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When I cam my 09 GT I dont want a cam that sounds choppy/lopey (spelling?)

What decides in the cam specs the choppiness of a cam? The LSA? I tried searching here and just online and just couldnt find a direct answer.

I want it to idle smooth stock sounding.

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G8 fiend
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jus look up all sound clips with cam swaps theres prolly a few dozen floating around and tons more on utube i tihnk it was the vegas guy got a custom cam sounded really good not all that ruff and hes selling his car too forget the name :( ut has 600+hp
 

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When I cam my 09 GT I dont want a cam that sounds choppy/lopey (spelling?)

What decides in the cam specs the choppiness of a cam? The LSA? I tried searching here and just online and just couldnt find a direct answer.

I want it to idle smooth stock sounding.

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the lsa will be your "chop" factor .. i think ours is like 116.25 or something if i remember so if you want a stock sounding cam stay in that range or a degree less .. put some lift there and little duration and you will have a cam that will do ok but it wont have big hp gains..
 

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LSA (lobe separation angle) determines the choppiness, it has to do with the overlap of when both valves are open, as in when the exhaust valve is closing and the intake valve is opening to pull fresh fuel in on the intake stroke after pushing out the burnt fuel.

Most GM cams come on a 112, 114 or 116 LSA. bu I have seen cams as low as 109. 116 is going to be pretty much factory, most guys who want a mild cam, for DD type cars and anything that gets frequent use go with a 114. 112 is pretty choppy. that cam isn't the best for a DD and will require a pretty solid tune to idle worth a damn and not stall, it also will not want to start in cold weather.

Just go to youtube and pick the name of a cam, like "tourquer V2" and search 3 times first with 116 LSA, then again with 114, and lastly with 112, youll get plenty of results that will show you the difference
 

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Also, I may be backwards on this, but higher LSA gives you more power lower in the RPM range, and an overall larger under the curve area, lower LSAs will get a higher peak HP, but it wont come until high in the RPM range, and wont have as much under the curve area, hence the reason its more appropriate for race applications where the ending spends a lot of time at 4-7k RPMs
 

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While it's true that the LSA plays a big part in this, the duration of the cam also contributes. The higher the duration, generally the choppier the idle is. Typically the higher the duration, the closer the LSA is too, but not always.
 

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Car RamRod
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I have a 114+4 advance and it chops like cuisinart!

Duration plays a HUGE part.
 

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Yep, that just happened..
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I like the chop... As long as the driveability isn't hurt, I wanted the lopey idle. Hell, why spend the money to sound stock? JMO though....
 

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GOT VTAK?
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My First Cam 1
Cam Spec - 224/230 .581/.590 114 LSA

My Cam now
Custom Grind Spartan Performance cam 232/240 .630.630. 114 LSA
 

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Its is true that the LSA has something to do with cam sound but its more about overlap more than anything. Overlap is the sole reason why a cam will "chop" or not. Sure, LSA can control overlap but its the mixture of duration and LSA that fully controls the amount of chop a cam has. You can make a stock cam lope if you get the overlap big enough by tightening the LSA but you can have a cam lope with stock LSA if the duration of the lobes are large enough.
Search "cam overlap" on the internet and read more about it.
 

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Discussion Starter #14

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LSX Mechanic
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Contrary to popular interweb beliefs, there is no "1" set value that determines "chop". It's the entire camshaft profile that determines this.

I can make a 112LSA camshaft idle smooth as butter if I make the intake & exhaust lobes open/shut the valves at a very fast rate.

Duration, overlap, lobe design, AND lobe separation all play a factor. Overall lift is the only figure that really has nothing to do with idle quality.
 

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Its is true that the LSA has something to do with cam sound but its more about overlap more than anything. Overlap is the sole reason why a cam will "chop" or not. Sure, LSA can control overlap but its the mixture of duration and LSA that fully controls the amount of chop a cam has. You can make a stock cam lope if you get the overlap big enough by tightening the LSA but you can have a cam lope with stock LSA if the duration of the lobes are large enough.
Search "cam overlap" on the internet and read more about it.
+1

I just ordered a custom cam from Brian Tooley that is very much like the LPE GT11:
215/232 .604/.575 118 +5
I wanted a cam with great street manners, stock stall, and stock exhaust manifolds for now. I was going to go for a 115 or 116 LSA but Brian pushed me up to a 118 when he heard my exhaust plans.... He also recommended going with the Extreme RPM lobes on the exhaust. We'll see how it works. Many may disagree with my choice, but since what one considers driveable is so subjective, I wanted to err on the conservative side. So yes maybe I'll be giving up some power. At least I will provide a valuable data point to others in the future once I dyno it.... Should be doing the install within a month....
 
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