Hi there, and welcome to HondaSwap. My name is Mike, and I honestly don't give a damn if you're "hot" or not. You're a person asking intelligent questions, and I respect that. In addition, you have a boyfriend and I'm happily "almost married".
SO... Long solid answers to your questions:
LS/VTEC
People build LS/VTEC engines for a few reasons.
1. They already have the non-VTEC B18 block.
2. It can be put together for less money than a B18C, and put out almost as much power (but you really shouldn't cheap out on it).
3. They want the slightly different power curve (read earlier and more torque) given by the longer stroke bottom end.
The B18A and B18B differ from their B18C VTEC conterpart by having a longer stroke and no VTEC. The B18C has an 87.2mm stroke and a displacement of 1797cc, while the B18A/B both have an 89mm stroke and a displacement of 1834cc. The slightly longer stroke gives the crank more leverage to act on the rod and piston, and combined with the 37cc extra displacement- gives the engine more torque earlier in the power curve than the B18C. If you start building up the internals of the LS/VTEC combination, you can have that slight edge over your B18C counterparts because of the added displacement.
Some of the
disadvantages of the LS/VTEC setup are:
1. It doesn't come that way from the factory, so quality of build varies
2. Rod/stroke ratio is lower than other VTEC B blocks, but most of the ranting around it is just hype from people that don't know what they're talking about
3. No girdle, oil squirters, or oil cooler like the B18C
4. You have to source parts from different engines instead of buying one ready-to-go package
You don't hear too many people using B16 heads on GSR blocks because you lose static compression, which lowers your power output. The B18C combustion chamber is 41.6cc while the B16A combustion chamber is 42.7cc, so you lose when you change heads. You
do hear of some people dropping B16 heads on GSR blocks to build a "poor man's Type-R" engine, since the B18C5 is essentially a GSR block with a slightly massaged B16 head. The B16 head works well on the GSR block if you build the engine to take advantage of it. The B16 head has a single set of runners in the intake manifold (easier to tune), and a larger base of support in the aftermarket. Couple a built GSR block with a B16 head and properly matched internals, and you have a pretty potent combination.
Example... the engine that's going into my car this week is a GSR block with a B16 head. Sorta.
Ok, now some general rules on
I/H/E fitment:
Intake- buy one that fits your car, unless you swap in an engine with a B18C head... then you'll have some fun.
Header- buy one that fits your engine
Exhaust- buy one that fits your car
So... if you drop in a B16A2, get a 96-00 Civic hatch intake (or the 99-00 Si intake, it'll be a perfect fit), get a B16 header, and use the exhaust that's made for your EK hatch platform. The catback exhaust system only goes from the catalytic converter to the rear bumper, so it makes sense to buy the system that fits your car and not necessarily the engine. You
DO need to buy a different exhaust manifold / header when you drop the B16 into your car, since the D series and B series heads can't share manifolds. The catback that fits your car and the header that fits your engine don't always match up perfectly though, especially if you're swapped... so you'll probably have to get a custom connection (or custom flanges on a catalytic converter) to get everything to fit properly.
Compression...
Basic view- lower compression for boost, higher compression for natural aspiration.
Advanced view- higher compression is always better. It's just more painful to tune.
Higher
static compression (that's your 9.2:1 in your D16 and stuff) gives you more power because you're increasing the potential for the combustion charge in the cylinder to do work on your piston. The more potential you have for work, the power potential you have. If you can
capture that power potential, you successfully make more
usable power. The key is being able to
tune for your higher compression. Street cars typically don't come with compression ratios much higher than 11.0:1 from the factory. Manufacturers have to deal with user error, bad gasoline every now and then, and some wear and tear on the engine later on in the car's life that will make high compression hard to deal with.
In the aftermarket, there are people running 13.5:1 compression or higher on the street using pump gas. It's pretty rare, but those engines are out there. It's all in the tuning. Maximize your potential to make power, and you can capture more real power. Screw up in the tuning, and you blow up your engine. You start walking a fine line when you play with compression ratios that high on pump gas.
As for boost, you increase the potential for more power by adding more fuel and air to the system. You're ramming more combustible mass into your cylinders, so you effectively increase compression. People typically lower the static compression on a forced induction engine so that they can ram more air and fuel in while maintaining a tunable effective compression. Lower compression is easier to tune. On race cars, you'll see turbocharged setups with static compression ratios of 17:1 or higher, but that's not for us peons and our street cars.
So... lower compression will only increase your power if you have the extra fuel and air added to the engine to take advantage of it. The aftermarket is full of parts that
both raise and lower compression.