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willy
PostPosted: Wed Oct 25, 2006 1:02 pm 
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4 Ways of Building Torque

Cubic Inches
Stroking creates more displacement, and displacement means power.

Compression
More displacement makes it easier to produce high compression without massive domed pistons.

Lever Action
A longer stroke is a longer lever acting on the crankshaft, thus providing more torque.

Pressure Power
Longer stroke creates faster piston speeds, which means that the piston can create a more accurate pressure drop to fill the cylinder more thoroughly at low rpm for torque.
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FatMaserati
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PostPosted: Wed Oct 25, 2006 1:13 pm 
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...All of which my Mini has in spades! :P

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benjamin
PostPosted: Wed Oct 25, 2006 5:09 pm 
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turbo charger
providing more torque.

:)
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jbeenz
PostPosted: Wed Oct 25, 2006 5:24 pm 
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ive got em all too :D 84mm stroke, 12 - 13: 1 compression, 122cc up from stock, and i dont know what kinda torque itl make, probably less than a stock 1275 :roll: :lol:

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Blokeinamoke
PostPosted: Wed Oct 25, 2006 6:21 pm 
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willy wrote:
4 Ways of Building Torque

Cubic Inches
Stroking creates more displacement, and displacement means power.

Compression
More displacement makes it easier to produce high compression without massive domed pistons.

Lever Action
A longer stroke is a longer lever acting on the crankshaft, thus providing more torque.

Pressure Power
Longer stroke creates faster piston speeds, which means that the piston can create a more accurate pressure drop to fill the cylinder more thoroughly at low rpm for torque.


All useless if it doesnt breath. You want more torque or power concentrate on breathing first, displacement either by stoke or bore second.
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jbeenz
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PostPosted: Wed Oct 25, 2006 6:29 pm 
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bloke, when you have 5.3 british litres, your going to have torque anyway! :D

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drmini in aust
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PostPosted: Wed Oct 25, 2006 7:13 pm 
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Stroking a Mini is a law of diminishing returns, a bit helps, but the more you stroke it the higher the internal friction.
Anything much past 86m in a 1275 block is a waste of time, according to Mr Vizard...
:wink:

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Spaceboy
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PostPosted: Wed Oct 25, 2006 7:38 pm 
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the point being willy's building a MONSTER
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cush
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PostPosted: Wed Oct 25, 2006 7:45 pm 
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jbeenz wrote:
bloke, when you have 5.3 british litres, your going to have torque anyway! :D


don't you mean 9.3 pints? :)

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supercharged 850
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PostPosted: Thu Oct 26, 2006 1:25 am 
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Spaceboy wrote:
the point being willy's building a MONSTER


... to sell to the highest bidder...

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simon k
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PostPosted: Thu Oct 26, 2006 10:23 am 
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that's a very nice concise explanation willy - I described point 4 to someone on Saturday night..... not so eloquently though :D

it's the reason why you need to rev the nuts of these Japanese motors to produce power - they just don't have the stroke to produce decent intake velocities at low revs

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GTi_Mini
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PostPosted: Thu Oct 26, 2006 12:22 pm 
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^^^^^^^ hence why my GTI has been bored and stroked. but it the perfect square 77mm stroke 77mm bore.
whats the bore on a 1275 anyway????

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simon k
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PostPosted: Thu Oct 26, 2006 12:33 pm 
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GTi_Mini wrote:
whats the bore on a 1275 anyway????


1275 (standard bore...) is 70.6mm x 81.3mm stroke.... well under square ;)

there's actually a typo in my book (Pedr Davis' Mini Minor Downunder) which states the bore of a 997 cooper is 6.46mm x 81.33mm stroke - they may have been fairly gutless, but they didn't have biros running up and down the cylinders! I'm sure it's meant to be 64.3mm :lol:

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drmini in aust
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PostPosted: Thu Oct 26, 2006 5:29 pm 
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skssgn wrote:
GTi_Mini wrote:
whats the bore on a 1275 anyway????


1275 (standard bore...) is 70.6mm x 81.3mm stroke.... well under square ;)

there's actually a typo in my book (Pedr Davis' Mini Minor Downunder) which states the bore of a 997 cooper is 6.46mm x 81.33mm stroke - they may have been fairly gutless, but they didn't have biros running up and down the cylinders! I'm sure it's meant to be 64.3mm :lol:

Actually the bore of a 997 Cooper is smaller than an 850. :shock:
It's only 62.43mm. :lol:
People used to bag the 997 for its `long stroke' of 81.33mm. It's actually the same as a 1275S, and shorter than a 1098 (83.7mm).

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Spaceboy
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PostPosted: Thu Oct 26, 2006 5:54 pm 
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i dont believe in stroke, the ford twin cams were awesome.. if only bmc had given the mini a decent engine!
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