4" vs 4.125" stroke pros and cons
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TECH Junkie
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From: East Brady, Pa
4" vs 4.125" stroke pros and cons Trying to figure out what stroke I want. What are the ups and downs to each one? This would be on an ARE block that has been relieved for upto a 4.125" stroke and the motor may see nitrous in the future. Not sure on bore size yet....at least 4.100"
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From: new england
Re: 4" vs 4.125" stroke pros and cons If you consider rod length to stroke ratio, than shorter stroke is better, especially where induction limitations are concerned.Bore side loading is extreme with either stroke you listed, and will show up in cyl. bore wear. I dont like idea of over square motor size so i would stick with 4" stroke and 4.100" bore. On the plus side stroker pistons are usually lighter and have more powerfull hi ring placement, great unless you want to use nitrous( i wouldnt anyway!) <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
Re: 4" vs 4.125" stroke pros and cons </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LS1derfull:
<strong>If you consider rod length to stroke ratio, than shorter stroke is better, especially where induction limitations are concerned.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">How do you figure? I don't know, but I'm asking and looking for information. I would think if your intake was a limitation that a longer stroke would be better because it takes longer to suck in the air than a shorter stroke. It just seems like a shorter stroke would overwhelm the intake by trying to suck in a lot of air in a shorter amount of time since there’s more bore per inch. Got me. If the engine was just N/A what stroke would produce more power? Or would it even matter since it's only what, 1/8 of an inch difference either way with a 4.125/4.00?
<strong>If you consider rod length to stroke ratio, than shorter stroke is better, especially where induction limitations are concerned.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">How do you figure? I don't know, but I'm asking and looking for information. I would think if your intake was a limitation that a longer stroke would be better because it takes longer to suck in the air than a shorter stroke. It just seems like a shorter stroke would overwhelm the intake by trying to suck in a lot of air in a shorter amount of time since there’s more bore per inch. Got me. If the engine was just N/A what stroke would produce more power? Or would it even matter since it's only what, 1/8 of an inch difference either way with a 4.125/4.00?
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From: new england
Re: 4" vs 4.125" stroke pros and cons Your questions are all goodbut LS1 in the 400+ cubic inch range are going to be induction limited, mostly by intake manifold but also somewhat by the heads.It is just the opposite of what you stated, longer stroke will pull harder on induction stroke but intake will be more of a restriction than on a shorter stroke combo.Short stroke is limited by induction when engine rpm exceeds its capabilities.Most LS1 motors are not built for max rpm and power unless a custom shorter runner length, bigger plenum intake is used.As for power differences longer stroke will make more torque at less rpm, but probably similar horsepower at peak as 4" stroke because of mechanical efficiency differences between the two.
