An internal combustion engine runs on what is often referred to as the “Triangle of Life”. The Triangle is composed of fuel, spark and air. If just one of these key components is missing from the Triangle, the engine will not run.
An internal combustion engine is essentially a big pump. The more air and fuel it can ingest and expel in a given amount of time, the more power it will make. This is why turbochargers and superchargers come into play; to make the engine ingest and expel more air and fuel.
For naturally aspirated engines however, it’s not quite as easy to make power, especially if you’re not willing to go for a full race build. This is why car owners should be conservative in their expectations when splurging on an exhaust system or a piggyback ECU.
Speedworks has put a lot of research and development into their tune-up kit for the City. They’ve created a full Hot Bits exhaust system, a K&N intake kit and also fitted a GReddy E-Manage Ultimate to fine tune the air fuel ratios to make the most of the exhaust and intake mods.
In stock form, the City puts out a paltry 87.5bhp and 108.6Nm of torque at the wheels. With a K&N drop in filter, it makes slightly more, 89.7bhp and 110.4Nm. With the K&N Injection Kit, is makes 92.4bhp and 111.3 Nm.
Hot Bits’ exhaust system for the City is a full system, starting from the extractor all the way to the back. Something worth knowing is that the City’s engine has its exhaust manifold runners cast into the cylinder head, so there’s only a single pipe coming out from the exhaust side of the cylinder head instead of the usual four.
With the exhaust system, the City makes 91.4bhp and 113.8Nm of torque. So now that we know how much power each individual mod can give the City, it was time for Speedworks to bolt everything on and tune it up with the E-Manage. With the Hot Bits exhaust system, K&N Injection kit and the E-Manage Ultimate, the City makes a more respectable 95.9bhp and 116Nm of torque, an increase of 8.4bhp and 7.4Nm.
We also got the chance to try the car out with its new parts. The power increase isn’t dramatic but there definitely an improvement over stock, especially in the top end. Finally, the exhaust system also sounds pretty good and isn’t too loud, but audible enough to make each drive more exciting.
Hot Bits full exhaust system
K&N Injection Kit
Hot Bits heatshield
GReddy E-Manage Ultimate
Speedworks – 03 7955 5533