Wiseco 440cc? Nah...it's a 435cc!!

[GPracer2500]

Anyone know why Wiseco lists their 89mm pistons as creating 440cc of displacement? The math works out to 435cc. The displacement of an engine is defined by it's bore x stroke. The formula for the volume of a cylinder is Radius^2 * Pie * Height.

89mm / 2 = 4.45cm (radius of piston)

4.45cm^2 * 3.14 (pie) = 62.1799cm

62.1799cm x 7cm (400EX stroke) = 435cc

JE lists thier 89mm piston as 435cc. So, what gives with Wiseco? Did they start saying 440cc for marketing reasons way back when and figured they better stick with it since everyone now refers to their 89mm piston 400EXs as "440s"??

:confused:

[underpowered]

Originally posted by GPracer2500
Anyone know why Wiseco lists their 89mm pistons as creating 440cc of displacement? The math works out to 435cc. The displacement of an engine is defined by it's bore x stroke. The formula for the volume of a cylinder is Radius^2 * Pie * Height.

89mm / 2 = 4.45cm (radius of piston)

4.45cm^2 * 3.14 (pie) = 62.1799cm

62.1799cm x 7cm (400EX stroke) = 435cc

JE lists thier 89mm piston as 435cc. So, what gives with Wiseco? Did they start saying 440cc for marketing reasons way back when and figured they better stick with it since everyone know refers to their 89mm piston 400EXs as "440s"??

:confused:

It just has always been marketed as a 440. Even people with an 89mm JE pisotn still way they have a 440. just like your 400ex is only a 397 from the factory.

[jordan_m6]

400ex are not 400cc they are 397 or so. but anyway they ar not the full 400cc

[jordan_m6]

oh..... underpewered already stated that

[#8red]

I think its cuz you are boring 40 over - so people just add it - like a 250r becoming a 330 - it's actually way less than that - but the piston is 80 over - so people just add it I guess -

[underpowered]

Originally posted by #8red
I think its cuz you are boring 40 over - so people just add it - like a 250r becoming a 330 - it's actually way less than that - but the piston is 80 over - so people just add it I guess -

no. a 440 (a 435cc) is actually .160 over. .040 over is only a 406. people dont just add it, it is just how it was marketed

[GPracer2500]

Stock displacements are rarely accurately reflected in a machines model name--I understand that.

I guess I just found it strange about the "440s" since it's a replacement piston and it seems the manufacture (Wiseco) should tell you what the actual displacement is. If they want to call their kits 440 kits--that's understandable for marketing reasons. But they should at least tell you the actual displacement in the specifications. Instead, their specifications say it's 440cc rather than indicating the correct 435cc.

I guess I'm just a stickler for details on such matters...

[jordan_m6]

440 is easier to say than 435. all companys do this.

[coryatver]

the 416 is actually 416:D

[Flyin-Low]

440 sounds WAYY better than 435. And who needs to be exact, that 5 cc isnt gonna make a differance :blah:

Just my .02

-Martin