_-Night-Shade-_ wrote:Nothing, people just misinterpreted it. It wasn't directed at anyone. A lot of people have their own theories in their heads as to how things work, so whenever there is a real life practical example that disproves them, I find it funny. Lots of people make claims, few actually do the work.
Btw all KL heads are externally the same. That's why you can port the DE heads to be like ZE, and even outport them. And there is room for improvement on the ZE heads too. Eventually you can port both out to the maximum practical limits. The difference is with DE heads you'll have to do a lot more work. So call me crazy but I prefer the more practical route.
This pretty much sums up your understanding of cylinder heads.
That is NOT my understanding of cylinder heads, don't try to twist words here. I'm simply sticking to the subject. We're talking about porting, and what is the purpose of porting?
The purpose of porting is more than just enlarging the ports. Shape is more important than size, bigger doesn't equate to better. Would you put a 5" exhaust on a K8? I would hope not.
Wikipedia is hardly a perfect source of information, but the first sentence under "Cylinder head porting" is: "Cylinder head porting refers to the process of modifying the intake and exhaust ports of an internal combustion engine to improve the quality and quantity of the air flow."
You have now repeatedly stated that the ZE ports are already of the most efficient shape. Stating that ENLARGING them will be the best route for performance is flat wrong. Do you really imagine that porting the DE heads means copying the shape and size of ZE ports?
Now, if your assumption about ZE heads coming stock with the best performing port shape and angle was correct, then ENLARGING the ports would be the best route. Since they are NOT the ideal shape and or angle for performance, this logic is flawed.
I am going to say this and only this, the SIZE and SHAPE of your ports are only relevant to that of your goals. That be told, the size and the shape of the port doesn't really matter as much as the area around the valve it self. Changing the valves up to a better 3 angle or 5 angle grind will yeald better results, or back-cut valves. So far I am the only one I have seen utilize Back-cut valves in a build on the forum (i could be wrong).
So STOCK for STOCK the fact is ZE heads out perform that of DE heads. We are not talking about potential that they may have that is fact.
Like I said earlier show me some bench flow results or some CFD on the two and then we can open this can of worms back up, agreed?
So, I think the OP (me) was asking about IM's and and we have strayed from that to this.
Igor never mentioned the word enlarging once, just want to point out...
the thought is, the heads are milled out pretty much the same between 31 and 101. disregard cams/retainers/springs, focusing on ports.
the only point he was trying to point out is both have pretty much the same "maximum limits" of size/shape.
If the aluminum head can be ported out to say a maximum of 32mm (I'm just throwing numbers for examples, they mean nothing) and a stock 101 head has a 21mm size, the 31 has a 25mm size, you can still port both heads to a 32mm "maximum" port size. It doesn't matter if the shape is O or [] or [} or D or <>. you just have more aluminum to shave off the 101.
Plus, by modifying those ports in that picture on the KL-101, you do realize that they are enlarged, right? If you created a port that size without changing the volumetric capacity OF that port over stock, it would be much smaller, and you would have diminishing airflow over the stock setup.
Josh wrote:I am going to say this and only this, the SIZE and SHAPE of your ports are only relevant to that of your goals.
Indeed. A flow test would need to be done to see which is better. The cylinders need to suck in air, and of course, the more the better. It depends if the smoother air can allow more air in than a larger, more turbulent port, depending on how turbulent it is. Depends also on the RPM, the airflow changes the faster it's getting sucked in, depends where you want to optimise your power.
Josh wrote:Changing the valves up to a better 3 angle or 5 angle grind will yeald better results, or back-cut valves.
I've read and I've been told inquiring on my own heads about valve job, and he confirms most of what is said on the net, that they're is minimal gain to be had from a 3 angle, and a 5 angle was pointless.
Last edited by Nd4SpdSe on February 28th, 2012, 7:02 pm, edited 1 time in total.
1992 Mazda Mx-3 GSR - 2.5L KLZE : Award Winning Show Car & Race Car ['02-'09] (Retired) 2004 Mazda RX-8 GT - Renesis Wankel : LS3 Coils, BHR Mid-Pipe + Falken RT-615K 245/40r18 2011 Mazda Mazda2 GS - 1.5L Manual : Yozora Edition (1 of 500) 2003 Nissan Xterra SE - 4x4 Supercharged : 2" Body Lift, 4" Suspension Lift & 33" MTR Kevlar 2001 Nissan Frontier SE - The Frontrailer : Expedition/Off-Road Trailer Project
Josh wrote:I am going to say this and only this, the SIZE and SHAPE of your ports are only relevant to that of your goals. That be told, the size and the shape of the port doesn't really matter as much as the area around the valve it self. Changing the valves up to a better 3 angle or 5 angle grind will yeald better results, or back-cut valves. So far I am the only one I have seen utilize Back-cut valves in a build on the forum (i could be wrong).
So STOCK for STOCK the fact is ZE heads out perform that of DE heads. We are not talking about potential that they may have that is fact.
Like I said earlier show me some bench flow results or some CFD on the two and then we can open this can of worms back up, agreed?
So, I think the OP (me) was asking about IM's and and we have strayed from that to this.
I agree with this for the most part, you're right on the back-cut valves too, that's one of the first things on my list for machining. Any chance you still have the spec sheet for the machining you had done? I've been comparing the specs that I've been able to gather from people, and am always looking for more!
Nd4SpdSe wrote:
Indeed. A flow test would need to be done to see which is better. The cylinders need to suck in air, and of course, the more the better. It depends if the smoother air can allow more air in than a larger, more turbulent port, depending on how turbulent it is. Depends also on the RPM, the airflow changes the faster it's getting sucked in, depends where you want to optimize your power.
I've read and I've been told inquiring on my own heads about porting job, and he confirms most of what is said on the net, that they're is minimal gain to be had porting those heads.
The problem with flow-benching, is that it will only show the amount of air flowing through the head. You're dead on about the turbulent passage, but it goes much deeper than that... I've got a decent understanding of how it works, but the truth is the people who design these know more than any of us ever will. So much goes into it, that the most we can do is improve on the design as we see fit.
I do have to disagree on the head porting, without a doubt... Speaking generally, the BIGGEST gains you will see in any stock engine are from the heads. Specific to KLs, there's a reason that people bother to have their heads ported. Everybody likes to speak of the breadth of knowledge on ProbeTalk, well this is something almost everybody on PT agrees on... I know I've said it before, but Michael Perry is the guy to talk to, he has more KL head porting experience than anybody out there, and he'll be the first to recommend it for anyone serious about performance. He'll stress the importance of doing a well rounded job, from modifying the combustion chamber shape, to opening up the valve seat and throat, and seamlessly adjusting the angle between intake port and intake manifold runner. It's a complete process, and the fact is you will always get the most benefit by making every mod work together.
Nd4SpdSe wrote:Wow, sorry, I had a massive brain far! I actually meant a valve job in responce to Josh, not porting. I'll edit that quickly, but too late, heh.
I hate that, any time I go to edit a post and somebody's already replied to it... It makes for a confusing discussion when people come back to read old threads later.
MrMazda92 wrote:I hate that, any time I go to edit a post and somebody's already replied to it... It makes for a confusing discussion when people come back to read old threads later.
Indeed, brain got stuck on porting, lol
1992 Mazda Mx-3 GSR - 2.5L KLZE : Award Winning Show Car & Race Car ['02-'09] (Retired) 2004 Mazda RX-8 GT - Renesis Wankel : LS3 Coils, BHR Mid-Pipe + Falken RT-615K 245/40r18 2011 Mazda Mazda2 GS - 1.5L Manual : Yozora Edition (1 of 500) 2003 Nissan Xterra SE - 4x4 Supercharged : 2" Body Lift, 4" Suspension Lift & 33" MTR Kevlar 2001 Nissan Frontier SE - The Frontrailer : Expedition/Off-Road Trailer Project
Michael Perry aka KLZE Porsche wrote:I somewhat hate to post any of my info anymore because someone is either very quick to jump onto me or the serious doubters come on with no real good input and only a goal of being troublesome. But I will try this I guess.
I think if some people on here know how much experimentation I have done with heads they would back me. I have cut heads apart for porting templates, water flowed heads but not with a professional metered set-up, ported both KLZE heads and KLDE heads to the max possible limits, experimented with combustion chambers, experimented with valves, made metal exact-porting templates, and I am now experimenting even further with some radical port shaping.
In all of my experimentation I have gotten better results with the DE heads no matter which cams were used. I tried KLDE cams on both, KLZE cams on both and KLG4 cams on both. And yet - the results were always the same. I was always able to get better results out of modifying the KLDE heads.
The reason for this is that the KLZE ports are not the most efficient flowing design. And there is a lot of mis-information that KLZE valves are larger and I have never found any KL31 heads yet that had larger valves. I have swapped valves back and forth from KLZE to KLDE and visa-versa. Also there is a lot of mis-information about installing larger valves. If you install larger valves alone this will actually reduce your hp because you are increasing your obstruction of incoming air/fuel mixture. To properly install larger valves you would need to install larger valve seats. How can putting a larger obstruction in front of an identical sized orifice increase flow? It can't. The orifice is still the same size and you have only increased your obstruction. Also larger valves without de-shrouding the chamber increases your valve shrouding which also reduces your flow into the cylinder.
I found that the KLZE heads worked best with very minimal porting and with port matching. I found that KLDE head performance could be significantly improved and like I said - I got better results out of the KLDE when I worked them.
Remember that both castings are very similar externally. So this means that since the KLZE larger ports have less material around them to work with before you get into the danger zones with too thin of walls. I call this water injection. So you are limited on what you can do in the ZE port. But when you look at the DE heads - the port shape is better to begin with and the meat around the port is thicker and so you know what you are doing - they can made to flow significatly better because of a more efficient port shape. And when done correctly they WILL outflow KLZE heads because of the in-efficiency in the KLZE port shape.
It is true that larger ports will flow better under forced induction because with FI you want the least restriction possible and with not as much concern for flow efficiency. But when it comes to N/A and making the most possible - port shape and efficiency as well as combustion chamber anre extremely important.
Lol poor Josh. Saw you're getting hooked up on mx6.com
AZ-3 1498cc Turbo! EVO 8 turbo and manifold, 5 stud swap, SSR Type C, DIYPNP seq Megasquirt Mx-3 2.5 V6 Turbo 291 BHP 251 lbft @ 8psi - Retired due to rust and back at uni View Worklog
So much goes into it, that the most we can do is improve on the design as we see fit.
I actually meant a valve job in responce to Josh, not porting. I'll edit that quickly, but too late, heh.
