1970 Chevy Chevelle Turbo-Diesel - Biowarfare
Making Close To 1,000 Hp And 2,000 Lb-Ft On French Fry Grease, This Duramax Diesel-Powered Chevelle Puts Gasoline Big-Blocks To Shame.
From the June, 2009 issue of Popular Hot Rodding
By Stephen Kim
Photography by Roberto De Los Macafino
We've got your weapons of mass destruction right here, buddy. The thing is, it's not fueled by enriched uranium and you can't find it in Iraq, so it's highly unlikely to be named to the Axis of Evil any time soon. Damn. Fortunately, the WMD in question here will further fan the flames of the raging horsepower arms race. The specimen at hand is waging biological warfare on all gasoline engines in existence one tank of biodiesel at a time. Stuffed, quite literally, with a 6.6L Duramax V-8, Mike Racke's '70 Chevelle has the goods to bury Rats, Hemis, and 460s 6 feet under, and kicks out enough torque to pull them back out.
To understand why anyone would commit to such an unorthodox engine swap requires nothing more than glancing at the stats. At 950 hp and 1,700 lb-ft of torque, Mike has more than tripled the output of a stock LLY Duramax, which is rated at 310 hp and 605 lb-ft from the factory. The Chevelle even knocks down 32 mpg. Despite such staggering figures, the engine combo is surprisingly simple. Other than a set of Carrillo steel rods, the short-block is completely stock. The only other major modifications are a set of CNC-ported factory 32-valve heads, upgraded twin turbos cranked to 30 psi, and a bigger solid-roller cam. Once he hooks up the nitrous, Mike hopes to pump those numbers up to 1,200 hp and 1,900 lb-ft. This begs the question: How much can these suckers take before they go kaput? "I've built tons of small- and big-block Chevys in my day, but I've never seen anything like this Duramax. The thing is built like a tank," he explains. "It's a deep-skirt block with huge cross-bolted main caps and reinforcement webbing everywhere. There are six studs surrounding each cylinder, cast aluminum covers on the front and back of the block, huge lifter bores, and a gear-driven water pump and timing set I'm not sure what the limit is, but there are people putting 1,500 hp through these blocks."
Granted, the Duramax is one beastly hunk of iron, its virtues were only one of several factors that inspired Mike to build this project. "My first car was a '70 Chevelle, which I still own, so I've always been partial to them. I've built so many different Chevelles over the years that I started getting bored doing the same thing over and over again," he explains. During the brainstorming stage, Mike read some books that piqued his interest in biodiesel. He found the notion of burning cheap, domestically produced fuel with enormous power potential that happened to be environmentally friendly inescapably appealing. All the while, one of his buddies who worked at a GMC dealership couldn't stop raving about the power potential of the Duramax. Ultimately, what sealed the deal was a ride in a Duramax-powered Hummer H1. "I was at Pacific Performance Engineering one day when my friend Joe took me for a ride in his Hummer that he just finished swapping a Duramax into. This huge 8,000-pound truck pulled just as hard as my 10-second big-block Chevelle wagon. I couldn't believe it, and decided right then and there to put one of these motors into my next car."
The project started out as a beat up rolling chassis. Mike stripped the car, fixed up some dings, and replaced a rusty quarter-panel before mocking the motor into place. Wanting to maintain a low-key external appearance, Mike decided to fit everything under the stock hood, which proved to be an enormous undertaking. "A stock Duramax has a single turbo mounted right on top of the motor, along with a bunch of other junk hanging off of it that I had to remove for clearance. To make space for the drive accessories, radiator, intercooler, A/C condenser, and turbo piping, the motor had to be moved back 8 inches from the stock location," Mike recollects. "Another issue was the stock location of the A/C compressor and alternator, which I had to reposition lower in the engine bay by making custom brackets and pulleys. The Duramax uses injection pumps driven off the crank to pressurize the fuel rails, plus I had to add a second pump in order to meet the increased fuel demands of this setup. Taking an ugly truck motor and cleaning it up to make it look like something that belongs in a muscle car is a huge challenge."
How the custom twin-turbo setup came to be is a story in itself. "While Fast Eddie's was doing the chassis work on my car, I rebuilt the motor at home and started porting the heads. I took one of them to a local Chevelle gathering to show to one of my friends," Mike recollects. "As he was looking at it, a man walked up and asked what kind of car this crazy-looking head was for. I told him it was going into my '70 Chevelle, but after five minutes of guessing he couldn't figure it out. When he found out it was for a Duramax, he was stunned and handed me his card. It turns out I was talking to Darryl Bassani of Bassani exhaust, and he offered to make the entire exhaust system for the car and put it in his booth at SEMA. Mind you, he had never even seen my car."
Almost lost in all the diesel hoopla is the cutting-edge technology infused into the chassis and suspension. After installing the motor, Mike realized that the stock frame wasn't adequate for the power loads it would endure. Consequently, he ordered up an Art Morrison front clip, complete with C5 Corvette aluminum suspension components. Fast Eddie's (Orange, California) handled the install, and in order to stand a chance of putting the power down, a 9-inch rearend was narrowed and anchored into place with a custom four-link. Big tubs accommodate gargantuan 22-inch-wide Mickey Thompsons, which still aren't enough to harness all those rampant pound-feet despite the tall 3.25:1 ring-and-pinion set.
Numbers printed on paper is one thing, and the visceral sensation of driving a diesel-powered hot rod is another thing entirely. As someone quite well versed in dropping the hammer in fast muscle cars, Mike reports that the diesel experience is like nothing he's encountered before. "Driving this car is very weird and very different from anything else out there. Even without any mufflers, it's very quiet and sounds just like a stock Chevy truck at idle," he explains. "When you first get on the gas, it sounds almost like a gasoline V-8 that's misfiring, then it quiets down again as the boost builds. The Duramax only turns 4,200 rpm, so the power hits real hard. The motor never feels stressed at all and it just kills the tires. It's way faster than any 10-second car I've owned, and when I get a chance to run it at the track, I'm sure it will run 9s easily."
With the magnitude of fabrication that goes into a project like this, there's no getting around the fact that it's going to cost megabucks. That said, credit must be given where credit is due, and Mike's hands-on aptitude is right up with the most down-and-dirty of enthusiasts. He tackled most of the bodywork himself, built a custom showcar-caliber interior, assembled the motor, ported most of one head before running out of steam, stitched together the custom intake manifold, designed the intercooler and cooling systems, plumbed the oil and fuel lines, ran the wiring, and completed the final assembly all in his garage. The wiring and plumbing alone took six months to finish. "One of my favorite cars is a Chevelle I built a long time ago with a 509 big-block that runs 10s. It's a nice car, but anyone can build something like that," Mike opines. "Not only is this Duramax project different, it's very difficult to pull off. That's why I don't think a swap like this will catch on. Most people probably wouldn't have the time or patience to do it."
Even with the Duramax, rollcage,...
Even with the Duramax, rollcage, and an extremely heavy Allison five-speed trans, the Chevelle weighs in at a reasonable 4,400 pounds, which is just a hair more than a new Cadillac CTS-V. Mike hates the look of small rotors behind big wheels, so while it doesn't do much for performance, he fit 16-inch rotors out back. Anaheim Prestige (Placentia, California) laid down the Mist Turquoise paint.
Maybe that's a comment the hot rodding public will perceive as a challenge, or maybe it's just words of wisdom from a man who's been there, done that. Either way, if it spawns more diesel-powered muscle cars, we won't complain. One thing's for sure--truck-based diesels have what it takes to go toe-to-toe with conventional big-blocks and embarrass them in the torque and mileage departments. Whether compression ignition trumps spark ignition is a debate for another day, however, because after just watching and smelling the Duramax Chevelle annihilate its 33x22 Mickey Thompson's, we're getting kind of hungry. Hey Mike, do you think you can get a McDonald's sponsorship out of all this madness?
Diesel To The MaxFrom a performance standpoint, the fundamental design of a diesel has significant advantages that gasoline engines just can't touch. Unlike a gasoline engine that relies on fuel and ignition spark for combustion, diesels operate on the principle of auto ignition. In lieu of spark plugs, the extreme cylinder pressure and heat produced by a diesel's extreme compression ratio (between 17:1 and 20:1) initiates the combustion process. This is part of the reason why diesels aren't very picky about the type of fuel you dump into them. (Banana peels anyone?) Detonation beats up bearings, pops head gaskets, and blows holes through pistons, but without ignition spark, diesels live in a world where harmful detonation doesn't exist. Combine all this with a turbocharger and the result is tremendous bottom-end torque. GM's latest 6.6L Duramax cranks out 660 lb-ft at 1,600 rpm to go along with its 365 hp. Since diesels aren't limited by octane like gasoline engines, they can handle enormous boost pressures, making them exceptional performance platforms. According to the diesel specialists at Pacific Performance Engineering (www.pacificp.com), an upgraded turbo, basic fueling upgrades, and a 4-inch downpipe on a stock Duramax will make 800 hp and 1,600 lb-ft. In addition to gloriously swollen torque curves, diesels offer far better fuel economy as well. While gasoline engines operate at a 14.7:1 air/fuel mixture, diesels are lean-burning machines that run 20:1 mixtures under normal driving and as lean as 60:1 at idle. Needless to say, the potential is there for phenomenal performance and fuel mileage.
GM's Duramax line of V-8 diesels was introduced in 2001, and is the product of a joint venture with Isuzu. Over the years, it has earned a reputation for excellent reliability and stunning power potential. The Duramax has been regularly updated with minor revisions every few years, at which time it's been re-labeled with a different designation (LB7, LLY, LBZ, LMM). Each variant is very similar and an equally capable performance platform. All 6.6L Duramax diesels feature a 4.050-inch bore, a 3.900-inch stroke, an iron block, aluminum heads, and direct common-rail injection. Their internals are forged, and compression ratios vary between 16.8- and 17.5:1. Although the camshaft is mounted inside the block, the Duramax has a forked rocker arm design that enables actuating four valves per cylinder. Like all modern turbo diesels, the Duramax operates at extremely high fuel pressures of up to 26,000 psi. The going rate for a used Duramax complete with a computer, wiring harness, and Allison transmission is about $7,000. Although some will make the argument that they technically aren't big-blocks, Mike Racke reports that the Duramax is very similar in size and weight to a Rat motor and even has the same bellhousing pattern. However you choose to label them, there's no disputing that diesels aren't just for trucks anymore.
The fuel system of a Duramax...
The fuel system of a Duramax relies on a lift pump that pushes fuel from the tank, or cell, to the front of the car at roughly 6 psi. From there, a gear-driven injection pump mounted in the lifter valley feeds the injectors by cranking up the pressure to about 26,000 psi. In addition to an aftermarket PPE lift pump, the Chevelle has a second injection pump that's driven off the crank pulley. Fast Eddie's built the custom cell.
For hood clearance, the motor...
For hood clearance, the motor was mounted as close to the ground as possible, which required reducing the stock oil pan height by cutting it. The alternator, A/C compressor, and secondary injection and power steering pumps are all mounted off of custom brackets and hidden under the turbos.
One of the most impressive...
One of the most impressive home-built pieces is the custom intake manifold. Mike started with a -inch aluminum plate for the base, cut the dual plenums out of 3.5-inch aluminum pipes, then carefully grafted 16 intake runners out of aluminum stock. He figures that the whole setup cost him only $30.
Almost every part of the interior...
Almost every part of the interior was custom made by Mike. For the dash, Mike cut two original SS pieces and fused them together with fiberglass and foam. A satellite navigation screen sits where the heater controls and center air vents used to be. The Auto Meter gauges have been re-screened to match and blend in with the stock Chevelle gauges. Other highlights include a suede headliner, Recaro seats, and an Alpine stereo.
By The Numbers
|’70 Chevy Chevelle |
|Mike Racke, 29 • Fullerton, CA |
|Total cost to build: $250,000 |
|Type: ||GM 403ci Duramax LLY turbo-diesel V-8 |
|Block: ||standard 4.050-inch bore production block |
|Oiling: ||stock pump and pan |
|Rotating assembly: ||stock 3.900-inch |
| ||forged crank, Carrillo steel rods, |
| ||and stock 16.0:1 pistons |
| ||modified by SoCal Diesel |
|Cylinder heads: ||CNC-ported SoCal Diesel factory |
| ||four-valve castings fitted |
| ||with stainless steel 33mm intake valves, |
| ||Inconel 33mm exhaust valves, |
| ||and custom valvesprings |
|Camshaft: ||SoCal Diesel custom solid roller; |
| ||specs classified |
|Valvetrain: ||stock geardrive timing set |
| ||and rocker arms; |
| ||SoCal Diesel custom pushrods |
|Induction: ||custom sheetmetal intake manifold |
| ||with 16 runners and dual 3.5-inch plenums; |
| ||custom ram air scoop and inlet piping |
|Ignition: ||none |
|Power adder: ||Twin Garrett T-38R |
| ||turbochargers set at 30 psi, |
| ||custom dual Bell intercoolers |
|Fuel system: ||PPE dual fuel pumps, PPE lift pump |
|Computer: ||stock, reprogrammed by PPE |
|Exhaust: ||custom Bassani turbo headers, |
| ||custom dual 3-inch exhaust |
| ||with no mufflers |
|Cooling: ||Ron Davis radiator, |
| ||dual Spal electric fans, |
| ||stock water pump |
|Output: ||Estimated 950 hp and 1,800 lb-ft |
|Transmission: ||PPE-built Allison 1000 |
| ||five-speed auto, |
| ||ATS 2,200-stall converter |
| ||and billet flexplate |
|Rear axle: ||Fast Eddie’s 9-inch rearend |
| ||with 35-spline axles, 3.25:1 gears, |
| ||and Detroit Locker differential |
|Front suspension: ||Art Morrison front clip |
| ||with C5 Corvette aluminum control arms, |
| ||sway bar, and spindles; Koni coilovers |
|Rear suspension: ||Art Morrison four-link, |
| ||Koni coilovers |
|Brakes: ||Wilwood 14-inch rotors |
| ||and six-piston calipers, front; |
| ||Wilwood 16-inch rotors |
| ||and four-piston calipers, rear |
|WHEELS & TIRES |
|Wheels: ||DPE S-5 18x8, front; 20x16, rear |
|Tires: ||Mickey Thompson |
| ||26x12x18 Sportsman radials, front; |
| ||33x22x20, rear |