B20B, B20Z: The B20 engine is the newcomer in the game and is highly acclaimed by its supporters. It has several key characteristics that give this engine real potential no matter what route you decide to pursue. The B20B came on the 1996-1998 CRV and the B20Z came on 1999-2000 CRV. The B20B made 126 hp but the real jewel was the 133lbs of torque that was easily achieved almost anywhere in the RPM band. It is a small displacement engine that has flat torque line!!! Additionally it was a comparatively low compression engine which means that turbocharging to decent levels is possible without the need to spend hundreds on rods or pistons. The B20Z was more or less the same as the B20B but they changed several head characteristics and the compression was bumped up to increase the horsepower to 146.
There are really two choices for dealing the B20 as far as power goes. You could leave it as is and simply swap the head for B16 model. The cylinder head on the B20B model (particularly the tall intake manifold) doesn't clear the hoodline of the civic, which is ok since the B16 head swap will add Vtec abilities and increased power. OR you could go about what is called a CR-VTEC conversion. This is what I consider to be the ultimate engine build-up for civics’. The first thing you need to know about B-series engine (B18, B16, B20) is that they all have, for the most part, interchangeable engine parts. So the CRVTEC buildup basically consists of taking the best parts of all the engines and making an unprecedented Frankenstein of motor that has a perfect Rod to Stroke ratio of near 1.75 which allows for great naturally aspirated performance (A HUGE redline) or the ability to turbocharge the engine to very large proportions without worrying about engine stability. It is unfortunately rather expensive but this setup will take you anywhere you want to go. The simple B20/B16 swap costs as follows: $1000-$1500 for the B20 short block, +/- $600 for the B16 head, +/- $300 for the B16 ECU + tranny and other small parts. The price for the CR/VTEC could be calculated on the aforementioned site.
Unless you’re simply happy with the stock B20 swap, the only reasons it should be considered are CRVTEC conversions or Forced Induction. The aftermarket support isn’t as plentiful for the B20 as it is for the other engine mentioned so any engine upgrades usually come from other B series or upgraded aftermarket parts for other B series. Which is more less slowly building a CRVTEC engine. But I still highly recommend this engine for the best bang for the buck power adder.