Seven hundred and sixty seven horsepower?! What are we talking about here, a humungous turbo-diesel marine engine? A big cube drag car? An earthmover? What?
Well, this is Nizpro's flagship performance VL turbo (which is owned by Ben Visconti) - and it's a car that we're sure you're gonna like to meet. With credentials like 767hp at 6750 rpm and 713 ft-lb at 5000, it's no wonder this Holden Calais sedan has managed to blast off to a quarter mile best of 9.95 at 140 mph! Ben sure is serious about cracking some heavy numbers! And all that from a SOHC in-line 3 litre six....and still with the standard block.
Deep Within
Simon Gishus of Nizpro started this mammoth engine project with your average RB30ET, which Ben delivered to him with the goal of 9 second passes. And armed with a swag of knowledge gained through experience Simon knows this to be a good, solid engine that's quite capable of making real power. 'Real' power? Maybe 'unreal' power better sums it up!
With everything pulled apart, he first set to work assembling a bullet-proof bottom end that would be able to withstand the anticipated 750-plus hp. About the only block preparation required was a Nizpro W-ring to improve head gasket sealing. Nissan's standard crankshaft had its gallery plugs removed and tapped with grub screws, and the whole assembly was then linished and balanced. Stock bearings - which are an often-underrated item - were used in the build. Simon's extensive experience with RB30s also taught him that you can't expect the standard rods to live long when you step over about 500 ft-lb of torque. To overcome this problem, he's fitted a set of billet steel rods.
Piston choice too is always very important in an extra high performance engine. This one uses Cosworth forged items that deliver a relatively high compression ratio of 7.5:1 - a ratio that Simon tells us is generally okay for up to about 40 psi boost. But to further improve durability of this A$36,000 engine (yes, A$36,000!), the new pistons were modified to accept a larger set of piston pins. Factory Nissan parts were again used for the piston rings. At the very base of Mount RB30 lies a high-volume 9 litre fully baffled sump. Oil pressure through the engine is increased too, with Nizpro's own high-volume pump that runs at up to around 120 psi.
Mobil 1 is the oil of choice for Ben's car, with a catch can also used to salvage any black stuff that goes wayward. Mother Nature's cleanest of fluids - water (mixed with coolant too, I guess!) - is sent on its path through the engine by a Nizpro water pump, which builds up quickly to deliver slightly more than standard flow.
Up Stairs
The single cam 2-valves-per-cylinder head is always going to be a bit of a bugger to get power from in comparison to the twincam RB25 and 26 Nissan engines. Nevertheless, 767hp proves that you don't need to go for a twincam head for heaps of power.
Nizpro de-burred this alloy cross-flow bit of gear, de-shrouding the standard valves. Crow high tension valve springs were put in because Simon knew from the beginning he'd have to rev the engine a bit past 6500 to get the desired power output - more than the standard car's rev limit. (But nothing like the expected rpm to get this much power from a swept capacity of just 3 litres, is it?!)
Standard rockers and hydraulic lifters are kept in service. Cam selection was made based on experience and the one that got the nod was a Nizpro grind giving 500 thou lift and 220 degrees duration at 50 thou lift. Nizpro's own custom vernier cam sprocket was used to dial the cam in for best performance while on the engine dyno. And while we're up there, we should mention that another interesting mod of Nizpro's is to slightly modify the underside of the rocker cover in order to help reduce oil surge. Finally, the whole head assembly was placed atop of the bottom bit using a standard head gasket - something Simon says you can only get away with if you use a W-ringed block.
Take the Pressure Down
The focal piece of the forced induction side of things is Nizpro's custom "650hp" T4 turbo unit. It's exact details aren't the sort of thing to be given out though. This is fed the RB's wastage by an in-house developed tuned length stainless steel extractor manifold with 1½-inch diameter primaries. After the turbo, the exhaust pipe hung from the car is a 3 incher ("a dog of a thing" according to the tell-no-porkies Simon).
Interestingly, there is no wastegate system to be found. Instead, dual electronically controlled valves - of about 32mm diameter - are placed in the post turbo intake to control boost pressure. It's an approach that Simon claims is more precise and keeps turbo speed very consistent.
Boosted intake air is then put through a 2½-inch pipe into a Nizpro air-to-air intercooler that's built up using a US-sourced aluminium core. Mounted in front of the car's engine radiator, this sucker measures around 60cm x 40cm x 7cm (plus the custom end tanks).
A fat 3-inch pipe takes the intercooled air right up to a now-commonly-fitted-to-VLs 65mm Ford throttle body, which gives extra flow due to its larger size. The polished intake manifold you can also see is far from standard. It's Nizpro's own fabrication that incorporates internal trumpet rams and large diameter inlet runners.
Fuelling Around
Simon went for a fuel injector that would be good for 130hp each and still give the ability to give Ben good drivability (by not being overly-large). Rochester 850cc 128s fitted the fill perfectly and were accordingly plumbed into a custom-made billet fuel rail. A static pressure of 2.5 Bar is provided by a Bosch regulator, while Avgas is put through 3/8-inch lines by two Bosch 984 pumps. But it all starts off at the 40 litre competition fuel cell contained in the VL's boot.
This fuel delivery system is controlled by an Australian-designed MoTeC M4 programmable management system that's run with an engine load input provided by a 100 psi Data Instruments MAP sensor. Simon has configured the ECU to run in open loop, since the engine is run on Avgas. Then, of course, there is the OzNos nitrous system. Feeding a 50hp dose of N20 directly into the intake port certainly gives the RB a fair-sized whack of torque. This is done to bring the trans up onto its converter earlier, in addition to giving increased peak horsepower.
The ignition arrangement is made up of a MoTeC CDI, a Bosch coil and Magnecore 8mm leads. A cold set of NGK plugs helps to ward off any detonation. But another function the MoTeC ECU serves is to control boost through the aforementioned boost control valves. Simon adds that the boost control maps in the MoTeC program also allowed him to return the car to Ben with a "big engine feel" and a trimmed boost curve to give optimum traction.
Back-Up
So what the hell sort of driveline do you hang behind a 700-plus horsepower VL? It's purely all 'drag' in this case, with a modified PowerGlide trans equipped with a ratchet style shifter. A bit more experimentation needs to be done with the torque convertor though, as the current 2800 rpm unit is probably a bit too low to pin Ben right back into his Aerotech seat. A trans brake is controlled by one of two steering wheel mounted buttons - the other is used to bring on the nitrous at anytime.
Working back, a built-from-scratch 3 inch thick-walled tailshaft takes the elephant-like torque on to a standard diff (?!) with a spool centre and 3.45:1 gears. On the track, the VL sprints on 10 inch Mickey Thompson slicks while on the street it looks a lot more mild mannered with Simmons FR18s wearing Falken rubber.The suspension is surprisingly stock. The only mod is a pair of 90/10 front shocks.
Incidentally, the engine now sits rearward by around 25mm to help create more available space in the engine compartment and to shove more weight in the direction of the drive wheels.
Dyno Might
By now you'd have realised that we've pushed the numbers 767hp and 713 ft-lb pretty hard.
But we'll now fill you in on the exact configuration of the engine when it achieved those impressive numbers. It was run complete with 50hp worth of nitrous, Avgas fuel (with 33% tolulene mixed in), a full 3 inch exhaust, cold spark plugs and boost pressure limited to 30 psi. Simon added that around 703-710hp is easily achieved in the same tune minus the giggle gas.
He readily admits though, he must have been stretching it a bit when he turned the boost up to 40 psi. Once again, with the engine in the same configuration and a 50hp shot of nitrous, power rocketed away to 839hp and 689 ft-lb at 6300 rpm. "But it must be close to breaking at that point", Simon tells us with obvious admiration of the engine, "I'd think block flex would have to start to become an issue."
Gee, I wonder why....? That's in excess of four times the factory RB30ET's peak output!!! Good enough to deliver nine second passes... what else can you say?
Contact:
Nizpro
+61 3 9761 1522
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