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Quentin Feast's Twin-Turbo LS-Powered 1974 Holden LH Torana - GMPWR

By Iain Kelly | Photos: Chris Thorogood, 23 Mar 2018 Features

holden lh torana 1896 nw

Quentin Feast has won Street Machine Drag Challenge every time he's turned up in this seven-second Torry

Quentin Feast's three-time Drag Challenge-winning Holden LH Torana proves the old adage of working smarter, not harder

This story on Quentin's Holden LH Torana was originally published in the February 2018 issue of Street Machine

IT’S tempting to solve problems with overkill, like curing overheating with a fresh engine. But there are smarter blokes out there who take a more analytical approach, and Quentin Feast’s seven-second, street-registered LH Torana proves the benefit in studying data before making changes. If you doubt that, he’s got three Drag Challenge wins and an undefeated record at that event to back him up, along with a PB of 7.75@178mph at the car’s first test outing after recent upgrades.

Holden LH ToranaHis Wild Plum ’74 LH Torana has evolved over time to become the 1300rwhp twin-turbo, LS-powered monster it is today, though it had a big birthday before Drag Challenge 2017. In fact, Quentin and a crew of close mates managed to build a fresh engine (twice), swap to a new transmission, and tidy up the engine bay in just eight weeks!

But it all started with a 15-year-old smashing up his old car around 17 years ago. “I had an LH SL/R until some turd rear-ended me, writing that Torry off,” the Victorian explains. “So I bought a rolling shell from Corio Bay in 2000 and began the first build of what was to become GMPWR. The paint was fresh and clean, the car was very straight, and it was tubbed with the nine-inch.

Video: Quentin's twin-turbo LH Torana at Drag Challenge

Holden LH Torana sideOne big change for 2017 was the move to a three-speed TH400 transmission over a two-speed Powerglide. One of Quentin’s good mates, Paul Rogers from Paul Rogers Performance Transmissions, built a wicked box of gears including a new billet aluminium full-manual valvebody, and transbrake on both first and second gears

“The tubs were a backyard job and the diff was terrible,” Quentin continues, “so I ended up making my own control arms, mounts, put chassis connectors in it, and made new floorpans in the rear. The tubs themselves are made from some ridiculously thick metal. My mate Mark McCoy, who also tunes the car, was a suspension engineer before he worked at MoTeC and we got the rear end much better.”

Video: Quentin's LH Torana dyno test

Holden Torana rearQuentin originally had a go at smoothing the engine bay back in 2007, before Steve Cassy squirted it and the whole car in the retina-bashing Wild Plum two-pack. In 2017 the boys from Tankards Panel Service went to town; Dale Ward redid the bay and prepped it for Terry Brown who laid fresh Wild Plum in the bay while the motor was out for its refresh

Fitting the LS into the LH required some careful work with the welder, and, as Quentin was doing all this in his home garage, plenty of time. He used a K-frame out of a UC Torana, which required some modification to clear the twin 3.5-inch exhausts from the old turbo mounting position. But that was just the start of the fab work.

Holden LH Torana“I made my own engine mounts, as far back as possible,” says Q. “They’re about 45mm further back than other bolt-on mounts available, and they’re much stronger; I gusseted them as I wanted to make sure they wouldn’t move with the power we were looking for.

“However, moving the engine back so far caused more problems; like I had to drop the K-frame two inches to get the ’box or converter out. It’s now quicker to drop the K-frame and wheel the engine and ’box out in one go; in fact, I can pull it out with the pipes and turbos attached. That makes re-fitting it much easier and I can have the ’box out in 45 minutes, but we haven’t had to since changing from a Powerglide to the TH400!”

Holden LH Torana wheelThe heart of GMPWR is an iron-block sixlitre LQ9, a truck variant of the Gen III 5.7-litre LS1. The LQ9’s machine work was done by Joe Sammut of JC Engines, with Clint Dalton and Quentin handling assembly.

Street-driven twin-turbo Holden LX Torana

Holden LH Torana engine bay“Clint is a good mate and he helped me out massively to get the engine assembled before Drag Challenge,” Quentin says. “I actually learned a lot of new stuff from putting the motor together with Clint, as he has many years’ experience with race engines and is a very smart bloke. Some people have told me this engine should have exploded by now. But they have been saying that for three years now!”

The 364ci block was taken out to 404ci using CP Bullet pistons, a DragonSlayer crank and Compstar conrods from Callies, with compression around 10:1 and Clevite calico bearings used to handle the stresses of a potential 2000hp.

Holden LH Torana engineThe fuel system is conventional, using eight Siemens Deka 2400cc injectors and three Walbro 460E pumps in a bootmounted cell, pushing United E85. The three fuel pumps are staged to come on at different boost levels. One pump is all that is needed for mild street driving, but once the power needs to build the second pump is turned on, and when you ask for more the third is activated

The oil pump is a Melling 10296, while Quentin made his own sump at home to house the black gold. “It is a VE 6.0-litre sump,” he says, “and the first thing I did was cut it out to clear the K-frame, then I went to town remaking it. It retains the factory oil filter mount, has 8.5 litres’ capacity, and still retains a standard windage tray, plus I also added four gates and baffles in the sump, and we’ve never had oil problems.”

Holden LH Torana engineThe bumpstick is a Crow hydraulic-roller measuring 238/250@0.50, with .600 lift. “We know the cam is holding the power back,” Quentin says, “but a big cam will cost us power down low, which hurts driveability.”

Another change for 2017 was the LS3 rectangle-port heads that have been reworked by guru Nathan Higgins. They’re matched to Trend pushrods, Morel hydraulic street tie-bar lifters, single beehive PSI valve springs, 2.165-inch REV intake and 1.6-inch Inconel exhaust valves. The rocker gear is just stock LS3.

Holden Torana engine bayQuentin added larger twin 67mm Garrett GTW turbos capable of producing up to 30psi each during the rebuild and, once again, made all his own piping, including for the front-mounted air-to-air intercooler. The huffers sit on stock VE Gen IV six-litre castiron exhaust manifolds, flipped from left-toright, and Quentin has found they are a long way from holding him back. “Originally the cast headers were a budget factor,” he says. “A lot of turbocharging experts will tell you a turbo requires air flow and heat. A cast-iron manifold keeps the heat in, so by having the standard manifolds, you don’t get as much lag.

“The old exhaust set-up was the first turbo kit I’d done, so I worked through datalogging to find what was stopping us going faster. We found the factory manifolds weren’t causing us as much grief as the old turbos were! For the new set-up I went under the guards to keep it neater and get some heat out of the bay, and we have twin four-inch dump pipes now.”

Holden LH Torana turboSo far GMPWR’s new set-up maxed out one chassis dyno, with a peak of 1279hp, though there is a lot more headroom to explore, with the turbos theoretically capable of making the LH spit out 2000hp at the engine. “I don’t want to just jam a bunch of boost into it to make it go faster,” Quentin says.

The charge-air pipe feeds from the intercooler into the stock 90mm LS3 electronic throttlebody mounted on a stock plastic LS3 intake manifold. Quentin didn’t fit a simpler cable accelerator thanks to the better street manners the GM unit gives.

Holden LH Torana bootThat Jim Beam tin is actually not for consuming once racing is done. “That’s my radiator overflow,” Quentin laughs. “ANDRA told me I had to have a 4.0L-minimum metal radiator overflow, so the Jim Beam was in the shed. We drink a lot of Beam, this team!”

“Fly-by-wire throttle gives me better driveability,” he laughs. “My accelerator pedal isn’t at 1:1 with the throttlebody – we needed to adjust this when I put the new turbos on, as they behaved very differently. My throttle pedal position is essentially ‘torque request’ – so we adjust the fly-by-wire throttlebody and control to keep power delivery driveable and predictable.

“People say my car idles like a baby and sounds near-stock; this is due to very fast calculations and adjustments to the throttle position and ignition timing controlled by the MoTeC – like how GM runs its cars – so idle is a closed loop. Holden didn’t design these 90mm throttlebodies to make 1500hp, but they’re not a shit part. We’ve tested and proved the throttlebody isn’t a restriction on my engine.”

Holden LH Torana interior frontInside, the LH has been trimmed by Kevin Cain’s Upholstery with Ford Futura front seats and a custom rear, custom hoodlining, an OMP steering wheel, B&M Magnum Grip Pro shifter and custom-ordered Klippan belts. Mischa Cooke was responsible for the custom six-point ’cage, while Quentin reads info off the MoTeC C127 display as well as Auto Meter gauges

Along with helping him set up the suspension, Quentin’s good mate Mark McCoy handles tuning duties on GMPWR, and as he works at MoTeC you know there’s going to be some NASA-spec computing power in the old ’Rana. The ECU is a MoTeC M150 unit, though the real story is in all the sensors and datalogging capability the LH has. This gives the boys the information they need to refine their package to the current point of brilliance. Quentin also uses a MoTeC E888 CAN network expander, dual MoTeC LTC (Lambda to CAN) modules, and a MoTeC C127 dash.

Holden LH Torana dash“Logging is everything for us,” Q says. “If we couldn’t make changes to the computer or read what the car is doing, we’d be pretty much done. We took a spare Ethernet cable to Drag Challenge last year because if the one cable we had failed we would be caught out. We brought a spare $12,000 transmission along, yet we could have been out due to a $5 cable, which mind you can be bought at any supermarket!”

Holden LH Torana interior rearThe boys don’t just log information from the engine, either. “It is your whole package that adds up,” Quentin says. “Before running Drag Challenge I put new shocks in it, which is paramount to running a radial car fast, but we also wanted data on what’s going on with the suspension.

“We have a suspension position sensor on the front and I borrowed a laser ride-height sensor off a Le Mans car on the rear, so we could calculate the suspension’s position and rate of change, which will hopefully help us write anti-wheelie software down the track if needed. Theoretically, this would let us have the wheel one inch off or just touching the track for the whole run. I’d prefer the wheel stays just in contact with the track, as if a car carries the wheel a long way and then drops down, it unloads the back tyres, causing wheelspin.

Holden Torana roof lining“You’re always pushing the limit, until it breaks, then you upgrade it,” Quentin reasons. “That’s just the way drag racers are. We upgraded the shocks to get the 60-foot better, then we found the anti-roll bar wasn’t working right, and then that showed other things to fix.

“We went to Sydney and ran 8.34 but we ran 8.0s at Calder just working on suspension and getting it to go straight, so it covers 400m, not 405m criss-crossing the track or wasting energy twisting the car and lifting wheels.” Yep, working smart instead of trying to squash flies with a sledgehammer is what gets the results – as proved by Quentin’s incredible achievements so far.

Holden Torana LH dash“You have to be able to communicate with the ECU and the dash,” says Q of the two diagnostic ports under the dash, either side of the ciggie lighter. “One of these is for the dash and one is for the ECU. We have telemetry so if Mark wants to pull the log over WiFi while the car’s still driving, like a V8 Supercar, he can. There’s no point doing anything live during a drag race as it is theoretically over in 7sec”

WINNER’S CIRCLE

“I have to say a huge thanks to all the guys who helped get me to Drag Challenge, because the real story with this car has been the amazing effort people put in to help me out,” Quentin says. “I had my pistons coated for the first rebuild before Drag Challenge. After that first race meeting at Calder the oil filter was full of not only metal but a blue coating. We knew the blue was Teflon off my pistons. Thankfully Ryan from Race Coatings rectified someone else’s work, sand-blasting the old coating off and recoating them. He’s done all the ceramic coating on my pipework, and I’ve had the exhaust manifolds and turbines glowing red at 1000°C and they’ve gone straight back to  black. I’m very impressed with his work! I had to call Lou from Dandy Engines and ask him to machine my block and crank for the Torrington bearing conversion, and he did it in two days the week before Drag Challenge – legend!

Holden LH Torana at Drag ChallengeRight off the mark the 2017 upgrades knocked GMPWR’s PB from an 8.02@172mph down to a 7.75@178mph at Calder Park on its first pass. At Drag Challenge 2017, Quentin got his first red hat of the event with a 7.99@174mph at Swan Hill on Day Three

“Everyone pitched in to help us get to that event, and it’s a credit to guys like Joe Sammut from JC Engines who did my engine machining; Clint Dalton from Dalton Racing for the engine assembly; Mark and Phil from MoTeC; Pete and Mick from Demak Timber; Tony and the team from Bob Jane; Lee from TCE Converters; Nathan Higgins from HRD for the head porting; Lou from Dandy Engines, Shannon and the team at Tankard Panel Service who prepped and painted the engine bay; Luke from Modern Visual; Pete from Casey Automotive for the late-night dyno sessions; Penrite Oil, Kav Auto; Speed Pro; Coxy; Jacob; Burko; and Grant.

“I also have to thank my good mates Mark McCoy, Paul Rogers and Michael Trewin, who crewed on the car for the event.

STIFF PROPOSITION

Knowing he was going to make bulk grunt, Quentin fitted chassis connectors under GMPWR to stop the LH twisting up under launch. The Strange Pro iron-centre 9in diff has Aikman Engineering 35-spline full-floater axles, with a Truetrac centre and 3.25 gears, with Pro9- supplied Strange coil-over springs and AFCO dualadjustable shocks holding it off the underside of the shell. There is also a Pro9-supplied anti-roll bar, which Quentin fitted along with the coil-over rear suspension.

Holden Torana LH onroadThe beauty of GMPWR isn’t just its brutally quick timecards, but the fact it really is a joy to drive on the street. “We spent so much time on cold start, probably four times as much as on the race tune,” Quentin says. “But that’s where the manufacturers also put in time. We were at an event where there was a frost in the morning and the other E85 cars were coughing and farting and wouldn’t start, but I just leant in my window and my car fired right up and idled”

QUENTIN FEAST
1974 HOLDEN LH TORANA

Colour: Wild Plum

ENGINE
Type: Chevrolet Gen III LQ9
Capacity: 404ci
Turbos: Garrett 67mm GTW3884
Crank: Callies DragonSlayer
Rods: Callies Compstar
Pistons: CP Bullet
Heads: HRD LS3
Cam: Crow hydraulic-roller 238/250
ECU: MoTeC M150

TRANSMISSION
’Box: Paul Rogers TH400
Converter: TCE 10.5 Pro Mod sixbolt 3500rpm
Diff: Strange 9in, Truetrac LSD, 3.2 gears, full-floater 35-spline axles

SUSPENSION & BRAKES
Front suspension: Pedders springs, Pro9 AFCO dual-adjustable shocks
Rear suspension: Strange Hypercoil springs, Pro9 AFCO dualadjustable shocks
Rear end: Tubbed, custom four-link control arms, Pro9 anti-roll bar, Pro9 rear coil-over suspension, chassis connectors, modified K-frame
Brakes: BA Ford two-pot calipers and BA DBA 4000 discs (f), Nissan GT-R Skyline two-pot calipers and HZ Kingswood discs (r)

WHEELS & TYRES
Wheels: Weld; 15x5 (f), 15x10 (r)
Tyres: Mickey Thompson 26x6 (f), Mickey Thompson Radial Pro 275 (r)