Stroker Kits

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civic_ferio

Junior Member
hi. i was just wondering how does it work? can you cange the displacement just by changing the crank shaft?
 

Slo86GT

Super Moderator
it's all about the math.

If you increase the stroke on the crank, the piston will push further upward, so you either:

A: get a shorter rod and shoot the rod/stroke ratio to shit

or

B: Move the wristpin in the piston upward, possibly causing oil management or compression issues.

It's really a tradeoff, but alot of companies are making some nice stroker kits now for B series cars that have a decent Rod/Stroke ratio, while they increase displacement .1-.2 liters.
 

phunky.buddha

Mad scientist
Moderator
VIP
Yes, but at the cost of a lot of those stroker kits on the market, it might be cheaper (or the same price) to bore out larger and run custom pistons. Your engine will be stronger with a new sleeve built to handle the larger bore too.
 

K2e2vin

Senior Member
heres the equation for displacement: (B/2)²*pi*S B=Bore, S=stroke. if you change the stroke, the total would be greater.

ie. B16a2.. (8.1/2)²*pi*7.7= 397.78*4 (for 4 cylinders)= 1587cc
r/s= 1.74
throw in a b17 crank... (8.1/2)²*pi*8.14=419.45*4= 1678cc
your r/s ratio will decrease though, r/s= 1.62 (this is still pretty good)
or you can change the bore.... b16a2 84mm rebore=
(8.4/2)²*pi*7.7=426.72*4= 1707cc, you get same r/s ratio but more displacement.

combine them... b16a 84mm rebore, b17 crank=
(8.4/2)²*pi*8.14=451*4= 1804cc
 

NoJokE

Senior Member
Originally posted by K2e2vin@Apr 5 2003, 01:46 PM
(B/2)²*pi*S B=Bore, S=stroke.
(8.1/2)²*pi*7.7= 397.78*4 (for 4 cylinders)= 1587cc

why do you represent bore as 8.1 and stroke as 7.7?
 

phunky.buddha

Mad scientist
Moderator
VIP
Originally posted by TypeRcivic+Apr 5 2003, 01:32 PM-->
@Apr 5 2003, 01:46 PM
(B/2)²*pi*S B=Bore, S=stroke.
(8.1/2)²*pi*7.7= 397.78*4 (for 4 cylinders)= 1587cc

why do you represent bore as 8.1 and stroke as 7.7?

Centimeters... since we calculate displacement as cubic centimeters, not cubic millimeters. It's just easier to start with the right measurement scale than try to convert it later and get confuzzled.

:lol:
 

K2e2vin

Senior Member
Originally posted by Calesta+Apr 6 2003, 10:38 PM-->
Originally posted by TypeRcivic@Apr 5 2003, 01:32 PM
K2e2vin
@Apr 5 2003, 01:46 PM
(B/2)²*pi*S  B=Bore, S=stroke.  
(8.1/2)²*pi*7.7= 397.78*4 (for 4 cylinders)= 1587cc

why do you represent bore as 8.1 and stroke as 7.7?

Centimeters... since we calculate displacement as cubic centimeters, not cubic millimeters. It's just easier to start with the right measurement scale than try to convert it later and get confuzzled.

:lol:

:werd: :withstupid:
 
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