How does LSA affect performance?

[Spikito]

I'm looking at buying a torquer V2 cam, and you can get it with all the same specs, except the LSA is available at 111, 112, 113, and 114. Ive seen other cams as low as 108, and as high as 116.

All I know is that the lower the number, the choppier the idle. 114 is stock, I've heard a 111, it was too choppy for me, so I'm thinking 112 or 113.

My question is, when it comes to track times or dyno numbers, what end affect does the LSA have.....

[ls1camino]

Condition---------------Wide Separation Angle-----Narrow Separation Angle
Overlap-----------------Decreased-------------------Increased
Low End Power---------Higher-----------------------Lower
High End Power--------Lower------------------------Higher
Detonation Potential---Lower------------------------Higher
Intake Events----------Later-------------------------Earlier
Exhaust Events--------Earlier------------------------Later
Overlap----------------Decreased--------------------Increased
Manifold Vacuum------Higher------------------------Lower

[Firebirdjones]

There is one descrepancy with the list. Detonation potential is backwards. A narrow lobe seperation affectively increases overlap, which is the area where the intake and the exhaust valve are open at the same time. This actually bleeds off cylinder pressure, which in turn lowers the dynamic compression ratio and reduces the chance of detonation at slow speeds. That's why the vacuum signal is so weak with a tight LSA, cylinder pressure is low when both valves are open.

Tighter lobe seperation works great on cars with more compression than pump gas can handle, especially cast iron heads. As it bleeds off cylinder pressure it gives you some wiggle room before detonation becomes a problem providing the tune is spot on.

Tighter lobe seperation does give you that choppy idle, but what it also does is bring the power curve in sooner.

One of the reasons these LS1's seem to make endless top end power is because of their very wide LSA from the factory (116 or more) It kills the bottom end potential however. It's one reason why these cars love gears.

[mark21742]

But Firebird, the wider lsa should give a later intake valve closing point which would also drop dynamic compression.....right?

[WICKEDLS1]

if your wanting a choppy idle the just go with a 112 or 113 when you get into the 114 or higher its smooth and below 112 you are going to have a hard time finding a tuner that will mess with it

[Spikito]

i think 113 will be good for me...

[5abivt]

just a different perspective. I like to think of it as an oval on say a dyno graph. think of the oval as the powerband. tighter/narrow lsa and the oval gets thinner but taller. Wider lsa and the oval gets wider (more rpm range) but shorter (less power). Alter duration to where you want the peak in the rpm range.

[Lunatikgixxer]

112lsa is not hard to tune. You live in texas so there are probably a handful or good tuners out there so i wouldnt be worried if i were you

[WICKEDLS1]

just a different perspective. I like to think of it as an oval on say a dyno graph. think of the oval as the powerband. tighter/narrow lsa and the oval gets thinner but taller. Wider lsa and the oval gets wider (more rpm range) but shorter (less power). Alter duration to where you want the peak in the rpm range.

this is by far one of the best posts i have seen on the forum yet. i wish this was around when i wasnt too sure about cam selection

[nhraformula]

I'm looking at buying a torquer V2 cam, and you can get it with all the same specs, except the LSA is available at 111, 1 114 is stock,

114 lsa is not stock

[35th-ANV-SS]

For a 2000 LS1, the cam specs stock are:

202/210 int/exh @ 0.05" duration
0.496" / 0.496" int/exh lift
116 LSA

[Spikito]

oh wow, i didnt know it was that wide...somewhere i read 114, guess it was wrong

[mark21742]

just a different perspective. I like to think of it as an oval on say a dyno graph. think of the oval as the powerband. tighter/narrow lsa and the oval gets thinner but taller. Wider lsa and the oval gets wider (more rpm range) but shorter (less power). Alter duration to where you want the peak in the rpm range.

I agree, this is a GREAT example!

My 115 lsa cam is very choppy......but it is a 255/266.

[Lunatikgixxer]

this is by far one of the best posts i have seen on the forum yet. i wish this was around when i wasnt too sure about cam selection

I agree that makes a lot of sense.

[smslyguy]

I'm looking at buying a torquer V2 cam, and you can get it with all the same specs, except the LSA is available at 111, 112, 113, and 114. Ive seen other cams as low as 108, and as high as 116.

All I know is that the lower the number, the choppier the idle. 114 is stock, I've heard a 111, it was too choppy for me, so I'm thinking 112 or 113.

My question is, when it comes to track times or dyno numbers, what end affect does the LSA have.....

I have the torquer v2 cam with a 112 lsa +2. I tuned this car myself, and by no means am i a tunner, so to say that there isn't a Professional tunner out there that can't tune a 112 is wrong.. Most would and could tune a 112 and even a 110 isn't out of the question... Just my 2cents..

[pajeff02]

Lots of good info in this thread. Not sure why I missed it the first time, so let's get it stickied for future reference.

[SMWS6TA]

just a different perspective. I like to think of it as an oval on say a dyno graph. think of the oval as the powerband. tighter/narrow lsa and the oval gets thinner but taller. Wider lsa and the oval gets wider (more rpm range) but shorter (less power). Alter duration to where you want the peak in the rpm range.

I'm one of those visual hands on kinda person. Could you post a pic to show this^^^?


I'm trying to picture what you stated.

[reaper ws6]

ey thats the cam im getting for the trans am v2 with a 112 lsa and 3600 stall

[Spikito]

very nice...my heads cam build is currently on hold due to funds

[reaper ws6]

im waiting on tax returns lolz Thank you uncle sam!