Tooley Talks Ep1 : LSA Explained! (Lobe Separation Angle)
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- Опубліковано 31 січ 2018
- Brian takes a moment to explain what LSA means, how it's calculated, and why it ISNT the end all decision maker for your cam needs! As always, contact our sales staff for custom applications. 888-959-8865.
CAMS!!!: goo.gl/8FPt49
I remember Brian from his days at TEA. I also remember seeing him in a photo in a major Magazine about 15-16 years ago when his C5 caught fire. Brian calmly stated-directly, I might add-"That was a bad day". Like that he didn't whine or complain a bit that such a horrible event had just happened. Most guys I know would have!! I'm glad you have your own company now, Brian. Next time I need anything engine related, I'll check your company out......
The way you're doing it is certainly a way to do it.
However, using characteristics of the engine to determine LSA's is very accurate also. Engine type, bore & stroke, valve sizes, compression ratio, and rocker ratio being the main characteristics needed.
A couple of examples goes like this:
A 400 inch engine will want a narrower LSA than a 350 inch engine, given the same heads and valve sizes. This is because the cylinders are harder to fill in the bigger engine, and so we will have to open the intake valves earlier (narrower LSA) to help get it done.
A higher compression in the same engine will want a wider LSA. This is because cylinder pressure decay (expansion ratio) in the higher compression engine is much faster, and so the earlier opening exhaust valve (wider LSA) cuts into the power stroke a lot less.
Great video Brian. Very informative. I’ve been watching Richard do his countless cam tests on LS engines. He likes the ls9 cam coz it makes good power but loses torque because of the wide LSA. Factory blower helps with the torque.
I’ve bought a ls9 cam for my turbo ls1 5.7ltr
Hopefully my 3000rpm stall will help get the revs up quicker so as to get out of the low torque power rpm region. From Victor Harbor Australia 🇦🇺
thank you for simplifying... makes total sense.
that is the most obnoxious intro ive ever heard lmao oml
No shit! I almost didn't watch the video due to it lol
If you don't like engine sounds maybe you're watching the wrong video.
Great video, thank you. I would like to know more about LSA advancing too
What about David Vizard's camshaft theory...Overlap being the most important event which in turn makes lsa pretty important.
I've also considered that. But Vizard's focus was on SBC & BBC, and not so much LS's. I've been trying to compare the 2. The LS heads just work so much better than any factory SBC head, so Vizard's studies may not correlate, though they do have merit. Harold Brookshire was always concerned with the valve events first, and let LSA fall where it did. Mike Jones does as well. So BTR falls in line with that. That being said, the more I study this, the more I feel like I should leave it to them. I agree with BTR's thought; give the engine what it wants.
@@jeffwooton7138 David's calculations do apply and work great with LS engines. I know this from experience.
@@jeffwooton7138
It has no bearing it being and LS. The rules still apply. Tooley simply does not understand how to properly use LSA.
@@AB-80XI like David Vizard but if we use the 128 formula and plan to run high to 7000rpm, its going to have higher duration, with the lsa under 110 there will be ton of overlap which makes it worse on mpg and manners. If we're racing I'd give it a shot but if you keep in mind fuel economy and drivability you may adjust for less overlap. there's more than 1 way to feed the cylinder with consideration to other characteristics. Users say these cams work and drive well. Id love to see someone with a big cam to only adjust lsa to DV specs and let us know how it acts in the real world with all the extra overlap. I guess you could raise idle and anything will drive nice. Btr pays more attention to ivc timing to make the most out of your choice of overlap/stage. I'm guessing a well mannered DV spec cam will make less power than a well mannered BTR cam.
@@slick408 You can't do it like that it's upside down thinking.
If you just go by some "arbitrary" rpm number e.g 7000 rpm, you will be losing a lot of power in order to make that engine potentially street friendly.
You need to use the correct LSA that will give you the maximum torque. You may not get 7000 rpm, but you get more torque. Then you use the final drive ratio to make sure you trap at the correct speed. If you wish to run 7000 rpm with a 427, well, then you also need to understand that you will have to make a lot of power. If that gets too aggressive, drop the rpm or build a smaller displacement engine. In short, you need to build what you need, that's what makes you fast. Also, when you get into an engine that is more efficient, you also get the RPM. There has been several instances where engines that ran the proper LSA with a similar overlap to the wide LSA engine, made peak power at close to the same RPM. All you get with the wide LSA is an engine that is weak down low, massively inefficient and not as fast as it could be. Another thing many forget is that especially with an LS, you can run a lot of lift with modern lobes and the 55 mm cam. So few take advantage of this. That lift will also drive your RPM up. If you get a cam with good lift, the proper LSA etc. the RPM will very much still be there, and so will the driveability. It's all about building the correct package. If you build a 475 ci LS and still want that thing to make peak power at 7500 rpm, well then you better be ready to build something that will make upwards of 900 hp and be fairly aggressive. Optimise what you have, rather than trying to dictate what you want.
"Don't focus on LSA." he says yet none of the advertised specs tell us the Opening/Closing event specs, just Lift and....the LSA that we are not supposed to think about! LOL
You're IQ is too low for you to understand :-)
You are an idiot Mr. Mysterious. You didn't even comprehend (that means "to understand") my comment, but you feel safe since you hide behind a Screen Name.
@@stephen4764 Awww poor thing. I will get you a tissue. Go and get a hug from your mommy.......
You clearly do not understand what Brian Tooley was explaining.
I do. That's the difference.
It makes perfect sense to me and I spec camshafts the same way for myself.
@@mrmysterious6006 Learn to read dude. You started this crap because of your inability to comprehend, only because your safe in your bubble hiding behind a Screen name.
My Post was not even about any misunderstanding by me, you idiot.
Sounds similar to gun powder burn rates. A powder that propells a .357 magnum to good velocity will not do the same for a 9mm Luger or .45 ACP.
Burn rate to velocity is similar in function to LSA and valve events.
Anyone?
Well explained
I just bought a 222/226 .597 .600 custom cam from your shop. Can't wait to get it and install it. Plus 7.400 chromoly push rods, platinum dual valve springs, LS7 lifters and trunion rocker bearings.
Very cool
Brutal customer service. Tried calling these guys to help pick a VVT cam for a ls 6.0. After listening to what I was looking for and telling me they would have to check with the “cam guy” I’m still waiting to this day for that call back. I’ve purchased many items from BTR unfortunately good help is hard to find.
When someone says "we will call you back" I get called back about 1% of the time these days.
Right on
In my opinion lsa is more important in higher elevation then at sea level due to air density you can tighten it up to create a vacuum or overlap sooner with a lower lsa which is why carburetor motor work well with lower lsa cams
Except you're WRONG. A wider LSA produces more vacuum than a narrow LSA.
@@Thirdgen83 Exactly. Many guys also assume a tighter LSA means losing low speed torque. This is not true in every application. After a certain point, yes, but you also gain midrange torque with a tighter LSA. The high rpm horsepower of a tighter LSA usually means that the HP also doesn't drop as dramatically after the peak number.
You're wrong.
The LSA should be a fixed input that is directly related to engine displacement, valve size and compression.
I believe you said as you tightened it up that you decreased the exhaust duration. That's why your evo number is going down. Ls's are a different cat. I agree you can adjust your lsa for needs of the motor. I have 406 gen 1 with a solid lifter cam on a 104 lsa. Absolutely love it. Before he died, bill metzner with lazer cams taught me a couple things. Tight is right as long as all the other values fall inline with the combo.
what are the full specs on that cam you're runing? if you don't mind me asking
@@Noeysuarez sure would be glad to help. Its a howards cam part number-HRC 112452-04. duration @050, 252/260
lift- 530/555
104 lsa/ 100 ICL
It is a soild flat tappet also. This one will raddle the windows! Sounds and runs great. Hope this helps and good luck..
Absolutely, not all cylinder heads are created equal. LS heads are extremely efficient, older 60's and 70's "muscle car" era heads... not so much. The heads of the 60's utilize a tight lsa to crutch their poor flow characteristics when used in a race application. That tight lsa = more overlap which is beneficial for a comparatively poor flowing head at high RPM.
@@Torquemonster440 Just an FYI. A tight lsa benefit all engines, no matter how good or bad the heads. Now a big block or a big cubic inch engine that has good torque production already, you can widen them out a touch.
@@Scubasteve22 agreed, Richard Holdener did a video where he compared lsa's on an LS and the tightest one made the most power. I was just trying to illustrate why that old school 60's muscle car sound is so popular. A tight lsa is very beneficial to V8's of that era in a race application.
I just spec'd out a custom roller from comp.. ground on a 107° lsa. 😁 I cant wait !! This is going into a 448ci big block Mopar that currently has a solid flat tappet ground on a 112° lsa.. 🥴
Great point, thanks
What do the +1 or +2 numbers mean after the LSA#?
Highlex degrees advanced
Does that mean you're supposed to install the cam that many degrees advanced? Ex..Stage 2 turbo 113+4 should be installed 4 degrees advanced from 0?
@@brianfox5546 who knows? we got about half the info needed out of this vid.
@@brianfox5546 the degree is built into the grind.
"Advance ground in" means the cam is made that when the cam gear is indexed to the alignment peg, and the cam for is aligned with the crank sprocket line, the cam will be oriented so that each valve ever will happen x° earlier. Cams are designed around the 4 valve events, the cam data 228/230, 112+4 is the functional equation that generates "when" each of the events occur. To alter the LSA or advance alone alters "when" each events happen. "when" meaning in relation to degrees of crank rotation, which in itself dictates the position of the piston in its stroke.
What does it mean on some of your specs where it says 113+2 ?
LSA is Lobe Separation Angle, and is the included angle in degrees between the centerline of the I and E lobes. The +2, or whatever the number after the + sign is, means the cam is installed advanced that number. Many cams already have the advance ground into the cam, so it's installed "straight up", i.e., by aligning the marks on the sprockets. Most knowledgeable engine guys don't use the "marks", they degree the cam....
Why do oval track cams run 106 and 108 to get punch early at tire hookup?
Because it make more power
BTR is the king of cams
Is he now?
ua-cam.com/video/0kDFS72mYdA/v-deo.html
He's so full of it.
Nope.....LSA is an INPUT.....not an outcome.....LSA is determined by engine size, valve size, head flow, compression ratio and intended use.....it's up to the builder to create adequate valve to piston clearances.....
Maybe for electronic fuel injection engines that have sensors. And for a newer HEMI where the top of the ring land is close to the valve relief in the piston. But Brian is clueless to think that it is not important. The EPA hates over lap because of the scavenging affects and spending up the incoming air.
yep David Visared explains it as well, just talks too much or should i say, take to long to explain it?
He does not. And David has a much better understanding of how to actually determine LSA.
BTR-has the best high performance products in the business...
Based on what an engine likes... so pick a cam based on lsa... dont listen to this guy, david vizards formula will get anyone in the ballpark... listen to the man. Toolbag is good with profiles and valvetrain stability... thats all, he is just spitting b.s here
sir , kindly explain from where 108 and 118 comes. i am not understanding this. from where these angle calculated.
You're smart but wrong
Look how many of you guys believe everything he says. Lol