there's the sound. The 2nd gen swap gives the 6. 7 that classic "12-valve scream. " Since the manifold has better flow and the turbo isn't constantly adjusting its vanes to muffle the exhaust, the truck sounds incredibly healthy. It's loud, it's proud, and it finally seems like the heavy-duty engine it is.
Would you Lose the Exhaust Brake?
This is the big question for guys who tow. The 2008 6. 7 Cummins includes a built-in exhaust brake function through the VGT. By closing the vanes, it creates backpressure to slow the truck down. If you choose a 2008 6. 7 cummins 2nd gen swap , you already know that factory functionality.
In case you tow heavy through the mountains, you'll probably want to add an aftermarket inline exhaust brake (like a BD Diesel or Pacbrake unit) into your exhaust system. It's an additional expense, but it works just as well—if not better—than the factory VGT brake. In case you mostly just daily drive or drag race, you probably won't even miss it.
Tuning Is not really Optional
You can't just bolt these parts on and drive away. Your truck's computer is expecting to see a VGT turbo. If it doesn't find one, it's going to throw a fit, put the truck in limp mode, and light up your dashboard like a Christmas tree.
You'll need custom tuning—usually through EFI Live or EZ LYNK. The tuner will "delete" the VGT logic from the ECM so the truck knows it's now running a fixed turbo. This really is also where you can dial in your fuel maps to help that bigger turbo spool up faster. A good tuner can make a 2nd gen swapped 2008 feel incredibly snappy and responsive.
Installation: Can You Do It Yourself?
If you're handy with a wrench and also have a weekend to spare, a 2008 6. 7 cummins 2nd gen swap is definitely doable in a home garage. The hardest part is usually getting the old, rusty manifold bolts out without snapping them in the cylinder head. (Pro tip: start soaking them in PB Blaster or Kroil a few days before you plan to start).
The physical space within a 2008 engine bay is actually pretty decent once you get the factory airbox and VGT out of the way. Everything inside a swap kit is designed to bolt up, however you might find yourself wrestling with the downpipe or trimming a few things to get the perfect fit. It's not a "one-hour job, " but it's not a frame-off restoration either. Just take your time, make sure your oil lines are secure, and double-check for leaks before you go for a test drive.
The Bottom Line
Ultimately, the 2008 6. 7 cummins 2nd gen swap is about taking control of your truck's reliability. It's for that guy who is sick and tired of his truck in the shop for turbo cleaning or replacement. It's for the owner who wants to see lower EGTs when pulling a hill and wants to hear that sweet Cummins whistle every time they hit the gas.
It's an investment, for sure. Between the manifold, turbo charged, the piping, as well as the tuning, you're looking at a decent chunk of change. But when you think about the cost of a replacement factory VGT and the reassurance you get from a simplified setup, most 6. 7 owners can confirm it's the best money they've ever spent on their rig. Whether you're looking for 500 horsepower or 800, the 2nd gen swap provides the foundation you need to get there without the VGT holding you back.