The background of Peter Luxon and APS...
Peter Luxon started his apprenticeship as a motor mechanic in 1973 and, at that time, much of his efforts were focussed on German vehicles.
"I did quite a bit of servicing on Porsches, Audis and that type of thing," he says. "But I remember I had a real interest in both 4x4s and performance vehicles and I saw a very big opportunity to power-up 4x4 vehicles."
The only hurdle, however, was most petrol vehicles at the time were carburetted.
"Carburettors and forced induction is a difficult combination to get right so we did a few low-volume conversions, but it became pretty obvious that diesel vehicles were becoming very popular. That's when we started production engineering of diesel 4x4 turbocharger systems," says Peter. "After a while, the market for petrol 4x4s then grew with the introduction of fuel injection and it was at that point we thought they were a viable project as well."
Meanwhile, Peter had also been involved in a number of one-off turbocharged passenger cars - Falcons, Commodores and that type of thing.
"EFI made forced induction conversions more cost effective and it gave a much better end result in terms of driveability, fuel economy and emissions," explains Peter. "We have always, as a company, run and tested vehicles to comply with relevant ADRs."
According to APS's David Inall, ADR 27 and 27A were the leading emission standards in the early days, but ADR 37-01 is today's standard.
"Our interest in high-performance passenger cars had always been there but, in those early days, there wasn't sufficient marketplace in Australia to tool products the way I wanted to," says Peter. "We spend more on product development than probably most other people in the Australian aftermarket put together. By the time we've finished our XR6 Turbo project, for example, I'd say we'd have spent about quarter of a million dollars.
"I mean let's say someone wanted a rotated mount turbocharger for their WRX - they would typically pay for a hand-fabricated arrangement that could either be a well done one-off or a piece of crap that wouldn't do thirty kilometres. In terms of doing that as a true production quality part, you might be looking at $90,000 to $100,000 of tooling - and that's our approach. In our view it's not a question of whether we can do it once or not - it's a question of what our large number of consumers will think about us in five years from now."
David Inall explains, "a lot of that product philosophy comes from our 4x4 background - certainly, big companies like ARB view things the same way. If you come out of the high-performance end of the aftermarket industry, though, that's completely different. To start with, they're normally two to five man workshops and they may not even be here in five years."
The APS Power-Up Approach
"The first thing we look at with a particular car is whether there will be a sufficient market for us to justify the investment we need to produce a kit at an APS level. Generally speaking, we would not usually start a Ford XR6 Turbo project since we are very globally driven. In that case, though, both David Inall and I have a long history with the Ford in-line six and I think that, emotionally, got the better of us.
David adds, "it was definitely a borderline commercial call, but Ford are selling double the original projection for the car. That fact also played a major part in our decision."
Peter resumes, "the next step is to purchase our own engineering car and, on top of that, we gain access to another two or three cars; we normally have those out in the field for testing. When we have the cars here at our facility we then look at things like turbocharger matching, manifold matching, air cleaner capacity, exhaust system capacity, engine management, etc. David has spent many years at Garrett and I've spent twenty-two years working with their products, so - collectively - we have a very good idea of what airflow a turbocharger will support and what its potential horsepower is.
David comments, "we also look at the limiting factors that are unique to each car - what goes in to our RT or Club spec kit for a '97/'98 WRX is different to a '01, for example. In the case of the Falcon XR6 Turbo, Ford has been very, very clever in that they have sized the fuel injection system around the maximum horsepower they were going to make - the injectors are the first limitation. Ford also went through a lot of trouble to make the computer difficult for people in the aftermarket to manipulate the areas we're interested in - there are two MAP sensors, for example.
"I think there will only be a few people in this country - outside of full stand-alone engine management, which has its own negatives - that will be able to communicate or work with the standard management system," says Peter. "We're lucky because we can do it with the UniChip.
"Of course, we also need to look at the potential of the exhaust system. We use a backpressure gauge to determine that and, no, I'm not prepared to give you the XR6 Turbo's exhaust backpressure figure. At this moment, we haven't quite determined what sort of packages we'll release with our XR6 Turbo kits. We'll have a number of kits matched to a specific power output, but once we get to a certain point we'll also have to seriously consider drivetrain issues."
David Inall comments on the XR6T's driveline; "We have some good relationships around Melbourne and have access to data that is not commonly available. We know precisely what the torque limits are on clutches, gearboxes, prop shafts, half shafts, etc; we obtain that data directly from the people who make the parts. Forget Ford in this instance - they probably don't know a lot of that stuff themselves. Ford buys the parts off manufacturers to a specification they require for their standard power output - so long as it meets their durability requirements that's all Ford care about."
So - as rumoured - is the XR6T's driveline marginal in strength?
"I wouldn't say that," replies David. "I would say, however, that we have the ability - unlike any other two or five man workshop in Australia - to acquire that information from the manufacturer."
Peter then adds, "I think it's fair to say we're conscious of the XR6's drivetrain. Once you get outside of Germany, gearboxes all get fairly ordinary pretty quickly. Nissan S15 6-speed gearboxes are very marginal, for example - I've had three in my car in about nine months. But the Nissan six-speed is a good transmission at the standard torque and power curve."
APS has been long aware of the limitations of the standard WRX gearbox according to David Inall. "Many people have made or sold one-off products that make huge power numbers, says David, "but we haven't done this because we've known for years that the standard transmission has a particular torque limit. People ask us why we don't take our RT kits any further - the answer is that the transmission falls out of the car. Unlike the XR6 Turbo, though, we unfortunately don't have access to the engineers behind the WRX's gearbox and someone like Subaru Australia knows nothing about the limitations of what they sell."
'What we did have in the case of the WRX," continues Peter, "was about seven or eight WRXs and STis running at any one time. We do a fair amount of durability testing and can clearly identify when a component is likely to fail. We are very conscious when we are doing development to find out where the limitations are in drivelines and, at least, we need to be able to make recommendations to consumers depending on their application.
"In a lot of particular cars we actually tailor the power and torque curve around what we consider is the practical limit of a driveline component. A lot of people in the aftermarket don't understand that it's torque - not power - that breaks transmissions. It's the amount of torque at about 3000 rpm that's going to part a gearbox."
So, getting back to exhausts, does having a cat converter in your new exhaust ensure your car is emission compliant?
Absolutely not according to David Inall. "There's a lot of variation in cat converter performance and there's a lot of shit sold here, " says David. "Some have an American name on them, but they don't come out of the United States and they don't have a CARB approval number. Some of them are just terrible."
"Even the position of the cat is critical," adds David. "When we first did MY01 WRXs - when the rules changed to ADR 37-01 - the first emissions test we ran failed miserably. We then did a lot of investigation into cats, their position, light-up times and we ended up passing it reasonably well. For sure, though - if it's not a particular kind of cat and in a very particular location you will fail ADRs. You won't get within a bull's roar of it - and I've got the bills to prove it!
"There are a lot of people that couldn't give a rat's about ADRs - in particular ADR 37-01 - but to us it's everything. If we don't achieve compliance we won't sell the kit."
Peter continues, "In the case of the XR6 Turbo, there is only one technically correct approach for the exhaust system. When I say technically correct I mean something that offers good performance, very low backpressure, good durability, emissions compliance and can meet 90dB (which is the maximum tailpipe noise allowable in Australia). That takes a considerable investment in design and tooling and - surprise, surprise - I think we'll be the only one in Australia to take that approach.
"We don't do any testing of cat converters or mufflers on a flow bench - we simply test them on the vehicle," says Peter. "Just checking the flow doesn't tell us a lot - nothing, of course, in terms of noise. We don't use any commercially made mufflers in our high-performance passenger cars - none of the mufflers we use are something you can just go and buy."
And what is the importance of a divided or separate wastegate pipe?
"Well, none of that is straight cut," tells David.
"The principle reason for dividing wastegate flow and major turbine flow is to enhance major turbine flow. Normally - in a mass-produced internal wastegate turbo - the discharged gas from the bypass valve interferes with the main gas flow from the turbine wheel. If you correctly separate them it improves the flow from the main turbine wheel and will have little effect on wastegate flow.
"There are other parameters though," continues David. "If you've got a situation where a large portion of the gasses are coming out the back of the turbine wheel, the divided outlet will have a sizeable bearing on engine backpressure. On the other hand, if you've got a lot of gas coming out the bypass valve you won't get much difference at all.
A lot of modern turbo fitments on passenger cars are sized so that over half of the gas flow - at the rated power - is actually coming out the wastegate valve. In these cases, a divided turbine and wastegate passage makes a relatively marginal difference. That's why on the WRX, for example, Subaru has configured the front section of exhaust the way they have; fitting a divided passage has a very marginal effect on the factory rated power output. Once you start developing more power and go up in turbine size, though, there's a greater percentage of the total gas flow coming out of the turbine and the divider might make more of a difference. It's not a black and white situation."
Peter explains why APS does not - at present - offer a separated or divided dump pipe for the WRX; "One of the major reasons we've had our single-opening high-flow turbine outlet cast - rather than fabricated - has to do with the light-up time of the cat. We want to get it up to operating temperature as quickly as possible and, in addition, the cast housing also improves durability. Anyone that's been around turbo cars for a long time knows it's the area of the exhaust manifold, turbine housing and dump pipe where you have a lot of temperature related failures. We haven't yet seen a failure of our component."
And how does APS approach air intake enhancements?
"The air intake modifications that are part of some of our kits are all based on measurements on a manometer," says Peter. "In some cars the air cleaner might have a flow capacity well beyond the standard output of the car - hence, no need to do anything. In other cars, though, it may be marginal.
"On a standard car I would say that most aftermarket filter elements would make a marginal - if any - difference at the standard power level. On a modified car, though - depending on the power output - the difference can be more dramatic. It can also affect air-fuel ratios," tells Peter.
Stay tuned for Part Two - the final - of this interview with APS!
Contact:
Air Power Systems
+61 3 9720 9170
http://www.airpowersystems.com.au/
