Big Torque with easy ProStock Techniques
HTML-код
- Опубликовано: 7 авг 2024
- In this, episode 93 of PowerTec 10, DV explains how and why top pro engine builders, including NASCAR and ProStock Teams get such high torque numbers. Within the range of what is covered here this is virtually a tell all episode. Once again it is performance tech you simply won't get from any other youtube source.
Авто/Мото
David, I’ve been reading your work for years. Can’t put into words how grateful I’m am for these videos. Sincerely, thank you!
I fully agree bud!!!
Hi, David. I'm a mostly retired 72 year young automotive machinist with almost as much enthusiasm as I ever had still. I couldn't wait for a new issue of Circle Track magazine to come out, especially if one of your articles was inside!.. I have every Circle Track ever published along with too many others to mention. Wouldn't surprise me if I have read 99% plus of everything you have ever written. Just want to thank you for being so gracious with your vast amount knowledge over all these years. All the best to you my friend.
Everyone who thinks DV isn't correct, needs to go and buy his 'How to Build Horsepower' books. DV goes into much more detail than he is giving here. There are 2 current books. I've also bought an older, pre updated version, which also provides excellent information. What I can tell you is that you need to read the camshaft section about 20 times or more. Every time I read it, I learn more. Funnily enough, it confirms a lot of of what I thought worked, but didn't understand why, that came out of my personal R&D ( Rev & Destroy) program. Anyone who actually wants to learn something, needs to go and buy the books anyway.
DV, thanks for sharing your 60 years of learning with me (us). T like to watch many of your episodes more than once as I need to make sure that I understand the episode. Again, thanks for your generous soul. The world needs more people such as yourself. Cheers from Canada. Also thanks to Andy and the rest of your team.
thank you so much for sharing your knowledge, and helping Saint Judes's Children ! God Bless you David !
I tightened up my lsa when I built my current stroker motor, 598 cu in bbc. I had a 112 lsa in my 496, and now run a 110 lsa cam in my 598 and as you can guess, it works unbelieveably well. Im making over 700lb ft from 3,800rpm all the way up to 6,800rpm. Nice flat torque curve, and plenty of hp!
Another amazing video! I would love to know your opinion on underbalanced vs overbalanced engines, particularly underbalanced engines around 48%-49%. Thank you for continuing to educate us younger engine builders, it is very much appreciated.
David is A Genius, We Have almost all of His books. Thank you Sir David.
The great engine research pioneer C.F. Taylor once said that the horsepower above the torque peak is what he called *"unavailable horsepower"* because you can't access any of it with a fixed gear ratio. It is an illusion. Torque is REAL. The only way to make use of horsepower above the torque peak is with a constantly variable transmission CVT. Understanding that is fundamental to getting engines to work how you want them to.
I have a 434 small block crate street engine from a major builder in New York. Rated at 595 HP and around 540 Tq. 10.5 cr but around 205-210 lb dynamic. I have run 10.25 @128 in a 3200 lb. 73 Nova. It has only .600 lift and I assume early intake valve closing to build the pressure. Smallish 210 AFR heads and a 950 Quick Fuel carb. I shift a 6500 rpm and run through at about 6900. Up here in Canada I run 94 octane with 36 degrees timing. No pinging. Listen to what this man says, I am proof. Thanks David !
Always learn something watching your videos. Any Gear Head no matter what kind of cars you are into should watch these.
Had a Z1 kawasaki Hemi head 2V DOHC 1325cc 10.5.1 comp (almost a flat top). Pro prepped head, .100 milling, sunk valves and small base circle cams. Compression was around 12.1, 106 int 108 ex, 4 to 1 header with a collector slightly larger than the primary pipe size to stop that scavaging effect. Tons of torque on pump gas. Love your videos, keep them coming!
Thank you DV…..In your givens regarding mixture, spark and friction, I would add: reasonably durable assembly (piston speed) and the fuel you plan to use. Your program makes picking the max compression possible too easy! I like how you explain in your books that compression can, within reason, fill in the bottom of the power band ( partnered with the appropriate LSA)to tolerate more over lap and make a very wide power band. Almost every Engine Masters competitor followed that recipe. v/r wh
I was just about to post about piston speed...playing with connecting rod length can affect piston speed during that intake cycle he mentioned where filling the cylinder post BDC was a concern.
I can't wait to have my ej22e making 170+ lbs of torque. You have no idea how much a new school import tuner appreciates this info. The Vizard valve cut from your mini presentation has me over the moon.
Sorry for the loss of your daughter 😢
Love your videos. My father a Porsche tech and I, built an all iron 351w for my 85 Mustang. It's was great...10.5 Keith Black pistons, ported stock heads, larger valves. Offenhauser intake. Comp 270H cam. Not sure what it made hp wise but the machinist, a circle track guy in my area, guessed 350hp. Would like to revisit that build and see what more could have been done. Had a detonation issue. Thanks for the content. Be well 🙏
When i was kid, i always wondered How a otherwise stock 70's or 80's engine would behave. If the only modification was fitting pop-up pistons with 12.5:1 or so. So go from 8.5:1-9:1 , to a much higher compression with the stock anemic cam, it would probably require 110 octane fuel, and possibly run like a non turbo diesel!
Back then we had a basic formula, cut the heads, replace the dishes with flat top or slight pop-up pistons, and go to a mild cam, usually looking at duration and power band, , and a highrise dual plane intake, mostly street engines, trying to stay in the 10.5:1 range,
What gets me about compression, diesel engines have like 20:1- 22:1 possibly higher compression, that's crazy! Then they add a turbo!! Im sure there is higher boost, but i have heard of engines running 90+psi , I'm fairly convinced the video with the Cummings 5.9 that blew the cylindersoff the crank on the dyno, making over3k hp, was running more boost, 😮 i just wonder if the head gaskets were still intact,
Awww 😔 😢 the Jacque message at the end rips my heart ❤️ out.. sad. Sir I’m so very sorry for your loss. I so wish we didn’t have to deal with death or tragedy in life.. Please know that
My thoughts and prayers are with you and your fam
Mr Vizard Jacque is tuning on the lords hit rods im sure 😉 😔 😊. God bless 🙏🏻
Great video! Your insight and experience is always a pleasure to add to the enthusiasts thought process, PARTICULARLY, and seemingly with INFINITE VARIABLES in valve timing events, compression, displacement, stroke, compression, etc.! You have the best theory and experience in this PARTICULAR area- the BRAIN of the engine. Your enthusiasm, knowledge and way of thinking is invaluable, and very appreciated!
Wow, would like to know the times of that all iron 302. Thank you David for always sharing the good stuff. Im sure Jacque was always surprising people with her cars performane and her skills of course learned from the best.
David, once again, an informative video which assists me in cam selection for a upcoming 350 => 383 stroker in a 86 TPI L98 Corvette. Of particular note is (1) a narrower LSA at about 106 (2) lesser duration for a softer idle and (3) the importance of knowing one's compression ratio. My aim is a low revving quiet engine with torque. Good to note your final remarks that the standard long TPI intake runners would likely be suitable. THANKS again!
Yes I wish I’d know this before sticking a 112 LSA cam in my 10:1 331 ford (have good flowing heads, great exhaust, wrong cam timing because I thought I needed wider love center for vacuum for power brakes/steering.
It’s unimaginable what the pain must feel like to have to bury your child . It almost happened to me when my father backed halfway over my 26 month old son.
I hope god has given Mr Vizard peace in his heart by now to know we’re all heading for that same destination 🙏🏻
😢😢😢😢😢
Thanks for sharing your knowledge and helping us all learn to design & build better/higher output engines
I'm building a stroker motor with high compression right now, so this is very interesting. It's a mercedes m103 3,4liter with 11/1 static compression and the cam has an LSA of 110 + 272 duration on both. Thanks for all the great info!
I am building a 302 on a very strict budget, but have decided to use every trick I can find to increase torque and bring max torque in as close to 4000 rpm as possible. Dual plane intake, 211 duration low lift cam, ported Cleveland 2v heads, 10:1 static compression or higher. A ton of powertec 10 is going into it.
Thank you Mr.Visard, again ! ! ! I have been listening to you through your books for years. I like your videos, and have to say that, partially due to your help I have been able to build engines that work above average. My clients are limited but very satisfied. I will continue to listen and put what I learn into practice. Looking forward to the next video. Cheers !
Thank you for sharing your insight and experience! Love your videos
DV, thanks again for another great video!!....I've been reading and listening to you since 1975....you kept me out of a lot of trouble....and still are!!
Great content as usual. Thank you David
Always great upload
Thank you for sharing all your wisdom and knowledge.
David, I appreciate your years of experience shared. 40 plus years in the automotive industry behind me reminds me to humble myself, continually learn, strategic adjustments, enjoy sharing to those that struggle if they listen. Without help from humble poeple I never would of got this far in my motorsports carreer. ( automotive, off highway motorsports, motorcycle on and off road, marine. I appreciate your sharing your knowledge and experience.
Thank you David. This information is pure gold.
Thank you so much very good information i was looking into a camshaft for my build 383 sbc 13-1 compression on e85 so I'm now leaning towards Howard's camshaft 110061-08s again thanks for your knowledge
Great videos I have just found. I have a couple of your books I keep very close to me. Your knowledge is priceless. My condolences for the loss of Jacque.
Great information. I had never thought about dynamic compression ratio before.
Excellent tutorials, please continue and Thanks.
DV! 17 minutes in you tell exactly what my motor is being used for! My project is a 292 truck motor (from a 69 Chevy 1/2 ton) that is carrying a slide-in camper from 6,000 ft elevation to 9,000 ft elevation in 20 miles on the weekends! Nearly wide open throttle for my 56 GMC 4x4. I will be watching and rewatching this video! Stan’s ‘CarFor’ program is an action item for me now! Thank you so much!
What a fantastic, fantastic video. Really a good info. A good food for our brain
Another great learning opportunity. Thankyou
Wow. Thank you David. That was gold.
Excellent info David. Thankyou
what you are telling here fits perfect for my applicatoin and helped me to get further.
tank you.
Another great video, thank you David.
Thanks again for sharing David.
FINALY, I needed this information soooo much that when i will explain my Torque understood theory will be backed up by the Best of the Best.
Owning Pontiacs is all about Torque to push my hot rod 66 starchief executive !
Great content, as usual. Thank You!
Thank you for you vast knowledge giveaway. Im fairly new to this wnd even i can see the brilliance of your knowledge. I am now a.subscriber to your channel and your vast knowledge
Love the videos. There’s no replacement for experience!!!
This was very informative. I am definitely getting th Carfor program.
Wow, thank you. For everything. Including the ending.
Thank you sir, I do appreciate you share you knowledge
Great tech Keep it coming!
Best tech ever. Thanks for the video.
Great content! Subscribed
Love the videos thanks for the knowledge
Another great video. I'm still hoping for the Jag V12 series 🤞🏻
Thank you for the great information!
LOVE YOUR WORK MATE
So what are your thoughts on the magnetic fuel atomizers from the 70's? Just kidding, love the videos, have a great day!
Great job! You're Torkin' my favorite language. Much thanks!
Great vidja my friend 🤙🏼👊🏻
Great content thxs DV
Thanks for your knowledge!
Mr Wizard that was brilliant
Can't wait for more tuned port info!
Me too! TPI is mentioned in this video and we await a dedicated segment on TPI ...
Thank you for the update
Not to argue: but isn't an adjustable LSA one of the key benefits of variable valve timing (on twin cam motors?)
Since no LSA or cam advance is perfect everywhere, being able to move it around throughout the rev range and engine demands (throttle openings / manifold vacuum) gives real world benefits. Especially in regards to improved mid range torque (engine efficiency,) idle quality, emissions and general driveability/performance.
I can't thank you enough for sharing your knowledge and experience with a us, not many if any would do this and it is much appreciated Mr. David thank you, Kody
Great information David! I am very interested in what key factors need to be considered for a SBC TPI engine and stroker engine. I think a 383 stroker TPI would make an excellent truck engine.
Thank you DV👍🎩
Thank you David.
Thank you. DV
I think about building a 377 sbc 400 block with a 350 crank. With David' s cam fromula the cam 107 degrees lsa with a 2.02 intake valve.
Rabe - that sounds about right!
I’ve been wanting to build one for years but everyone I talk to said I’ll be better off with a 406 lol
Thank you again David for sharing. I learned first hand of the mistake of adding cubic inches without changing my camshaft to match. Before adding stroke to my little 302 my valve timing events were on par and I could run on pump gas without any issues. After going to 347, I had to run 110 aviation fuel so the engine would shutdown when I turned the ignition off. On 93 it would continue to try to run when I would shut the ignition off, and I concluded that the exhaust valves had closed before the piston had reached the top of the cylinder and the cylinder pressure was so high and hot the engine would detonate the charge left in the cylinder thus it continued to turn the engine over. Let me know if my hypothesis is correct please sir. Thank you
The exception to the "when you move to a larger bore, you need a tighter lobe separation angle" rule, is "but if you increase the intake valve diameter at the same time, you might NOT require a tighter lobe separation angle", right? (That's my interpretation of the 128 rule, for a typical CR SBC, anyway...)
gave me chills reading about Jacque and her abilities sorry for your loss
Higher compression ratio also creates a stronger vacuum to initially fill the cylinder on the intake stroke.
how so? because you're beginning with a smaller volume that is being increased as the piston rushes to BDC? Connecting rod length is going to affect piston speed, and that would affect "pull" as the volume decreases at a faster rate due to piston speed increasing (or vice versa)
@@albertgaspar627 Yes pretty much. Con rod length is only half of the puzzle, crank throw has a larger impact on piston speed. Since crank throw effectively increases the lever arm from the crank centerline. Usually when you increase the crank throw, via stroker crank, you generally have to shorten the rod because the deck height is difficult to change on an engine. Regardless of the shorter rod, you will still increase piston speed.
@@rolandotillit2867 well, crank stroke length won't necessarily increase the compression ratio--i can choose a piston crown design that can raise or lower the static compression ratio. I can also swap a cylinder head with a smaller combustion chamber to increase compression ratio. so how will either of those create a stronger vacuum as you originally posted?
@@albertgaspar627 Simple, less physical space for air at TDC. Air pressure depends on the difference between a volume and atmospheric pressure.
A suction pad works better when you squeeze all the air out. You squeeze the air out and the vacuum you created sucks the pad.
The closer the piston gets to the head, the stronger the vacuum.
thank you david
Back in the 80's they had "Rhodes Lifters" which had a controlled leak down of the valve lifters (both intake and exhust) which gave less valve overlap and valve timing at low RPM. This gave great Torque from a racing camshft. My 70 mustang w/4V high compression Cleavland heads had big problems idling without a big 'ol Rumpty Dumpty that was annoying. The Rhodes Lifters made it idle reasonably smooth at like 750 ish RPM. Sounded like a mechanical cam.. a little tappy, but not bad at all. Tamed the Beast! Why did this die? I didn't notice any camshaft wear problems with Crower springs. Lost Technology..
Best part of the day watching a DC video, thanks. So I have a Comp XFI hydraulic roller cam with 202°/212° in. and ex. with .550" in. .546" ex. lift on a 113 LSA using the called for 1.6:1 rockers. Will I gain even more torque and HP with a tighter LSA all other specs being the same?
I have this cam in a sbc 383 with Patriot Performance 195 aluminum heads with a Weiand version of an RPM Airgap. The engine is backed by a 700R4 with a 3.07:1 rear gear. The thing in first gear(3.06:1) pulls like a freight train! I have also got as good as 26 mpg with this setup. Would I gain performance and lose a bit of fuel economy if I had the same cam made except have a tighter LSA or would be minimal difference, or with duration that low it doesn't really matter? Thanks in advance.
videos are ausome!
Thank you David! Yet another very informative instalment of power tech 10. Using your graph on my Ford 400 in my 72LTD with the Keith black pistons and 9.5/1 CR once 26,000th off the 2V heads that I’m porting using your book and PT10 tips and methods. The torque figures are looking like 520-560 lb’s ft of torque. Once my heads are ported and I get the flow bench numbers I’m getting the cam from demos cams if I remember. I’m hoping for over 450 HP from the 2 V heads if matched up right to cam. And my porting skills are up to it!
Thank you again David! And Andy!
God bless you both!❤
hailz vizard you are so gracious. Thinking of a 395 c.i. out of this 355 build with 5.85" rod. Painting it corporate GM blue with the th350 also. And 305 valve covers. For late 2nd gen F body camaro firebird thing. Going to use any larger or brodix 221cc iron heads and EPS intake. 282 hydraulic roller on 106* LSA. It probably needs a ported RPM intake although could go ahead and build a long cross ram octa plane even though it defeats the purpose of the 305 valve covers at that point LoL.
Do not use a stock eps with those heads!
@@servediocylinderheads too small?
@@zAvAvAz Yes, that manifold has smaller runners than even an rpm has.
Thank you for your information so for the pro stock really high compression deals much much LSA do you go wider on them like say 1 point wider from 10.5 to 11.5 is it .6 from your forum i found or 1 point. I want to make sure i get this right on my 14:1 407 in my dirt oval car and my 11.6 359 i might make it 13 for next year not to mention our rule is a 2 barrol if that has any affect on lsa. But thank you for your information you share i have learned a lot from you
Thank you!
Good points David! I was just commenting on how it drives me nuts that on something like a SBC street cams commonly come with wide 112 LSAs and circle track cams come with 106. When, outside the more mild street stock stuff, the circle track engines will like a wider lobe separation with quite a bit more compression, better heads, more aggressive valve train and usually more rpm.
Now how about when we introduce asymmetrical lobes and offsets into the equation? As the lobe centerlines act differently (different offsets with different lobe separation angles can have the same valve events with a given duration).
Also it would be nice to see more examples of race combinations. As we go from a 24 degree AFR 335 on a 7,400 rpm 496 to a 598+ high rpm application on a set of MBE Big 9s (9 degree)...
There's another edition or another book please and thank you 😆🙏
Should point out my comment on assemetric lobes aren't directly pointed at this video but rather the baseline calculation you get as a starting point via your books. Perhaps your software has offset (and profile of the opening and closing ramps) factored in.
Always something to learn, that's what makes it fun.
Another great video that brings this question to my mind. So how does quench affect combustion and torque production? Does this have any influence at all? I was taught years ago that a strong street engine required a .035-.045 quench to enhance combustion. However, the prevalence of dished pistons seems to negate this. If we look at the top of the piston as the floor of the combustion chamber, the use of a dished piston eliminates the advantages of modern combustion chambers and throws away a load of torque even if you have the compression ratio correct. On the other hand, I see these engine builders in their videos turning pretty good numbers on the dyno with dished pistons. Am I getting this right?
It all comes down to what you are doing with an engine the camshaft duration and Lsa. If you want a big stroker engine to turn more RPM it takes more duration and wider Lsa. Tested it many many times in the past 25yrs.
Great session as per usual DV. Tell me would similar dynamic CR be as suitable for a racing marine engine (jetski) where mid range to top end are possibly more the focus. i.e. 8500-9000 Rpm for sustained periods, any advice in this area would be greatly appreciated. many thanks!
Thank you sir
I support this content.
Thanks Dave for sharing your knowledge with us!
Question: Is the 200 psi cylinder cranking pressure you mention absolute pressure or gauge pressure (as might be measured on a compression testing gauge)?
the gauge shows the absolute pressure
Hi David. Just got on with your channel. Got done watching episode 93. I understand all what you are saying. Is this the same principle for diesel engine for the same guidelines range. And is there another formula for a 3valve and 4 valve to get the centerline angle. Thank You
Question related to dynamic compression calculations:
I can calculate the IVC point using the 0.006” lobe lift duration values and accounting for 4 degrees cam advance. I thought I read/heard that DV suggests adding about 3 degrees to more accurately calculate the DCR, which would be closer to a 0.004” duration. Is that the correct method?
I need a Cam for my 7.3 Powerstroke diesel with 17.5:1 Compression that will limit overlap, drop EGTs, increase MPG and increase low end torsue that can also be reliable for the long run. I know it can be done. What’s your thoughts on this matter? Great Videos btw, I do watch every notification that alerts my phone. .430” intake lift , .433” exhaust lift, 186 in dur, 195 ex dur, 107 LSA… it can be improved
Can you do a video on calculating thermal and volumetric efficiency.
Hi David, first of all thank you for your time and information.
I want to ask 2 questions.
Can you exceed the 9 to 1 dynamic compression ratio?
What type of fuel should be used with a ratio of 9 to 1 dynamics?
Thank you, I'm looking forward for your answer.
Greetings
ProStock motors go quite a way past that 9/1 dynamic CR. Just use race gas when over 9/1.
@@DavidVizard Hi David, thanks for answering.
So the rule between 7 and 9 only applies to stock engines?
I ask him because I am making a 4-cylinder BMW engine, forged, with a 90mm stoker and 86mm diameter, and I have a dynamic compression of 10/1 and a static Rc of 14.25/1, I don't know if I'm doing a good job. job.
That's why I was asking about the dynamic RC of a competition engine among which it usually is.
Greetings and thanks for everything you give, which has taken you a lifetime to learn.
More no bs tech
Thanks DV
Does turbocharging effect the ideal lsa?