POWER VS HANDLING

In what is now a regular event, two of Australia’s best know specialist workshops, go head to head in what is simply described as; the Grudge Match. The premise of the battle is quite simple: take two top of the line performance Subarus, in this case, brand new MY08 Impreza WRX STis. Give one to MRT, where they go to work on it aiming to improve power and response by fitting one of their well-developed engine enhancement kits. The second STi goes to suspension specialists, Whiteline Automotive, who apply a similar level of modifications, but only to the suspension components alone.

So one car has more power, response and driveability, but it uses standard suspension. The other has standard power, though it’s still a significant 221kW, but the suspension has been fettled, optimised and had the shortcomings fixed. Both would be pitted against each other to answer the age old question of which is better – power or handling?

Which would be victorious? Where would the gains be? Which would be nicer to drive? Wakefield Park was the venue which would provide the answers.

Wakefield is known as a technical track, where stability, corner speed and adjustability are key to a good laptime. Power does make a difference, however the main straight is less than one kilometre long, so there is little opportunity to make the most of a powerful top end.

The car MRT used for their development is a partnership between MRT and Morphos Construction, who actually own the car. Custom graphics, with a black and white two-tone theme is the evident visual mod but, of course, there’s the engine work. The larger exhaust and subsequent more vocal burble is the only clue to the power modifications. Apart from the 3-inch turbo back exhaust (cat in down-pipe, split collector off turbo, full flow centre muffler, twin outlet rear triple chamber muffler), most of the work has taken place within the car’s ECU. MRT are major users of EcuTeK software, which allows flashing and tuning of the standard computer, and their results have made them renowned amongst the Subaru and Evo fraternities. 

The 2.5-litre engine that Australia receives isn’t as highly strung as the Japanese market 2.0-litre, so solid power gains can be coaxed. MRT claim an improvement of 40kW at the wheels from their exhaust and tune package, quite a significant improvement over the factory 221kw flywheel figure. Torque is also boosted dramatically, with a peak increase of 21 percent at 3600rpm.

On the other side of the fence, we have the Whiteline car, which has to make do with the factory power alone. Its modifications consist of an assortment of parts from the Whiteline catalogue, both newly developed and existing enhancements. It includes; a 22mm adjustable front sway bar set on the hardest setting, a rear 20mm adjustable sway bar set to the middle setting, spherical sway bar links, Whiteline’s famous anti-lift kit, front lower control arm front bush, rear cradle inserts, adjustable rear upper control arm bushes, diff bush inserts, a four-point alloy lower control arm brace, strut top brace, front and rear control lowered springs, heavy duty gearbox mounts, front camber adjustment bolts and roll centre adjustment kit.

Surprisingly, the ‘handling’ car still uses the standard shock absorbers as after comprehensive testing by Whiteline, they were deemed more than good enough for the job. Although the rest of the list is quite comprehensive, when you break it down to its core categories; springs, swaybars, bushes and braces, it is realised the modifications are nothing too radical. Whiteline have simply done what is required to amend the factory settings, make the car more adjustable and handle the way they want it to.

With both cars’ being sorted, one last determining factor was left to be decided; the driver. A test of this nature needs someone who is familiar with the type of cars, and to ensure consistency, one driver has to steer both cars back to back. Hand picked for the job was one of the most experienced WRX racers in the country; Wayne Boatwright. Having piloted Protechnica WRX to victories in the hey day of Australian GTP showroom class racing, Wayne was certainly the right man for the job to get the very best out of both cars.

So the stage was set and it was showdown time. Both cars were started, warmed up and tyre pressures were checked, equalised and noted. The first car to go out was MRT’s, with the Whiteline car waiting its turn patiently at the pit exit. With both cars still running standard tyres, it only allowed for one warm up lap and a handful of laps before the heat would take its toll.

It also has to be noted that on top of the engine modifications, MRT did augment one other area; the brakes. By fitting upgraded brake pads and brake fluid, MRT believed it would ensure the car could do a few hard laps without the brakes overheating. As to how much the change would affect lap times would only become apparent once the Whiteline car was driven and results compared.

Once the MRT STi had its time, Wayne rolled into the pit lane with the brakes ablaze and smoking from the heat. The Performance Box and timing gear was removed from the MRT car and quickly transferred into the Whiteline car. The car made its way out and the process was the same as before; one warm up lap and as many as the standard tyres and brakes could cope with. This time round, with the standard brakes, three laps were all the car could deal with.

This series of testing was performed twice during the day, with the first session on a wet but drying track and the second with a completely dry surface. And the results delivered a few surprises.

The brake change MRT performed on the car had a significant impact to its performance. In straight line braking, the MRT car could brake 11.7 metres later than the Whiteline car. Even with the improved suspension of the Whiteline Subaru allowing it higher corner speeds, the braking performance alone could not be overlooked.

On top of that, Whiteline suffered some alignment issues, caused on route to Wakefield or during an earlier session. This caused the car to understeer slightly due to the tyres not being able to cope with the aggressive camber. A later diagnosis at Whiteline HQ revealed toe-in on the front axle was found to be the culprit with 10mm difference to how the car was initially set up.

Despite its fallbacks, in the wet session, Whiteline took the win with a best time of 1:11.32, as compared to MRT’s 1:13.17. So with the damp track conditions, the superior handling allowed the Whiteline car to be almost two seconds quicker.

But in the dry session, the tables had turned. The Whiteline car mustered a 1:10.63, while MRT improved radically over its wet time to record a 1:09.88. Sure, it’s not huge disparity, but it’s still close to a full second difference and on a tight circuit such as Wakefield, it matters even more.  

Analysing the record data also produced some further tantalising information. The Whiteline STi generated a maximum of 1.21 lateral g, compared to a maximum of 1.04 g for MRT. Whiteline also consistently carried an average corner speed 7.9km/h faster than MRT on the final corner onto the main straight (66.62km/h for MRT and 74.59km/h for Whiteline). This higher exit speed resulted in a higher maximum top speed on the straight for Whiteline, something the power difference the MRT STi simply could not overcome (177.85 for MRT and 180.09km/h for Whiteline).

These testings have shown that handling and engine improvements are still worthwhile with the latest generation of cars. Although laptimes and statistics don’t lie, there were other variables at play which affected the outcomes. The weather had played its part, skewing the results. Could Whiteline have been quicker if it received the same brake upgrade as MRT? How much time could be cut if the alignment issue was resolved? I guess we’ll have to wait until these two clash heads again. The rulebooks are safe for another year.