A snippet of a post by Larry Meaux on the subject... Larry has ported heads for a few championship winning Mopars

Funny thing is... when you get the guys who really know what they're talking about together. They all say pretty much the same thing. I heard that ".50-.60" target from my good friend Don Losito.

By the way LR, Don owns Ultra Pro Machine. They are one of the premier cylinder head R&D shops in the country.

He says that air speed and VE are directly related. Chuck did the work on my heads and he works with Zytek, Dyson and a lot of other names in motorsports competition. He's strictly R&D as well, so the guy has a lot of time to test. A couple of engineering degrees as well so he's a pretty sharp guy.

I feel pretty confident in following the advice of these guys. They have thousands of dyno and flowbench hours behind their theories. Not to mention, those theories all line up. You talk to one and you'll probably get the same advice from the other. It's those guys way off in left field you have to worry about.

-Mindgame

 

Larry said it "could" be delayed until .5-.6. Is this in a buyable 23* casting??? You are limited by the material in the head.
The guys I know are dealing in Nascar Nextel Cup stuff and drag stuff and treat the engine like a restrictor plate engine.
I am saying that .5-.6 Mach is not achievable in a SB Chevy at 7000RPM's and make power below or to 7000 unless you have a BLOWER.
If you want to take my 9500RPM-500CID with a bore large enough to provide that much pull on the intake, maybe.

Boy, you sure are busy looking up quotes.

I feel like the guy's I know and have delt with for year's also know what they are doing and I have made plenty of power with my set up's.Soooo I see no reason to go off on a tangent to prove a point.You can do it however you want but I don't have a budget to experiment with ideas that are to me unproven. I will just go along making my HP the way I have for years and drive it in the trailer instead of pushing it in, at the end of the day.

I still disagree with the MACH #.

 

i still don,t under stand why ....even if i go to the 210 or 220 why can,t or should i not go to these heads,

If the heads are out of the box and matched right with a costom cam on a 383 ..then there is room for me to grow....

Mindgame all the set up's you speak of are big heads small SR cam .. I would like to do as well so what am i missing here

I have allot of eng 383 a 210 or 220 outm of the box should not be to big and with the right matched cam...

I really only want to buy a head once...

 

Larry said it, will occur near .50 to .60 speed of sound. Just like I've been trying to get across.......

in heads like older 23 deg valve angle with more abrupt turn into bowl area.

I'd assume that the "older 23º stuff" he mentions is still buyable.

And I guess I'm saying you don't really understand what makes the head go sonic.

If the minimum port area is small enough, it will achieve that.

I don't doubt that They do. Maybe you've misunderstood somewhere along the line. Avg vs maximum port speeds or something like that.

That'd be tough given the lack of data you bring to most discussions LR.

Always lots left to learn.

Good luck.

-Mindgame

 

Schurters,
You have to understand that the port form is much more important than the volume. Volume can be misleading.

I would suggest you talk to a professional porter about your needs. Buy the head he suggests and let him put the work to it to achieve your goal.

PM me if you'd like to talk more about this.

-Mindgame

 

MG,
I don't go looking for things to post to back ME up,I got better things to do. I know what I know and don't really care who thinks I know anything.

You still can't achieve .5 Mach At 7000RPM's and make power with a small block Chevy without a blower.

And that's my word's for today.

The original post was about AFR heads and somthing to grow with,not about .5 MACH.

You spend a lot of time looking up quotes.

To each his own.

 

Just facts to back up statements. Typical of any technical writing. Check out some SAE papers some time, they're loaded with refs.

Ok LR, how do you know choke occurs at .40-.45?

What makes all these other guys wrong and you right?

Hey, I'm willing to learn and I like to learn from the best. You must be one of the best so school me up. Start by answering those questions and I'll tell you what I've seen/heard. Maybe we can both learn that way.

-Mindgame

 

I didn't say "Choke" happened at .4-.45.I said if you go over .4-.43 you won't have a daily driver and be out to lunch.You would have to cam it to where it would be tore up all the time.I also didn't say that a head on a bench was not capable of .5-.6 MACH before "CHOKE",I said that a SBC would never see it in a real DRIVEN pump gas engine without a blower.If you purpose built an engine to achieve that number it won't make correct amount of HP. It might be OK down low but won't feed itself up high with the port size and run on the street on pump gas. IMO you don't have the bore size to pull on the intake hard enough to reach that .5 number and produce the flow it takes to make HP in a SBC.You reach a point of deminishing returns with those kind of number's quickly.

Never said anybody was wrong,either.That's your words.

I said that the people who I deal with don't agree with the .5Mach theory and I don't either.This is a discussion like long rod-short rod,you run what you want or believe in and let the other people do their thing.It doesn't get you anywhere but an argument,it proves nothing.

 

Larry, the whole point in this forum is for people to learn and the only time anyone learnes anything is when a little debating takes place. It's nothing personal, just the way things are.

In my business, we encourage debate cause that's when you get the really good ideas out. If everyone is simply happy to agree, no one learns anything new.

Backing up your own thoughts with the work of others is commended in most colleges. Why try to extrapolate on theories that have already been proven? Kinda goes along with reinventing the wheel... no point in that.

The theories on airflow and what is conducive to strong street and race engines is not some new thing....

WHY won't you have a good daily driver anymore? If the port velocities were higher then engine would realize even better volumetric efficiency because the charge would have more inertia and continue filling the combustion chamber.. even as the piston rises. Even beyond wave tuning, the inertia ramming works over a broader rpm range. So I just don't know where you're coming from here.

What do you think magically happens to the air when it gets over .43 that's going to hurt power? Must be one shoddy port with a 90º short turn.

Listen LR... the port area is sized such that it will reach sonic conditions at some rpm. Throw a 200cc port with a 2.1" cross section on a 350 and it may turn 7000rpm. Throw that same head on a 427 and it may fall on it's face at 5500rpm. The port cross section and rpm is the real factor. Throw more cam at the 427 and it still won't do much because of the sonic conditions in the port.

Is there something confusing about this?

No arguement. Just debate.

-Mindgame

 

I,understand all that but the 350CID won't see .5MACH wile making it's HP and the 427 won't either and be a DRIVER.

 

Ummmm,

Why can't you achive .5 Mach at 7K? Are we talking this is too high to make HP at that RPM or it's too low?

This is puzzling to me.... why for some reason physics change on a SBC motor? A motor is a motor and the minimum cross section area is going to be the choke point because of port velocity.

Saying that Guys like WJ and Anderson ( would add Sonny and Kaase in there too, and might as well throw in Maskin and Grumpy since we are talking high end NA drag motors here) I find it hard to believe that they don't look at MACH numbers. Max port velocity has a huge amount to do with RPM range that a motor will work in. Then again it's relative to the cubes pulling on it too. If the min cross sectional area, cubes and RPM band are not matched then the motor is not going to work up to it's potential.

As far as all this goes I'm with MG and these guys:

Dynomation
Vizard
Ricardo
Don Losito
CF Taylor
Chuck R
Larry Meaux

If you sit down and talk with any of these guys and look at their pedigre I would say they all probably know a dam good amount about cylinder head development and making HP. The scary thing is Ricardo did it all first 100 years ago.

In reguards to the Engine Masters heads I had a conversation about the top two guys last year with Scott Parkhurst today. You take Kaase and his SCJ heads that had a .675 lift cam, take 85% of that lift and you come up with .575. Take the flow of his heads at that lift (360cfm) and you can figure out the flow factor of that motor..... 745hp / 8 cyl = 93.125 Hp per hole / 360 cfm = a flow factor of .258 which is a good for a street motor. Now take he back yard W enterprises head from Weld Tech. They had a cam around .580 lift so we look at the .500" cfm number (297cfm averag cyl =e since it's a BBC with left and right ports) They made 700hp so.... 700hp / 8 cyl = 87.5 hp per hole / 297 cfm = a flow factor of .294! If you have ever looked at Larry Meaux's posts on flow factors it tells about how well a motor uses each CFM. The higher the flow factor the higher the hp per cfm. .260 is good on a street motor, .280 is good on a super stock motor and over .300 is good on a pro stock motor. I just find it amazing that a guy his buddy and his kid build a motor that kills IHRA champs like Kaase in hp/cfm effiecency. Basically if these guys had more head then they could have beaten Kaase in the EM last year.

Kaase's quote "We started the testing with full-size intake ports and later shrunk them down, which made very little difference at any rpm."

Obviously the heads worked well and the cross sectional area was correct the first time around and all they were doing is filling in the dead spots of the ports. It would be interesting to see the peak MACH numbers in the smallest area section of the port during the shinking phase of the head ports on his motor though.



Schurters,

A AFR 210-227 casting bare is the best bet and have it matched for your motor. Build it all right the first time and don't grow into anything. Once you do that the motor is comprimised as far as working as a package. I only say the 210-227 casting is good because you can put the biggest valve in it, where the 195 or TFS casting will take a smaller valve but essetially give you the same amount of port to work with. Since you have a small bore engine here larger valves are not always the answer either.

If we get into flow factors again and you work on tweaking the motor to get the most out of it a 195 or TFS casting should get you where you want to be pretty easily, it just takes talent to make the motor get higher flow factors. Guys like Overton are really using the big AFR casting to it's full potential, that why he runs like he does. Getting a tame street motor into the .250-.260 flow factor range is not easy since you probably don't have any cam in the engine, but if you can take a more aggressive motor then .270-.280 is doable IF you know what you are doing. Once the combination is comprimised then you are dropping that number down a good .10-.30 since most good street motors are in the .240-.250 range.

Bret

 

Let's try this again....

It's ok to not know.

-Mindgame

 

I have had to document,discuss,back up,and argue on decissions on the Manitowoc cranes all my working day's(40+ years on the crane's).Now that I am retired,life is to short for me to argue about anything.My oppinion's are shared and if you want to make use of them-fine-if you don't that's fine too.Maybe some of the young rodder's can learn something,in the manner of what NOT to do and learn the difference between a fast car that is driven and a fast car that stays in the garage all the time and seen only on the trailer or at the race track.

 

Try cam as to not being a driver and nothing "magic" about it.

 

Where's that emoticon where the smiley is beating his head on the brick wall?

No thanks... you can keep that one.

Bret,
Yeah, it would be interesting to see Kaase's port Mach speeds at and around the torque peak. That engine had to have pretty good VE and I bet they were pretty high.

-Mindgame