Lobe separation question
08-18-2005, 02:24 PM
#1
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Lobe separation question What lobe separation should I use with a 4200 stall? I see all these different specs and this is the one thing I don't understand well.
08-18-2005, 02:31 PM
#2
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No answer for that question.
LSA is simply the sepration between intake and exhaust lobe centerlines. For example, with a given cam different LSA's will affect the powerband (a little), piston to valve clearance (moderate) and the idle quality (a lot).
Have you read the cam guide sticky??
Do you know what overlap is and how to calculate it?
[(intake duration + exhaust duration) / 4] - LSA, and finally multiply by 2.
As you can see, LSA is a big factor in overlap.
If you really want solid cam advice post up EVERYTHING possible about your cars current setup, future setup, goals, uses and personal tolerances. Help us help you by doing enough research to have an idea what you want or it's all but hopeless. I advise you to get an idea on what you want and ask more specific questions.
LSA is simply the sepration between intake and exhaust lobe centerlines. For example, with a given cam different LSA's will affect the powerband (a little), piston to valve clearance (moderate) and the idle quality (a lot).
Have you read the cam guide sticky??
Do you know what overlap is and how to calculate it?
[(intake duration + exhaust duration) / 4] - LSA, and finally multiply by 2.
As you can see, LSA is a big factor in overlap.
If you really want solid cam advice post up EVERYTHING possible about your cars current setup, future setup, goals, uses and personal tolerances. Help us help you by doing enough research to have an idea what you want or it's all but hopeless. I advise you to get an idea on what you want and ask more specific questions.
08-18-2005, 02:33 PM
#3
Oh my gosh, there's so many other more important things that go into a cam selection than LSA. The lobe separation angle is the distance (in degrees) between the peak of the exhaust lobe and the peak of the intake lobe. As a general rule widening the LSA will either open your exhaust valve earlier or close the intake valve later. Widening the LSA of a cam will decrease overlap, give a smoothe idle, make the power peak less peaky (flattening the torque curve) and may extend the rpm level of the motor.
Whether a wider LSA cam is right for a 4200 stall totally depends on your current mods and the size cam you want to run in the future. Give us some more details and we can give a better recommendation.
Whether a wider LSA cam is right for a 4200 stall totally depends on your current mods and the size cam you want to run in the future. Give us some more details and we can give a better recommendation.
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2013 Corvette Grand Sport A6 LME forged 416, Greg Good ported TFS 255 LS3 heads, 222/242 .629"/.604" 121LSA Pat G blower cam, ARH 1 7/8" headers, ESC Novi 1500 Supercharger w/8 rib direct drive conversion, 747rwhp/709rwtq on 93 octane, 801rwhp/735rwtq on race fuel, 10.1 @ 147.25mph 1/4 mile, 174.7mph Half Mile.
2016 Corvette Z51 M7 Magnuson Heartbeat 2300 supercharger, TSP LT headers, Pat G tuned, 667rwhp, 662rwtq, 191mph TX Mile.
2009.5 Pontiac G8 GT 6.0L, A6, AFR 230v2 heads. 506rwhp/442rwtq. 11.413 @ 121.29mph 1/4 mile, 168.7mph TX Mile
2000 Pewter Ram Air Trans Am M6 heads/cam 508 rwhp/445 rwtq SAE, 183.092 TX Mile
2018 Cadillac Escalade 6.2L A10 Pat G tuned.
LS1,LS2,LS3,LS7,LT1 Custom Camshaft Specialist For custom camshaft help press here.
Custom LSX tuning in person or via email press here.
08-18-2005, 02:50 PM
#6
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Originally Posted by Patrick G
Sorry, but without knowing your mods and your goals we can't help you. Give us some detailed info and expect a detailed answer. No info, no answer (at least not a good one).
Seriously, how do you expect any kind of help when all you ask for is the LSA to use with a 4200 stall and that's ALL the info you give?
How does that go....**** in = **** out
I'd post up specifics. Or if for some reason you don't want to post them up even though none of us probably have a clue who you are, etc, PM them to Patrick and see what he thinks.
08-18-2005, 02:51 PM
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Maybe I'm not asking the right question because it's really not just for my setup that I am asking. I just want to understand how lobe separation numbers affect higher power bands.
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08-18-2005, 02:56 PM
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And just so you know, I don't mind posting up my mods...I will put my mods in my sig for everyone to look at. I'm just trying to understand lobe separation better.
08-18-2005, 02:58 PM
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Originally Posted by monicaz28
Maybe I'm not asking the right question because it's really not just for my setup that I am asking. I just want to understand how lobe separation numbers affect higher power bands.
In general and put simply the wider LSA's spread the powerband out and narrower LSA's shorten it up.
BTW: Still now answer. To get a good answer, you have to have specifics!
08-18-2005, 03:03 PM
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Originally Posted by blkZ28spt
search for the camshaft discussions.
Yeah, actually I think it is
08-18-2005, 04:28 PM
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Bah, it is. 
Dang, I'm on a roll today. Seriously. I almost got T-boned earlier turning left in front of somebody that was leaving a parallel parking spot. Then I almost pulled in front of somebody else thinking they had a stop sign, when they didn't. Luckily I realized that and didn't keep going. And I'm involved in a long roundabout thread with
flags flying where I mistook one person for another.
It's just not my day!
Dang, I'm on a roll today. Seriously. I almost got T-boned earlier turning left in front of somebody that was leaving a parallel parking spot. Then I almost pulled in front of somebody else thinking they had a stop sign, when they didn't. Luckily I realized that and didn't keep going. And I'm involved in a long roundabout thread with
flags flying where I mistook one person for another. It's just not my day!
08-18-2005, 04:40 PM
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i know how you feel, the other day i ran a stoplight not realizing it was red and then when the guy with the green light almost hit me, I honked at him...and THEN i realized the light was red 
08-18-2005, 11:33 PM
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Originally Posted by blkZ28spt
In general and put simply the wider LSA's spread the powerband out and narrower LSA's shorten it up.
