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What are the true benefits of a higher LSA?

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Old 07-25-2005, 08:56 PM
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Default What are the true benefits of a higher LSA?

Hypothetically:

224/224 .570/.570 108lsa

vs.

224/224 .570/.570 120lsa

Extremes of both sides.

What are the beenfits besides the less chopiness? Benefits? Pros/cons?

Sorry for such a broad question.

-Wade
Old 07-25-2005, 09:01 PM
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well the 108 lsa will idle pretty rough and have a gassy smell at times and when you hit the gas its gonna have a torquey feel prob from as low as 2500 rpm and pull nicely to about 6k and the 120 lsa cam will have a pretty nice idle no gas smell and when you hit the gas its gonna feel like a dog until you hit prob 5500 then its gonna feel like a turbocharger just kicked in.Big durations(220 and up) dont go together with a lsa of 115 or higher because its just kills your low end.
Old 07-25-2005, 09:20 PM
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what ICL's?
Old 07-25-2005, 10:42 PM
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I dont have anything ground yet. Im just curious. This is a completly hypothetical question. So go ahead and fill me in.
Old 07-25-2005, 10:54 PM
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A 120LSA with a 120ICL will make its torque uptop, especially if you throw duration at it. However, you are limited by intake runner to make effective use of such a topend-oriented cam. But the benefit is, in theory, that you will make power at a higher rpm, because your torque curve has shifted. But that's hard to do on an LS1, so it's a waste of time unless you have a really small cam that otherwise is simply too small for the cubic inches it is feeding, i.e. the stock cam. It's also good for emissions and drivability or boosted applications.

Running a 108LSA on 108ICL (which isnt really that dramatic, especially with the larger cams) would be the opposite. A small duration cam would be an excellent stump pulling cam but would die off above 4500-5000rpm. Ideally, a 108ICL would be mated to a huge duration cam, because the duration will push the power up in the rpm range, and the tighter LSA and ICL will bring it back toward the midrange, but at a much more violent output. Will not idle well and will be poor on emissions because of the overlap. That also rules it out for boosted applications. Requires compression to bleed off, or else it will not make good power.

Am I forgetting anything?
Old 07-25-2005, 11:09 PM
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So something such as a 238/244 598/614 on a 120?

What do you think? Has anyone tried it? Not theoretically...Has anyone given a 120 a try with that big of duration on a stock bottom end?
Old 07-25-2005, 11:10 PM
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BTW, Smog in Cali is horrible. Thats where i am right now, not texas.
Old 07-25-2005, 11:17 PM
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Like I said above, there are other limitations with the LS1 that will make that cam a very stupid choice. Unless you are going to run a sheetmetal intake with extra long runners and a 2"+ headers and rev it to 7500rpm+ you probably won't see a whole lot on a 346cid. The solid roller cams that run in the 260+ range have very tight LSAs of 108 or 106 with similar ICLs and they still rev to 7500. A 240 duration cam already runs to 7k or so with the 346 on a 110LSA. Granted, pushing it out further will probably make a load of power, but it's close to unusable because of the current engine design. Not to mention, a 240 duration cam doesn't have a lot of low end grunt even with the tight LSA. Widen it and you'll feel like a 1600cc motorcycle engine is powering a 2500HD.

On a bigger displacement, that might work if it were a tad smaller, say 224-230, but then it would act like a 200 on a 119 in the 346. Broad power, but it never really "wakes up." Would pass emissions with ease, though.

What is your goal? Just to be different?
Old 07-25-2005, 11:25 PM
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Originally Posted by JakeFusion
Just to be different?
Yes...

And to see what happens.

Theories are meant to be disproved. Simple law of science. People are always out to disprove themselves with something better.



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