FULL RESULTS-CHANGE ONLY LSA-LS CAM TEST. What happens when you change ONLY the LSA of the cam and keep the lift and duration the same? Does LSA change power? Do LS motors like narrow (108-degree) LSA or wide (120-degree) LSA?
Three months of videos but if you pay attention when he's pulling up the graphs, some of these tests go back to 2007/8 if not further. They are an amalgamation of the tests he's done in print for 20+ years.
You have to watch generlizations. The reason this picked up so much is because the duration was so undersized to begin with. If you have much larger duration on this and do the same thing, the reverse will start to become true where a bunch more overlap kills low end
If I ever get a chance to either build or simply can swap an LS all I have to do is watch your video series, pick the combo I think will work best for my intended vehicle and just duplicate it. You’ve take all the guess work out of it for us all. What a service you’re providing. Thank you.
If I had Richard & Brian Tooley a large bank account a time machine a girl with a short skirt and a Long Jacket small hands...that would be all I need, ok the girl has a twin sister, That would be all I need, 😏
I did the same test on a 4.6 2v back in '09 for my buddy David Vizard... My results mirror what you came up with on the LS! David is a huge fan of tight LSA's and he even has come up with the controversial 128 rule.... Awesome job like always!
DV's 128 formula says an LSA 107 should be ideal for this combination. I'd like to see a cam test using an LSA of 107 with duration numbers starting at 225 and increasing by 15-25 degrees. I think this could show how David's thinking works across the range of street to race cams.
Exactly! LCA is a calculated using the ci & intake valve size. AKA allowing enough time for fill. We advance the cam to help lower the rpm when it will start making power. Every 2 degrees advanced lowers it 100rpm, aka 4 deg = 200 rpm sooner. This is a total shift, top rpm is also lowered the same amount.
Crazy part is BTR thinks LCA is a mear byproduct, I don't follow that line of thinking. I have never gone as tight as 104, 106 is my tightest & I usually shoot for a 108 by using better heads. Different rocker ratios (larger) can also allow a slightly wider LCA but is limited & small. All about choosing the correct combination of parts that will all work together.
What do I think? Hell, I don't know anymore...between you and Engine Masters everything I learned as a kid was false. Can't wait for the next installment.
I understand physics... and english. My point is, all the hearsay and conjecture are being disproved through a scientific method and theory to practice. Sorry, I didn't have all this information available so easily at a younger age. Thank you, Mr. Holdner for sharing.
@@bigboreracing356 All he said was that he was taught some things as a young person that wound up being inaccurate. No need to be a jerk, I'm sure you have fallen prey to misinformation at least a time or two. We all have. Some of us are man enough to admit it. They knew everything in the 1930s that we know now? You're out of your fucking mind.
@@bigboreracing356 The truth about what? That you're a keyboard warrior who thinks he's "the bad man"? How would I have your comment removed? It's not my video. I'm a commenter just like you, but with some substance. You talk about safe spaces, but probably drive a mustang. Kill any bystanders lately?
STREET RACER what’s your point in trashing someone for something they learned or were told wrong when they were young? Don’t be a douche, we all have been told things that were wrong. Doesn’t give you the right to jump all over someone. 🤷🏽♂️
I have been reading and have David Vizards books from the early 80s and have built numerous engines on his specs, they have never failed to impress, starting on the Mini A series, Ford Pinto, Chev 350 and now finally the LS series.
Around 50 years ago I was taught to run narrow LSAs as much as conceivable to help capture cylinder pressure at higher elevations like in Denver. We were always happy when we got cams at 110, and really happy at 108.
My NHRA SS/J 66 Chevy II uses a custom ground solid roller with a 109 LSA I had ground using David Vizards 128 rule. My heads are NHRA Superstock legal Edelbrock highly modified by Edelbrock to coincide with NHRA rules. I shift @ 9000 so its wound up pretty tight and pulling off a consistent 8.60s with a .060 over 327 and M22 tranny is no easy feat. Listening to David Vizard and reading his books has made not only my Superstock fast but my Stock Eliminator K/SA Monte Carlo SS (with the factory L69 305). This test Richard just run backed up the 128 rule big time. For big blocks and Fords is 127 and he has videos on it if you are wanting to learn. Thanks for this video Richard you are very entertaining and easy to listen to unlike Freiburger and Dulcich.
GREAT test Richard! This test repeats ALL other dynos I've seen where only LSAs are changed. Yet you read all the tech info they say the reverse. Well done.
Exactly what I was saying on a different video about the intake tests. Just because you have a long runner intake you don’t need to run a wider lsa. The reality is that tighter lsa cams tend to make more power even more so when naturally aspirated. Thanks for the video!
Very interesting. I run in a tightly-regulated race club where LSA is basically all we have to play with (DOHC, adjusting stock cams) and we are typically living in the realm of 103-105 LSA. Our duration numbers are pretty high (streetbike engines) and we operate around 6000-12000 rpm. There is definitely a point of diminishing returns in wide LSA for top end! This is why we test!
Thank you! I only just discovered this vid of yours and I been looking for this test and demonstration for a long time. Now I'm really interested how this would apply to other smaller NA engines such as 6 & 4 cylinder engines which are not just V8's. Thanks again. Really like how you conducted this test in a real objective way.
Good one thanks. That's what I wanted to know and that was my hope that tighter lobe separation will give me better low-end power and a wild chop without increasing lift and duration.
David Vizard been saying that for years and I believe it`s true. 106 seems to be the magic number for circle track and higher compression, 2bbl seems to like the wider LSA along with bigger CID like 454 and bigger.. There are so many contributing factors I don`t think a person could pick the perfect cam with out a dyno, back when I was a kid cams were listed by lift, duration (advertised) and overlap. I think Isky was one of the first guys to start tightening up the LSA and he made a high mark to reach for
Nice this is a topic iv always thought about. Few things I knew for sure was the lower the LSA = more chop @ idle but also slightly more difficult too tune. Now we need the results on smaller cube, less radical builds like your budget 5.3 & 6.0.
Awesome, awesome video Rich... Guess I now know what to expect when I install that Truck Norris cam into my Pontiac LS2... More chop, and more down low-mid range, and hell maybe even more up top as well
I've had the opportunity to work with a few engines using a 108LSA over the normal off the shelf selection. Two 347 SBF's and a 388 LT1. All engines were amazing street strip combos. Still had manners down low, came on strong in the middle and ripped up top. For the 330 to 400ci range, I don't think it can be beat.
Been watching david vizzard lately and he has a formula that puts this engine’s ideal lsa right around the 108 that made the most power, maybe he is on to something. Oh yeah and as always another great video by richard
Welp, I'm seeing this two years hence, but of course it's still very interesting. I've wondered the same thing about LSA for many years now. I'm positing the lower numbers at lower RPM for a wider LSA have to do with how the wider LSA bleeds off more cylinder pressure. Both valves are still open for several degrees of rotation, and you can't build cylinder pressure until they are both shut. My bit of homework on the newish cams sold for use on low compression engines run in line with this. Comp Cams' Thumper series, Hughes Engines' Whiplash cams, all have very tight LSA numbers. As you say, they give the hot rod guy the lope he likes, but the smooth out early. And they actually make more cylinder pressure than an OEM cam. The lope isn't desirable for an OEM for sale to the general public. All in all, very interesting and thanks for taking the time and effort to do it. One other factor I've wondered about for years, how about the installed angle of the cam? Would installing the 112 LSA piece, maybe even the longer one, make these valve events soon enough to compensate? Thanks!
Back in the70's Isky and Clay Smith had a bunch of cams at 108, they were ahead of the curve compared to most cams. They also made very good power through out the rpm range. Nice test
Nice I loved my Lunati Bootlegger in my sbc 406. 108LSA nice chop great power band. Running a Summit cam in my budget junkyard 307 build, 106lsa, gm 601 heads that I cleaned up a bit. Fun little mighty mouse motor. Going to build the 406 right and put a forged rotating assembly in.
YOUR VIDEOS ARE GETTING BETTER AND BETTER. I LIKE THAT YOUR PUTTING MORE TECH DATA . I WOULD LIKE TO SEE A TEST ON HYDRAULIC LIFTERS VS LIFTERS LIKE RHOADS.
Wow! Great video Richard! Had no idea that a tighter LSA (with choppy idle) would make more low end power!?!?! NOW.....I can have the best of both worlds!!! I can put a 108 LSA cam in my work truck, have a bada$$ idle and tow my trailers (enclosed tool trailer, 6T flatbed and my I/O boat trailer) all day! ALL your videos have awesome content and enjoy the heck out of them. I watched several of them more than once to make sure I'm absorbing the content for my LS/OBS swap coming up.
Don't get too excited... If that were the case, all cams would be ground on a 100 degree LSA. You get more low end to a point, and then, nothing... Makes your power-band more like a two-stroke.
my take away: don't rush out and buy a camshaft on a 108 degree lsa. the 112 degree lsa cam is so close to the same power numbers it makes more sense to use it in a speed density fuel injection system because it gives better vacuum at idle and allows the map sensor to work correctly.
Good video - people are realizing the tighter LSA means more acceleration torque AND NO LOSS upstairs- bigger displacement responds even better, of course vacuum drops due to more overlap and worse throttle response below 1500 to 1800, so an automatic and smaller engine should use a somewhat looser converter, BUT make sure converter stall speed is below top gear or overdrive RPM at highway cruising speeds.
That last part is basically impossible for a good street car. Cruising RPM in top gear at highway speeds needs to be under 3000 for anything approaching acceptable fuel efficiency. Most underpowered ecoboxes and sport compacts (the normal ones, not the extra weak ones under 130hp) run 3000rpm at 75mph in last gear. The way I spec it is roughly 1/3 redline should be your normal cruise RPM, and that should match up with 0-10mph over your local hwy limits. Or if you have an abundance of torque and/or enough gears that they don't feel too long, 2000rpm cruise no matter what, and between 60-80mph
You said you did this in a reply to my comment on an old video and I looked a couple of times to find it, but now I see why I didn't find it. Now take the 112 and change only lift. Then do the same with the duration would be awesome.
Hey Richard, camshaft theory is fascinating to me and watch this video often. In fact, I had a custom Bullet Cam for my 454 ground partially based on this video. Theorizing here, a tighter LSA generally increases cylinder psi, because it increases the dynamic compression, which may have contributed to not only the expected bump in low speed torque but also the power across the board.
Interesting how it gained without really losing anything with LSA. I guess the next thing to do like you said would be to change the engine size and test again 👍
At first I was wondering why you were on one knee in front of the truck. Then I noticed the nearly perfect Rembrandt lighting profile on your face. Well done. Oh yeah, the cam LSA info was great too. 👍
I read the artical on this back when I was building my Ford 250 Crossflow, had it suggested to me for a 108LSA, then after seeing the 108 was better everywhere I went with it & found low rpm is alright in it. Made a nice 252rwhp, thinking of putting it on engine dyno for fun when I change to a C4 & 3500 stall from stock Borgwarner BW51 auto & stall.
More awesome work Richard, you're cranking out the best content on YT right now! Now can we see the 108 LSA vs the 120 LSA with turbos? Maybe even SC? I know you saw it's the same, but we'd love to see it proven!
that was an awesome comparison in perfect time for me. could you do the same test on a gm lsa motor in relatively stock form? i would love to see how a cam that size goes with such a tight lsa on boost escaping
@@RadRidesByCru I run a 228/234 .614 lift in/exh, 108 LSA in a 355 CI gen II SBC (LT1) and my vacuum at 825 RPM is 13.5 to 14 In/hg. So vacuum in that engine was likely similar given more duration and more CI @volvospede it really depends if you plan on running an auto or manual? As I just pointed out my engine doesn't produce a ton of vacuum at idle, but since I have a manual and a working checkvalve on my vacuum canister my brakes are no different than stock because on decel at cruising RPM my engine will easily produce 25 in/hg at about 2000 rpm with the throttle closed of course. This is plenty of vacuum to charge the canister, and have never noticed a change in my brakes. An auto would obviously be a whole different game though.
Great comparison. Can we also assume that the ICL was (obviously) different for each cam? And in addition, would you be able to test with the same installed ICL across all three cams? I know, I know, asking for the world! In addition to letting everybody see the difference in lobe separation is valuable, but (I think) more importantly, starting to understand how the ICL and intake closing event have on the actual powerband. Generally the lobe separation automatically alters this, unless advance is ground into the cam to "compensate"
@@richardholdener1727 the idle is car porn, yes. I've got to get a better tune though. Still dealing with vacuum issues and the brake booster since it's a high lift cam.
The L.S motors are a whole different animal than the old small block when it comes to cams and l.s.a it seems to me they can do so much more with the l.s cams as far as all of the numbers more lift and longer duration and thus not needing to tighten the lsa as much and fight with the choppy idle and vacuum issues like in the past if I understand right it's due to the cam actually being moved up and ,made larger is this correct ? I'm interested in anything I can. Learn. Pls
From what I understand, which ain't much, it's all about the EVC point. Start there, and adjust the rest. This is per the great Harold Brookshire, and Mike Jones, and even David Vizard. It would be interesting to see that installed +4.
Itd definitely be interesting to see header primary length, merge choke, and LSA comparisons. I hear the larger LSA the tighter collector choke can be, and shorter primaries can be too.
Hey I recently bought the sum-8718 camshaft from the ls series line of cam shafts and I’m curious to see the torque gains out of a lq4 6.0 if you could maybe make a video.
Richard very good video , I hope your subscribers realize how much work and effort you put forth in your videos, we use to call Bob Glidden the mad dog , cause he work continuously , my friend he has nothing on you great job, much appreciated,
I would like to see this test run again, but this time with the icl set to 108 for every cam. 12 degrees advanced for the 120lsa, 4 degrees for the 112 lsa, and straight up for the 108 lsa.
this....if they were all installed straight up, then the 120LSA cam's intake valve is opening much later on the intake stroke.....would like to see them all installed on the same ICL, too. would be interesting to see idle vacuum and manners for each, as well as maybe some part throttle fuel consumption (say, 40HP load at 2000 RPM, about what running down the freeway at 75MPH in OD would be)....more than just power to consider with a street car
all that would change is make the wider LSA even worse as it would then open their exhausts even earlier, kill off all low speed torque and still make less HP up top, The low LSA would just make more power everywhere
The stroker needed the overlap. Stock 5.3 will limit how much overlap you can throw on it I think. We need to test that!!! Title “how much overlap a 5.3 can use? How does the graph looks!!
Hats off to ya for another interesting vid Got to be a bunch of work, setting up on the dyno, making pulls to get the time dialed in, then swap cams, then another pull or two (or more...) getting the timing and fuel optimized, then swap cams, then... yeah, a bit of a chore, even if you hold the front cover on with Velcro And when you're done - we want more! That being said, if you want a reason to swap more cams in the dyno cell... I'd be interested in seeing u yet *another* cam comparison: this time 3 cans with different LSA, but the duration adjusted so the intake valve closed point stays the same. So, a can with (for instance) a 112° lobe spread and 230° duration would be compared to one with 238° ground 108. To try to make things as even as possible, use lobes from the same family, with as similar lift and ramp characteristics. My theories: a) the length of the header tubes and exhaust runners on this engine was tuning in make peak torque from 4200-5400 RPM where the 2 bumps in the curve are) - regardless of where you set the IVC, and b) a tighter LSA combined with more duration might allow similar cylinder filling (or maybe even slightly better) up top, and allow the harmonic tuning of the intake & exhaust to make a bigger bump in the middle of the torque curve. Some of the tests you've run with larger duration cans, that didn't seem to pick up much top with long runner intakes made me kinda' think this may be the case Then again in theory, theory is as good as practice...
I find it super interesting. Well done sourcing exact same spec cams other than LSA. If any cam had even a slight duration or lift difference, results would be controversial. Power increase up top with 108 lsa cam is confusing. Could it be due some kind of harmonics? Matching with Intake runner length or something like that? I’d love to see a test with same cams on different displacement Ls motors. Thanks for sharing. Love the content you putting out.
I am leaning towards exhaust scavenging as well. As for the increase in low end torque with tighter LSA’s, this occurs due to earlier IVC which increases the dynamic compression. That’s the whole premise behind variable valve timing. Advance the intake cam down low for higher dynamic compression (tighter LSA) then retard the intake cam up top to take advantage of port velocity cylinder filling (wider LSA).
Now I know why I have always ran a 112 LSA advanced 4 degrees. Intake is always more critical than the exhaust. Also with a 10 - 12 degrees more on the exhaust duration. This is what I have found to work best in the vast majority of cases, over the last 45+ years. What we also found was that a 108 LSA, (MPG) suffered on the street. It was not worth the loss of gas mileage for the little HP that was gained. That was why we started advancing the camshaft, and it worked...
literally all wrong, you change the DURATION to bring the overlap down, you do not change the LSA to help with drivability, having too much duration and then widening the LSA to help drivability is all wrong, if you need to do that you have way too much duration for your application
@@danawilkes6174 Yeah, but I think we'd all like to see a direct comparison of a 112+4 adv vs a 108 with reduced duration to have the same overlap (both advertised and at .050) with the same lift, too.
Nice was curious my self I kinda had a feeling what was going to happen but this makes me happy with my 250 4.1 crossflow 6 Aussie eng 😉 262,262 with 105 lsa chop chop and still made 400nm at 2500 and will pull till 7 👍nice vid
Let's see the same test on a 4.8 (same cam). I think the smaller displacement will emphasize the torque differences much more than the stroker, and show the curves better.
I would like to see 108lsa waste gate spring pressure and the 120lsa waste gate spring pressure and see who makes the most power on five pounds and 20 pounds with egt gauge hooked up
@@chomin3025 So with a smaller engine will it make hp and torque in a higher rpm than a bigger engine (lets say 305 vs 400 , or a 350 as they have the same stroke) with the same 108 lsa camshaft. Or??
@@Skoog. smaller displacement = It makes the power and torque higher in the RPM (with the same camshaft as the bigger one)(Generally , bigger CI can take more advantage and make more power throughout the whole curve. and bigger CI always means more torque with the same mods as a smaller engine)
This is why i love the mod motor. you can degree lobe seperation angle, intake and exhaust centerlines, and basically tailor the specs to fit your application.
Interesting to see that most basic "Turbo cams" have a wide LSA if tighter LSA produces more power down low. I would think that's what you'd want to spool the turbo up faster on most combos. It seems like you can't go wrong with tighter LSA for a street/strip motor where you aren't worried about driveability. I guess that's why the turbo cams have wide LSA, just to help driveability. Interesting to see for the build I'm trying to piece together, looks like I might try and spec out my own cam for the fun of it and see where it takes me :)
@@TurboGreggZhow are you getting reversion when most modern turbos have a pressure ratio close to 1:1 (pressure in the exhaust equal to what's coming in the intake)
