When Two Turbos Just Aren’t Enough!

I was having a deep, intellectual discussion with my friend Jon yesterday. We were talking about turbos. This is not uncommon for us; exhaust-driven air compressors are a form of religion around here. We were discussing what the proper number of turbos for an engine should be. I suggested two; he said either one or four. Then the question arose: has there ever been a car with three?

“Good question,” I said. “I really don’t know.” A little research turned up a most interesting result. Of course it would come from the world of diesel truck tuning, where injecting propane into an engine is not only normal, but encouraged. A company called Bullseye Performance has a triple-turbo kit for the 5.9L Cummins 24v Turbodiesel I6 that is available in heavy-duty Dodge Ram trucks, and it’s unbelievably serious. This led me to pictures, articles, and multiple insane YouTube videos. You have to check this out.

Yup, that’s three turbochargers. THREE. Count ‘em. How does this work? It’s a 2-into-1 compound setup. The two CompR 62mm turbochargers feed the larger 66mm CompR turbocharger, in perhaps the world’s most badass “twin scroll” setup. Oh, your Celica GT-4 has a twin entry turbo? My dodge has a twin-turbo turbo. Mull that over in your head for a minute.

This engine is the very definition of nuts. It’s currently making 946rwhp and 1,916 lb-ft of torque at the wheels. That’s almost, umm, literally a ton of torque. Even wilder? It’s last dyno run, the truck was pushing almost 100psi of boost. Internal modifications? Well, the truck has a stock bottom end and connecting rods (the rotating assembly in a Cummins 5.9 is ridiculously overbuilt from the factory, but c’mon!), fire ring and upgread head studs on the stock head, with a Hamilton street cam and springs. A Level 4 CP3 pump and custom (presumably massive) injectors deliver fuel, and an enormous AFE air-to-air intercooler keep intake temperatures down when running 100psi of boost.

Of course, if you have a truck making almost 2,000 lb-ft of torque and almost 1,000 horsepower, it needs smoke stacks coming out of the bed. Naturally.

In addition to being a daily-driven street truck that Bullseye uses as a delivery vehicle, the triple-turbo beast recently layed down a 10.95 @ 124.5 in the quarter-mile. Which doesn’t sound like an especially amazing number, except this is a full-weight 2005 quad cam 4WD truck with A/C, all it’s seats, etc -- so the kerb weight is probably near or over 7,000 lbs. Under 11s in the quarter mile in a 3.5 ton vehicle? I’m interested.

The amount of unburnt fuel pouring out of the exhaust is alarming, but watching something that large move that quickly is pretty amazing. Here’s a video of Bullseye’s truck on a dyno. Quite a bit of compressor noise!

And this video is proof of why you don’t dyno a truck like this indoors. It’s what diesel tuners call a blackout. Oh, and this was back with a previous tune when the truck was only making 743 horsepower and 1,312 lb-ft of torque. You know, chump change.

Is a triple-turbocharger setup practical for a daily driver? Absolutely not. Even when it’s a tricky compound setup like this, there’s still a huge amount of plumbing and heat associated with this many turbos. It’s needless complication when today’s ball-bearing twin scroll turbos can spool off of exhaust gasses right above idle rpm. But still, what’s cooler than popping the hood and watching jaws drop as they count three turbochargers? Exactly, nothing.