In the final part of our interview with HSV's Chief Engineer - John Clark - we discuss products, testing and planning...
Obviously, there are friction losses and fuel consumption penalties associated with large capacity engines. Why was the decision made to run a 5.7-litre single-cam 2-valve engine?
Of course, the big thing is that it comes in the Holden core vehicle. The costs to do all the validation, the testing, the fitments to buy a different engine to put it in - it'd blow the cost of doing the car out of the water. The amount of testing these cars do amounts to millions and millions of dollars. You need a great base engine - and that's why Holden chose the Gen 3.
Why not go for a smaller capacity (say 4.0-litre) engine with a good forced induction system? I mean, having already developed the supercharged 3.8-litre V6, why not add an intercooler and maybe some more boost?
You could get the power up there, but then you've got to go through the testing. To put an intercooler on you've got to run plumbing and coolers that are out the front. We've got to pass all ADRs and also be cost effective. The backyarder can go throw a blower and an intercooler on, but the thing won't start in the morning and won't run in the hot weather - and you get crappy performance. We're looking at the whole package of the car to include good performance, but also something that's affordable.
Are there any car manufacturers running an intercooler with a supercharger?
Yes, Jaguar for example.
Yes, fair comment. But with forced induction comes the extra underbonnet temperature and all that - and that's one thing you have to take into account.
How much of the decision to go for a huge V8 engine is to do with marketing?
Australian people love V8s, they love 4-door cars and they love rear-wheel-drive cars. Why do people like that sort of scenario? It's because your Dad had it, you're Dad's Dad had it and you Dad's Dad's Dad had it. Also, another thing that Australians like is the opportunity to go and tow their boat or caravan on the weekend.
How many people really use their HSVs for towing heavy trailers?
You'd be surprised. We've got specific tow bars for our cars and people do buy them and tow with them. Of course, in America you'd have your F-whatever to tow your boat, and a car to go down the street. Also - when you do have two or three kids, and you go out on the weekend - some of the smaller cars are difficult to get into. I've got two-and-a-half kids and, with myself being tall, I have the seat all the way back - other cars don't suit the application. A lot of our customers are CEOs or whatever and do have families.
This is Australia - and it's a damn good place to live.
What are you angling at?
I think the Gen 3s use an absurd amount of fuel to deliver the performance that they do - I think we were getting about 16-litres per 100 kilometres in the GTO Coupe during urban driving. Any turbocharged engine - giving around the same power - would give far better day-to-day economy.
I'd be intrigued to see what your fuel consumption was for the first two weeks of driving around. When you drive a different car you drive to enjoy it and all that - I would say, normal driving in the GTO, you would get better economy. Look, you can drive these cars in 4th gear most of the time - and, really, that's what our customers want.
I think our car's fuel economy is pretty good for what they are - an 1800kg car that can carry a family with a boot full of luggage and you can take it to the track on the weekend. We're very much a niche market at 3500 cars.
Can you reveal any plans to improve fuel consumption, such as piston coatings or cylinder de-activation, which was used on some Chevrolets?
Yes, as with anything in the auto industry, we're always looking to improve. Specific details I wouldn't want to go into at this point, but we're always looking at what technology is out there.
We've recently driven a grey-import Ford Mustang SVT with its 4.6-litre, DOHC 4-valve engine - if Ford Australia brings an engine like that in, what contingency plan will HSV use?
I suppose we'd do it even better [laughs]. I can't answer that at this point. Yes, there are plans for future models - but I can't discuss it.
The Gen 3 engines - even the 300kW variant - don't have an awful lot of torque down low, given their swept capacity. Why is that?
As a comparison between the past Holden 5.0, the Gen 3 likes to rev. We wanted a revvy engine, and we wanted to get maximum torque up (in revs). The characteristic we wanted in a cam brought it up there - and top-end. The refinement of our cars is one thing I'll hang my hat on - and to say what you're saying - is not a surprise.
How are HSV's kilowatt figures derived?
Peak power readings are to a standard. I'll come back to that.
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Later Supplied Information...
Kilowatt figures are rated to ECE standards.
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And how much car-to-car variation do you find?
We find there might be 3 or 4 percent difference - quite small. The build process is very controlled.
Does HSV drive a wide variety of cars to compare against?
We've had the Evo 6, WRX, STi, BMWs - M3 and M5, Lexus LS430, Tickfords and Toyotas - we swap cars between manufacturers. That's common practice. Driving other cars is part of the job - you've got to see what else is on the market. Some have good features that we do or don't have - but a big part for us around here is the bang for the buck.
Cars like the Evo 6 Mitsubishi for 75 grand or whatever, they've got some performance - a serious amount - but our customers want some interior comforts as well. Our buyers want air conditioning and a CD stacker and all that.
It's horses for courses.
The SV300 is nearly $100,000 - how can that cost be broken down?
Well, there's the engine, wheels, tyres, interior, shift light, brakes, Hydratrack diff, exhaust, body kit. Interior wise, there's leather - a specific leather and all this.
It's all small run stuff for a limited build.
The engine is a fair bit of that cost - it's hand built, with the billet throttle body, and there's a lot of machining. It's low volume - we only produce about three hundred 300kW cars in different guises.
The first HSV - the VL Walkinshaw - had huge gains with its add-on body kit. How much of a gain to you pick up with the kits on today's HSV's?
The VL Group A was specifically set up for racing - there was a lot of work done for that application. For our cars, with the lower front facias, side skirts and rear apron, our big thing is to reduce the amount of airflow under the car - to increase stability at high speed. We have had cars in wind tunnels before when we introduced VT, but the costs involved make things quite difficult.
The latest model we haven't had in a tunnel.
What was the last shape you did have in a wind tunnel?
The VT shape was in there and the race teams do a lot of testing that we get info from as well. We do a little bit of computer simulation of the shapes. At the end of the day, though, reducing the airflow under the car is critical. We do testing through the Northern Territory at speeds that are legal through there and it's of benefit.
At this stage, the effect on down force is based on driver input, or output I suppose.
What sort of durability testing does HSV perform?
We do testing with Holden in their durability cycle. There's normal durability testing, there's rough track testing, towing 2100kg through a cycle, opening and closing doors and their overall vehicle tests. There's also specific tests, like a roll back test for the transmission, and handbrake evaluation.
How long are the cars evaluated?
Usually you're looking at about 4 or 5 months. That includes hot trips through the Northern Territory and cold trips through, say, Hotham - probably about 60-80,000 km in different cars. During the cold trips, they dig it out in the morning - and they look at the crank time and drive away. Holden do the same testing. We go on the same test trips as Holden - hot trips, cold trips, altitude testing - we compare a lot of the results. We also export cars to UK so all that has to be investigated.
What would you say are the best and worst aspect of your vehicles?
Pffff. [pauses]
On our 300kW cars, the performance is a good aspect and the overall grip of the car is a good aspect. I suppose a bad aspect is its weight - 1800kg or whatever it is. Commodores are a heavy car, but that's because they're designed to carry five people comfortably. I think the brakes are fantastic.
There's heaps of good stuff.
[pauses]
What are some specific areas that you see can be improved?
I think drivability can be continually improved and the suspension - the auto industry is such an evolutionary one. Safety on all our cars and feature levels are huge - you can always add more, but you've got to work out where you want to get to.
Okay, so what are the worst aspects - can you think of any?
No, not really [laughs].
Are there any final comments you'd like to make?
I just want one... [laughs]
No, look, what we try to achieve is a high level of overall engineering integrity in the car. It's the overall car. You could make a stinking great engine, but of the car can't handle it, it's useless. With that comes a lot of design and development and a lot of customers don't realise how much we do.
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