allblowdup

Anyone make one? In my application I run a fairly low engine speed (5600 max) but am looking for all the torque that I can get at that rpm. Beinmg that the stock ones are 260 cc a head close to 200 would be way better for me.

Beau@SDPC

iTrader: (14)

No one makes that at all. You would have to epoxy the runners into a good design. But I would def not try to imagine these heads in traditional SBC style like what you appear to be doing.

allblowdup

Is there some sort of voodoo in these heads that makes them respond different than other heads?

Beau@SDPC

iTrader: (14)

Port design is where its at. Dont just look at runner volume. Getting stuck on numbers is a losing battle with newer stuff.

allblowdup

I hear what you are saying but I guess I am just not getting it. The port on that head has like a 3.4 csa on the short turn. On a 376 ci the avg port speed at 5600 is like 240fps. Unless there is really something way different that is ussually to slow for optimum torque on a v8 engine with runners in that range.

Beau@SDPC

iTrader: (14)

I will tell you that the new rectangle port head makes their best power in the mid and upper RPM range. They are not made for peaky high rpm power. They produce results as such as well. They make KILLER tq with a proper camshaft.

SweetS10V8

iTrader: (4)

What is your application to start???

Think about the fact that these heads come OEM on the biggest and heaviest vehicle GM basically makes, the Escalade.

If they can put 260cc runner heads on that, they cant give up too much torque. I have a CNC version them on my 6.0L that are 275cc. I love em.....

What is making you think you must run an L92 port?, OEM cathedral port heads are 200-210cc. Just run a cathedral port.

bozzhawg

The OP has bought into internet myths vs realworld.....

Funny thing is most smaller duration cams with L92 Heads make more avg torque and power than the most cathedrals that require more cam......

He must want to put a Dick Dong Mega Cam in there.....

allblowdup

Nope. Just looking at why such a large port seems to defy the laws of physics. I am sure they don't but I have yet to find someone who can explain to me why the rules that have applied to pretty much every head out there don't apply to this one.

My application is a jet boat and as such I could care less about idle or hp much above peak torque. So having a head that has an average flow velocity of less than 240 fps looks like it may be leaving some power on the table at close to peak torque.
Us jet boaters are weird, we always run more cam and less cyl head than what you run for road, street, or drag race. We run 260 cc sbc heads on a 358 ci engine with a cam for peak hp at 7500 rpm but we make 25 ft lbs more torque at 6000(were we run at) than a larger head.

Beau@SDPC

iTrader: (14)

Port design does not defy physics. You can think of it as the flow modifier, where it turns a standard 2d graph into a 3d graph.

Again, you are stuck on cylinder head runner size alone. Contrary to popular opinion, size isnt all that matters.

bozzhawg

You clearly need to do some more research, because your post truly shows that you are misinformed and do not understand the functionality of these heads or head design period... These are not catherdral port heads, nor SBC 23* heads....

Looks like you are still buying into the smaller port vs velocity theory that has been promoted and marketed here and on several boards by a certain head manufactor... But the one thing that debunks their theory is the L92 head design..... They still cannot explain it and when head to head test were done, they clearly were a better choice for the price and out performed the high dollar heads when cammed properly... So know you have most aftermarket head desiners trying to design heads that can rival the L92 because they are loosing money.....

My advice to you is be a shepard and not a sheep.. The internet is full of sheep....

But this is nothing new GM has done it before...... ex old vortec heads... you could not touch the vortec heads for the price and the performance gained...

allblowdup

[QUOTE=bozzhawg;13799243]You clearly need to do some more research, because your post truly shows that you are misinformed and do not understand the functionality of these heads or head design period... These are not catherdral port heads, nor SBC 23* heads....

Actually I am doing research right now and that is why I ask the question. I am not stuck on any kind of head design but I would like to know why the L92 port design does work like it does. A few others would like to know also.

Lets see the last time I talked to Darin Morgan about port design we did talk about air speed at different areas of the port. Now he did agree with me on specific port speeds in some areas and did mention that a faster port designed properly will always work better. How about 375 fps over the short turn. Most people would tell you that it won't work but they do(REAL WELL)

Well if you think I am a sheep then I guess you must think that Darin Morgan is a sheep also but I am pretty sure that there is alot of people that would disagree.

So back to origanol question. If I buy into the magic of the L92 heads then who can explain why they would not work better for torque if they were a little smaller so that I may be enlightened.

bozzhawg

[QUOTE=allblowdup;13799869]There is no magic....If your knowledge is above novice level you would understand how :
valve angle
valve size
raised intake port design, raised roof and raised floor
the reason why you run an offset inlet valve rocker arm
the degree of turn in the intake port
just a few.......

I see where this is going..... You asked a question and when people answer, you argue as if you already know the answer or if you are against the L92 and are sticking with your conventional beliefs or myths, so to explain it to you or go in dept about the functionality of the L92 head is a mute point.... You should ask the question then listen and learn vs ask the question and be pestimistic... There is a wealth of knowledgable people here and this has been talked about before...


Call Darin Morgan since you feel he has the answers, evidently your previous conversations with him still left you thirsty for more knowledge....

Goodluck

Beau@SDPC

iTrader: (14)

If you are talking to a learned cylinder head porter etc he should be able to let you know right away that there are so many ways to design an intake port or redesign one, that it is unbelievable.

This one design has alot of cylinder head companies even using them and their design in the newer heads coming out. You can tell this in the LS3 port design of the Mast Small bore heads. They use a better valve angle, ls3 style port, a smaller valve of course and a cnc program to produce some stellar numbers on the smaller bore engines and even the larger bore engines.

I do not know how many published test have been run, but I know if you look in the dyno section you will see these heads with what is considered small cams produce more power than a larger cammed setup that is sometimes undrivable.

allblowdup

This is true. Thanks for your time guys. Time will tell soon enough.

Hard Core Z28

Mast/PI makes a small bore LS3 head now.
http://www.mastmotorsports.com/2010/...sembled&id=360

Beau@SDPC

iTrader: (14)

See post 13.

allblowdup

Actually I have recieved no answer at all. All that has been said here is it works because it works. There shape is right, the valve angles are right, the spark plug placement is right. Well no kidding! My question was actually what makes the heads work so well with such alarge cross sectional area. The airflow still accelerates over the short turn and slows coming to the valve. Air has mass and if you can accelerate it and move it around the corner without going turbulent. The faster you can move it will give you more energy in the moving air for when you get to slow it down in the bowl. Those are the very basics of course but you get why I would ask how a head that will not speed up the air enough vs one that would, could work better everything else being the same (valve layout, port placement, etc)

If you guys want to call me a novice thats ok but at least I am looking. If it is such a simple design then why did it take 50yrs to find it and most of the aftermarket head guys don't know about it yet.

Thanks for the info hardcore z28, John@scoggin

Bozzhawg
I am asking and listening and learning. I agree that the head works great the way it is. I am just wondering what laws of physics it adhears to that give it the ability to fill the cylinder with such a large port at a low rpm and air speed.