Cam LSA Explanation
Cam LSA Explanation Sorry it this seems a dumb question, still learning this technical stuff.
I often see cams with an LSA of 110 + 2 or 112 +3 etc.
What does +2 or +3 after the LSA mean ?.
Thanks for your help.
I often see cams with an LSA of 110 + 2 or 112 +3 etc.
What does +2 or +3 after the LSA mean ?.
Thanks for your help.
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Joined: Jul 2002
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From: Somewhere I Belong
+4 is 4 degrees advanced, +1 would be only 1 degree advanced or 3 degrees retarded from +4.
Retarding cam timing results in all valve events happening later.... advancing the cam results in valve events sooner.
the most influential valve event is intake closing, by retarding cam timing the intake closes later and since duration does not change cylinder pressure will bleed off as the piston comes upward with intake valve still open, result is less cylinder pressure = less torque at low rpm.
they should do away with LSA because it is dependent upon duration.
there should only be duration and centerlines for intake and exhaust.
Retarding cam timing results in all valve events happening later.... advancing the cam results in valve events sooner.
the most influential valve event is intake closing, by retarding cam timing the intake closes later and since duration does not change cylinder pressure will bleed off as the piston comes upward with intake valve still open, result is less cylinder pressure = less torque at low rpm.
they should do away with LSA because it is dependent upon duration.
there should only be duration and centerlines for intake and exhaust.
To conclude am I correct in saying that a 112 +4 deg LSA will give me more torque than a 112 +1 deg LSA ?.
I'm looking at two custom cams for an LS2, will I notice much difference in on road performance between the two.
1/ 228/228, 588/588 112 +4 LSA
2/ 228/228, 588/588 112 +1 LSA
All opinions appreciated.
I'm looking at two custom cams for an LS2, will I notice much difference in on road performance between the two.
1/ 228/228, 588/588 112 +4 LSA
2/ 228/228, 588/588 112 +1 LSA
All opinions appreciated.
To conclude am I correct in saying that a 112 +4 deg LSA will give me more torque than a 112 +1 deg LSA ?.
I'm looking at two custom cams for an LS2, will I notice much difference in on road performance between the two.
1/ 228/228, 588/588 112 +4 LSA
2/ 228/228, 588/588 112 +1 LSA
All opinions appreciated.
I'm looking at two custom cams for an LS2, will I notice much difference in on road performance between the two.
1/ 228/228, 588/588 112 +4 LSA
2/ 228/228, 588/588 112 +1 LSA
All opinions appreciated.
Look into how valve events affect intake centerline
If you were to move ICL it will change your IVO and more importantly IVC, thats largest effect and move you exhaust centerlines. Thats modifying a camshaft backwards.
Constantly i'm asked, can you take this cam 112ºLSA and put it "on a" 11X, my response to that is, of course, did you look at the valve events of that? its a rhetorical question, the answer is no 10/10. NHRA Pro stock engines have in the area of 117º LSA, so LSA is mearly a 'by product' of the valve events.
camshaft #2 should show more usable RPM and potentially higher peak hp.
Last edited by Fraser@SpeedInc; Apr 4, 2008 at 11:59 PM.
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IMHO you won't see nor feel a difference between those cams under the curve, I think cam 1 will peak sooner and limit peak power, it will drop off at 6200
Camshaft #2 will run out to 6500rpm and have potential for higher peak number
LS1 dyno graphs peak tq at 4800rpm, no camshaft is going to slide that to 2000rpm for a peak tq.
by the numbers at .050" lift
camshaft #1
IVO 6º
IVC 42º
EVO 50º
EVC -2º
Camshaft #2
IVO 3º
IVC 45º
EVO 47º
EVC 1º
Camshaft #2 will run out to 6500rpm and have potential for higher peak number
LS1 dyno graphs peak tq at 4800rpm, no camshaft is going to slide that to 2000rpm for a peak tq.
by the numbers at .050" lift
camshaft #1
IVO 6º
IVC 42º
EVO 50º
EVC -2º
Camshaft #2
IVO 3º
IVC 45º
EVO 47º
EVC 1º
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Joined: Jun 2002
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From: Upstate NY
valve timing You want the cam events to happen at certain points in the piston cycle to create velocity, compression a certain power band for your given application. The same cam in the same size engine but with 2 different length connecting rods will perform differently by a vast amount just because valve events happen at different point of the piston movement. read this article its one of the best by David Vizard http://www.hotrod.com/techarticles/e...ech/index.html
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