Here it is Holden Gen 3 fans - an effective power-up kit that doesn't involve a supercharger!
Melbourne's Nizpro workshop has recently been doing a heap of work with Holden LS1 engines, and has now introduced their '285' kit. This is a thoroughly developed intake, extractor, exhaust and MoTeC package, which is retailing for around AUS$7500 - supplied and fitted in-house. Note, however - if you aren't local to Nizpro - they can send the gear out (complete with a pre-programmed MoTeC) so your trusted workshop can do the installation.
So what does AUS$7500-odd get you?
Well, it elevates your 225 or 255kW spec engine to a solid 285kW at the flywheel - and, if you want to talk momentary power spikes, there's the capacity to nudge over 300kW. (And these figures are those recorded on the Nizpro engine dyno - not extrapolated from rear wheel numbers!)
Take a look at this averaged dyno run and you'll also see the beautifully flat torque curve - there's between 430 and 510Nm all the way from 2000 to 6250 rpm. Note, however, torque tails off after 5000 rpm - that's the limitation of the stock cam and intake manifold.
We're told installing the kit on a 300kW-spec engine - with its factory revised camshaft, springs and retainers - sees a repeatable 325kW generated at the flywheel. Not a bad serving, eh!?
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Rubbery Figures...
Be wary of making any comparisons with factory claimed LS1 power figures. Simon of Nizpro tells us the quoted 225, 255 and 300kW numbers aren't particularly sustainable on his engine dyno. In fact - using his particular dyno pull averaging procedure - those outputs are more like 215, 245 and 288kW respectively...
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Tell me more!
The Nizpro kit begins by releasing exhaust gas flow.
After evaluating various aftermarket and HSV extractors, Nizpro ended up designing their own set. The final incarnation is a mild steel 4>1 arrangement, with 1 7/8-inch primaries leading into a 3-inch flange. Interestingly, the primary pipes aren't quite equal length - we're told this resulted in the best spread of torque.
Note that the extractors seen in this photo are purely development items - the ones sold in the kit come HPC'd inside and out.
Backing the custom extractors is a custom exhaust system. Again - having tried various configurations - the final product sees twin stainless 3-inch pipes bolted to the collectors. These pipes neck down to 2½-inch and merge into a single 3-inch pipe, which continues to the rear of the car. Fitted along the way are twin 3-inch straight-through mufflers, a baffled 3-inch rear muffler and a modified pair of Holden cats. Simon explains the Holden cats - which have simply a larger inlet and outlet welded on - help to keep emissions relatively low.
Next comes enhancing intake airflow.
Rather than whack on an aftermarket pod filter, the Nizpro kit retains the standard Holden airbox. Why? Because the guys have thoroughly put it through its paces on their dyno, and - with some slight mods - it performs very well. The only alteration is a larger diameter feed pipe into the bottom of the box. Simon tells us they even keep a standard filter insert, because none of the aftermarket replacements made any improvement!
Next - on both 225 and 255kW factory engines - Nizpro tackles the restriction of the airflow meter and the less-than-ideal elbow that links it to the throttle body.
The pre-throttle body elbow is simply replaced by a fatter 4-inch version (similar to the one on the factory 300kW engine), but the airflow meter situation is a bit more involved...
First up, Nizpro removes the airflow meter and places a straight length of convolute pipe in its place. The associated under-bonnet wiring for the now-gone airflow meter then gets tidied up, and a completely different type of load sensing device is introduced - a MAP sensor (the same one as factory-fitted to the 300kW engine).
Because a MAP sensor measures only pressure in the intake manifold, its output signal is completely different to an airflow meter (which, as the name implies, measures intake air flow). That means you can't convert to a MAP sensor and expect the standard 225 - 255kW LS1 computer to cope; so for this and other reasons Nizpro adds a programmable MoTeC M800 management system.
Note that a AUS$4700 chunk of the kit's AUS$7500-odd ask comes from the supply, fit and tune of the MoTeC computer. Its inclusion, however, is absolutely necessary. It allows the fitment of the restriction-free MAP sensor, optimal tuning to suit the intake and exhaust mods, and - as a bonus - it gives you enormous tuning flexibility further down the track. You can slip in a different cam or add a blower and all you need is a re-map.
Interestingly, Nizpro run the MoTeC M800 unit in tandem with the factory ECU - a so-called piggyback set-up. The MoTeC computer controls only the injectors and ignition; everything else - from power steering compensation to idle control - is left to the standard Holden computer. As Simon explains, "all we want to do is adjust our fuel and ignition. Holden have already spent countless hours developing the rest of it, so it's best to leave it in place".
One hurdle involved in taking this approach, however, is in regard to fuel rail pressure. Because the standard computer actively controls fuel pump voltage, rail pressure could have varied without the MoTeC computer realising what was going on. That means - for a given pulse width - the injectors would have delivered too much fuel if the rail pressure was high, or not enough fuel if the rail pressure was low.
Nizpro fixes this situation by attaching a pressure sensor to one of the rails, and feeding its output into the MoTeC unit. Thanks to the computer's programmed fuel pressure compensation curve, the injector pulse-width is then appropriately adjusted on the basis of actual fuel rail pressure. It's this sort of attention to detail that really sets this power-up kit apart from the many other upgrades available.
Given the MoTeC's capacity for cylinder-specific fuel and ignition adjustment at 256 different load points, we're told a thorough mapping job can release a l-o-t of power.
Simon runs the modified engine at 0.92 Lambda (13.5:1 AFR) at full noise, and has added a couple of nice touches that are indicative of a well thought-out tune. When the MoTeC detects coolant temperature above 120 degrees (which you might get, say, towing a heavy trailer up a hill on a hot day), it'll dump in a massive over-abundance of fuel. This serves to cool the engine, reduce power and protect the engine.
Because each of the 8 cylinders uses individual ignition timing (via the standard direct-fire coils), it's difficult to give you a single full-noise advance figure. In any case, we get the impression Simon's not real keen to give it away...
We do, however, know mapping has been optimised to suit premium unleaded/Optimax - but be ultra-cautious that you don't inadvertently fill the tank with regular unleaded. Surprisingly, the MoTeC has no knock detection function, and - as a result - low octane fuel could spell engine damage.
Simon tells us the final item on the kit agenda is to put the engine through for emissions certification. Given his careful tune-up and the OE cats, he's hopeful of getting through - stay tuned.
Contact:
Nizpro
+61 3 9761 1522
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In a Nutshell...
The bang-for-buck effectiveness of the Nizpro kit varies greatly depending whether the 225, 255 or 300kW factory engine is being used as the platform. Because the 225 and 255kW factory engines both generate 285kW once the kit is fitted, the biggest percentage gain comes on basic 225kW model. In this instance, you're AUS$7500 outlay returns around a 30 percent increase in power. In comparison, installing the kit to a 255kW factory engine gives about a 15 percent gain, while the 300kW factory engine picks up only around 10 percent. Inevitably, chasing in excess of 300kW - without forced induction - will be expensive.
On the undisputed plus side, the Nizpro 285 kit delivers sustainable power (because compared with supercharging there are no major heat issues to contend with), it's unobtrusive when you pop the bonnet, and it comes with one of the best programmable management systems on Earth. Keep in mind that the MoTeC tuning flexibility could prove invaluable down the track. Backing the 285 kit is a 12-month warranty on the MoTeC computer, while Nizpro offers a 6-month warranty on all of their gear. Not covered is the engine or any of the driveline. So there you have it - at last there's an 'off-the-shelf' naturally aspirated power-up kit to suit the Gen 3. It's definitely worthy of consideration - especially if you're looking to upgrade your factory 225kW vehicle.
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