I have a 93 gs-r. it currently has skunk2 cams/gears/intake manifold and no ther head work. i need to build my bottom end now and i was wondering what i should go with… i am looking for something that is “bullet proof,” i wanna be able to rev high and not have a single worry about hurting anything, thus i want to build the ultimate bottom end for a gs-r. should i build a ls/vtec hybrid and dump my endless funds into it and make it indestructable so to speak or would a gs-r bottom end do me just as good? If i do go with that bottom end would i need anything else bisides the block such as a new ecu or anything of that nature… plus i was wondering if it is possible to put a gs-r cracke with the shorter stroke into a b20 with a larger bore thus making a 1.8 that can rev high and i wouldn’t have to worry and snapping rods or throwing bearings. i am not to knowledgable in this feild so please let me know what i can and should do.
If I were you I would get a b18c bottom end and biuld it to minimize your downtime. I think in the end if you want a “bullet-proof” bottom end this is the way to go. Since you are rebiulding the bottom end with your endless funds you of coarse can use your b17 head and not worry about the difference in compression cause you can get pistons to get whatever compression ratio you want. As far as the b20 question with a GSR crank, i’m not sure but if this was do-able and/or benifitial I think someone would have done it already. This is not to say I know from a fact it can’t be done, all i’m saying is I haven’t read/heard of anyone doing it.
Which crankshaft for forced induction? B20b/z, B17a, or B16a?
We recommend the stock B20b or z crankshaft for forced induction. Yes, the B17a crankshaft will give a better rod to stroke ratio but because of the quality of the stock crank, the lack of availability for the B17a crankshaft and the incredible price of custom length rods we like the stock crank. We’ve seen instances of guys purchasing the B17a crankshaft directly from Honda for close to $1,000, which is insane. That money could be better spent on lightweight rods and pistons for the B20b/z crankshaft.
Why isn’t the B17a crankshaft recommended anymore?
Because the power produced by the B17 is inferior to what the B20b/z can produce. Sure the rod to stroke ratio is worse than what the B17 produces, but the stock crank still has good geometry. Additionally, the market refuses to produce products (read: rods) for this combination jumping this all ready expensive engine build even higher. We just can’t recommend it because we never seen this crank produce as well as the stock crank.