What produces more HP

[uwenr]

Curious what make more power, bore or stroke. For instance 421 cheetah 4 mil vs. 417 7 mil stock cylinders.

[AKheathen]

more stroke gives more leverage on the crank which increases torque and compression. larger bore gives more leverage to the crank per amount of air, allowing it to rev higher without the piston/rod assy. countering it's efforts so much, which also means the pistons have to push many more times to accomplish the same amount of work. kinda like the differenc between a dump truck and a mini truck. a dump truc won't do 145mph, but can haul 10 times as much. at least that's the way i see it

 

edit---> a better example, it's not uncommon for a 383 stroker to push 500 ponnies, but a 377(exact opposite-350 crank & 400 block) can turn 10'000rpms

Edited December 20, 2008 by AKheathen

[brian]

On a small engine like the banshee, I believe you would see a bigger

difference with stroke increase.

I have not seen that much increase in power from boring bigger. I have only

been up to .08(2mil) over on a banshee engine, but with the exact same ports

I felt no difference in the seat.

Really hard to qualify though since most strokers get ported to correct timing

and the bigger increase in power probably comes from that porting.

 

Are you trying to figure out which mod to do next ?

[boneyardbanshee.]

Assuming you are modding a given topend, stroke will always create more hp than bore. At least on those variables alone. For example if you inrease the bore AND the compression you may see a bigger increase over stroke alone.

[locogato11283]

most people go with a stroked motor over some huge bore. youre not gonna gain as much going with a bored motor as you would one with a 4mm stroker crank.

[J-Madd]

most people go with a stroked motor over some huge bore. youre not gonna gain as much going with a bored motor as you would one with a 4mm stroker crank.

 

 

Yep. Stroke. 4mil dragported stock cylinders and 68mm bore stock stroke Cub that I know of seem to comparable at the track and dyno.

[flotek]

alot of times boring and stroking would be ideal to keep the relationship withing reason but on a banshee your bore diameter is already 10mm larger than the given stroke .note that a 421 cub which is wel l know to be great bang for the buck engine combination retains this same relationship in MM to bore and stroke ..so if you were to choose one it would be stroking the crank for most noticable worthwhile gains .