comp ratio help
#1
comp ratio help
Hey all, I am a little challenged on the tech side of things so I have a question. If my jugs on a 1340 evo are bored .020" and I leave the heads stock and add 9.5:1 domed pistons will the ratio be higher then the 9.5:1 or below it. The reason I ask is Crane says the 9.5:1 ratio is the limit at which the 310-2 fireball should be. Thanks for your time, Bill.
#2
a .020" overbore isn't going to put you over the edge. Here's a set of formulae copied from RBRacing's website that'll help:
Displacement = (Bore ÷ 2)2 x 3.14 x Stroke x 16.387
Head Gasket space = (Bore ÷ 2)2 x 3.14 x Gasket thickness x 16.387064
Deck Height space = (Bore ÷ 2)2 x 3.14 x Deck Height x 16.387064
Compressed Volume = Head Gasket space + Deck Height space +
Piston Top volume + Combustion chamber volume
Uncompressed Volume = Compressed Volume + Displacement
Compression Ratio = Uncompressed volume ÷ Compressed volume
Displacement = (Bore ÷ 2)2 x 3.14 x Stroke x 16.387
Head Gasket space = (Bore ÷ 2)2 x 3.14 x Gasket thickness x 16.387064
Deck Height space = (Bore ÷ 2)2 x 3.14 x Deck Height x 16.387064
Compressed Volume = Head Gasket space + Deck Height space +
Piston Top volume + Combustion chamber volume
Uncompressed Volume = Compressed Volume + Displacement
Compression Ratio = Uncompressed volume ÷ Compressed volume
#3
#5
#6
Aces&8's,
I beleive he is referring to the Crane Fireball 310-2. It is only 236/242 duration and .490 lift. The H310 is a completely different animal, 266/276 duration and .550 lift. A Strip/Street cam works best with Big Bore and 10.5 + compression. Must have hi-rev springs and have the head-valve clearance confirmed.
I beleive he is referring to the Crane Fireball 310-2. It is only 236/242 duration and .490 lift. The H310 is a completely different animal, 266/276 duration and .550 lift. A Strip/Street cam works best with Big Bore and 10.5 + compression. Must have hi-rev springs and have the head-valve clearance confirmed.
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