How to figure CC's

DAG

DAG

Yes, my balls tickled from that landing
Location
Charlotte, NC
I got a 03 SJ abouta month ago..
the guy said it is a 701cc bored 2 over, (what ever that means?)
has wiesco pistons (not shure what size)
44s with 46 mani and cross over is epoxied (WTF is a mani)
tassinarri 2s (??????)
riva reed spacer
riva head 35cc domes
freestyle port by riva (not shure how much?)
wamiltons b-mod pipe with port macthing (Agen how much)


Wish i could ask the seller more info about it, but he is MIA.

I just wont to know how to test to figure out how many cc my orgional 701 has... and the specs on the other porting/milling accessories

-Grif
 
N

njfl

X-H2
Math time (Wax, you're a teacher, right, so this is right up your alley).

The ccs are found by calculating the volume of two cylinders, one for each bore (basic 7th grade math).

The formula would therefore be: 2 x pi x r x r x h

pi = 3.1415927 (no units)
r = half your bore, or bore divided by 2 (suggested units are mm)
h = stroke (suggested units are mm)

OEM 701s have an 81mm bore and a 68mm stroke.

Be careful on keeping the units all the same and do the math.

I created an Excel spreadsheet with this formula so that I can quickly play with engine combos. For example, if you wanted to see how a 5mm stroker setup increases ccs, change the 68mm to (68+5=73mm) and recalculate.

As you start to get up in the 800cc range, using the spreadsheet, you begin to see that a 1mm increase in bore has a bigger effect on ccs than a 1mm increase in stroke. However, on a properly built engine, the 1mm change in stroke may be better for lower end than the 1mm increase in bore and that is beyond the math.

But, nonetheless, math is important kids:)
 
N

njfl

X-H2
Mile9c1 said:
I don't think it'll make any difference, 701, 718, 732, or ???
Click to expand...
Agreed. I used to be all into the numbers game, but I learned that unless you are taking a huge leap, like 700 to 800, there's not a lot of difference, assuming proper machine work and build.
 
W

waxhead

wannabe backflipper
Location
gold coast
i like 83mm bore
it makes them run smoother than 81mm
i think it balances them more
still leaves you one over bore as well
 
N

njfl

X-H2
Also, you can have a well-prepped 701cc that will blow the pants off a half-witted-built or parts-mismatched 785cc.
 
W

waxhead

wannabe backflipper
Location
gold coast
yup there is more to it than cc
volumetric efficency of those cc is whats important
Make sure you are getting all those cc you have
also remember that you arent getting all that cc ethier until the piston closes the exhaust
so the difference between 701 and 800 is less again
 
You must log in or register to reply here.
Top Bottom