My guy in 3 months has proved more combinations than ls1tech has for the past 12 years

@n5yiz

4 жыл бұрын

Agreed!

@crw3673

4 жыл бұрын

Sad but true!

@RumblestripDotNet

4 жыл бұрын

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.

@JunkGaragehome

4 жыл бұрын

@@RumblestripDotNet yup amazing the information people have forgotten or ignored

@jefflowry4112

4 жыл бұрын

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.

@escuelaviejafarms

4 жыл бұрын

Please, pass the knowledge along and share the crap out of his content!

@kevinwest3689

3 жыл бұрын

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!

@richardholdener1727

4 жыл бұрын

David's has done a lot of crazy and cool stuff over the years

@UnityMotorSportsGarage

4 жыл бұрын

@@richardholdener1727 you sir are correct! I know that he is impressed with the work you have done as well... Keep up the great work!

@Warloch1

Жыл бұрын

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.

@darrinstone49

Жыл бұрын

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.

@darrinstone49

Жыл бұрын

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.

@chandannel

4 жыл бұрын

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.

@shelbyavant5081

4 жыл бұрын

@@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.

@shelbyavant5081

4 жыл бұрын

@@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?

@dburkh91

4 жыл бұрын

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. 🤷🏽‍♂️

@jaredfarney675

4 жыл бұрын

@@bigboreracing356 I really enjoyed CT magazine growing up !

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

@davidreed6070

Жыл бұрын

Vizard is up to something He has been DYNO testing for 40 years

@petercermak4095

4 ай бұрын

Me too. 128 sb chevy formula

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.

@GregHuston

Жыл бұрын

I think I need to dump the 112 in my Olds 350 for a 108!

David Vizard published very good book with great explanation on LSA and how t choose best one for particular application.

@jaredfarney675

4 жыл бұрын

Great book!

@adamsweet3587

4 жыл бұрын

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.

@jaredfarney675

4 жыл бұрын

@@adamsweet3587 I really enjoyed his how to port and flow test. Also how to build horsepower. Really great stuff!

@frankrizzo2724

4 жыл бұрын

Shota Makarashvili whatever happened to him?

@jaredfarney675

4 жыл бұрын

@@frankrizzo2724 he has a KZread channel to promote his lectures and books.

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.

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

@AB-80X

6 ай бұрын

That really depends. If you have high compression, you need more LSA

You run tests I've always wanted to see. Thank you again for the awesome data you create and provide. Great job!

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.

@dreece2000

Жыл бұрын

Good point, I hope most people can understand that.

Was just trying to choose lsa for my new tsp cam last night! Thanks for the test Richard, you're the man!

Richard giving the people what they wanted. Awesome. Patiently awaiting SBF combos.

@aaronford7124

4 жыл бұрын

Brian Meyer Cleveland’s forever!!! J/k. Me 2.

Yes, it would be cool to see this test done on a 5.3L and 5.7L

I am learning so much from your videos! Thank you and keep them coming!

Another great informative video Richard. Thanks for showing what’s behind the curtain when it comes to making power.

I was always told this and all our drag cars had the super tight LSA. But it was nice to see it in a graph to prove the point. Richard. Your the man.

Great test but with the 108 LSA looking better all the way it would have been nice to see another with even less LSA to see what would happen.

Thanks Richard, you have answered my next cam choice. This info is priceless and worth gold.

Man, I have always wondered what the change in LSA would affect!!! Thank you for the information!!!!

Just subbed, you really get to the point without unneeded banter! Thank you for an informative video

@richardholdener1727

3 жыл бұрын

Welcome aboard and thnx for the support

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!

@dennisrobinson8008

Жыл бұрын

Excellent. Richard test gives the explanation point. I wonder about 104 or 106. I've even seen people run 102.

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.

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 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.

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!

Great job explaining LSA. Tighter more chop & more bottom end, wider less chop more on the top ! Thanks Richard!

Thankyou! These dyno tests where you change one thing are the cool ones!

THIS IS WHAT IVE BEEN WAITING FOR!!!

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.

One of your best tests. Great job

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.

Gotta have that chop! Besides power down low with good torque is what I need!

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.

Thanks for doing this test Richard, really interesting.

Great test , another always asked question answered

Great test 👍🏻 Would be great to see these exact three combos now fitted with a blower. Richard keep up the great work

@richardholdener1727

4 жыл бұрын

same

A lot of great info on this channel. Clearing up a lot of misconceptions. Keep doing what your doing brother!! We appreciate you!

Very good experiment, thanks Richard

Great video! Highly appreciate this one.

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

@darrellsomers5427

Жыл бұрын

Racer brown made good cams too back in the day

Nice, separating fact from fiction as usual top stuff,

Great video, very informative as before watching your videos I did not know much about LS engines except for basic generalities.

This channel rocks!! Very very informative!

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.

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.

@michaelangelo8001

4 жыл бұрын

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.

@EGGINFOOLS

4 жыл бұрын

It has to be sized to the motor properly. In this case the 402 just happened to like the 108

subbed! totally explained LSA's to what I was hoping to understand on paper! also totally explains my ls swapped cruisers cam behavior now too

Truck norris cam makes sense now. I just revisited this video and glad I did. Truck norris is what I'm rolling with. Thanks

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.

@86chrysler5thave

6 ай бұрын

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

@strong_voice_of_truth

6 ай бұрын

@@86chrysler5thave Also dynamic compression ratio should be the same if they're all installed on 108 icl. That would be a true comparison of lsa.

@ezmny1387

5 ай бұрын

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

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

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.

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.

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...

@alphaghost1633

5 ай бұрын

Fool - that does not change the LSA - you need to go back and study

@ezmny1387

5 ай бұрын

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

5 ай бұрын

@@alphaghost1633 Really. If I advance a 112 LSA camshaft 4 degrees. Then the Intake would be 108 and the exhaust 116.

OVERLAP Ls9 = -24.50 Crane 210/218 122.5 = -18.00 Crane 232/242 (.624/.624) 120 = -3.00 112 = 13.00 108 = 21.00

@indyrock8148

4 жыл бұрын

Exhaust scavenging induction event. The fifth cycle.

@autobodyspecialistsinc.4397

4 жыл бұрын

all those number can change with different grind timing ...

@n5yiz

4 жыл бұрын

@@autobodyspecialistsinc.4397 If I hand you a cam with 10 degrees of overlap, you can change that?

@autobodyspecialistsinc.4397

4 жыл бұрын

Yes, I agree. for some reason i was thinking in terms of the timing events in relation to crank position...

@glennmanchester1568

4 жыл бұрын

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

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

Love your videos Richard keep testing

There is an exception to every rule, with a few exceptions.

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.

@indyrock8148

4 жыл бұрын

I'm thinking it's from extra exhaust scavenging during overlap. Starts air in runner moving more, sooner.

@meetthecarolinas9638

4 жыл бұрын

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).

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.

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!

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!

Tell em what happens to the vacuum. The brakes 😁 Great video 108 centers rock ⚔

@volvospede

4 жыл бұрын

Do you think vacuum suffers much with smaller LSA? I need good vacuum for the brakes or need to go hydroboost.

@ttank94

4 жыл бұрын

@@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.

@jgkk5862

3 жыл бұрын

I have run as big as 266@50 on a 99LSA and still had enough vacuum for brakes...

Thanks so much for answering my exact question is a very easy to understand format

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.

Would love to see this focusing on higher rpms on a 4 cam mod motor. Would be super easy to change only LSA without even pulling the cams

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.

Thank you I been asking you to do this for 6 years!

@richardholdener1727

4 жыл бұрын

this was done long ago

Great Job Richard! I learned something!

The work never ends... Same test with turbo, supercharger and nitrous. Thanks for everything you do Richard!

@richardholdener1727

4 жыл бұрын

it's the same with boost

@rayjon237

4 жыл бұрын

Every cam is a turbo cam.. lol

How about some lsa +0 vs +2, +4, +6 intake lobe advance. That type of data would help understand ground in advance a bit more while helping with camshaft selection.

@euba0149

2 жыл бұрын

I would love some more information on this … currently trying to learn what I can and there isn’t a lot of resources I can find on ground in advance

@hefftoneGA

2 жыл бұрын

Valve event timing is what you need to be comparing.

@bainracing

4 ай бұрын

This changes everything! this test is a bit missleading without optimal intake timing.

Great test thanks again!

Very good watch! Would be curious to see the same test on a few different engines!

I’d definitely like to see this on a smaller displacement engines possibly comparing the 4.8L/5.3L to the bigger 6.0L is also be interested as to how the LSA can affect specific boost pressure

@baggedandlsswapped67suburb59

4 жыл бұрын

I was just thinking about making a very similar comment to this. Lol

@toflaherty84

4 жыл бұрын

it would be very interesting to see this on the 4.8L/5.3L, as well as comparing, for example, what BTR did with their truck cams between V1 and V2 where what used to be 113+3 LSA is now 110 LSA.

@richardholdener1727

4 жыл бұрын

same under boost

@joew7897

4 жыл бұрын

Have you not watched his videos? The difference it makes na will be the same under boost. Almost every time he tests a motor na vs boosted the curve is the same just higher up the graph obviously.

@lukemorgan3368

4 жыл бұрын

Joe momma I wasn’t really thinking when asking my question tbh initially I was thinking about degrees of overlap

I think you needed to go below 108 to see the drop off on the top end because 108 is about the optimum lsa for that combo.

@michaelangelo8001

4 жыл бұрын

Good Point...

If you ran a sweep with a fewer rpm/second change would the dyno be more stable and allow you to do a broader sweep? Or is it just the brake size is too large and at those low rpms and the very small amount of water in the brake makes it rpm unstable?

another way of seeing this for someone with a DOHC engine. Is the stock camshaft timing, then advancing the exhaust camshaft 4 degrees. then another 2 more degrees. ( however because everything has an equal and opposite reaction this is Also decreasing the overlap period by closing the exhaust valves that many more degrees before. Thus decreasing the overall amount that both intake and exhaust are open together at the same time.)

If you can only run a test over a limited RPM range .... Why don’t you run two tests? For a street car I would like to see what is lost low down.

Was the cam advance changed for each cam to keep intake valve closing the same? I have to wonder how much of the low end power was from the earlier IVC of the 108LSA cam then just LSA (or overlap) by itself. Obviously changing LSA moves all the valve events, but keeping the IVC the same might be more of an accurate test of LSA? Especially since IVC is considered the most important. Great vids btw.

@hefftoneGA

2 жыл бұрын

This is a really good point about the IVC. Changing.

@crd-nz_001

2 жыл бұрын

Intake Valve Closing is becoming earlier when LSA tightens. An interesting test would be to install the 112LSA cam 4 degrees advance. This would have the IVC point the same as the 108LSA. However, the difference would be that the exhaust would open and close 8 degreese advanced, as the intake would be 108 Lobe Center Angle and the exhaust would be 116.

@baby-sharkgto4902

2 жыл бұрын

I was wondering the same thing

Yessssss I've been waiting for this one!

Hey I stayed up late enough to catch the upload! BTW, awesome video Richard!

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!!

Very intersting, expected more low and mid but thought there would be loss on the top. Did they sound much differant at idle? I have offten used curci track cams in my projects with sbcs with narrow lsa they work well on the street but ruff idle

@michaelangelo8001

4 жыл бұрын

There would have been. He just didn't take it high enough. Those cams had a lot of duration.

This test has always interested Me.

Richard! People want that down low power for part throttle feeling of the motor. If you have a gutless bottom end you feel it trying to accelerate from a stop. Even though you don’t floor it there people still want to it to feel powerful everywhere. ONLY if it doesn’t have a higher stall converter

@michaelangelo8001

4 жыл бұрын

That's right.

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.

@poncoolride

4 жыл бұрын

IVC, is the most critical event.

Idle videos would be a nice add to these videos, LSA tends to change idle characteristics correct?

@michaelangelo8001

4 жыл бұрын

A lot...

@richardholdener1727

4 жыл бұрын

idle is choppier with 108 as mentioned in the video, but wish I took idle vacuum and had clips

@adamsweet3587

4 жыл бұрын

The engine sees only overlap, not duration or LSA. wide duration and tight LSA will give low manifold vacuum and lopey idle. David Vizards extensive testing with LSA has proven with 2 valve motors that optimal LSA is dependent on engine size, 302ci for 110LSA, 350ci for 108LSA, 383ci for 107-106LSA.

@meetthecarolinas9638

4 жыл бұрын

When designing custom cams for my car, I paid no attention to LSA. My main focus was on the 4 valve event timings with some attention to overlap and the consideration of variable intake advance up to 15 cam degrees. LSA alone doesn’t matter.

@GroovesAndLands

4 жыл бұрын

@@adamsweet3587 There are no absolutes

Do you have any tests of single pattern ls cams vs dual pattern? I've seen the cathedral port vs rec port cams videos but dont recall any being single pattern.

This is another great post by RH. That 210/218 duration cam might really wake things up with 102-106 LSA

I feel like a certificate is in order after watching all of your videos.

The only thing I would like to see included in this test is Idle vacuum. Have a set rpm, 800rpm or something, and tune the idle for maximum vacuum to see how smooth they idle.

@johncholmes643

4 жыл бұрын

Who wants a smooth idle??

@Ribbityibzki

4 жыл бұрын

@@johncholmes643 certain race classes.

@deantape2759

4 жыл бұрын

@@johncholmes643 dailys, but its not just about the idle either. Theres a reason street driven ls cams mostly use a 112lsa. Otherwise everybody would use a 106lsa in their na builds.

@timothybayliss6680

4 жыл бұрын

@@deantape2759 the factory ls9 cam has something like a 122.5 lsa. Even the ls1 cam is 117 as far as I know. With short duration and 11:1 compression, they idle really smooth with so little overlap

@deantape2759

4 жыл бұрын

@@timothybayliss6680 im talking popular aftermarket cams sorry not stock ones, i agree they do always favour a really smooth idle on stock cams.

Richard, you say the dynamometer won't measure the entire operational rpm range. But last year when I was building my Cadillac stroker, I spoke with the engineer at "The Cad Company" extensively. He brought this very subject up in our conversation. Oddly enough he mentioned Westech specifically. He said: "Westech says their dyno won't measure across the whole rpm range, and that's just BS". Said: "we have the exact same dyno, and we had the factory come out and did a add on modification that allows us to do the entire sweep from idle to redline accurately. They could easily do the same" So, maybe this is something you'd want to have Westech look into? If they aren't interested in cooperating, you could still do both a low, and high sweep. At least then we could compare the relative low and high characteristics of the different cams, or whatever you are testing at the time. I think the duration on these cams was too long for your rpm cutoff point. Like you, I would expect to see a sharper drop off in the curve for the shorter LSA cams on top. I think you would see an even more dramatic drop on the low end, also. My experience has been that a closer LSA tends to concentrate the power in a tighter rpm band. Thanks for this data, though. Anything at all in this regard is helpful.

@richardholdener1727

4 жыл бұрын

Thnx-we were past the power peak of the motor so further rpm won't any higher numbers, although possible differences, for more rpm, this motor needed a single pkane intake. Idle to redline!

great job richard. your engine tech vids are great and so are your books.

@billythebake

4 жыл бұрын

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...

@richardholdener1727

4 жыл бұрын

Glad you like them!

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.

@ezmny1387

5 ай бұрын

you want tighter LSA with more cubes as it takes advantage of the larger displacement for filling sooner

Where were the intake centerlines on each of the cams when they were installed? Was each cam installed straight up or were they all installed on the same intake centerline?

@richardholdener1727

4 жыл бұрын

installed dot to dot-I don't have cam cards

Richard, love your videos! Is there anyway you can give us sounds clips of the cams so we can hear the idle characteristics for each in future videos?

Awesome as ever, thanks for the data!

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 :)

@Tyler_Mattson

4 жыл бұрын

awebke You’re exactly right. Back when they raced the grand nationals, Kenny duttweiler tightened the LSA on them for the very reason you stated.

@TurboGreggZ

4 жыл бұрын

Egt can sky rocket from tight lsa. Overlap causes issue due to the reversion.

@ezmny1387

Жыл бұрын

​@@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)

Great video, I would like to see this type of test ran on a stock 5.3 and 4.8.

@chomin3025

3 жыл бұрын

rideswift It will be pretty much the same, just shift the power curve towards the right, and it will be a more linear power band.

@utahcountypicazospage5412

3 жыл бұрын

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

@Skoog.

2 жыл бұрын

@@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??

@chomin3025

2 жыл бұрын

@@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)

@Skoog.

2 жыл бұрын

@@chomin3025 Thankyou..!! I always thought it made power at the same rpm.

All you read/hear is tight LSA = peaky/narrow powerband that will fall off up top. Yet every dyno test ive seen they actually have more spread between between peak torque and power.

Thank you. Informative. Please continue!