An internal combustion engine’s power output is dependent on the amount of air and fuel that it can pass through its internals. The more air and fuel that an engine and ingest and expel, the more power and torque it makes. In a forced inducted engine, one simply needs to turn the boost up to make more power. In a naturally aspirated engine however, things can get a little trickier.
In a naturally aspirated engine, the cylinder head is the most important part of the power making equation. For an engine to make good power, the cylinder head needs to be able to have a good flow rate so that air and fuel can enter the combustion chambers more efficiently. Things like camshaft lift, camshaft duration and the flow characteristics of the intake & exhaust ports all need to be calculated and executed properly in order to get good results on the dyno.
This month’s Power Pages demonstrates the impact a well prepared cylinder head has on a naturally aspirated engine’s output. This Celica, which has been featured in Hypertune before, packs a high-revving 2ZZ-GE, 1.8-litre four banger which has been given a couple of tweaks by renowned MME and S1K competitor, Kegani Autotech.
Kegani Autotech are well versed with high performance Toyotas of all types and are most known for achieving great racing success with the humble AE101 Corolla and the venerated 4A-GE powerplant. This relatively new outfit not only tunes and modifies cars; Kegani Autotech also has a race team management service, a race driver training course and even a race car rental service.
What they’ve done with this Celica seems simple in theory, but execution is key to getting good results. Kegani Autotech has given this Celica a decent power increase with port-and-polish head job and a set of high performance camshafts. When it comes to enlarging and polishing a cylinder head’s intake and exhaust ports, it’s not a simple case of simply boring the ports out to make them larger; key factors such as the curve and angle of the ports is also important. Getting the flow angles just right is key to achieving good results.
Before the camshafts and the port-and-polish job, the Celica made 156.26PS and 15.68kg/m of torque at the wheels. With the new camshafts and ported cylinder head, the Celica gained a respectable 24.1PS and 2.41kg/m of torque, bringing the final power and torque figures to 180.36 PS and 18.16kg/m. Kegani also claims that the biggest improvement can be felt in the middle of the engine’s powerband, especially just before the high cams are kicked into play.
Kegani Autotech high lift camshafts
Kegani Autotech port-and-polish
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Kegani Autotech – 03-8075 7411