IT'S ALL IN YOUR HEAD

[@mongoose60ft42]

I absolutely love Richard. The time it takes for head swaps, cam changes and intakes is very tasking.. I hope he understands how we all greatly appreciate and saves us time and money to make more reliable, faster cars

[@ng6424]

Richard be thankful I or a ton of other people on here are not you neighbor we would be picking your brain all the time. Thanks for all the info I am taking notes.

[@chadgardee1496]

Richard holdener is the best thing that could have happened for us I especially like all the ls stuff but he puts a twist and does the good ole old school stuff too thanks r

[@Co-xm1nt]

Agreed.

[@Scootermagoo]

Richard we as your audience thank you for buying a mic. Your videos are so much easier to listen to now.

[@richardholdener1727]

glad it helped

[@timothybayliss6680]

@@richardholdener1727 the quality is good but the mic is still a little far away from you. There is a bit of background noise from the software cranking the gain to normalize levels. You can hear your shirt sliding on the chair. Thanks man. Some guys still act like getting a good recording is some kind of voodoo.

[@lukestrasser]

I'm in the all the camshaft, all the intake, all the compression and all the head camp. Up until I price that all out, then I realise I can only afford to be somewhere in the middle. Thanks Richard!

[@ryanmalin]

Just get a cam, intake exhaust, injectors, fuel pump and tune. Thats all. Easy 450hp on a 6.0l.

[@drivinwithdrew7676]

I have commented about 706 heads before, once I figured out coefficient of discharge, I ordered a set of 706 heads to port myself, I have a BMW M Roadster With a LS1 tuned with headers and a 5000 rpm launch it would do 0-60 in 4.8 seconds max. Later added my ported 706 heads with summit racing 231/242 600 lift cam, now it would do 0-60 in 3.85 with a 3500 rpm launch. No wheel slip on either occasion, both tuned my me

[@scottspencer8358]

It seems the more i watch your videos the more i learn...yet it also raises more questions.. My head is starting to hurt at this point..

[@UnityMotorSportsGarage]

You hit the nail on the head! No pun intended..haha. All kidding aside.. that is why I love using David Vizard/Stan Weiss's IOP (Induction Optimization Program) because it adds Port Volume , Cross Section, Port Velocity, and finally Port Energy Density to the mix!

[@deanstevenson6527]

Structured engine building. Its about not saying no to head modifications. Finding the Head Intake and cam profile to suit your torque and power targets! And dont forget...fuel economy follows if you just follow through this process. Great info all.

[@UnityMotorSportsGarage]

@@deanstevenson6527 you are exactly right... It is about the entire combo and the intended use of the combo!!

[@adamarndt7617]

Thanks for posting this! I've been MANUALLY calculating port speeds via MinCSA and C/D for engine combos and it's stupid time consuming. I bought a copy of Stan Weiss's PipeMax for intake and exhaust wave tuning and I didn't even know DV and Stan Weiss had this IOP XLS, too! -I'm going to go try out the trial... Will probably save me stupid amounts of time....

[@mrmysterious6006]

This is why i went an afr 245 head instead of an ls7 on my 434 Both heads flow the same with the afr having a 25cc smaller port and better mid lift numbers which equals comparable power with a much punchier powerband and torque delivery as well as a higher acceleration rate due to efficiency.

[@Crysmatic]

Even stock LS7 has a higher coefficient than the AFR. Ported LS7 heads flow 390-400cfm.

[@Ninelinegarage]

I’ve been preaching coefficient of discharge for a while now. I even made a video on my channel about it! Specifically when talking about the 706/862 heads on a 6.0 engine. Thanks for putting this information out!!!

[@samlankford9333]

I must've missed this talking point. Please inform. Thank you

[@Ninelinegarage]

Mr. Holdener didn’t talk about the heads. I was referring to why I make an argument for the 706/862 heads on a 6.0.

[@drivinwithdrew7676]

SierraC3TV Black_Widow_C3 yeah I hand ported some 706 heads to put on my LS1, and all I’m going to say it that I believe it was the right decision, some people say they don’t like the 706 heads because of the small valve. I say if you’re not trying to make over 550-600 hp, the 1.89 valve will give you more average power from idle to redline, and especially idle to 5200.

[@Ninelinegarage]

Drivin with Drew I couldn’t agree more! Everyone is on the 243/799 bandwagon but I’m a firm believer in the 706/862 heads. They are more than sufficient to make one very powerful and streetable hot rod!

[@hemi4837]

One other thing I have heard from a very talented head porter was that he found that the heads that were the quietest on the flow bench would make the most power. They had less turbulent airflow.

[@scotthatch4653]

Flow quality is very important .... Though we like to look at big numbers if the port starts to surge or back up (drop in cfm) it will not work well on the motor

[@adamarndt7617]

I think this technique is specific to or at least particularly important on exhaust ports. Darin Morgan from Reher Morrison / Profiler for a while, then back @ Reher Morrison regularly talks about how an exhaust sounds being more important vs. max CFM flow on a flow bench.

[@fntony4967]

Full Geek Mode Thank you! This is one of your best vids. Don't get me wrong I still want to see a Big Bang Big Block Chevy.

[@cconnon1912]

Excellent detailed information. 50 years of horsepower tv wouldn’t have as much as this video on head cfm and what is important.

[@jwillettgn]

Was getting worried about you!!! LOL Great Info!

[@iliketacos2763]

Critical thinking by Holdener always has value . This video is very informative and I quickly found myself looking for CFM @ valve lift stats for the heads I have . Once again , thanks Richard !

[@DandersonGM]

Damn what a great video lots of information. I have been back and forth about going rec port on my 6.0 but after this thinking about just running my 243’s or even get them ported and running them. Keep up the great videos.

[@AllTheBoost]

I’ll be doing the same on my 5.3 fi

[@johncalhoun8011]

I'm trying to decide on Rec Port or Cathedral Port myself.

[@perrybaines]

I have both (ported 243s) & (824s). Based on this info, I would do better using the 243 between 0.4- 0.6 lift. This is a great equation to know.

[@scottsigmon926]

Thanks for sharing your knowledge with us. This is what happens when you collect YEARS of knowledge dyno testing EVERYTHING and being around lots of smart friends that share their knowledge with you then Richard will test it!!!

[@scottworelds2933]

I think grafting the coefficient of cross sectional area and port volumes in an Excel graph would be very telling.

[@adamarndt7617]

It is. The "Coefficient of cross sectional area" of the intake port is just called the port air velocity, though, and its measured / estimated in feet per second. To calculate /estimate it, you take the CFM of the head at each lift point * 2.5 and divide both by the min or average CSA of the intake port. FPS = (CFM * 2.4) / CSA. Looking at the min csa or choke point will help you estimate the maximum FPS at the choke, looking at the average gives you a good view of the average port speed throughout the port. The Profiler 195cc SBC heads have a min csa of 2.15" and using their flow curve you end up with 161.8 FPS @ .200" lift, 283.5 FPS @ .400" lift, 305.9 FPS @ 600" lift. Compare to the bigger Profiler 210cc heads which have a min CSA of 2.19" and using it's flow curve you end up with 158.9 FPS @.200" lift, 282.7 FPS @ .400" lift, and 312.3 FPS @ .600" lift.

[@bigtyme2055]

This is the info I have been looking for. Thanks

[@billlittle4285]

Good video for young people who think bigger is better,my superstock head is 170 cc csa 2.12 flows 255 at .500 and makes 580 HP and 512 torque peek power at 6900. 364 CID 9.33 compression 3000 lb car has run 9.85@133 finish line rpm 8300 and that's an olds 350....use the smallest port with the best flow and proper cam and you will car lengths ahead of a guy with big lazy ports with more up, that's really simple... listen to the old guys they have been there!!

[@bryanunion5110]

I wish we had a guy like this for the hemi world.

[@richardholdener1727]

he wrote a hemi book and has lots of hemi vids up

[@MrBlackbutang]

Thanks for making Mercia smart and great again.

[@f1junky63]

Excellent volumetric efficiency explanation. Really helps.

[@adamarndt7617]

Great discussion in the first 4 min! Plotting the piston CFM air demand at each degree of rotation against the cylinder head + cam lift curve at the same degrees also highlights another important part of why the theoretical and actual #'s vary. -If a given head and valve lift at most degrees of rotation are already exceeding the piston demand, moving to a bigger head won't help you make much more power, PLUS when you do this, you see that as the piston approaches BDC the piston CFM demand exceeds what's being delivered by the induction system +cam (or you wouldn't have any vacuum, would you?), and the cylinder finally gets fully filled only as the piston is rising back up the cylinder -> at this point filling the cylinder fuller (beyond 100% VE) is aided by high VELOCITY and a matched cam (the smaller head at a certain point will make more power). -As the RPM increases, the amount of time you have to shove air into the cylinder also decreases, this is the other place where more velocity, will make MORE power than having a bigger head than required. (Like you highlighted, though more CFM per valve curtain area and per intake port min CSA, still makes more velocity.)

[@richardholdener1727]

you are missing a big part of power production here-reflected wave from the induction system that dramatically improves cylinder filling at BDC (if time correctly)

[@adamarndt7617]

@@richardholdener1727 Thanks for adding that. It was definitely missing from the post. (I'm a long-runner nut job, so it generally doesn't apply at my HP peak, but my torque peak, so when I'm thinking around HP peak it never applies to me as I'm outside my tuned RPM.) --Do you happen to know whether wave tuning impacts the VELOCITY of the incoming air or just the DENSITY? (I'm thinking only the latter, but that's a guess, for sure...)

[@supercharged6771]

Great video, I've never heard the coefficient name before. If I were picking out heads this video would be THE ANSWER

[@jasonpowell4847]

I'm glad Richard brought up this topic. People talk great about 4.8 and 5.3 engines. Truth is the power is in the head. Take a 305 with 3.736 bore. They came during emissions era. Do with junk head they were considered junk. The 5.3 4.8 engines are 3.780 bore. So basically a .044 wider bore. So give the 305 similar flow heads and cam lift and see what it makes. I would love to see a gapped ring 305 with a Richard picked camshaft and turbo be a boost till it busts video. Cubic inch is potential and cylinder head,cam is the power.

[@RRMGarage]

this is exactly how deep I dove geeking out on my newest engine combo. great info man!

[@josephnubile1970]

What a great video, Thank You for the Education. I have friends that are like Bigger is Always better and its nice to know they are Wrong. Keep up the Great videos, love the channel.

[@patlandymore7035]

Awesome info, thanks for making a video to educate us about it!! 😁

[@02badfnz]

Wow I’m learning way to much. Thank you sir!

[@richardholdener1727]

Glad to hear it!

[@michaelparadisis4076]

Great insight Richard. I’ve been asking myself how 2hp/cfm makes hp etc. my 572 with 380 cfm heads (AFR 300cc ovals) made 810hp , has nice designed camshaft.. you’ve cleared it up thank you.

[@clarkmcmahan1595]

Love this He is realistc knows his business

[@snakeeyes1877]

Would love to see a test of Liberty performance LS heads on 408.

[@kylemilligan752]

Mr Holdener, please look into short duration, single pattern cams(205-215) on 104-110 lsa for us LS guys with heavy trucks, who need ALL the torque 2500-5500rpm.

[@richardholdener1727]

I ran the 202/202 truck cam from BTR

[@kylemilligan752]

@@richardholdener1727 the 202/202 on a 110lsa was just right on for towing. Give us a 210/210 on a 106lsa😁

[@raylaux8295]

You mean ALL the torque 1500-4500

[@mikejohnson9118]

@@raylaux8295 Yes! this. This is much more useable at part and mid throttle.

[@kylemilligan752]

@@raylaux8295 Yes!!! All the torque possible at 2000rpm, all the torque at 4500rpm, then who cares out past the 5500rpm shift

[@interceptor0166]

Richard telling the truth. Most ls guys not using their heads potential. Intrigued.

[@marcusprice3199]

Yep, the LS3 intake too. You can do so much on an LS3 with just cam and headers. PTV clearance is something to keep an eye on though.

[@kylemilligan752]

All in for your cams!!!!

[@PeggyParrow]

Its velocity of the port, cod. And port density and proper ratio of intake flow to exhaust flow .Hope this helps

[@ImpalaSSRulz21]

I've learned so much from you. Great vid

[@hillbillydeluxe08]

Most useful video yet. Thank you

[@gregkeen4907]

Love your channel brother! Keep up the great work!

[@rondyechannel1399]

Ok Richard, a camshaft question. It's is relatively obvious that highest possible lift on a camshaft will create the most flow at a certain RPM, (and torque?) for the amount of duration. When do ramp rates get excessive and of course isn't this the reason why roller cams at the same lift and duration make more power. Off road applications sometimes need favorable torque without the duration and cam manufacturers do not seem to offer high lift low duration camshafts.

[@richardholdener1727]

lots of spintron data needed to make sure the high-lift, short duration cam will be stable-also more lift does not always add power

[@thedude7726]

Id love to see pro ported heads vs a back yard job someone might do themselfs. Maybe a purposely bad port job

[@nathanielmackinnon6738]

Lol me to fuck around and make a ton of power on an accident

[@thedude7726]

@@nathanielmackinnon6738 it happends man. Less is more with porting. I recently did my xr100 dirt bike and it woke it up alot

[@NPC-gq4nq]

Another great video. Now Im second guessing my cam choice, thanks.

[@richardholdener1727]

your choice is good

[@NPC-gq4nq]

Hope so. 225/236 629/615 112 lsa, in an l92 with a TSP 418 stroker @10:1cr

[@wayneireland4802]

Cool vid Richard.actually write smaller size port runner produces a better mean port velocity hence better cylinder fill not so much off a lazy port which needs higher rpm for better cylinder fill. Don't forget there's heaps off variables. Just share this if you take a percentage off 65 to 70 off engine's cubic inch displacement there's intake runners mean port velocity flow.67 percent of 498 ci =333.66 cfm.

[@EricErnst]

The cfm/hp formula is written wrong. you explain it correctly, but you have it written wrong. Hp=cfm X 2, not cfm/2. Also, this only works on v8s. V6s are 3/4 and 4 cylinders are half. I love the content. Keep up the good work!

[@richardholdener1727]

good point

[@1magnit]

How does it work for 4 valve heads and what about staggered lift cams?

[@EricErnst]

@@1magnit 4 valve heads don't matter. It's a cfm game. Look at the peak lift of your cam and you double the intake cfm at that lift. And remember, this is just a general guideline on what the HEADS can support. Other factors can limit power too. If you have a perfect cam and killer heads and induction, it won't make power if the exhaust is trying to blow out of a tiny 1" pipe. Dual profile or vvt cams won't matter for peak power. Look at the peak lift. Remember, it's not what the engine can make, it's just a quick estimate of what those heads could make with a matched combination. A 1 ton pickup truck won't use the same cam profile as a 10,000 rpm Honda s2000. Like Rich says in the video, many guys choose heads by cfm alone. If you have a specific power number in mind, this can help you choose the right heads to hit your number but not break the bank. You don't need cnc heads to make 500hp. My pickups 355 sbc has heads that flow 245cfm@.600". I do not make 490hp because my camshaft and intake are limiting factors. It's a 3/4 ton truck so I want high lift to utilize the head flow, but low duration so I can have off-idle towing/hauling power. My cam is a top of the page xfi252hr. 252/264 advertised, 202/212 @ .050" and .550"/.546" lift. The cam limits my rpm and my peak lift limits flow a little. Luckily, my heads still flow 242cfm @.500" so I'm only losing 3cfm between .500 and .600 lift. I don't have a measurement for .550" lift, but let's just go with 242. So with my cam lift, the heads could support roughly 484hp. My duration shifts the powerband down to a lower rpm at the expense of top-end power. That limits my power too, there's not a super easy way to estimate power from a cam, based on engine size and duration. According to comp's camquest software, I'm making about 406hp@5500 naturally aspirated. As Rich has said in the past, boost mimics the NA curve, it just makes it higher. If you're a fuel injection guy, KPA is a super easy way to see how much hp you're gaining. Wide open throttle should be roughly 100kpa. If your data logs show 200kpa, you can figure that you're making double the power... provided that you have good fuel and didn't have to pull timing to avoid pinging. Rich is alot better at explaining this than me, go back and watch his videos. He has a wealth of knowledge.

[@nellyfarnsworth7381]

@@EricErnst Just buy a Dodge CUMMINS, if you want to Tow.

[@EricErnst]

@@nellyfarnsworth7381 I don't want a Cummins. This was my uncle's truck. He died in 2005. I'm building it into a fun and badass truck. Some guys buy what they want to suit their needs. Others build them.

[@robertb3409]

Thanks for another great video Richard :) On my fox body mustang with a rebuilt 302. I picked the afr 165 heads because of the great flow numbers in the lower lift ranges which works great with the stock cam.

[@richardholdener1727]

those work well

[@chevydyall7619]

Geekier the better mate. Love it keep up the great work

[@kramnull8962]

What about the old theory that if you have offset center piston pins you can swap and reverse the piston and make more torque? Vs. buying new centered pistons?

[@badstimpy]

I double dare you to do a comparison between Small Block Chevy heads . Dart vs Edelbrock Vic vs AFR vs China !?! Never been done on youtube ! Love your content Richard .

[@richardholdener1727]

I've run all those

[@badstimpy]

@@richardholdener1727 I can't find 1 uploader that has done anything on the Edelbrock Vic Heads on a small block chevy ...... Except on "guy" that ported a set with a drill !!!!

[@fascistpedant758]

Great video! Something interesting to think about. Thanks.

[@03c5z]

Great video Richard. Thank you

[@l96sierra14]

Every company advertise their head flow numbers using different piston size and exhaust primeries. The data out of all the calculations for different heads will be miss leading, if based on advertisement.

[@timoneal9654]

Another great video-as always. I must say, I enjoy these formula, theory, and applied math videos a little more than the parts tests. Yet I still like the parts tests so don’t read that wrong. I would enjoy seeing how someone like a stock or super stock racer applies this science. They make some real power on limited mods.

[@richardholdener1727]

dedicated class racing is very specific

[@Nicholas-im8bd]

So I have a 2007 Silverado 4.8 with a btr stg 4 truck cam. I’m in the middle of pulling the 243 heads off, and putting 862s that I milled 0.030 on it. Hoping this lil 4.8 will sing with 150 shot with some compression. Figured the huge jump in compression will offset the smaller intake valve and flow

[@fascistpedant758]

A full point of compression will get you about 12 HP on a NA 4.8.

[@richardholdener1727]

the 702 will make even more power than the 243 on the 4.8L, even before milling

[@hoonaticbloggs5402]

Fascist Pedant torque?

[@Nicholas-im8bd]

Richard Holdener It feels pretty snappy... but now I have a crazy noise from the rear diff. Never ending fun!

[@Michael_Lorenson]

Sounds like the Coefficient of Discharge combines volume with velocity. So higher velocity at a given CFM yields the most efficiency and therefore power. That's what smaller ports and valves for a given CFM literally MUST cause - higher flow velocity. I'm guessing it promotes things like uniform mixture in the combustion chamber, and exhaust scavenging. Please correct me if I'm wrong, I want to make sure I understand this correctly.

[@AreaThirteenThirteen]

I suck at math but have always heard to get the best flowing head you can afford then go from there as far as the short block or bottom end is concerned, with that being said putting a cam in a stock headed engine gains power because it holds the valve open longer/ higher etc and so on to ultimately increase the airflow through the un modified head. I would like to see a test putting a high flow head on any given engine without any other modifications to see if that alone makes any difference to start with.

[@richardholdener1727]

I tested ported LS3 heads on an otherwise stock LS3-only 10 hp gain (with flow rates of 350 cfm)

[@sporkit]

Confused at 9:06. If cathedral and rec head that make the same flow numbers. The rec port will make more power because of its smaller valves? Why is that? Better mixture?

[@enchantedwenis4994]

Bare with me, I’m buzzed and it’s late but you have HP equals cfm divided by 2 on the slide but you are saying hp equals cfm times 2.

[@pandaEXPLOSHIN]

I Think it was just a visual mistake. I would imagine the x2 is for the fact we're talking about v8's with two cylinder heads.

[@richardholdener1727]

the formula was written wrong-should be hp=cfm x 2

[@enchantedwenis4994]

Richard Holdener thank goodness. I’m looking at a pair of heads that flow 257 at .500 lift for my .512 lift cam. I’m going for a 400-450 hp with a stock SBF block. I was thinking I was going to have to get 800cfm heads and change my cam out to like a 2.012 lift or something. Hahaha

[@aDaWaN]

@@richardholdener1727 I guess it is valid for a 2-cylinder engine? Thanks for the rectification and the videos!

[@econrey]

Was about to say the same thing

[@papacapra1908]

That’s awesome! I love simple automotive equations!

[@B4CMARO]

What about tests on how different bore sizes and exhaust pipes affect the overall flow numbers. Hard to compare heads when the testing parameters are different.

[@rustysausage69]

exactly my thoughts, cubes determines real world flow

[@richardholdener1727]

lots to consider-this formula is just one more to help

[@adamarndt7617]

Re: Airflow / valve size for coming up with C/D, the one problem that I see with the approach is that most heads are tested on a pretty large bore size, and if your engine has a much smaller bore size than what the head was tested at on the flow bench, you no longer know the actual CFM flow and therefore don't know the the C/D. (At a certain point of shrinking the bore size you'll get shrouding and the air not flowing equally around the head of the valve is going to reduce the C/D. I love what you're advocating for and I'd love it if we'd start seeing head MFGR's providing airflow charts on multiple bore sizes or at least the most typical bore sizes. -A 180cc or 195cc 23deg SBC head flowed on a 4.125" or 4.155" bore doesn't help us make this decision well, when most people are going to be running those heads on a 4.000" - 4.045" bore size. (SOME head porters ARE at least offering head designs specific for small bore applications and are providing CFM charts for those bores, along with min CSA #'s and C/D #'s *Cough Chad Speier Racing * Cough!) -Now if only the big guys would follow suit.

[@mre7283]

So it sounds to me like coefficient of discharge has a direct correlation to the air velocity through the port. I’ve heard good velocity at low to mid lift provides good usable torque which on the street is king.

[@firstdaddy]

This further supports why the 706/862 heads produce good power despite their "lower" flow rates.

[@scottworelds2933]

Yup!

[@YoungerPrice]

Mainly its the chamber size compression boost

[@drivinwithdrew7676]

You’re right, once I figured out coefficient of discharge, I ordered a set of 706 heads to port for my ls1, and it turned out fantastic, killer low end and still pulls to 7k no problem

[@rustysausage69]

Its mainly a function of compression ratio with the 5.3 heads. You gain a full point of compression if you swap from a 317 to a 5.3/4.8 head. You gain power everywhere across the entire RPM range which is why it makes decent power.

[@arturos.3973]

Thank you, thank you, thank you Richard

[@laiky71]

So coefficient of discharge reflects air velocity as it enters the cylinder? Similarly, to how port volume (actually cross section) reflects air velocity through the port? Faster being a benefit to efficiency and drivability?

[@richardholdener1727]

coefficient of discharge is the airflow relative to the valve size

[@alexthompson5172]

having watched this, how do you calculate how high you need to rev your engine in order to maximise air flow? if you have a head that flows X cfm at 1.000 lift, how do you figure out how high to rev your engine to optimise your 1.000 lift specd camshaft?

[@drivinwithdrew7676]

To the moon brother, and the camshaft manufacturer can usually tell you what the cam will like,

[@rustysausage69]

A dyno is how you determine it, because theres far more variables to take into account than flow numbers and camshaft. Cubic inches and camshaft have far more an effect on redline than flowbench numbers because they determine the real world flow. Specified RPM range from a cam manufacturer is a decent place to start, but a dyno is the only way to know.

[@keithstarner6724]

You need to find the minimum Sq In area of the head , and that with the Cu Inch of the engine will determine what RPM the head will support.

[@scottb7559]

@@keithstarner6724 good call there. Minimum cross sectional area is so important. If you know what it is you can determine what rpm a given displacement will make peak power. Also be sure what size fixture the head was tested on the flow bench.

[@wyattwunderlin4445]

@@scottb7559 Don't forget about the length of the intake runner. That will position the peak torque number, this effect horsepower peak.

[@Procharged32]

Excellent video

[@robhudson6133]

Awesome love content thanks Richard

[@davidcakers6818]

@Richard Holdener ... I'm not clear on your use of the formula, HP = CFM x 2. is it times 2 because a V8 has 2 cylinder heads?

[@richardholdener1727]

It's times 2 -example-300 cfm x 2 =600 hp potential

[@ariczacari]

Keep up the good work. 👍

[@beedub0218]

If it hasn't been asked yet, on a 4v engine, Coyote for example, to do the Coefficient of Discharge formula, are both valves added together or just one valve??? Example, two 1.460" intake valves added together equals one huge 2.92" valve. Thanks for the videos, I'm learning a lot.....

[@richardholdener1727]

that's a good question

[@Robbb8227]

@RichardHoldener have you ever tested a BMW N62B44 V8? I'm planning on building a stroker N62 for my 745LI but here is little to no info on these engines. Like head flow, camshaft specs, or even how much power they can handle. This is going to be a budget build sourcing heads, cams, intakes, maybe even pistons, roods, and cranshafts from junkyards/wrecker yards. Thank you for time, effort, and great content.

[@richardholdener1727]

I have not

[@MunCompetition]

Can you do how to tune efi videos? Explaining how much fuel and timing changes as you go up the boost and how to read knock tables etc?

[@richardholdener1727]

I don't use the factory ECU or knock tables

[@garykarenmcgruther6386]

Richard Holder, it's published in A few books that you should use this instead of 2. CFM x 1.46. it's more realistic at this number. A few top notch books has that formula. Engine Airflow by John Baechtel, Engine AirFlow by Harold Bette's and David Vizard How to Port and Flow test Cylinder head's. I'm more interested in velocity, velocity, velocity, then CFM 😉😉😉😉.

[@richardholdener1727]

CFM X 2 is a better measure for a good motor and when you might benefit from a head upgrade. 157 cfm x 1.46 = 229 hp (less than what a stock 5.0L Ford makes with a head that flows 157 cfm)

[@scotthatch4653]

The third problem I saw is when talking about low speed power (torque) that has to really do with airflow at peak piston speed on the initial fill of the cylinder ... This is why mid lift flow is important ... The better job you do of filling at peak piston speed the better the low end will be ... Again this can be calculated but the math for it is a little bit harder ... But if you look at torque made by tightening the load center on the cam you will see this up to the point of too much overlap

[@jtthill5475]

One thing has never made sense to me. A 300 cu in engine has a static volume. How many CFM will that 300 cu in engine move? Is it a division by 12 to make it a 25 cu ft engine? Would a 25 CFM carb run that engine? How much carb is needed for that 300 cu in engine to perform properly and how do you know? Might seem like a trick question but I get confused with the different nomenclature of cu in and CFM or Liter and CFM. Is there a realistic relationship between engine size and needed carb air flow? Thanks for sharing your knowledge.

[@smokenchoken1736]

If you have the offenhauser 4bbl intake a 390 cfm Holley vacuum secondary works absolutely amazing on that combination especially with the dual headers

[@richardholdener1727]

you are confusing volume to flow/time-the airflow of a fixed 300 CI motor varies with engine speed and efficiency

[@jtthill5475]

@@richardholdener1727 As I said, I don't understand the correlation. Is there some relationship between engine size and carb needed? Does that 300 CI engine flow 300 CI/sec or /min? Thanks for responding.

[@fascistpedant758]

Your 300 ci is the volume the piston displaces between TDC and BDC times the number of cylinders. 1 cubic foot = 1728 cubic inches. There is one intake stroke every 2 revolutions, therefore your 300 ci engine displaces 150 ci per revolution. 150/1728=.087 cubic feet. @5000 RPM, the engine displaces 5000 x .087=435 cu ft/min. These numbers are theoretical, assuming the cylinder displaces 100% of it's volume (100% Volumetric Efficiency). VE is typically much less than 100% at low speeds and reaches~80% at peak torque on a stock production engine. Cylinder head flow is measured on a test bench with the valve held open, at a series of lifts, with a specified pressure drop across the valve. Airflow through the engine isn't directly related to head flow numbers.

[@jimmymartin3714]

What to see your 408 LS with fogger carburetor cathedral and rectangle port heads

[@goader190]

Have u made a video on picking the most efficient cam for the heads that u are running

[@rustysausage69]

"Efficient" is vague in this instance. Horsepower goal, desired RPM range and cubic inches are more important factors than cylinder head for the right camshaft.

[@goader190]

Yes I understand all of that and yes efficient I a vague word and I understand u want everything to match the best u can but I'm sure at some point ur cam choice could be optimized with some nerd math to squeeze all that u can out of the flow of a head

[@rustysausage69]

@@goader190 I get the question, thing is that theres so many port designs and flow rates of all different cylinder heads so there won't be one equation that you could use for all engines, because even the worst LS head flows as much as a decent big block chevy head. If the engine family in your question is LS then I can steer you in the right direction, I'm not familiar with other engine types.

[@richardholdener1727]

the best cam choice won't come from math-it comes from your definition of best-where you want things like power production, idle quality, fuel mileage, chop, etc...

[@goader190]

@@richardholdener1727 he said "fuel mileage" 😃😃😃😃. Cool got it thanks

[@gregtheegg3576]

I'm surprised how no one I've watched here on youtube talks about maximizing the "area under the curve". For example, maximum hp at the expense of torque below 3,000 rpm is hardly ever discussed, as dyno testing starts at full throttle and 3,000 rpm. But just as mid lift flow is important because that's where the valve dwells the most, time spent behind the wheel above 3,000 rpm is a fraction of time spent at part to mid throttle. Driving the street, driving the twisties, driving a road course, there is a lot of need for the power you can put down vs spinning out or putting on a smoke show. Tractable power, efficient power, power density, durability, cost, and other things factor into optimizing your combo, so we could talk for days about all of that. But simply making a graph of two heads' coefficients of discharge across the lift range (like dyno comparisons) would be the quick route to visualizing how one big flow/small valve head compares to a big flow/large valve head. One is going to show a lot of "area under the curve", and my guess is a great track/street/sport head for power at any given instant. Am I wrong?

[@richardholdener1727]

WOT testing is done in the range where you will be running at WOT (usually 3,000 rpm and above). the lower ranges are usually for part throttle-also important but a different test

[@RadDadisRad]

Let’s go way way way in left field and look at Mercury Racing’s DOHC conversion heads for the LS. Curious at the flow rates of those.

[@hiramrodriguez9544]

Hello Mr. Holdener, can please tell me when you're coming out with your camshaft line? Thank you so much

[@richardholdener1727]

not sure yet

[@josephtravers777]

The evolution of the early Boss 302 is a good reference. Sixty-nine head was overkill.

[@tomhamilton9140]

Love the MMR shirt. How about those 4000 HP 351 Ford Mod Motors with factory cast heads. 😍

[@markholcomb3724]

How does the formula for coefficient of discharge change when you consider heads with more than 1 intake valve?

[@andyharman3022]

Multiply the diameter of a valve from the 4-valve head by the square root of 2. That will give the equivalent diameter of a single valve that would have the same area as the two valves. (This is not a joke.)

[@balance_it_all_out3688]

I wanna see a lsx 454 head and cam upgrade

[@marcusprice3199]

One thing we learned from this video, that motor might not need the head upgrade. I bet if you swap the cam for a bigger unit an upgrade/lighten the valvetrain if necessary, that you could get some bigger numbers out of those LSX heads.

[@OldGuy54]

Thank you

[@thunder57]

Have you tested a 6.2 with Cathedral port heads?

[@richardholdener1727]

yes

[@dogle9258]

Is it divided by both valve sizes in a duel valve per cylinder

[@marcusprice3199]

Perhaps working with total valve area instead of diameter will be more appropriate?

[@keithstarner6724]

When using the formula for coefficient of discharge wouldn't the correct math be to use the Sq In area of the valve and not the diameter?

[@richardholdener1727]

the air doesn't flow through the entire surface-its not an open hole

[@jessemurray1757]

So does higher Coefficient of discharge help because of less valve shrouding or port velocity? Both?

[@richardholdener1727]

more flow though smaller valve opening usually equals improved cylinder filling

[@marcusprice3199]

@@richardholdener1727 is it just the increase in the inlet charge velocity improving cylinder filling that is helping us here, or is atomization also improving to thanks to the high speed?

[@jessemurray1757]

@@richardholdener1727 that's what I said, the question is why.

[@overnovacated6481]

I'm not WORTHY! RICHARD AND BRIAN...Museum of knowledge bound 4/Ever thanks a bunch.

[@johncalhoun8011]

So if I have a 6.0 Engine, with about 550 Horses, my stock rec Port Heads are not gonna need to be ported and Polished for more flow?(54-469-11 Cam,Nitrous, 3.73 Gears, 1" 7/8 Headers)

[@richardholdener1727]

you are good

[@johncalhoun8011]

@@richardholdener1727 You Da Man Mr Holdener! Awesome Knowledge. 🙌🏾👌🏿

[@MALR7]

So how can we choose the right duration for a camshaft?

[@richardholdener1727]

ask the experts for your application

[@unclesquirrel6951]

Awesome once again mr 🐿👽

[@daveb1870]

This is at atmospheric pressure? Is there a different formula for boosted and would you ned the boost curve to calculate? I know this video is 8 months old but for some reason it just showed up in my email. If you have 10 lbs of boost it then adds a component of time over pressure(?), the cfm will be the same at/in the heads?

[@richardholdener1727]

forget airflow under boost-take the na power and double it at 14.7 psi (regardless of head flow)

[@Codizz88]

So does this equation go out the window with alot of boosted stuff? Because there are guys out there make 800hp or so with stock heads and cam, or close to it.

[@richardholdener1727]

boost multiples the na power output after the formula

[@obbyjep7597]

Thanks for sharing knowlage, all good info

[@farmair1380]

HOW CAN I TAKE THIS INFORMATION AND FIGURE HP POTENTIAL ON A SUPERCHARGED (ROOTS) COMBO.

[@richardholdener1727]

na hp x ((boost/14./7) +1), then subtract about 15-20% for the roots blower

[@MLFranklin]

So you're saying the CFM _per port_ multiplied by 2 is the power potential for a _V-8_ using these heads? And folks with 4, 5, 6, 10, 12 cylinders would have to adjust proportionately.

[@richardholdener1727]

yes-it gives you an idea on potential

[@alonzahanks1182]

the cathedrel port head has higher speed air on top causing it to roll but keeping flow speed up the fuel goes through the tumble spending double the time in runner creating fumes and fumes have a higher blast than gas the little chevy heads get 40 extra hp being vortec making the runner bigger pushes the start of the roll to a higher rpm is there a spot on rpm on cathedral ports that you see hp spike? the buick Dart heads on 307 ci, hitting 750 hp or the sb2 nascar engine The cathedral intake ports having the rounded top instead of exaust baffles me does the intakes start the big flow or tumble earlier on big ports ? The notch on lt4 heads intakes intreges me too. Is this all in my head?