Discussion in 'Engine' started by blaster1990, Mar 8, 2008.
what does this actually do
does it add more hp
and if it does how much
search. so much is on this forum about stroker cranks.
It will add torque and hp. We sell them for around $220 it think.
If you planning to abuse the engine go with something other than the Vito crank.
you can pick one up from ebay for 150ish, they say it adds 4hp, I don't think it is quite that much, but definitely better throttle response.
CAUTION THERES A SHITLOAD OF MATH AHEAD!
yes indeed it does add more horsepower but not 4hp like the manufacturer tells you. i will break it down for you. the stock crank is 57mm a +3mm crank makes ur crank 60mm
LETS DO SOME MATH!
ok heres how it goes
66mm bore converted to inches = 2.598 inches
57mm crank converted to inches = 2.244 inches
heres the formula (in inches to Cubic centimetes)
2.598 inches x 2.244 inches = 11.8957280573236 cubic inches
convert that to cubic centimeters
1 cubic inch = 16.387064 cubic centimeters
apply that formula to the above product (11.8957280573236)
1 cubic inch x 16.387064 = 16.387064 cubic centimeters
11.8957280573236 cubic inches x 16.387064 = 194.9360381379971 cubic centimeters
do your rounding...
194.9360381379971 ͌ 195cc
round 195cc and you get a stock yamaha blaster 200! (blaster 195 doesnt sound catchy lol so they rounded 195 up to 200 and also so it fits into the 200cc class)
now thats stock and that 195cc puts out ͌ 20hp
round 195cc to 200cc as yamaha did
now divide 200cc by 20hp
200cc / 20hp = 10cc
thats ͌ 1hp every 10cc
so the displacement to power ratio is 10:1
ok so now lets do that equasion with a 60mm crankshaft rather than a 57mm
convert that to inches
60mm crank shaft = 2.364 inch crank shaft
now the bore size is constant so we can leave that the same as before.
bore x stroke = cubic inches
2.598 inches x 2.364 inches = 12.531863247554806 cubic inches
convert the 12.531863247554806 cubic inches to cubic centimeters by applying the formula i have provided above in blue.
12.531863247554806 x 16.387064 = 205.360445076928449429584 cubic centimeters
once again do your rounding
205.360445076928449429584 = 205cc
displacement to hp ratio is 10:1
so with +10cc you get aproximatly 1hp more from that crank.
in combination with a bored cylinder and a big bore kit and a milled head there is no ending to how much horse power you can put into this thing.
posibilities are endless, so is math.
but if you look at the whole picture 20hp is awfuly low, yet keeps you satisfied, now 21hp will make it that much more satisfying!
please correct me if i am wrong with any of my calculations after all i did not use a calculator!=))
i hope i helped
cmon guys throw me sum rep this math took me an hour and a half to do!I:I
Since when does a stock blaster produce 20 hp?
ya... 16hp is stock.
i don't mean to correct you, but i was looking at that, and it didnt make sense. "2.598 inches x 2.244 inches = 11.8957280573236 cubic inches" inch x inch = inch squared not cubed. so i thought about it, and if bore times stroke equals displacement, then bore would have to mean cross section. in that case, stock bore, 66mm would be 6.6 cm. then area of that, which would be a circle is pi x 3.3 x 3.3 (radius squared) x 5.7 (stock stroke in cm.) and that equals 195.008 CCs. with a +3mm stoker then, it would be pi x 3.3 x 3.3 x 6.0 which equals 205.272 CCs.
if 195 CCs produce 16 hp, which is stock then 205 CCs should produce 16.8 hp. rounded up it's 17, or +1.
again, i didn't mean to correct you, but in that one equation, there was a missing inch and i stared at it until it drove me nuts and i had to find it. all the numbers match up though. im surprised that a stroker only adds 1 hp.
I'll get my +3mm Vito's crank this week and built it in my Dt200R Motor with my 68mm Woessner piston, so I'll reach 218 ccm. I'll tell you the rear wheel power during the next few weeksI:I.
be prepared to trench the case so the rod pin will pass.
and you may need to cut out the cyilinder skirt as well on some +3 or +4 cranks.
although vito's only offers as high as +3
hot rods offers a +4
no crusty4365 is right.its about 20 cuz i have seen plenty of stock dyno test and they all say about 20hp
Yamaha claims they only make 16 to the wheels, but ive never seen a dyno for one so i duno.
sorry if my math was off a little.... buttttt i doo beleive that its 18? to 20? hp stock, but hey you get the point none the less the +3 stroker should add about 1hp and 10cc.
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