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Vindicating DV's 128 lobe centerline selection formula
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- Опубликовано: 6 ноя 2022
- In this, episode 10 of PowserTec 10 DV takes the gloves of and wades into those who are doing nothing less than ignoring or contradicting solid hi-tech cam selection tech. Why? Who knows? Maybe they have a problem with new ideas that fall outside their comfort zone. Anyway see what you think of DV hard punching rational here and let us know if he has made his point.
There will always be stubborn and opinionated people but there will only ever be one David Vizard!
Mr Vizard you are an icon and a blessing to the performance world.
The first article of yours I read was how to build a 750 HP 350, way back in the 80's, in Hot Rod Magazine. I was only 6 years old and you were such an inspiration then and I became totally enthralled in "Engine Science"
Since then I have built many engines and at 46 I'm still learning constantly.
Thank you so much for doing what you do and sharing your valuable knowledge.
I appreciate you so very much.
Brad
i have that magazine. it was popular hot rodding
Love all the information you share. I've got a bunch of your books you put me in the winner's circle years ago. The information I've gleaned from your books. Is priceless. Thanks again
So much respect for David in listening to you for just 20 minutes I can see how great your wisdom is!
Thanks for UTG for providing me the link to your "youtube" channel!
Am I the only one who wants to hear the story of formula one turbo lag?
You are not
I wanted to hear the story as soon as he started talking about it. This is the wisdom I love hearing.
I am only a kid guessing but in another video he mentioned getting paid as a consultant in an emergency where he used a few small 1/8" holes to drop the back pressure on the exhaust! Would think if DV dropped the back pressure a formula 1 could spool up easier. I tinkering but my dad passed years ago, but maybe DV will share!
Back in 1970 Pontiac built a Special 1970 Trans Am RAIV just for a Pikes Peak Hill Climber Racer. Rod to stroke ratio highly modified. Malcolm McKeller had General Kinetics grind a special one off cam for with LCA at 95 degrees. Covered in vintage High performance magazine about 35 years ago now still have that HPP issue in my collection. It had so much torque it spanked every single Porsche in the field and that is no easy Feat as they are stellar world class powerful road race Cars.
The 1970 Trans Am RAIV Engineering special WON.
Sometimes the content here is over my head ("polynomials?"), but I still learn TREMENDOUS amounts of info from you, Mr. V. Thank you!!
That word is triggering my ptsd
“FLAT EARTH THINKING.”
I am only just recently 23, and for that fact alone I am constantly doubted and argued with regarding anything to do with “engine physics” and most of the time these people are just your average rural guy who is more “experienced” than he is knowledgeable…
But man does it feel like I’m setting a trap when we talk cam events, induction, or combustion, and I can’t thank you enough for giving me that leverage. Knowledge is Power - Vizard is a Wizard
Good job Trevor! Always check multiple sources to get to the truth. So many people just believe what to put in front of them. And excepted to be the truth.D.V. Is spot on in this case. But it’s very healthy to always check multiple resources. Keep up 👍the good work and share that with your fellow young people.
He is a Wize-Ard! lol
I can't believe I just recently found Mr. Vizard's channel. Most of what I know about the technical aspect of race engines is from reading several of his books dozens and dozens of times since the 80s. His Nitrous oxide book is probably my favorite. Thank you sir for putting out such great information for so many years for people like myself that are hungry to learn how to get the most horsepower out of our prohects. -Wade Moss
Can't wait to see the episodes with the 2 valve 4.6 mod motor heads , My 06 Crown vic has a 4.6 and i think they are a great little (square) engine !
I am really enjoying your info and videos David!!! Such a wealth of knowledge! Thank you for sharing all your years of experience with us!
Hello David. I bought your book on sbc horsepower over 20 years ago , and have susequently bought your older and newer books. GREAT information ! Ive seen others refute it with no comeback of their own. I have found that with enough of your books , the story becomes much clearer.. Im a street engine builder. dont want to be long winded, but I have a 377 sbc. I bought a comp cam . Special grind. 269, 275. 226, 224 . .462, .456 lift with 1.52 rockers. 108 LCA. Overlap 56. 0verlap at .050 of 9. Sacrificed some lift for longevity . 10.1 to 1 compression. Promaxx 185 heads. Lot of time just equalizing chambers ccs , in the correct places. I adjusted timing to 17 int, 34 total, 20 vaccum. My cruise timing is 53 at 2800. Highly modified 780 , 3310-1 Holley . Guessing at 835 cfm.. Exhaust is flowtech headers , but after much work ........1/58 , 3 in. collector, and a flange that sat squarely. Reduced to 2-5 in. into 26- 28 in. collectors. Guttted flowmaster termination boxes. I got the cam after your sbc book. Am I even close? 1981 Trans am, 4000 lbs. I thank you.
Ive learned more about engines from DV in the last 12 months, than I have in the last 25 years as a mechanic and race tech/engine builder…
Great content and I am learning a lot, taking notes! I just really wish you would include Mopar engines when giving calculation factors
Same!
+1 for more Mopar. This stuff is fascinating!
Yeah the 128 formula calls for a 109 lsa for my 318..I'm street driven and this sounds abit tight
@@billcat1840 That sounds about right actually. Check out a Hughes Whiplash. 109 lsa for 318, street cam, rowdy idle, strong bottom end and good cylinder pressure.
@@billcat1840 I saw in another guy's video (he was endorsing DV's 128 formula) that with this line of thought, you prioritize LSA over duration. If you have 109 lsa but lower duration, you won't have that much overlap. For example, this guy liked to pick his lsa, then determine how much overlap he wanted (4 degrees is kinda good on a street motor but it can be anything), then use that to determine his duration (by plugging the numbers into something like Summit's cam calculator).
The idea is that most street motors prioritize duration, then use a conservative lsa so that there isn't too much overlap. However, if you do it the other way around by prioritizing an aggressive lsa but using a more conservative duration (to help decrease overlap and rough idle, low vacuum at low rpm, etc.), you actually come out ahead. The assertion is that lsa helps you get your valve timing events more in line with the piston stroke, and that's a better way to make power then simply holding the valves open longer at more inopportune times during the piston's cycle.
Make of that what you will, I have not tested any of these things. Good luck with the build!
Edit: DV literally talks about this at the end of the video. Use the 109 lsa, just make your duration smaller to reduce overlap and you'll be good
Oh man I loved reading SS&DI back in the 80's, I still have them! Time to dig them out!!
You guys are the best
I enjoy the engine tech based on experience and calculations proven with dyno testing
The ft/ lb per cube tells the tale
I've had many successful fast cars, I really appreciate DV and have enjoyed many hours of his R & D video's. I have duplicated his work with success. My problem is that I use my desk top dyno to help me make a decision. The program is only as good as the information I feed it. My engine is a 406 sbc, 11 to 1 comp. solid roller, 208 int. valve. my best results come with a 109 LSA, and a 110 LSA. The 110 has a few more HP. The Lunati Voodoo series cams are more for street. The late Harold Birkshire from Ultradyne Cams set up the specs for Lunati. I wanted the 248-255 dur. @ .050 cam but the sales person pointed out something that I already knew was for a 406 pro street that I needed the 255-263 dur. @ .050, the desk top dyno liked it, so I went with the 110 LSA. It is both street and strip. On 1 of the video's for street & strip it said 70-90 and I don't know exactly what they are referring to?
Absolutely magnificent!
Every new video is an unexpected Christmas present - you never know what you'll get but rest assured, its gonna be spectacular.
Thank you. Well Done!
Thanks for the video. The problem with turbo cams, most people don't know what their pressure ratio across the turbo is, how that affects operation, and they certainly don't know how to adjust overlap accordingly.
That’s a good place to read Corky Bells book along with DV’s. They will come together.
@@Bbbbad724 Absolutely!
🔔😎
Thank youz for everything.
Everytime reading .. "This dedicated to.... " Makes me tear. Everytime. My condolences again for your loss 🙏.
Let's not forget St. Judes. They're #1 in my book since 1978. 👍👍😎😎
Thank you David & Andy.
You started teaching me threw your books in 1969 & on, 👀🥂 Thank You Sir David 🥂🏁. I studied Ed Iskenderian cam books & profiles / applications & let his product line teach me . I still have many of his cam books of profiles today . Some have a little more greasy finger prints than others 👍 it's just grandio to see & listen to you in person 🏁🥂🏁. I actually would like to have them personally signed .
Mr.Vizard (and Andy) I'd like to tickle your little grey cells a bit. We are building a 468 BBC for a jet boat. The jet pump has an "A" cut impeller and will load the motor pretty hard. So if we make 500 HP wide open, we may see 5,300 - 5,500 RPM. The intake valves are 2.25. The current flat tappet cam has 284* advertised duration, 504 lift and 111 ICL. Listed for marine applications. We have relatively smooth free flowing log style wet exhaust manifolds, but no header effect. Rhoads lifters to take about 12* of cam timing out below 1,800 RPM so we can try to minimize reversion (water being sucked in at slow speed). We are using 1.73 ratio rockers to boost the lift an bit. Your formula suggests a 107 ICL, but that flies in the face of most marine engineers advice cam timing vs reversion. So I know this is not a car engine and no headers. Can you comment about any of this ?
I must agree 100%. There are guys on the FABO channel that fight this, call me a repeater internet information, and claim their testing shows different. I will go with your resume and record.
Good stuff. I only run ISKY cams and lifters in my SBC, with a 108 LSA
I love the dramatic music.
With 24 and 26 degree heads 132 is the number everything else remains the same.
Would this formula work for a Gen III Gen IV LS (4.8L, 5.3L, 6.0L) engines. How would the formula need to be changed/modified to use these engines?
I've been watching your video and looking at cam catalogs and it looks like the circle track cams are the ticket for Street applications. I know what the little description says in the box but I think there's a lot of similarity between circle track racing and the way you drive a rowdy small block on the street
Yes Jim your reasoning is right on!
Same, ran my engine through his formula and all the closest off the shelf cams are listed as circle track
I'm seeing the same thing Jim! They are kinda few and far between, but a tight LSA with lower duration has a very wide powerband. Which is perfect for street use. I've been under the impression that tight LSA, meant poor idle quality...this changes how I look at everything.
I am new to your videos. Have only watched 6 or 8. Enjoyed every one. Great work.
David has tried every possible adjustment and modification and calculated the results to find the best option most people don't spend the time calculating the results of every change made, because different engines need different calculations
thanks guys for all your time and effort
Thank you for sharing your vast knowledge on engines . I enjoy listening.
GARBAGE IN = GARBAGE OUT IS AN "ID10T" ERROR. SINCE YOU DID IT, YOU'RE NOT BRAGGING DV. I APRECIATE YOUR HONESTY, INTEGRITY, AND WISDOM!
I just did all the math for my engine except it's a sbf and everything checks out with the cam I'm using, the only difference is slightly lower compression but the numbers were very very very close!
I’ve used the 128 formula for sbf also and if using off the shelf cam even with the corrections in the book it is still really close.
SBF 127 is one degree difference, obviously. Don't forget compression adjustment.
NOTE that the formula is for @ 350 cubic inches. If you have 302 etc there's another adjustment.
@@hotrodray6802 in the formula you divide the cubic inches by the number of cylinders so that is already accounted for and if you plan on using an off the shelf cam then 128 or 127 will give you a value close enough to the same cam
@@AndyGeesGarage - true that CID is in the formula, but the beginning number (e.g., 128) is different for different cyl head/valve configurations.
David, can you comment on the 128 equation results for a dual pattern cam vs the single pattern? I have a cam for my 6.0 LS that on first glance does not fit well with your guidance. However, the actual valve events at overlap may be much closer than it appears. The formula suggests LSA should be about 108.9. The cam is ground to be installed at a 109.5 intake centerline, less than a degree from your formula. The intake opening and exhaust closing events are symmetrical around TDC at this installed point. The advertised LSA, however, is 113 due to the longer duration of the exhaust lobe. Although this is an LS with rec port heads, it seems to me that this cam is very close to the recommendation of your formula. Am I missing anything?
Awesome video’s. I’m glad to get to learn this kind of information. Keep up the videos and I’ll keep watching.
Nope...me too.
Back in the early 1970's. I got to know Bruce Crower, and we discussed the LSA and he showed me on his testing that the 108 LSA was close to ideal. The problem I encountered was that the gas mileage was terrible when compared to a 112 - 114 LSA on the Street. When they went to the drags, the 108 LSA camshaft did run a little quicker, just not as streetable as I would have liked it. I discussed with Bruce over the years of just advancing the 112 LSA camshaft to 108 intake LSA. He thought that it was a good compromise and liked the idea of grinding camshafts 4 degrees advanced for Street use for the average daily driver that wanted a performance camshaft. I stayed with this idea all these years. Now since everything is pretty much fuel injection, I wonder if going to a 108 - 108 LSA is better? Or is the intake of 108 LSA the most critical part of this and not the exhaust? I do not build motors anymore, just performance 4L60E's and 700R4's. I try to stay on top of things when possible, and learned a lot from Smokey Yunick, Pepe Estrada (before he sold to Tom's Differentials) and others who were qualified in their fields. Somehow I only heard of you a couple of times many years ago and just recently he came into view, and I would sit down listen, and learn something. I am 73 and I love to learn things that go against the narrative. Thanks for still being around
Interesting, I just watched the Richard Holdner You tube Video of the BTR stage 1,2,3 truck cams vs the Truck Norris cam. In the video it showed the cam specs. Stage 1,2,3 were all within 112,110 LSA. The truck Norris which put out more torque and HP than the stage 1&2 cams and just slightly less HP than the stage 3 came in with a 107 LSA. Which is exactly where David's graph intersects for a SBC. Hmmmmmmmmm
I watch a channel that probably agrees with much of what you say, and their dyno proved just that. Their assertion is that even turbo or SC set ups will run on those same tight lsa cams better. I wanted some power up high and was convinced that a BTR LSA/LS9 cam at 119+5 lsa was it. Of course, I just didn't do a cam swap, so the testing results are not comparable. Your formula would have it at 106 lsa. 128- 419/8/2.165 x .91=105.9 The cam we swapped out was at120 lsa. In a 1.9 SC 15# boost, LSA motor, 6.8l ZL1.
specs. 235/252 .629/.600 119+5 BTR LSA/LS9
"Stage" cams. I always wanted to ask most providers: what do you mean? Crower, to their credit, describes rpm ranges for their performance level numbers.
It seems that one side is talking about Lobe Centerline Angle (LCA) and one side is talking about Lobe Separation Angle (LSA). I would agree that LCA is used to drive valve timing events; and that LSA is driven by valve timing advance. One is the driver, one is driven.
I am building a 427 LS motor that has 14 to 1 compression cylinder head flows 360 on the intake and 244 at 700 lift. 274 on intake 284 on exhaust lobe separation 112. 704 lift. I’m trying to make over 700 hp have not ordered the cam yet, but this is what was recommended for this motor.
did the math on a chevy 350 and it works, LSA seems low but i understand why. i found it dint work well with 455 Buick, i was told chevy 454 needed 134 as starting number, cool! how will this work with the low extreme 1.3 to 2 litre? for those struggling with the math remember your order of operation with the parenthesis.
The light bulb just went on: so many ls' run out there running good with wide(er) lsa's because they are usually 10-1 or higher compression, 1.7 rocker, larger cam core and decent airflow with a simple valve job. Essentially they follow DVs guide.
Mr. Vizard,
I have been devouring everything I can find related to the 128/132 formula. Posts on speed talk led me here. I believe I have all the correction factors, but I am waiting for your books to arrive to begin building my plan in earnest. That being said, would you suggest any other corrections, for a BBC in a 1 & 1/4 ton truck that sees 26000lb loads on a daily basis? Love the show, the premise and the knowledge you are sharing. Construction criticism is, have your video editor slow down and double check spelling of the on screen graphic.
I've always had the best results with my rowdy 350 SBC engines with a 106 lobe separation.
What type of duration cam do you run with that obviously it cannot be very much you need to put much more information in there other than a 10-6
@@eugenekillen5919 270 to 280@.050 range usually. Sometimes more. Built a 302 SBC with a 288@.050, 680lift. It also had a 106 lobe separation. Ran 9.70s in the 1/4 NA in a Vega drag car. Currently building a 355 with a 274/278@.050, 668/669 lift, 107 lobe separation.
NA SBCs making alot of power run better with tight lobe separation cams. Wide lobe separation is just a big shot in the fuckin foot. Might work better for EFI or a blower, but NA always runs better with a tight lobe separation. I'm building a 496 bigblock Chevy now with a 106 lobe sep. 714/714 lift, 274/282@.050. Bullet Solid roller. Expect it to make 800+hp NA.
@@thereluctantgearhead4544what kind of power did it make?
But how much vacuum will the engine create.
Love the video it makes perfect sense you can't tell the engine what it wants you have to let it tell you. If i make a 383 stroker is a 350 vortex heads a a good head to use
I built a 327 in 1997 and followed the recommendations he gave in his book and it was better than anyone believed. Everyone told me to build a big block, well I never had it dyno tested, but it was impressive. Dished pistons, milled 305 small chamber heads, etc. I'll say that I would prefer that engine at less than half the cost to the stock 6.2L LS3 I have now.
I came here trying to figure out what I need for a 327 I have in my S10! It has aluminum heads with 2.02 valves 64cc combustion chambers I'm unsure of compression. I'm trying to figure out how to work his formula. What cam did you go with?
@brandongibson85 isky mega cam 270, dual plane 4 barrel carb. intake. Better power off the line with great mid range. Close to the best set up IMO for a ENJOYABLE daily driver.
I’ve used this time and again and even used it on small block Fords too
I just subscribed to your channel very educational information but I would like to see you 128 equation used on both small and big block mopar thank you for your sharing with us what you have learned I'm 66 and still like to meet people like you
Hi David. Have you ever considered offering your cam school or other schools via zoom or download? The reason being that I ( and many other people )live far away from you and it is just not possible for me/us to attend in person. I would very much like to learn more and don't mind paying for your knowledge if there is just some other way other than attending in person. I know it would not be the same as being there but that's the circumstance that many of us are in. Thank you for considering my question. Andrew P.S I have most of your books. P.P.S. I live in Ontario Canada
Richard Holdener recently did an LS dyno test where he "says" he proves that lift doesn't matter! I kid you not.
I’m dying for a factoring number for a turbo overlap triangle now. Chamber up into the 16:1 zone and the triangle all in one area
@david vizard what calculation do we use for a 6 cylinder engine. Thanks Darren Thomas
Dave & Andy can you please do a video explaining difference between lobe centreline angle and lobe separation angle and what the formula works on (ie LCA or LSA) I’ve watched a lot of your videos on this and I have the book on BBC and I find that the terminology is mixed up from video to video. Maybe I’m dumb but a thorough explanation would be good 👍
Purple shaft cams are 108
I’ve noticed the same thing. The math in the book vs the math on these videos are two different methods.
I would assume the book is correct and the videos are to help promote the book... Unless the book has a latest revision.
As I understand it, from watching his videos, LSA and LCA are interchangeable. It's the same measurement.
LSA and LCA are the same
ok i agree with the formula, but are you referring to lobe seperation angle , not centerline of the intake lobe. LSA IS GROUND INTO THE CAM....WHILE centerline can be degreed to where you want it .. thanks
I just ordered your " how to build horsepower" book off of Amazon.
Absolutely loving the new channel!!!
Looking forward for these new episodes
Damn this is a video series well worth watching . Awesome video .
How much of a factor change would be for ~8.5:1 to 9:1 CR? '96 Gen II, 383, low
Thanks guys, how cool it would be to hang out in the shop together.
I love watching Mr Virard show 👑
I'd like to have a cam design by Mr Vizard for my 2016 Hellcat. I'd say most of the cams make minimal power and I think its because of the wide angle cams. I'm assuming LCA is the same as LSA. I'd like a mild duration moderate lift tight lobe cam. Flying Ryan makes a Tomahawk 2.0 cam that is close to what I would want. 228/238 111+3.
Mr. Vizard, have you by chance developed a variant of the LSA formula for late model LS7 engines? And are you willing to share it? Thank you for sharing your valuable time.
Ok. So I have Holley fuel injection on my car. If I tighten the LSA from 112 to 108 I’m worried about having enough vacuum for the FI to work correctly.
If you are worried about vacuum use less duration.. it will make more power having the right LSA vs having more duration on a wider LSA
I believe with Holley FI with low vacuum/large overlap cam you can custom tune the idle area of the fuel map then switch off learn in that area as the FI generally over fuels at idle as a result of overlap
Sniper EFI will run on pretty low Vacuum. I'm at altitude (7000') and my car makes 12"Hg barely enough for power brakes with a Vacuum reservoir but the Sniper works excellent.
great video.. iv been watching alot of Ben Alameda Racing he super switched on aswell
Hi David, you can buy Phase 1, 2, 3 etc cams in the UK now 😊
More like this please. Hilariously educational.
how does the formula change with 9.5 compression ? love the video
Have a 4L Ford engine from Australia with a CR of 10.3 and dual VCT. Can someone tell me if my calculations/understanding is on the right track? 4L = 243 CID/6 cylinders = 40.5. The intake valves are 35 mm and exhaust valves are 32 mm. 1.3775 inch x 0.91 = 1.253525. Therefore 40.5/1.253525 = 32.3088. When we subtract this from 128 we get a LCA of
Hey David ,why not produce an app that we will invest in , that all we have to do is put in the numbers and get the right cam for our application? Do it ,i am sure the cam companies will love that idea ! lol
Talent on-loan from God.
Talent hard won through years of testing, it's not magic, just years of doing things that do not work, occasionally finding things that do work. It is his life's work. No offense, but God has nothing to do with that. Just an above average intelligence man who has payed his dues. Sad thing is most of the people of his caliber are retired/retiring and not passing on their skills. It's a dying art form.
How about Pontiac V8 and Oldsmobile V8 David?
I changed the baseline number to BBC and found it dead on to LCA I use.
Vision Blinding acceleration. Also I am a Huge Fan and User of Iskenderien camshafts and components. Playing with a 1999 Big Block Chevy Gen 6 454 Daily driving fantastic 87 pump gas engine in my 1997 C2500. Spanking all the LS 6.0 6.2 Pickup guys and High boost Diesel Turbo guys on the Highways in IL. Still like SBC but no substitute for Cubic inches for me.
BBC - my favorite motor!!
How do you adjust this formula for different valve angles? Thanks.
I really agree with what David said because each engine will let you know where the sweet spot is.
Thank you again for this most helpful information.
David Vizard. Sir what is the formula for a big block Chrysler engine.. I see 128 for SBC, 132 for BIG BLOCK CHEVY.... I really enjoyed the breakdown of your system. I would love to know what numbers I should be working with.. Thank you in advance Mr Vizard. It's truly appreciated Sir. 💯
@18:00 3/4 cam ~ 540° crankshaft degrees is 3/4ths of 720° crankshaft degrees. Ed Iskenderian or Chet Herbert? we'll probably never know for sure who should be credited for the 3/4 reference, though... the valve off the seat 540° crankshaft degrees is the threshold of all out internal combustion excitement... providing the necessary cylinder head flow numbers are present. Credit where, Credit is due... I'll grind any cam for $39.95 Vizards right there with em'.
Dave, please tell the story of how you reduced Formula One turbo lag.
THIS, PLEASE.
He made a cam for F1?
@@mrmete DV was part of a team in F1 that crushed the competition. Other than Russ Collins I cant think of another engine builder on the same level as David Vizard. The top fuel guys (most of which are dead now) were on this level but very few others.
Would it be safe to assume that the formula is designed to pick a cam that results in the best horsepower and torque produced, but without regard for street drivability? In other words, if the formula resulted in selecting a cam with a narrower LSA of say 108 deg vs. 112 degrees, would the 108 deg LSA cam result in a rougher idle, and lower idle vacuum, resulting in potential problems for power brakes, the PCV system, and carburetor tuning? Would off-idle performance suffer? Is this why cam manufacturers typically spec out a wider LSA for street use? Thanks.
Good question
In other words, is the cam selection formula focused on max power for racing applications (which is valuable) without regard to street applications?@@billcat1840
I've been buying DV's books for over 30 years and always apply his published knowledge to my engine builds, including the 128 formula. I'm about to build my first small block Chrysler and wonder if 128 I is applicable, or if I should be using another factor, like 127 for SBF?
David Vizard, when you say lobe centerline angle, you are saying lobe separation angle. Right?
Right.
hoping you make a video showing how compression ratio changes works in your 128 formula.
I put together a little Ford 302. I'm not good with all the equations you're talking about so let me know if I screwed up and could get more power.
It's a 1985 GT block. Been bored 30 over and decked 15 thousandth. I'm running GT40P heads that have been shaved 8 thousandth and upgraded springs to match my cam. I'm running stock 5.0l crank and rods. I do have Chevy 350 30 over 11:1 compression pistons. I'm running the Typhoon dual plane intake with a 600 cfm Carter/AFB carb on a 1" spacer plate.
My cam is a Crane HT-284-2-NC. Part number 363941. I'm running timing gears installed straight up.
This thing is crazy fast now. I'm running a 3.8l torque converter with the 4r70w trans with 273 gears. I need traction help right now. I'm getting that together slowly.
Justifying it by saying it's according to when you want the intake valve to open and close, that can be done by changing duration and advancing/retarding the LSA.
I'm in the research phase to build a 598 BBC. I'm currently reading DV's How to build HP book. A just under 103 LSA on a such a huge engine? It seems that the cranking pressure (cylinder pressure) would be way too high for street use.
Could I spread that out to a 105 LSA and still have the engine run efficiently?
Can you please help me figure out what would be the best cam for me? Thank you for your consideration.
It took me a while but I think I got there. I was saying to myself what sort of cam is the TMC trying to select? We all know that a max HP cam won’t work in an RV. If I understand correctly what you are saying is select the LCA based on the engine and then stick with it no matter what valve events you finally decide on. I also found it interesting to hear what you were saying about stroker cams and the TMC program. Guess what, I have the 90 demo version and was getting LCA of 103 on the stroker engine I was imputing. I previously couldn’t work out why?
DV does this information apply to modern fuel injection engines for me specifically the 5.3L LM7 LS engine?
Centreline is not Seperation angle.
Hence the confusion
Time well spent, David!
I'm interested in your 128 formula to apply to the LS series of engine's. Is the correction needed in your book how to build horsepower?
No but I am in the midst of generating something here.
Looking forward to an LS version of this!
Is your cam class available online? First time 440 mopar stroker build and having trouble finding right cam choice. Stroker is 512ci ((4.250" stroke/7.100" rod) Stroker kit) , 10.6 to 1 compression, intake port that flows over 320 CFM on aluminum heads, 2.14 intake valve, dual plane edelbrock rpm intake (1000 to 6000rpm range on stroker). Looking for low end to mid range torque for street use. Quick shifting 6 speed auto trans. I must be doing something wrong with your formula because I get a LCA of 100.78. What do you recommend? Special grind? Online classes? Not looking for cheap, just correct right cam regardless of price.
Hi David. Just some ( I hope ) constructive criticism. If you were able to give some dyno examples to show the gains of the same spec cam with different LSA vs the correct LSA it would help. I think you did that in one of your books but it would help those here. Andrew
Yes, it's in the books.
Try watching Holdener's 108, 112, 120 lsa Dyno video.
@@Comet-hn3gm for us newbs what are the best books to buy? All I see pop up are the sbc/bbc books in a search.
@@joeinmi8671 The ones I have had for years are ' How to build horsepower ' SA24 'How to tune and modify Holley Carburetors' SA216 and 'How to port & flow test cylinder heads ' SA215. Good information, that is always relevant.
DV strongly emphasizes that when you have the proper cam it MUST be installed at the optimum angle FOR YOUR SPECIFIC ENGINE which can ONLY be determined by dyno testing. It might be +- 4* from what the cam grinder recommends. ONLY testing in your exact engine with it's exact intake and exhaust etc can give the proper installed angle.
And then we have to worry about timing chain wear/stretch retarding our results.
Ouch.
Great video, I love watching them. I used the 128 formula when I picked the cam for my 331 stroker small block Ford, the LSA came out to 110. But after learning more, I found out that for a small block Ford, you recommend 127 in the formula not 128. Why is the small block Ford different? I wonder if my cam is less than ideal now because using 127, it works out to 108.
It's because of your valve angle. Different valve angles use a different figure i.e. 128 for SBC and 127 for SBF, etc
@@troymecey It has Trick Flow heads. So the valve angle would be different than factory. So perhaps 128 would have been right?
Probably be the other direction seeing sbc is 23 degree, sbf is 20 and tfs is 15. I wouldn’t lose sleep over it. Is it worth something yeah I’m sure but will you ever notice probably not. You can’t feel 10-15hp and it’s probably even less.
@@raymondleathers5921 Isn't the point to get it right in the first place?
@@hotrodray6802 yeah I guess, define right. There’s more to consider than just max hp when building an engine for street use. I watch these videos to hopefully learn something. DV definitely is a intelligent guy but he has a chip on his shoulder when people question his research. Rather than hear him rant about some internet troll I’d rather hear about how he came up with these formulas.
Anyways why would you build a stroker motor like a 383 and not a destroked 400? I watched the video with your Uncle Tony about rod lengths and it left me with more questions than answers? Is stroker the best for a truck for hauling as an example or a shorter rod engine??
Gonna ask a dumb question.....for a turbo diesel engine, semi truck sized ( 12 liters and up ) that is going for better torque and fuel economy, can this formula be used? 6.00 per gallon diesel fuel is getting old.
4 valve heads
15-16.5 to 1 compression
Peak torque 1000-1200 rpms
Peak horsepower 1800-2100 rpms
Good question. I would also like to know the '128' number for an F. E. ford.
Hi I don't think it will work for you application because this is a simple version that is best suited for 4 inch bores on 2 valve engines, David does have a program that take into consideration everything on a motor but its for gas engines. Hope that's helpful🙂
@@jodypaul2695 I came up with 105 -106 for a 390 and 108 for a 428 . No one ever made a 106 LSA cam for the 390. They should have because it unleashes a monster.
@@Bbbbad724 I guess what I was asking for was the number to use in place of the 128. He says for a sbf use 127 and for a BBC 132. Do we still use 128 for the FE or do we use a slightly different number?
@@mackenziehutchison4838 fuel doesn't matter, reciprocating/poppet valve engines are all the same. Engines need what they need and given that most cam designs are guesses at best, bringing some proper thought can make some serious gains in efficiency
does this formula work for engines other than a SBC and different compressions?
Is there a formula for 9.5:1 CR SBF engines?
How to know what icl to install cam at once we have figured out lsa and duration?