I will go out on a limb here and say that STi2EvoX is probably on the right track. (No offense to you STi2EvoX, I am just expecting an argument or two).

I am not into Honda motors, but I seem to recall that they also need some sort of a head brace to strengthen the open deck? The Evo X has what I think is called a semi closed deck and while I do not know what the difference is between this and an open deck I have seen a picture of the 4b11 block and the water passages are open on the deck surface around the cylinders. Now perhaps the thickness of the cylinder walls on the 4b11 are such that they will put up withthe higher pressures but that is yet to be determined.

Are there strong Al block engines? Sure, but I would have to believe that the old 4g63 is stronger then the 4b11, but then again I do not need anywhere close to 500hp so I do not worry about it. What is more of a concern to me is whether the SST can hold some additional power rather then how much the 4b11 can hold, but that is just me personally...

Oh, by the way DRAG, some years ago I took the 4g63 head off of my Evo and did some simple bowl blending and smoothing of the chambers. The casting on my particular Evo head was pretty bad, there was at least a .75-1mm lip under the valve seat on nearly every valve. It looked like the seats were just crammed in there and the aluminum under the valves was kind of floded over or pushed down (hard to describe) but I am sure that the air coming in to the chambers had all sorts of turbulence. But who knows, maybe it helped the swirl...

 

Why would I be offended? That was polite and you didn't say anything that would instigate confrontation. Or maybe you meant that you were expecting arguments from other people for siding with me. Either way, I don't think either one of our posts will cause an argument because there has been no badmouthng of anyones car. Hell, I thought my post would get the nod from the 9 and X guys, because it points out the good points of each, and points that are generally factual and agreed upon even by the "haters."

 

No, no, I was not expecting an argument from you nor anyone in particular, but it is hard to say ANYTHING on here without someone argueing with you about it. That seemingly has not changed since I was on here a lot about a year and a half ago or more. Still the same forum...

 

Any one of these 4 bangers won't have a problem making over 1000whp with the right turbo. Since this motor processes air more efficiently, it will max the turbo out sooner. Given the same turbo, the more efficient motor will make the power at a lower boost pressure. You wonder why the 4G guys can make 38psi on a little 61 or 67mm turbo and the Honda guys have trouble making 38psi on a 42R? One flows like crap and one is very efficient, but if the turbo is pushed to its maximum efficiency either motor will make big power, just at different cylinder pressures.

This new motor WILL make more power at less boost given the same compressor, and that is an advantage on pump gas for sure.

For you guys worried about the aluminum block, the most powerful 4 bangers in the world are open deck aluminum motors. Don't get too bent out of shape

 

Its nice you can post the flow numbers and get all excited. But you left out one very important factor in comparing the 4b11 to the 4g63. When you flow the head you are only measuring static flow. IE the valve is held at a study state and flow is measured. What you left out of the equation is duration. How long is that valve held open? What flows more. 300cfm for .05 second or 300cfm for .065 second? teh 4g63 kicks **** on the 4b11 in the duration department. I have stated this earlier and stated this again. Dropping the 1.7 rockers makes cam profiles **** azz small. It aint the block thats going to hold the 4b11 from making big power. its the head. just my 2cents.

the following picture is astock 463 cam next to a solid lifter vw head. The 4b11 has much beefer lobes than the vw. But that just means they already stretched the max duration from them.

 

Has anyone ever considered looking at the area under the curve for these flow numbers? I would think that this is more important than raw peak values. Looking at the differences between each setting (.150,.250,.350, etc..) and summing them, it looks like the EvoX has a drastically higher area under the curve in the intake ports than the 4G63's intake differences. However, the exhaust area under the curve is slightly higher on the 4G63 than the EvoX. 4B11 head seems to have the advantage on volumetric efficiency. This leads us to yet another debate - it's combustion efficiency - which sux like the EVO8/9 concerning gas mileage....

And yea, 94AWDcoupe has a point. How long the valves stay open to maintain that flow is definitely important. However, it's not as apples to apples as he presents. We aren't looking at 300cfm @ .5secs vs. 300cfm @ .65secs since they don't draw in the same amount of air.

-M

 

The length of time the valve is open is dependent on the cam. The 4B11 cam looks like the VW cam that was pictured, I agree it sucks. That will come in time and be improved.

The area under the curve, on a cylinder head, I agree with too, much more important than just a peak flow number. You won't find us advertising our flow numbers (generally-this thread is the first printed flow numbers I think we've ever released) first because the bench reads low and 2nd because we don't concentrate on the peak number. I've had a LOT of heads sent through here that claimed some rediculously high flow number, none of them proved to be true. Some of them flowed really well at .500 lift, too bad there is no cam that went that high. The entire flow area of the cam lift needs to be concentrated on, not just what it flows at maximum lift. Just like a dyno chart, there is more to a car running good than just the peak number.

 

Dave I don't know who told you that your flow bench reads low, but it is right on par (if not a little higher) than a SuperFlow 600 that most of the industry uses, and considerably higher than my SF1020 Pro Bench. This is all based on the numbers you posted for stock heads. They are high.

The peak flow number is not like some spike on a dyno. You don't improve a head and it JUST picks up a flow spike at .450 or .500. It may lose 2 or 3 cfm below .200, but it will pick up flow where you need it. Anyone who is taking the time and money to mess with stuff like this is not going to be using the stock cam profile, so why even get into that?

 

Agreed, nevertheless, good stock info for us learners..

 

I didnt do any kind of math there. I just threw some numbers up so you would understand you cant just compare the static head flow numbers. The time the valve stays open can be calculated but it is not constant. Its a function of RPM. the thickness of the cam lobe at peak 80% or better lift is what you need to look at. The X cam stays open for like 20 degrees at 80% lift or better. And the 8/9 cams can have profiles that stay open 50 degrees and better. And there is no high performance correction for this problem. How long the valve stays open is limited by ramp rates. thats why mechanical cam profiles are so pointy. And conversely why the roller/rocker cam is so fat. Its just the mechanical advantage of a 1.7 rocker arm at work.

 

I am basing the flow numbers being low on this bench based on what the builder of the bench said, the guy who owns it/runs it and the 10 or so heads that were flowed on Superflow benches that I got my hands on and then flowed here. The numbers were either lies that came with these other heads or this bench flows less. I like to assume first that everyone is not a liar (which I am learning is probably not the case) and that the bench flows less.

I also don't agree from what I've seen that if you concentrate just on making a head flow at .500 lift (for example) that the low lift area of the cam can't be ruined in doing so.

 

It may have flowed less than a Superflow...all the SF models are different and the lower models require a lot more user input. It can be manipulated easily just like a dyno.

As for your second comment, I don't think I said anything like that, but I guess it could have been misunderstood. Most of these $1500 port jobs people sell will pick up flow in the high lift areas but they aren't changing the port enough to have more than a 2-3 cfm loss in very low lift areas....not enough to make a measurable difference in hp. An inexperienced porter can certainly goof a head with little effort

Thanks for the flow numbers BTW.

 

Good work David, looking forward to seeing what these motors are really capable of.

 

Any updates Dave? Been 6 months or so

 

No updates. Something will happen though soon as we are wide open on the EVO X now. The car is making great power. I believe we are waiting on valve to be made actually but the head will end up back on the flow bench again in the somewhat near future.

Thank you for asking.