Built Motors
- Thread starter JBHonda
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I'm not even going to comment on all the misinformation in this thread... there's TONS, and not much of it is from JBHonda. A boosted D15/D16 is very potent...
You can't get 1.8L just by boring out the D15. Your stroke it too short, and boring out will only get you from 1.5L to 1.6L (1615cc), and that's with a 78mm bore over your stock 75mm bore. Stroke it from 84.5mm (D15) to 90mm (D16), and you'll get to 1.7L (1720cc). Any more stroke, and you're looking at some no too rev friendly geometry and some really expensive custom crank/rods.
If you want to build up a D block for boost, you really should look into the D16 SOHC VTEC, since it's already a larger displacement engine, and more parts are available for it stateside than the JDM D15B. You're changing out the pistons/rods anyway, so don't bother with the higher compression and weird VTEC design of the D15.
D16 buildup- get resleeved by Golden Eagle or Darton, drop in some forged pistons by Wiseco/Endyn, Arias, JE, etc... big rods from Eagle, and maybe a custom camshaft ground for high lift and minimal overlap. One of my friends is making 240whp, and that's without enough fuel. With more boost (he got a new turbo kit) and more fuel, he'll be making over 300whp without any problems. He hasn't broken his transmission racing on that boosted D16- so just upgrade the differential with a Quaiffe unit and you should be good to go. Custom axles might help you on the launches, or you could just take it easy when you start a race.
Same displacement and compression does NOT equal the same amount of power... geometry matters and so does head design. A 1.8L engine with a longer stroke and smaller bore will make more torque but not be able to rev as high as a short stroke engine, so it'll make more power down low and not be able to rev up high to make the horsepower.
Example- my B20/VTEC is running 12.6:1 compression at 1997cc, and the S2000 runs 11.0:1 at 2.0L (not sure of exact numbers). My compression is higher, and my stroke is longer- but the displacement is the same. I make about 220/170 at the crank, while the S2000 makes 240/150 at the crank. My powerband ends sooner... so I'm making less horsepower than the S2k, but I have the same displacement and more compression.
Read and learn... relocked.
You can't get 1.8L just by boring out the D15. Your stroke it too short, and boring out will only get you from 1.5L to 1.6L (1615cc), and that's with a 78mm bore over your stock 75mm bore. Stroke it from 84.5mm (D15) to 90mm (D16), and you'll get to 1.7L (1720cc). Any more stroke, and you're looking at some no too rev friendly geometry and some really expensive custom crank/rods.
If you want to build up a D block for boost, you really should look into the D16 SOHC VTEC, since it's already a larger displacement engine, and more parts are available for it stateside than the JDM D15B. You're changing out the pistons/rods anyway, so don't bother with the higher compression and weird VTEC design of the D15.
D16 buildup- get resleeved by Golden Eagle or Darton, drop in some forged pistons by Wiseco/Endyn, Arias, JE, etc... big rods from Eagle, and maybe a custom camshaft ground for high lift and minimal overlap. One of my friends is making 240whp, and that's without enough fuel. With more boost (he got a new turbo kit) and more fuel, he'll be making over 300whp without any problems. He hasn't broken his transmission racing on that boosted D16- so just upgrade the differential with a Quaiffe unit and you should be good to go. Custom axles might help you on the launches, or you could just take it easy when you start a race.
Same displacement and compression does NOT equal the same amount of power... geometry matters and so does head design. A 1.8L engine with a longer stroke and smaller bore will make more torque but not be able to rev as high as a short stroke engine, so it'll make more power down low and not be able to rev up high to make the horsepower.
Example- my B20/VTEC is running 12.6:1 compression at 1997cc, and the S2000 runs 11.0:1 at 2.0L (not sure of exact numbers). My compression is higher, and my stroke is longer- but the displacement is the same. I make about 220/170 at the crank, while the S2000 makes 240/150 at the crank. My powerband ends sooner... so I'm making less horsepower than the S2k, but I have the same displacement and more compression.
Read and learn... relocked.
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