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Tom G.
LS-Based Engine Seeks Bonneville Record
Will This Ken Duttweiler LS-Based Engine Power the Speed Demon Streamliner to a New Bonneville Piston-Driven, Ground-Vehicle, Land-Speed Record?
Hot Rod1 May 2019Marlan Davis Marlan Davis and Julia LaPalme
[ Rolling a “7”: Duttweiler says Liberty’s clutchless seven-speed trans “can probably take 4,000 hp.” All gears are direct (no OD); that’s OK, as the Ferguson quickchange rear’s final drive ratio is 1.67:1. [ May the forced induction be with you: The trick Pro Mod 88 Precision Turbos are built to order. Ken Duttweiler: “We use the same turbos on all Speed Demon engines, from 258 to 441 ci.” [ Gear changes for the better: A steering-wheel-mounted electrical pushbutton switch actuates these Air-Logic solenoids and pneumatic valves to change gears. Definitely no missed shifts here. [ Engine-eering: Duttweiler Performance’s 441ci, 2,625hp, methanolfueled, dual-turbo, land-speed-racing (LSR) engine is based on Dart’s LS NEXT short-skirt LS Gen III block and full-race, 10-degree LS Gen III cantedvalve heads. Maxwell Industries’ Steve Watt, “Mr. Chassis Integration,” built the headers, the ducting, the hoses—in fact, the whole car.
h441 cubic inches. 2,625 hp. 1,767 lb-ft. 40 pounds of boost. That’s the current state of engine-builder Ken Duttweiler’s latest Bonneville land-speed-record (LSR) engine that, when fully developed and debugged, he hopes will recapture Bonneville’s fastest piston-engined crown, currently held by Danny Thompson in the refurbished, 50-year-old “Challenger 2” Streamliner originally first driven back in 1968 by Danny’s dad, the legendary Mickey Thompson. Danny’s new high-water mark of 448.757 mph over the 5-mile-long salt flats course set just last summer surpasses the previous 2012 Bonneville SCTA high-water mark achieved by a single Duttweiler-built, 347ci small-block Chevy in George Poteet’s Speed Demon (HOT ROD, April 2012).
Running in AA/FS (AA/Fuel Streamliner), Challenger 2 needed two 2,500hp, nitro-fueled, unblown, old-school, 500ci, dry-block Hemi engines to get the overall two-way record. Duttweiler plans to take it back with a single 441ci engine. Nope, it’s not a big-block Chevy nor even another highly evolved traditional Chevrolet smallblock. Instead, Duttweiler is moving to the modern GM “LS” smallblock architecture, albeit in “Pro” racing trim using Dart’s brand-new LS NEXT racing block and Gen III 10-degree, oval-port CNC racing heads that, out of the box, flow more than 450 cfm at 0.900-inch lift.
Why an “unproven” LS? Dart’s rendition of an LS has, according to Duttweiler, “better heads that flow even more than the best Gen I [traditional] small-block splay-valve heads. They also have better
water circulation. The NEXT block can be ordered with larger Ford Cleveland 351C main-bearing journals, which better support our Crower 4.050-inch-stroker crank.”
But the real clincher was shoehorning a larger-displacement engine into the existing, very narrow Speed Demon chassis. “I want to attempt to set the record in A/BFS (A/Blown Fuel Streamliner) because that’s one of the few high-end forced-induction classes the Demon has no record in. We’ve held, at one time or another, the B , C, D, and F/BFS records. A/BFS requires a 441- to 500.99ci engine. Officially, Dart’s LS block is available with up to a 9.450-inch deck height, and they made one for me that comes in at 9.465 (a stock LS is 9.240). If a traditional small-block Chevy could be built with that tall a deck, it would not fit within the Demon’s existing narrow framerails.”
During the first run at the flats in 2018, the new LS combo reached 440-plus mph one-way before encountering some issues 2¼ miles into the 5-mile course. “At that point, the car was already 30 mph faster than it had ever gone before,” Duttweiler says. Developing any new engine for extreme racing is not like waving a magic wand. On the contrary, it requires overcoming, one by one, various obstacles that only reveal themselves under the duress imparted over a 5-mile-long run. LS engines may have proved durable up to the 2,000hp mark in short-duration drag racing, but with an engine that must last for minutes—not seconds—Ken is going where no LS man has gone before. On these pages, you’ll see some of the high-end parts used in the engine, as well as how Duttweiler is overcoming some of the issues encountered in further refining the LS architecture. It also serves to illustrate some of the differences between an LSR engine package and the drag-racing motors many of us may be more familiar with.
time-consuming and exacting fabrication, or an aluminum spacer available through Dart that accepts normal LS-style pans and incorporates power steering, A/C, and oil dipstick provisions.
Second, the lifter oiling passages deadhead at the front China wall. An LS block is shorter than an old-school small-block; with Dart’s reversed valve order compared to a standard LS, this places the front No. 1 exhaust lifter closer to the wall (and therefore the end of the lifter oil passage) than an old-school small-block.
“Because of higher bearing loads at the power levels we are at, we like to run 100-plus pounds of pressure to keep the oil wedge up in a Bonneville motor.”
—Ken Duttweiler