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Originally posted by Calesta@Oct 21 2002, 12:05 PM
Whoa.. HOLY MISINFORMATION BATMAN!
You guys need a Honda engine spec lesson.
Let me set a few things straight:
The B20B and B20Z are identical except for intake manifold and compression ratio- the USDM B20B has 8.8:1 compression, while the USDM B20Z has 9.6:1 compression and a taller intake manifold stack for increased midrange torque. The JDM B20B has the same compression as the USDM B20Z, 9.6:1.
The LS block (B18A, B18B) has the exact same stroke geometry as the CR-V blocks, the B20B and B20Z. The only difference between the B18 non-VTEC blocks' and B20B/Z blocks' rotating geometry is the BORE.. Both blocks have an 89mm stroke- the B18 just has an 81mm bore while the B20B/Z has an 84mm bore.
The B18 non-VTEC blocks and the B20 blocks from the CR-V will rev to the same level because they have the same stroke geometry. Since the B20 has .2L more displacement than the B18, and all other factors are the same- identical frankenstein setups built with the same components (pistons at same compression) will yield more power and faster times with the B20 compared to the B18 block.
I don't know where you get your information, Havocprez, but you better double check before you go telling people the wrong stuff.
The B18C, on the other hand, has an 87.2mm stroke. Coupled with the longer 137.9mm rod compared to the B18A/B and B20B/Z 137mm rod, the GSR and ITR blocks have a slightly more favorable rod/stroke ratio of 1.5814 over the LS and CR-V blocks' 1.5393 ratio.
Common sense and engineering dictate that all things equal, the higher rod/stroke ratio will yield higher sustainable rotating speeds within your engine. Given that, engine builds are never equal. The .04 difference between the ratios of the GSR/ITR blocks and the LS/CR-V blocks really doesn't mean anything once you start building the bottom end of the engine.
If you're worried about stroke- tell me this... why does the B16A with its 1.745 r/s ratio have the same 8200rpm redline as the 1.581 r/s ratio B18C? You can rev a B18A/B and B20B/Z to the same levels as the higher revving B16 and B18C- you just have to use the right parts.
One more thing- the B20B came only in the CR-V, not the older Preludes. The older boxy Preludes came with the B21A and B20A, and never the B20B.
Originally posted by knowledge@Oct 22 2002, 05:29 AM
professor calesta at his best! lol