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This month's Power Pages highlights the importance of ensuring that everything in your engine runs and run properly. There are far too many people on the road driving cars which are full of expensive performance parts, but always neglect the finer details of building a high performance engine: the tuning.
While the owner of this car isn't completely to blame, it just goes to show that you should never skimp on the ECU. When we ran the car on the dyno at D'Tuning Services in Kepong, or DTS, we found that the poor Civic was running extremely rich. It had an A/F ratio of around 10:1. This was because he had a chipped ECU, but the chip was meant for another car with a different setup.
This EG8 has a hybrid motor under its hood, commonly known in the States as the LS/VTEC. What it is, is a USDM B18B engine, which is a 1.8 litre, DOHC, non-VTEC 4-cylinder engine, mated with the cylinder head from a B16A. This combination gives a torquey and powerful 1.8 litre VTEC engine; think of it as a smaller B20 CR-VTEC engine.
You may be asking yourself, “Why not just get a B18C and save the hassle?”. Here's why not: the B18B has a longer stroke than the B18C, 89mm vs. 87.2mm. While this translates to more torque and better low end grunt, this also limits the B18B from revving high safely. But that's not to say the LS/VTEC can't be built to be a torquey motor with exceptional high end power.
Anyway, the owner realized that something was wrong, and picked up a second hand A'PEXi VAFC II to take care of the inadequate computing power of the tuned chip. The VAFC may seem to somewhat simple and almost primitive compared to today's piggyback ECUs, but it still works very well and is very user-friendly and compact.
Daniel of DTS started working his magic with the VAFC and much to our surprise we gained almost 10bhp on the first run. This shows how out of sync the chip's tuning map was with the engine. More tweaking of the VAFC was required, as the fuel delivery was not constant.
On our way to DTS, the car bogged a little at 4000rpm, almost as if the ECU thought that the VTEC engagement point was at 4000rpm, hence squirting more fuel into the combustion chambers when the engine didn't need it. This led to a overtly rich air and fuel mixture, which was what cuased the engine to bog down.
Thanks to the VAFC, we got rid of that problem, and gained a total of almost 30bhp at the wheels. This has got to be the biggest increase I've ever seen with a simple AFC tune. It has to be mentioned again, that the ECU on this car was very badly out of tune, which is why we got such a huge increase. Don't expect the same with your car.

Next up were the adjustable cam gears. Adjusting the cam gears alters the timing of when the valves are opened, and when done right, translates into a smidge more power. Eric of Avantgarde was there to play around with the cam gears and it took him a few tries to get any power out of them. At first he only altered the intake cam's timing, as this is normally the route that tuners take. Much to our surprise, the engine didn't make much power, if any at all when the intake cam gear was fettled with. Eric then tried tweaking the exhaust cam gear, and lo and behold, the LS/VTEC made and extra 7 horses. What a result. Once Eric was happy with the cams, the VAFC was retuned to match.
The final power figure was 176.51bhp at the wheels and 17.67kg/m of torque. Considering that we started with a measly 140.9bhp and 15.21kg/m of torque, I'd say that this is a wondrous result.
This really goes to show that you must make sure that all your parts are working together properly and in harmony. As I mentioned earlier, there's no point in having a bunch of expensive parts which promise mega horsepower and torque if they all don't work in harmony.

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