XR6T Beyond 1000hp!

This article was first published in 2004.

If there’s one thing we’ve learnt about Simon Gichus of Nizpro it’s that he’s more than willing to spend the time and money developing the most super-duper tuned engines. Every time we have a peek inside his fully equipped dyno cell there’s something wild bolted to the engine stand.

The last time we poked our heads into the dyno cell we happened to see this – Australia’s most powerful Ford XR6 Turbo engine!

With a last run of 1035hp – running a mild 23 psi boost and with Mobil 98 RON fuel – Simon has been the first to crack the magic tonne. Interestingly, Simon says there will be quite a few people making big power with XR6Ts in the next few years. “We wanted to get in early and develop something that will make that 1000hp figure while still holding together and being nice an’ driveable,” he says.

Simon was drawing on his wealth of experience tuning Nissan RB-series engines when he tackled the new Ford six. “At 4.0 litre it’s a big engine and, in that context, it can rev alright with the right gear – we plan on taking it to around 8000 rpm.” And that takes us to one very important point. Simon says that achieving 1000hp+ reliably calls for a fine balance of torque and revs.

“We’ve held to an 800ft-lb torque limit, which we aim to get up to and maintain as far through the rev range as possible. This should protect the rods and various other parts of the engine, compared to sticking in more and more boost and watching torque go up,” he says.

With this in mind, the engine has been built to withstand high rpm as well as huge torque.

The standard crankshaft has been replaced by a fully counterweighted steel billet crankshaft, which Simon had manufactured locally. Rods are H-beam forged items working with local forged pistons. These provide an 8.3:1 static compression ratio (0.4 lower than standard) and slide in 0.05mm oversize bores. Rings are described as “special”.

The Ford DOHC has been slightly modified. “compared to a Nissan GT-R head, in standard form the XR6 head flows about 12 percent better on the inlet and 15 percent better on the exhaust.” Cam specs are a closely guarded secret but we can tell you upgrade valve springs are necessary.

Simon was concerned by possible oil starvation of the big-end bearings and has modified the oil system. An oil cooler is fitted for dyno use and will be retained once the engine is fitted to a car (Simon will be dropping the engine into his everyday XR6T ute for on-road trials!).

The whole purpose of an engine dyno is to allow extensive engine development. Simon has used his dyno to good effect, having tried three other turbochargers before settling on the current jigger. And, no, Simon isn’t going to give that info away... Likewise, the exhaust manifold design is a secret but Simon tells us fabrication of a compact, 6 cylinder turbo manifold is a very difficult exercise.

Simon went with his preferred approach to boost control – the combination of a wastegate and pressure relief valves on the intercooler plumbing. A 44mm Teal external wastegate and a pair of ex blow-off valves serve to maintain the desired turbine speed. Maximum boost pressure is about 23 psi, but Simon generally tips in a couple of psi more boost through the top-end to maintain his desired torque figure.

Intercooling in the dyno cell is left to a water-to-air arrangement. This provides a thermostatically-controlled 40 degrees C intake temp charge that we’re told is representative of what you’d find in a car with a front-mount air-to-air intercooler.

Pre-compressor intake flow is almost restriction-free thanks to a huge K&N pod filter, while a 4 inch dump pipe lets the turbine breathe. According to Simon, this flows similarly to the twin 3 inch set-up currently used in his car.

The intake manifold is the same set-up used in the off-the-shelf Cobra 3 kit. Nizpro has developed a replacement intake upper section of manifold that mates to the factory lower section. This replacement part features a revised internal volume and the factory Ford throttle is relocated to one end of the manifold.

The complete replacement engine management system is the only one on the market that’s up to the task of controlling the Ford’s electronic throttle and variable cam timing: a MoTeC M800.

Mapping of throttle strategies will probably be finalised when the engine hits the road, but – for now – Simon says the ability to alter cam overlap (by altering the relationship between inlet and exhaust cams) makes a huge difference. In the bottom-end, at about 2000 rpm, Simon has picked up around 100ft/lb...

When teamed with the factory rail, lines and regulator, a massive set of ‘drop in’ injectors provide the necessary fuel flow. Twin Bosch 984 fuel pumps maintain flow and pressure.

The ignition remains completely stock, except the plug gap is dropped from 1.0mm to 0.9mm.

Running straight Mobil 98 RON fuel, the mega XR6T engine has recently turned Nizpro’s DynoLog engine dyno to the tune of more than 1000hp – 1035hp to be exact. That, readers, is more than three times the factory output... Simon casually makes the point that he engine makes about 250 percent more torque than standard and revs 25 percent harder than standard.

Peak power is achieved at around 6800 rpm with the rev limit currently set at 7500. This, believe it or not, is a relatively conservative tune and Simon says the engine has now reliably racked up more than 24 hours of full-throttle dyno time.

Despite already owing about AUD$45,000, Simon plans to reset the rev limit to around 8000 rpm and install a larger turbocharger to satisfy his new goal. A goal of 1000 kilowatts...

And what kinda driveline is gonna cop with this, you ask?

“We’re planning a C9 auto trans and a stall converter of around 2500 rpm,” says Simon. Interestingly, Simon says there’s a good chance the factory diff should be able to cope with the strain – rear wheelspin will take some of the load off the diff gears.

We’ll be keeping a close eye on further development!

Contact: Nizpro +61 3 9761 1522 www.nizpro.com.au

1000HP Dyno Video 1000HP Ford XR6 Turbo Nizpro engine dyno