Tuesday, March 26, 2013

Start and Idle

Making power from a fully build engine is actually the easier part. Getting the engine to behave close enough to stock on things like a stable engine idle and starting from cold so that the car is good enough for daily driving is the tougher part. Let's face it, unless your car is a full time kereta perang (track only race car) and transported to the race track on a truck all these things which we take for granted matter a lot. Nobody wants to have to start their daily driver multiple times just to get the engine running cleanly. Or having to crank the engine forever just to get it to start. Or wait in the hot sun for 5-10 minutes till the engine reaches optimum operating temps before being able to turn on the air-conditioning. That's why piggyback controllers are so popular. Let the stock ECU where thousands of man hours have been spent perfecting the idle and start to control these while the piggyback controls only the fuel and for some the ignition timing.

However piggyback controllers are mostly limited by what your stock ECU can achieve and was never going to cut it on an engine build to make three and more times the power than stock and with equivalent larger capacity fuel injectors and fuel pump. With popular cars like the Mitsubishi Evo, there are lots of players and the body of knowledge is immense in the market so finding a suitable map is much easier with many people sharing their data. With the Shark nobody has yet fitted a fully programmable ECU and mapped the QG engine so we are essentially starting from point zero. This is where the skill of the tuner installing and mapping ECU is very important and IMHO in Bolehland and South East Asia, Toby Lee can be considered one of the best. Having a decent ECU like the Autronic SM4 helps too :)

The Shark initially had perfect manners when I first collected it but after close to 3000km of run-in the engine had developed some quirks. Quirks include occasionally having to start the engine 3-5 times before it could idle especially when cold. Upon start up the revs would go up but the engine would stall once the revs dropped. The idle would also occasionally hunt a bit especially on hot days. Toby has managed to eliminate most of the quirkiness with a recent remap when the Shark visited GT Auto recently. I'll let the following two videos do the talking. Enjoy..

Start and Idle 1

Start and Idle 2 - When engine is really cold

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