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bore vs stroke

PostPosted: Sat Aug 16, 2014 12:43 pm
by Forge91
So ive been wondering,
whats the difference between a engine having a bigger stroke than bore and vice versa?

Short but powerful question. :D

thx in advance!

Re: bore vs stroke

PostPosted: Sat Aug 16, 2014 1:50 pm
by Jakgoe
In essence, bore is the diameter of a cylinder, and stroke is the length of one up or down motion of a piston. This should provide some insight into how they affect engines.

Re: bore vs stroke

PostPosted: Sat Aug 16, 2014 1:56 pm
by gt1cooper
A couple things.
1. Higher stroke means more stress on the bottom end at high rpm
2. Lower bore means less stress on the top end at high rpm
3. Bigger bore makes a much heavier engine
4. Bigger bore makes a more expensive engine (more materials)
5. Bigger bore lowers your octane requirement

Re: bore vs stroke

PostPosted: Sat Aug 16, 2014 8:52 pm
by NormanVauxhall
I will add also to the gt1cooper list this --> Bigger bore = bigger valves = heavier valves = earlier valve float

Re: bore vs stroke

PostPosted: Sat Aug 16, 2014 9:11 pm
by Dragawn
NormanVauxhall wrote:I will add also to the gt1cooper list this --> Bigger bore = bigger valves = heavier valves = earlier valve float

that's pretty much the same as the lower bore meaning less stress in Cooper's list :P

Re: bore vs stroke

PostPosted: Sun Aug 17, 2014 12:48 am
by Jakgoe
Also, this is more of a problem in real life than in the game, but smaller bore can make it harder to put many valves per cylinder.

Re: bore vs stroke

PostPosted: Sun Aug 17, 2014 2:19 am
by Forge91
gt1cooper wrote:A couple things.
1. Higher stroke means more stress on the bottom end at high rpm
2. Lower bore means less stress on the top end at high rpm
3. Bigger bore makes a much heavier engine
4. Bigger bore makes a more expensive engine (more materials)
5. Bigger bore lowers your octane requirement


Thx, was looking for this info.
You're going in my list of heroes!! :P

Re: bore vs stroke

PostPosted: Sun Aug 17, 2014 2:48 am
by gt1cooper
I'm a hero! :shock: someone save the world from me!

Re: bore vs stroke

PostPosted: Sun Aug 17, 2014 8:00 am
by Daffyflyer
gt1cooper wrote:A couple things.
1. Higher stroke means more stress on the bottom end at high rpm
2. Lower bore means less stress on the top end at high rpm
3. Bigger bore makes a much heavier engine
4. Bigger bore makes a more expensive engine (more materials)
5. Bigger bore lowers your octane requirement


1. Super true
2. To some extent, as bigger bore means bigger and heavier valves
3. Yep
4. Yep
5. Wrong way around, bigger bore need more octane

Also im fairly sure bigger bore = more valve area and head flow.

Re: bore vs stroke

PostPosted: Sun Aug 17, 2014 12:00 pm
by gt1cooper
Daffyflyer wrote:
gt1cooper wrote:A couple things.
1. Higher stroke means more stress on the bottom end at high rpm
2. Lower bore means less stress on the top end at high rpm
3. Bigger bore makes a much heavier engine
4. Bigger bore makes a more expensive engine (more materials)
5. Bigger bore lowers your octane requirement


1. Super true
2. To some extent, as bigger bore means bigger and heavier valves
3. Yep
4. Yep
5. Wrong way around, bigger bore need more octane

Also im fairly sure bigger bore = more valve area and head flow.

Ah, 5 was the only one which I was unsure about. I wanted to test it, but didn't have access to my computer.