Which is better: turbochargers or superchargers? We talked to engine gurus and owners for their opinion on how best to blow your LS motor

This article was originally published in the 2015 issue of Street Machine LSX Tuner magazine

THERE are as many opinions on the best way to jam horsepower into your LS as there are ways to cook steaks. Out of all the options it seems that turbo and supercharged builds are the most popular for Aussies hunting grunt, but which aspiration option is better?

Popular players in the Aussie market on the side of the Roots-style supercharger include Harrop, Magnuson and Edelbrock. The Harrop is arguably still one of the top picks for someone wanting around 400kW at the wheels using an unopened factory long motor.

GM itself saw fit to equip its own production cars with Eaton TVS four-lobe superchargers that are very similar to Harrop’s Australian-made product, though the US-made Magnuson is also finding increasing favour among those wanting to push past 400kW at the treads. Neat, compact and simple, they’re found on many shop-built rides and work spectacularly well with impressive reliability. Centrifugal blowers – such as the Vortech and ProCharger – aren’t as popular as they once were, but they do have their advantages and attract some rabid adherents.

On the exhaust-driven side, Garrett, Precision, Turbonetics and BorgWarner are the most commonly found suppliers of turbochargers to Aussie LS builds. From racers like Paramount Auto’s Terry Seng and his seven-second VC Commodore to show cars like Adam Barnes’s immaculate HARDHT, and on a million backyard set-ups in between, turbo LS motors have arrived in a big way.

We spoke to Adam Rogash, Mark Sass, Luke Grima, Kent Dalton and Phonsy Mullan, five guys who have a wealth of experience with LS performance, to see where they stand on the debate.

ADAM ROGASH, MPW

“We’re finding a lot of guys are removing their blowers for turbo set-ups,” says Adam Rogash from MPW in Dandenong and Geelong.

As we went to print, Adam and his team were putting a blower-versus-turbo comparison through its paces.

“It’s a customer car,” Adam explains. “A VZ Maloo with a cammed 6.0-litre and Powerglide. It was already fitted with a Harrop HTV122 1.9-litre blower when it came to us. We did a little work and got it down to flat 11s at Calder. We could have gone further with the blower, but it seemed the right time to ramp it up to twin 64mm external-wastegate Turbonetics.

Mark Drew has run a best of 9.22@155mph in his wife’s HR. It runs a 403ci motor with a S480 BW turbo on 18psi, with the tune by MPW. The car has made 697rwhp on the MPW dyno, with eight-second passes seemingly only a matter of time

“It has gone from 360rwkW at 11psi to 450rwkW on 10psi, both on pump fuel. The fuel system is all the same, just with bigger injectors, and we fitted an air-to-air ’cooler. We’re looking forward to giving it a hit at the drags.

“The goal is for easy and reliable 10-second passes, though no doubt he’ll want more – once they feel that top-end rush, they usually want more!”

And it’s not just the earlier cars that are going turbo. Adam has done quite a few VE and VF twin-turbo deals, too.

“We have our own kit,” he says. “It doesn’t require body mods or cutting the car up. They are a low-mount kit, with the turbos down between the chassis rails and the subframe. That means that using the factory inlet manifold and standard airbox, the engine bay looks essentially stock to the casual observer. Yet, they can make well over 600rwkW through a Powerglide. You only run into trouble with the factory manifold when you start putting more than 20psi into them.

“We also have a high-mount single-turbo kit if that is the way you want to go.

“That is not to say you can’t get great results out of blowers. I’ve got a FTFI 2300 Harrop blower on my VF family car and I’m really happy with it. One of the advantages of the supercharger set-ups is that the power rises with revs – take your foot of the throttle and the power drops. Whereas in a turbo car, the boost can hit more aggressively at lower revs, which doesn’t suit everyone. There is also less maintenance with the blowers, so it comes down to what the customer is after.

“A big part of our deal is that most of our staff are heavily involved in racing themselves. Luke Foley runs our Geelong shop. He’s just removed the big single from his VH and put twin 62mm Turbonetics on. He’s already run 8.90s with the twins and a 408ci motor, but he’s just dropped in a stock L98, so we can see how far he can push it.

“We’ve also recently hired Tim Bailey, who did Drag Challenge in his VZ ute. Tim loves problem-solving and working out the best way of doing things; he’s so passionate about it.”

Adam’s own race project is his NOSHOW VZ. Despite the name, it is an elite-level build that will run in the sevens thanks to a 440ci powerplant equipped with twin 69mm billet Turbonetics turbos.

“Turbos are a big thing for us,” Adam says. “We stock the big four – Turbonetics, Precision, Garrett and BorgWarner.”

KENT DALTON, HI-TORQUE

Kent from Hi-Torque Performance on the Gold Coast has plenty of hands-on experience building both blown and turbo LS set-ups. This includes one customer who has a brand new 700hp Magnuson 2300-charged VF Clubsport and another with a twin-turbo VE ute making over 1000hp. So what does he prefer to build?

“It comes down to how they want to use their car,” he says. “Sometimes it can be simpler on a late-model vehicle to fit a cam, exhaust, intake and supercharger and get it all driving like a factory car compared to doing a full turbo set-up.

“I’ve done big turbo set-ups and supercharger set-ups for guys with similar cars, and it really depends on each customer’s budget and where they’re going to use the car. There’s no point building a mega Powercruise package if the car is going to live on the street.”

LUKE GRIMA, HASTY AUTO TRANS

Luke Grima from Melbourne’s Hasty Auto Trans has tried both options in similarly built Torana sedans, and found fewer issues running the supercharger.

From his blue twin-GT35 Garrett-fed 408-cube LQ9 LX sedan, he’s moved on to a Magnuson 2300-blown LS3 package in a very similar (but red) LX four-door.

“The blown car has far less maintenance as there isn’t as much strain on everything,” Luke says. “Heat was a massive factor on the turbo car; I melted paint off the bonnet, and I had to replace braided lines with Teflon ones.

The Magnuson-blown LS3 in Luke’s LX has made 455kW on E85

“It was a learning process to get it all right in the end but, in comparison, the blown car has a set of heat-treated extractors and it’s done. The Magnuson runs a water-to-air intercooler, so there are just a couple of lines to it and a pump under the guard and that’s it; it’s simple.

“The supercharged car is easier to drive as it is instant,” Luke continues. “Even though my turbo car had twin-turbos, it didn’t have the response. The supercharged car has a nice hit out of the hole, where you had to find that fine launch point with the turbo. Turbos are on or off, but the ’charger will gradually bring up the boost. My car didn’t have any launch control, it just ran off the wastegates.

For sheer outright power, Luke admits that twin turbos are the way to go. His twin-turbo Torana saw power levels of 600rwkW

“I thought: ‘Twin-turbos, little car, grouse! Let’s go!’ The Torana is a very small car to throw around and I can remember getting into a powerskid in the turbo car and as I was coming off the accelerator the car was still making torque. With the ’charger, you come off it and the belt isn’t turning as fast so it backs off and it’s a lot more manageable.

“We were making 455kW in the supercharged car; in the turbo car we were making over 600kW and we were way up on the mile-per-hour, but only half-a-second different in ET. I’d rather turbos for the power, and it’s easy to make power, but it’s a harder path.”

MARK SASS, SASS AUTOMOTIVE

Mark Sass, of Sass Automotive in Melbourne, has built a bunch of tough combos for customers and he runs a Vortech centrifugal blower on his own VT drag car LSXWAR. He has a wide-reaching view on the debate.

“Supercharger versus turbo is an interesting question because, like anything in life, there are pros and cons,” Mark says. “I’ve built plenty of cars with different combos, with blowers, turbos and nitrous. Most people look at the financial side of it, as typically it’s cheaper to fit a supercharger set-up because of the type of fuel system. Most drag guys go turbo because they provide a wide torque curve and they have the mile-per-hour over a blown car.

“Generally speaking, most road-going cars would benefit from having an intercooled supercharged set-up. Most guys are just giving their cars hits off the lights and there aren’t many places around that’ll allow them to hold turbo set-ups flat-out where the snail will really hit its straps.

“I say to people that a number is a just number; it’s the way the car drives that’s important. You could have two cars, one blown and one turbo, that make 500hp each, but the dynamics of each car is like night and day.”

Mark also points out an important factor in deciding on an aspiration format: maintenance. While Luke had issues with the reliability of his turbo combo, Mark points out that centrifugal blowers are not without drawback themselves.

“The only real downfall to a supercharged car like mine is maintenance,” he says. “There’s more maintenance with a centrifugal blower compared to a turbo, as anything blown has a belt, idler pulleys, and gearbox oil (depending on the blower). Generally you don’t have any maintenance on a turbo car, which is a definite plus.

“It really depends on what you’re going to do with your car and you need to work out a battle plan before deciding on an induction type. But, just as important, is picking the right tuner. You can have the right combo and the wrong tuner can make it a nightmare.”

Mark also makes an important point concerning what lies behind the motor.

“Gearbox choice can be affected by which power-adder you choose. In my opinion, if they’ve got a turbo car we expect them to use a Powerglide because you won’t lose any turbine speed with only one gear change. With a blown car you keep the speed up between gear changes; that’ll also change the dynamic of how the car feels and drives, too.”

PHONSY MULLAN, GM MOTORSPORT

GM Motorsport’s Phonsy Mullan has another angle on the forced induction argument. While he’s played with turbos, positive-displacement blowers, and 500-cube NA builds, he’s just finished buttoning up a new VF Commodore making 500kW thanks to a 1DC ProCharger.

One of the toughest ProCharged streeters getting around (until its untimely demise in a race prang earlier in the year) was Tim Bailey’s VZ. The daily-driven ute ran a best of 10.37 seconds over the quarter-mile

“I’m happy to use anything that works,” Phonsy says. “The ProCharger gives amazing throttle response and delivers its power in a very linear way. It comes on almost like a naturally aspirated engine. With a turbo you have to manage the exhaust gas velocity and you have to watch a positive-displacement blower’s instant torque.

“A Roots blower can give you so much torque at 2000rpm so you have to set the car up to get the power to the ground, plus intercooler temperatures with the ProCharger are a lot lower than a positive displacement supercharger.”

Mounted off the side of the engine, centrifugal blowers use a belt driven by the crankshaft to spin an impeller wheel on the back of the supercharger. The impeller is similar to a turbocharger compressor wheel, but uses a gearbox assembly to spin the impeller up to speed instead of a turbine wheel.

The LS Transplant kit is just the thing for those wanting a ProCharger on their non-standard LS conversions. GM Motorsport has them to suit EFI and carby applications and all power levels

They gained huge popularity in the early 2000s for their low cost, ease of fitment and generous power hikes on otherwise standard engines. Phonsy sees plenty of other benefits, too.

“Turbos, Roots blowers and centrifugal superchargers are all different disciplines and do different things well. You won’t beat the torque of a properly set up turbocharged engine, and nothing’s going to make more instant power than a positive displacement Roots-style blower.

“The ProCharger will make the most top-end power and be the most driveable, but it all depends on what you want the car to do. Another positive is that you don’t need to run oil lines to the unit, as you would with a Vortech – it’s very simple to set up.

“We’ve done an F3 ProCharged 430ci LS motor that made 2000hp at 36psi, so they can make the power, too.”