REPOWERING & PERFORMANCE
A supercharger is the latest weapon in turbodiesel tuner Jason Frost’s arsenal. NZ4WD editor Ross MacKay explains why.
Imagine a humble run-of-the-mill turbo-diesel ute with the power, torque and driveability of a sophisticated $100K+Euro SUV.
Jason and Guy of Auckland-based performance tuning operation ECU Chips did and came up with a Rotrex-supercharger-based twin-charge induction system which offers Kiwi vehicle owners the holy trinity of significantly more power, quantifiably more torque and driveability you – literally – have to experience to believe.
The idea of using a crankshaft-driven supercharger and in- house built intercooler to compress and cool the charge being fed into a diesel-engine’s exhaust-driven turbo is not exactly new, but is still not particularly common, here or anywhere else for that matter.
Certainly, no one else is doing exactly what Jason and Guy are doing – offering a drive-in/drive-out fitting service for popular turbo-diesel utes and SUVs using kits based round the distinctive traction drive centrifugal superchargers designed, patented and made by Danish company Rotrex.
To understand why ECU Chips has gone ahead and developed their own bespoke
solution to a common problem (getting more reliable power, torque and drivability out of a hi-pressure turbo-diesel engine) you need to know how good a twin-turbo, 3.0litre BMW X5 SUV is. In fact you can go back further, to when ECU Chips first got into the diesel tuning business. That was with the product which gave the company its name, an aftermarket ECU performance chip. Success in that sphere led to interest in complementary areas like ECU re-mapping, and uprated intake and exhaust systems. The improvements in power and torque that can be made to all late-model turbo-diesels is both significant and quantifiable. There is only one real Achilles heel when you are talking turbo upgrades – lag! “We knew that some sort of twin-charge system was the next step because I haven’t been able to find a big single turbo system that’s impressed me,” explains Jason. “Yes you can probably make more ultimate top end power on the dyno with a big single turbo but I just don’t like the cloud of smoke you get when you put your foot on the throttle. “Then there’s the lag. I’m not here to bag single turbos, we still offer upgrades and they’re good as a first step but you just have to look at the factories these days; all your Q7s, BMWs X5s, every grunty German diesel is multi turbo.” So why add a crank-driven supercharger into the mix? Wouldn’t it have been ultimately easier to simply plumb in a second, smaller turbo for the Kiwi-made equivalent of a factory-style sequential set-up? “No. It would be impossible for us to make a twin turbo system work. You’d need electronic control for both turbos meaning you’d need your own little
computer and the work involved in that alone would be way beyond the scope of what we are trying to achieve here.” That didn’t stop Jason’s mind working away at the problem and the Eureka moment came one afternoon when he and Guy were talking about the X5 and what an impressive piece of kit its twin-turbo six cylinder diesel engine was. “I was just saying that we had to figure out a way to twin charge and I asked Guy what was a good supercharger? He said Rotrex so we emailed them and a couple of days later we were on a plane to Denmark to go and see them.” The beauty of the Rotrex supercharger is that they are very efficient because they use compressed oil rather than planetary gears in a smooth-bore drive. “They’re what’s called a traction drive. When the oil is compressed it provides traction, when it is not compressed it lubricates. Because there are no gears there is no noise, and they are 97 percent efficient which, when you think about it, is pretty impressive.” There are several key benefits when you plumb a supercharger into a turbo-diesel set-up. “The key one is more efficient pumping. The pressure in the exhaust manifold can
be half of what it is in the inlet manifold, for instance, whereas in every other turbo system in the world the pressure in the exhaust manifold will always be higher than the pressure in the intake manifold so we have far better exhausting and much lower exhaust heat.” The company’s Isuzu D-Max was pressed into service as the development mule and ECU Chips have spent the past nine months developing what are effectively ‘bolt-on’ kits for popular turbo-diesel models. Craig Cardwell’s Toyota Hilux (see sidebar story) was one of the first and the guys have also recently completed their first V8 Land Cruiser conversion. No two kits need be exactly the same because you can fine-tune the amount of boost with the pulley sizes and the tune. “What we want (from a typical three- litre turbo diesel engine) is 200 to 210kW at the wheels and 800 to 900Nm of torque with drivability and no smoke, we want an engine where the power from 1300 rpm to redline is as linear as the BMW X5. “We’re absolutely not doing this to have a horsepower race with the guys in Aussie. We want to tune responsibly. We want the air flow ratio to be at a level that will make the engine last the life of the vehicle and not contaminate the oil and grow carbon, and we don’t want any smoke.” ECU Chips can supply a complete ‘twincharge’ solution for most popular turbodiesel utes and 4WDs. These include the Rotrex supercharger itself plus an ECU Chip and tune, hand-made intercooler, exhaust upgrade and all the fabrication work. To find out more check out ECU Chips; facebook age at www.facebook.com/ ecuchips.co.nz or the company’s website www.ecuchips.co.nz or tel/txt Jason Frost direct on contact Jason on 0-9-416 5444.
Plenty of room under the bonnet for the compact Rotrex supercharger.