why cant they make this a little easier...

got a B18b1, wanna bore the block out to 84mm for 2.0L like a b20, i wanna use CP pistons, and i wanna get about 10:1 compression, CP doesnt make 10:1 compression b series pistons....and the 9.7:1 compression pistons they make the compression they list, apparently is for a b series with a b16a1 head attached, according to the legend at the bottom. Now i know we have to account for things like decking the block and head, and the overbore going from 81 to 84mm will loose compression. Can someone help me with my selection here.

 

Now I may be mistaken, but it looks to me that if it has the number 4 under notes, it will work with a B18A/B head.

SC7017 looks like it's an 84mm bore piston that can get you close and work with a B18A/B head. I would try to find out what the dome volume is on those pistons so you can figure out what the compression ratio will really be.

 

yeh i figured out that much, but i dont understand why the compression is based off of using a different head on every b series block, im assuming that the b16 head has a lower height which raises the compression, so the estimate they are giving is for the maximum available compression the piston gives?

 

Why assume? If you find out the chamber volume of your head vs. the B16A, you should be able to figure out what the CR will be on your engine. Here are the formulae to figure it all out. The measurements (bore/stroke/etc) are meant to be in inches, not millimeters.

• Swept: bore^2 x stroke x .7854 x 16.39 = cc’s
• Head Gasket: bore^2 x crushed thickness x .7854 x 16.39 = cc’s
• Deck Clearance: bore^2 x distance in(+) or out(-) of the hole x .7854 x 16.39 = cc’s
• Piston: Measured Dish(+) or Dome(-) in cc's
• Combustion Chamber: Measured in cc's

 

yeh ill take a look at that tomorrow after i get some sleep lol cus right now it looks like its written in chinese at 2am

 

You are sleeving the block, right?

 

more then likely yes

 

b16 head will give you lower compression. So if you're using a gsr head with those same pistons you will be more like 10:1

 

ill be using a b18b1 head