From the Vault – The Demand for Power

Street Commodores – 11/11/08

In this time of green technology and high fuel prices it amazes me and at the same time excites me that car manufacturers and in particular General Motors are still committed to producing larger capacity, more powerful engines for their customers. I am sure it’s partially driven by the marketing hype and the “mines bigger and faster than yours” syndrome. It really does make you ask the question. Is the writing on the wall for the V8 or is their always going to be a V8 engine offered to us power hungry Holden owners? To answer that question I think we need to look at what is on offer now and what’s in store for the future.

In the workshop we recently had a new LS3 powered HSV on the dyno and in standard form it was making 245rwkw, by just fitting a cold air intake and a touch up to the tune the power jumped up to an impressive 265rwkw which equates to around 340KW at the flywheel or around 450HP for the old school people like myself. I know this is not going to break any dyno records but for an everyday road car straight from the dealer and $1500.00 spent on it, I reckon that’s pretty impressive, not to mention the 6.2 liter capacity that now produces close to 600NM of tyre frying torque.

We have also seen HSV release the W427, this weapon sports the now famous GM LS7 and has a capacity of 427ci (7.0Lt) pumping out a healthy 375kw (500hp) of power and 640nm (472ftlb) of torque not to mention a “lip licking” dry sump oil system, forged crank, titanium con-rods and all hand built and fitted with a plaque with the engine builders name stamped on it.  I know this is a limited edition vehicle with probably under 100 cars being made but it still shows a big commitment by a local manufacturer and customers who are still hungry for power.

If you head over to the US, GM has started to sell the 2009 Corvette with a few juicy variations including the ZO6 with the same LS7 engine as the W427 and if that’s not enough grunt for you they have also added the ZR1 to their line-up that sports a 6.2liter engine fitted with an Eaton^® TVS™ (Twin Vortices Series) supercharger and has a total power output of 475KW (638 hp) at 6500 rpm and 604 lb.-ft. (818nm)of torque at 3800 rpm, making it the most powerful engine to occupy the engine bay of a General Motors production car and there’s talk that this maybe the future engine for the HSV GTS mmmm.

Behind the scenes of all this power crazed madness, GM globally has been working hard on securing the V8’s future and to give us the best of both worlds by giving us better economy while still giving us our stump pulling tyre frying V8s. Holden has already started to make noises that it will be introducing its AFM (Active Fuel Management), commonly known as displacement-on-demand, which shuts down half an engine’s cylinders while cruising and GM claims the system delivers a fuel saving of around 10 percent. However at this stage is not available on any Holden built cars in Australia and the company has made no official announcement as to when it may arrive, although I have been told by my local dealer there is excellent deals and factory rebates on all current 6.0lt stock “to make way for the new displacement on demand V8 that is coming”.

Holden had originally attempted to have displacement-on-demand ready for the launch of the VE Commodore and the current  L98 6.0litre in the VE has all the AFM parameters in the ECU while the engine block has the modified oiling system minus the lifters and control solenoids. Holden however postponed the project due to “technical refinement “issues but then when Holden did the deal to re-badge the SS Commodore as a Pontiac G8, one of the requirements was that the V8 would run displacement-on-demand technology and Pontiac subsequently bankrolled the development work.

For those of you who don’t know how displacement on demand works it are quite simple really.  A  solenoid control valve assembly that is electronically controlled  is integrated into the engine valley cover and contains solenoid valves that provide a pressurized oil signal to specially designed hydraulic roller lifters, these lifters disable and re-enable exhaust and intake valve operation to deactivate and reactivate every second cylinder, according to firing order, during light-load operation, as the lifters deactivate a cylinder the exhaust valve is prevented from opening after the power stroke and the exhaust gas charge is retained in the cylinder and compressed during the exhaust stroke. Following the exhaust stroke, the intake valve is prevented from opening. The exhaust gas in the cylinder is expanded and compressed over and over again and acts like a gas spring. When more power is called for, the exhaust valve is reactivated and the old exhaust gas expelled during the exhaust stroke. The intake valve is likewise reactivated and normal engine operation is resumed. The net effect of cylinder deactivation is an improvement in fuel economy and likewise a reduction in exhaust emissions.

In addition to making the engine more fuel efficient and something that I think GMH needs to focus on, is making the vehicles lighter in weight. This would not only improve the economy but more importantly the performance, everyone knows taking weight out of a car is “free horsepower” and the commodore as an example is definitely heavier today, due to more built in safety features, not to mention options such as sun roofs, power everything, sound systems etc. To put it into perspective Imagine putting the L98 out of a VE into a VS Commodore with a weight of around 1500kg, It would be a rocket ship! With development in materials technology cars can be made with lighter materials that are just as strong but unfortunately at the moment this comes at a great increase in cost and is generally only seen in the more expensive European cars.

The good news is that GM globally appears to be committed to giving us a V8 option well into the future and to do so they are coming up with ingenious ways to make them still meet the stringent demands of government fuel efficiency requirements , and I for one a pretty happy about that as there’s nothing like the power and sound of a supercharged or turbo’d v8 and hey if I can get an extra couple of kilometers to the tank while cruising then that’s a bonus and who knows we might even find ways to adjust cam timing through our software via the new hydraulic lifters to improve the engines performance further?

You can never have enough power.

Rob Vickery