Im new at this so i might sound stupid but i plan on building up a LSV but i have no idea what to do in the bottom end.. I heard LSVtec are bad becuase of rod/stroke ratio. If i build my LS block should i keep the ls crank and rod with p30 pistons or put in a GSR bottom end into the LS block. If i do put in the GSR crank and rod with p30 pistons, does anyone know what ratio it will be and the COMPRESSION. What should i do?

 

The LS/CRVTEC rod ratio isn't all that bad a 1.54:1, 0.04 lower than the B18C. In my opinion if you're want the B18C's rod ratio for some reason just start with a GSR/ITR motor. For the bottom end besides the pistons upgrade your water/oil pumps to GSR/ITR and I would also run OS pistons which requires reboring/honing the block (just gives you nice clean cylinder walls to work with). As for your compression, it'll vary a little depending on what cylinder head you run. With the PR3 (B16/B18C/5) you'll probably be somewhere around 11.9:1 and with the P72 (B18C1) about 0.30 higher at 12.2:1. That's really all there is too it, Good Luck

 

Keep the LS crank, but have it balanced. I would personally run forged pistons and rods, but you should be fine with OEM Honda pistons. I wouldn't run anything less than PR3 pistons though.

 

rod stroke ratio is over rated, you shouldnt start worrying about it untill it becomes really really low, like if you trying to fit a big stroker crank in the motor

 

ok thx, i planning to stick with the LS crank and rod BUT i was wondering if the OS pr3 or p30 pistons affect the performance that much? I know i should hone the walls anyways but someone said that the OS doesnt even help that much at all, is this true?

 

OS pistons aren't going to gain you anything but ~0.05:1 in compression for every 0.25mm over stock bore. The real reason for them is to allow you to bore your motor over and still run the pistons. It gives you nice clean round cylinder walls for the new rings to seat and I personally will only build a stock sleeved motor if it's atleast been overbored. You can not run OS pistons without boring. If you only want to hone the block then stick with std. bore pistons.

 

Sorry to jack the thread, but I'm going to be doing an LS/VTEC and I know that you know your stuff Kataku.

How much compression can I safely run with 94 octance gas? What brand aftermarket pistons would you reccomend for a somewhat mild N/A LS/ VTEC? I'm thinking 180-190 whp.

 

With something like Hondata for tuning you should be fine at 12.0-12.5:1 but you will have to pull some timing. The highest pump we have around here is 92 and those compression numbers have worked with us. As for the brand of pistions I would go with JE's, CP's, or Wiseco's. Good Luck

 

well im pretty broke, but i do want to build this motor right. I cant afford aftermarket pistons but factory pistons are in my price range. If you were me, would you bore the stock walls for OS pistons or just leave it STD. Factory rings are coo right, i been hearing things about aftermarket rings like TOTALSEAL having problems...thanks

 

Yea, that's cool. If I were you I would bore your block and run OS pistons with factory rings. It's simple and will work fine.

 

exactly, just use p30's and arp rod bolts and be done...great cheap setup