AwwsChwA

haha...wow, lots of responses...ok, lemme try to sum these all up.

First of all, Kai is right. A D15 is really not a good starting point for heavy modification without aftermarket rods. I learned TONS about the D16 and D15 engines when I rebuilt my D16. The D15 uses tiny little connecting rods and wrist pins compared to the D16. If you want high output and you're looking to use stock rods and such, go with a D16 block.

A D15 with an Si camshaft and Si fuel injection should make 90-100hp at the flywheel. It won't make quite as much as a D16A6 because the D16 has a longer stroke. In order to hit 100 wheel hp you'll need around 125hp at the flywheel. The Honda powertrain loses 15-20% of its power thru the drivetrain. That's way better than a front engine/rear drive system, which is closer to 30%.

By "head work" I mean porting, polishing, flowbench testing, smoothing combustion chambers, deshrouding valves, things like that. There are infinite possibilities for what you can do. Head work needs to be matched to a camshaft profile for optimal results. Cam swaps are the same...there's no "best" option. A cylinder head that is ported to match a performance camshaft will give great power gains if it's done right.

High-compression pistons can be very expensive. But, any D-series piston can be used in any D-series block. The 1986-1989 Integra (D16A1 and JDM DOHC ZC engine) pistons have big domes on them, and when used in the SOHC D15 and D16, make approximately 11.5:1 compression. Raising compression won't make a lot more horsepower, but will make lots of torque. Just keep in mind that you can't go much past 11:1 in a Honda engine without some careful tuning work and premium fuel.

I hope this covered everything. Just ask if you have more questions. I didn't go into a lot of detail on any of this, so if you wanna know more, I can get more into it. There are also lots of great websites you can learn from. I learned tons about Honda engines by reading articles and forums.

Kai

Whoa there buddy, a decent front engine/rear drive still looses under 20%, and I have dyno charts to prove it. Incase any pre-88 guys are reading, that doesn't apply to us. Honda started using a standard 75mm bore in D-series engines in '88, but the older 74mm bore EW/D15A and EV/D13A can be overbored to take the standard 88+ pistons.

jaje

the typical efficient fwd drivetrain loses around 10-13% only...rwd loses 15-18%...awd around 20-25%

Pete

There's nothing you can do to lower the percentage lost, is there...

Kai

Unless you really want to get picky about what oil you use... no.

jaje

there are several ways to do this...just depends on the amount of money you want to spend

cheap...sythentic gear oil reduces friction slightly and lasts longer under heat abuse...i usually use 80w90 in my pr5 (running turbo though)...use 75w90 in the tsx

~$300...lightweight flywheel reduces loss but at the expense of rotational intertia (easier to stall the car...that is the reason stock flywheels are heavy to keep its momentum better)

~$1000...carbon fiber driveshafts (common for rwd and awd cars now) and lighter axles (have to do some research)

extreme $$...lighter and stronger drivetrain components...ala F1 (titanium & carbon fiber gears! and input shaft!)

Kai

I was trying to keep it within reason for the average pre-92 owner, but that stuff would help. Not much, but it would.

Pete

I thought the power was lost in cranking the differential, but idk h:

Kai

Nope, the power loss has more to do with the gearing (and oil used) and the mass of the system.

ED9man

chain drive conversion