Size makes a big difference. Whereas nobody in their right mind would pick a larger than average girlfriend, a real man wouldn't go into McDonald's and order a regular meal; obviously if there's a larger portion available, it's your duty to order it. And it's the same with engines, which is exactly the thinking behind a shop car--a 500-bhp Subaru Impreza WRX STi 8--to be unveiled by the boys at Graham Goode Engineering, one of the top Subaru tuners in the UK.
"A lot of people have built high power 2L Scooby engines but they are all real screamers," explained Alastair Mayne, GGR's technical & engineering manager. "They only have high power at high revs which is not really ideal for a road car, even if it's fine for the track. Our idea was to build a nice powerful but drivable roadgoing Subaru engine to publicize the abilities of the company." And that's exactly what they have done, based on a 2.5L short block engine which they imported from the USA, albeit with the majority of the components removed and replaced with higher spec examples. "It's now got a bulletproof bottom end thanks to a steel crank, forged Cosworth pistons and H-section con rods which have helped to dial out the engines inherent weaknesses," said Alastair.
"We wanted to end up with more than 400 bhp and more than 400 lbs/ft of torque which we though would be achievable, but it still has to be drivable enough to potter around town with or take on the track," he continued. "Building the engine was relatively straightforward although the actual install took quite a while. When we first saw the size of the inlet on the turbo, which is itself larger to match the larger engine capacity, we thought it would be too restrictive so we turned it round 45 degrees - like they do on the rally car--to get a nice airflow into it. It's the first time we'd ever done this with an engine conversion."
He admits that it's easier said than done as obviously there are numerous 'side-effects' involved with this process such as re-routing the turbos oil and water feeds, fabricating a modified exhaust, and then linking everything to the front mounted Perrin intercooler.